Cardiac Disease 259 100 75 50 25 0 % change in cardiac output Pre Early Mid- Late Second Immed. 10 min 1 h First stage Stage Postpartum During contractions Between contractions Figure 20.2 Fluctuations in cardiac output associated with normal labor, delivery, and postpartum. (Reproduced by permission from Bonica JJ, McDonald JS. Principles and Practice of Obstetrics Analgesia and Anesthesia , 2nd edn. Lippincott, Williams & Wilkins, 1994.) Table 20.4 Coagulation factors and inhibitors during normal pregnancy. Factor Non - pregnant Late pregnancy Factor I (fi brinogen) 200 – 450mg/dL 400 – 650mg/dL Factor II (prothrombin) 75 – 125% 100 – 125% Factor V 75 – 125% 100 – 150% Factor VII 75 – 125% 150 – 250% Factor VIII 75 – 150% 200 – 500% Factor IX 75 – 125% 100 – 150% Factor X 75 – 125% 150 – 250% Factor XI 5 – 125% 50 – 100% Factor XII 75 – 125% 100 – 200% Factor XIII 75 – 125% 35 – 75% Antithrombin III 85 – 110% 75 – 100% Antifactor Xa 85 – 110% 75 – 100% (Reprinted by permission from Hathaway WE, Bonnar J. Coagulation in pregnancy. In: Hathaway WE, Bonnar J, eds. Perinatal Coagulation. New York: Grune & Stratton, 1978.) some cases, an additional 50% by the late second stage. The potential for further dramatic volume shifts occurs around the time of delivery, both secondary to postpartum hemorrhage and as the result of an “ autotransfusion ” occurring with release of vena caval obstruction and sustained uterine contraction. Such volume shifts may be poorly tolerated by women whose cardiac output is highly dependent on adequate preload (pulmonary hypertension) or in those with fi xed cardiac output (mitral ste- nosis). Figure 20.2 illustrates the marked fl uctuations in cardiac output associated with normal labor, delivery, and postpartum [17] . The risk classifi cation presented in Table 20.2 assumes clean delineation of various cardiovascular lesions. Unfortunately, in actual practice this is only rarely the case. Optimal management of a patient with any specifi c combination of lesions requires a thorough assessment of the anatomic and functional capacity of the heart, followed by an analysis of how the physiologic changes described previously will impact on the specifi c anatomic or physiologic limitations imposed by the intrinsic disease. Such an analysis will allow a prioritization of often confl icting physiologic demands and greatly assist the clinician in avoiding or managing potential complications. Certain management principles generally apply to most patients with cardiac disease. These include the judicious use of antepartum bed rest and meticulous prenatal care. Intrapartum management principles include laboring in the lateral position; the use of epidural anesthesia, which will minimize intrapartum fl uctuations in cardiac output (although the use of epidural nar- cotic rather than epidural local anesthesia may be more appro- priate for patients with certain types of cardiac lesions); the administration of oxygen; and endocarditis prophylaxis, when appropriate. Positional effects on maternal cardiac output during labor with epidural analgesia have recently been detailed [18] . Additional management recommendations may vary according to the specifi c lesion present. For patients with signifi cant cardiac disease, management and delivery in a referral center is recom- mended. In many cases, management with peripheral pulse oximetry is replacing invasive hemodynamic monitoring. Congenital c ardiac l esions As previously discussed, the relative frequency of congenital as opposed to acquired heart disease is changing [2,7,19,20] . Rheumatic fever is less common in the United States, and more patients with congenital cardiac disease now survive to reproduc- Chapter 20 260 anesthesia are means to reduce cardiac work. All ASDs have some degree of right to left shunting, particularly with valsalva - type maneuvers. Hence, consideration of air trap fi lters applied to IV lines should be considered to reduce this possibility. New recom- mendations regarding the use of antiobiotic prophylaxis for pre- vention of bacterial endocarditis have recently been published [28] . The American Heart Association does not recommend anti- biotic prophylaxis for secundum atrial septal defects. Further discussion regarding the latest recommendations antiobiotic pro- phylaxis against bacterial endocarditis for congenital heart defects is found later in this chapter and in Table 20.5 . Ventricular s eptal d efect Ventricular septal defect may occur as an isolated lesion or in conjunction with other congenital cardiac anomalies, including tetralogy of Fallot, transposition of the great vessels, and coarcta- tion of the aorta. The size and location of the septal defect is the most important determinant of clinical prognosis during preg- nancy. Small defects are tolerated well, while larger defects are associated more frequently with congestive failure, arrhythmias, or the development of pulmonary hypertension. Those VSDs that are associated with other congenital anomalies may be much more complicated and can be associated with much higher risk of heart failure, arrhythmia, cyanosis or pulmonary hypertension, depending on the lesion type, prior surgery and residual lesions after surgical repair. In general, pregnancy, labor, and delivery are generally well tolerated by patients with an uncomplicated VSD. Schaefer et al. [25] compiled a series of 141 pregnancies in 56 women with VSD. The only two maternal deaths were in women whose VSD was complicated by pulmonary hypertension (Eisenmenger ’ s syndrome). Because of the high risk of death associated with unrecognized pulmonary hypertension, echocar- diography or cardiac catheterization is essential in any adult patient in whom persistent VSD is suspected, or in whom the quality or success of the previous repair is uncertain [29,30] . The primary closure of a moderately restrictive or non - restrictive VSD in early childhood usually prevents the tive age. In a review in 1954, the ratio of rheumatic to congenital heart disease seen during pregnancy was 16 : 1; by 1967, this ratio had changed to 3 : 1 [19 – 21] . A more recent report from Taiwan suggested a rheumatic/congenital cardiac ratio of 1 : 1.5 during pregnancy [7] . Similarly, in the United Kingdom between 1973 and 1987, the number of deaths from congenital heart disease has doubled, whereas the number of deaths from rhuematic heart disease has halved [2] . In the subsequent discussion of specifi c cardiac lesions, no attempt will be made to duplicate existing comprehensive texts regarding physical diagnostic, electrocardio- graphic, and radiographic fi ndings of specifi c cardiac lesions. Rather, the discussion presented here focuses on aspects of cardiac disease that are unique to pregnancy. Atrial s eptal d efect Secundum atrial septal defect (ASD) is the most common repaired and unrepaired congenital lesion that occurs in pregnant woment, and, in general, it is asymptomatic and well tolerated even in those with large left to right shunts [22 – 24] . The three signifi cant potential complications seen with ASD are arrhythmias, heart failure and “ paradoxical embolism ” . Although atrial arrhythmias are not uncommon in patients with ASD, their onset generally occurs after the fourth decade of life; thus, such arrhythmias, however unlikely, are becoming more of a concern with the recent prevalence of delayed childbearing. In patients with ASD, atrial fi brillation is the most common arrhythmia encountered; however, supraventricular tachycardia and atrial fl utter also may occur. Antiarrythmic or rate - controlling agents or other medica- tions may be indicated for symptomatic patients with these arrhythmias and in some, cardioversion may be necessary (see section on dysrrhythmia). The hypervolemia associated with pregnancy results in an increased left to right shunt through the ASD, and, thus, a sig- nifi cant burden is imposed on the right atrium, right ventricle and pulmonary vasculature. Although this additional burden is tolerated well by most patients, congestive heart failure and death with ASD have been reported [25 – 27] . In contrast to VSD or PDA, large left to right shunts at the atrial level do not usually result in pulmonary hypertension or even irreversible pulmonary hypertension at childbearing age. An extremely rare and unusual potential complication that exists with ASD is “ paradoxical embolization. ” If this occurs, it is most likely as a result of venous thrombosis but can be air or amniotic in the pregnant woman. Thromboemboli from leg or pelvic veins may be directed across the ASD into the systemic circulation, “ paradoxically, ” resulting in ischemic neurologic complications such as transient ischemic attack (TIA) or stroke or other arterial ischemic complications. The vast majority of patients with ASD, however, tolerate preg- nancy, labor, and delivery without complication. Neilson et al. [26] reported 70 pregnancies in 24 patients with ASD; all patients had an uncomplicated ante - and intrapartum course. During labor, avoidance of fl uid overload, oxygen administration, labor in the lateral recumbent position, and pain relief with epidural Table 20.5 Guidelines from the AHA 2007 Prevetion of infective endocarditis: Patients with highest risk of adverse outcomes from endocarditis. 1. Prosthetic cardiac valves (mechanical, bioprosthetic, homograft) 2. Previous history of infective endocarditis 3. Unrepaired cyanotic congenital heart disease, including palliative shunts and conduits 4. Completely repaired congenital heart defects with prosthetic material or device, surgically or interventionally placed, during the fi rst 6 months after the procedure 5. Repaired CHD with residual defects at the site or adjacent to the site of a prosthetic patch or prosthetic device 6. Cardiac transplanted heart with signifi cant valvulopathy (leafl et pathology and regurgitation) Adapted from: Wilson W. et al. 2007. Cardiac Disease 261 outcomes are generally favorable. However, in those patients found to have irreversible pulmonary hypertension such as those with equivalent systemic and pulmonary artery pressures, cyano- sis or bidirectional shunting, the prognosis during pregnancy is extremely grave. Eisenmenger ’ s syndrome consists of congenital systemic arte- rial to systemic venous shunt (left to right shunt), development of pulmonary hypertension and shunt reversal with bidirectional shunting/or cyanosis. This syndrome may occur from a variety of common congenital lesions including VSD, ASD, PDA and more complex anatomic disorders. The risk of developing pulm- ononary hypertension and Eisenmenger ’ s syndrome from con- genital shunts is determined by the the type of shunt and degree of left to right shunt as noted above. Whatever the etiology, development of irreversible pulmonary hypertension or Eisenmenger ’ s syndrome during prengnacy portends a poor prognosis. During the antepartun period, decreased systemic vas- cular resistance increases right to left shunting, acidosis and hypotension. With systemic hypotension against a fi xed pulmo- nary vascular resistance the degree of right to left shunting and hypoxia further increases, with a vicious spiraling circle of hypotension, cyanosis, hypoxia and ultimate death. Such hypotension can result from hemorrhage or complica- tions of conduction anesthesia and may result in sudden death [32 – 35] . Avoidance of such hypotension is the principal clinical concern in the intrapartum management of patients with pulmo- nary hypertension of any etiology. Maternal mortality in the presence of Eisenmenger ’ s syndrome is reported as 30 – 50% [26,27,30,31] . In a review of the subject, Gleicher et al. [33] reported a 34% mortality associated with vaginal delivery and a 75% mortality associated with cesarean section. In a more recent report, Weiss et al. [36] reviewed the published literature from 1978 to 1996 investigating Eisenmenger ’ s syndrome, primary pulmonary hypertension and secondary pul- monary hypertension during pregnancy. Despite advances in maternal and cardiac care during this interval, the overall com- posite mortality rate for Eisenmenger ’ s syndrome during preg- nancy remained 36% – relatively unchanged for the last two decades [37 – 41] . In this series, however, there appeared to be little difference in mortality when comparing vaginal delivery (48%) to cesarean section (52%). These investigators also con- cluded that maternal prognosis depended on the early diagnosis of pulmonary vascular disease during pregnancy, early hospital admission, and individually tailored treatment during pregnancy with specifi c attention focused on the postpartum period. Table 20.6 reviews the management and outcome of pregnant women with Eisenmenger ’ s syndrome [36] . In addition to the previously discussed problems associated with hemorrhage and hypovole- mia, thromboembolic phenomena have been associated with up to 43% of all maternal deaths in Eisenmenger ’ s syndrome [33] . In the more recent report by Weiss et al. [36] , however, pulmo- nary thromboembolism accounted for only 3 of the 26 (12%) maternal deaths in this composite analysis. Sudden delayed post- partum death, occurring 4 – 6 weeks after delivery, also has been subsequent development of secondary pulmonary vascular hypertension and therefore permits an uneventful pregnancy. Fortunately, signifi cant postoperative electrophysiologic conduc- tion abnormalities are rarely encountered. Although very rarely indicated, successful primary closures of VSDs during pregnancy have been reported. Intrapartum man- agement considerations for patients with uncomplicated VSD or PDA are similar to those outlined for ASD. In general, invasive hemodynamic monitoring is usually unnecessary. Patent d uctus a rteriosus Although patent ductus arteriosus (PDA) is one of the most common congenital cardiac anomalies, its almost universal detection and closure in the newborn period makes it uncommon during pregnancy [20] . As with uncomplicated ASD and VSD, most patients are asymptomatic, and PDA is generally well toler- ated during pregnancy, labor, and delivery. As with a large VSD, however, the high - pressure – high - fl ow left to right shunt associ- ated with a large, uncorrected PDA can lead to pulmonary hyper- tension. In such cases, the prognosis becomes much worse since shunt reversal can occur with fall in systemic vascular resistance during pregnancy, delivery and early postpartum leading to a spiraling cycle of cyanosis, acidosis and hypotension. In one study of 18 pregnant women who died of congenital heart disease, three had PDA; however, all of these patients had severe secondary pulmonary hypertension [27] . In most circumstances, however, an asymptomatic young woman with a small or moderate - sized PDA, without pulmonary hypertension, will have a relatively uncomplicated pregnancy. Apart from a single case report of a spontaneous postpartum rupture of a PDA, in a patient with normal pulmonary pressure and without ductal aneurysm [31] , the risks are minimal. Pulmonary h ypertension and Eisenmenger ’ s s yndrome As discussed in the previous section, women with secundum ASD rarely manifest pulmonary hypertension in the childbearing age range and those with VSD or PDA are more likely to develop pulmonary hypertension compared to those with ASD. Patients with left to right shunts may have a continuum of progressive pulmonary artery pressure elevation and varying degrees of reversibility. It should be of note that with large left to right shunts, echocardiographic studies may suggest the presence of pulmonary artery systolic hypertension. Elevated pulmonary artery systolic pressures can be seen with high fl ow states in left to right shunts and should not be confused with irreversible pulmonary hypertension. Degree of left to right shunting and degree of pulmonary artery hypertension reversibility can usually be assessed before pregnancy or even during pregnancy with clinical evaluation, echocardiography along with other laboratory tests. A general rule of thumb is that pulmonary artery systolic hypertension in association with a left to right shunt of 1 : 5 : 1 or higher has some reversibility, otherwise, there would be no capcity for shunting. In these patients, in the absence of profound uncompensated left heart failure from volume overload, maternal Chapter 20 262 hypertension, and the pregnancy is desired, pulmonary artery catheterization with direct measurement of pulmonary artery pressures may be performed on an outpatient basis in early preg- nancy. This can be done with no to minimal radiation exposure in experienced hands using a brachial or internal jugular approach. Where signifi cant fi xed irreversible pulmonary hyper- tension exists, pregnancy termination in either the fi rst or second trimester appears to be safer than allowing the pregnancy to progress to term [44] . Dilation and curettage in the fi rst trimester or dilation and evacuation in the second trimester are the methods of choice. Hypertonic saline and F - series prostaglandins are con- traindicated, the latter due to arterial oxygen desaturation seen with the use of this agent [45] . Prostaglandin E 2 suppositories appear to be safe under these circumstances. It is highly recommended that the woman with signifi cant pulmonary hypertension/Eisenmenger ’ s syndrome who elects to continue pregnancy undergoes hospitalization for the duration of pregnancy. Alternatively very close clinical follow - up and early hospitalization at a center specialized in treatment of this condi- tion at the fi rst sign or detection of clinical deterioration may be considered on a case - by - case basis. Continuous administration of oxygen, the pulmonary vasodilator of choice, is suggested and may improve perinatal outcome. Consideration of anticoagula- tion in the peripartum period has been suggested as a method to lower this risk but there has been concern that this may instead contribute to a fatal outcome. Patients with Eisenmenger ’ s syn- drome have abnormalities with coagulation factors, and with platelet function and number. The very real possibility of fatal intrapulmonary hemorrhage and hemoptysis while on anticoagu- lants has to be weighed against the possible risk of suspected peripartum thromboembolism as the cause of death in these patients during the third trimester and postpartum. Since death has been reported with fatal hemorrhaging while on anticoagu- lants and benefi t of this therapy is not proven, routine endorse- ment of this treatment modality cannot be given. In cyanotic heart disease of any etiology, fetal outcome corre- lates well with maternal hemoglobin, and successful pregnancy is unlikely with a hemoglobin greater than 20 g/dL [13] . Maternal P a O 2 should be maintained at a level of 70 mmHg or above [46] . Third - trimester fetal surveillance with antepartum testing is important because at least 30% of the fetuses will suffer growth restriction [33] . Although the overall fetal wastage with Eisenmenger ’ s syndrome is reported to be up to 75%, more recent information suggests a more favorable outcome. Weiss et al. reported a neonatal survival rate of nearly 90% in cases of Eisenmenger ’ s syndrome. Unfortunately, since only late pregnancy cases were reviewed, no conclusions can be drawn about the rate of early fetal wastage. For pregnant patients with Eisenmenger ’ s syndrome some experts previously advocated placement of a Swan – Ganz catheter in the intrapartum period in an effort to minimize changes in cardiovascular hemodynamics, cyanosis and the shunt that occurs with uterine contractions [47] . However, placement and stabilization of a right heart catheter in a pulmonary artery reported [33,36,42] . Such deaths may involve a rebound worsen- ing of pulmonary hypertension associated with the loss of preg- nancy - associated hormones, which leads to decreased pulmonary vascular resistance during gestation [17] . Caution should be exercised when evaluating for the presence of pulmonary hypertension with non - invasive techniques such as Doppler/two - dimensional echocardiogram. The assumptions used by many cardiologists for assessment of pulmonary pres- sures do not take into account viscosity (Hb) nor pregnant state when assessing the tricuspid jet or estimating the right atrial pres- sure based on IVC size. The ordering physician should directly communicate with the interpreting physician these issues when trying to determine pulmonary artery pressures since other methods to assess these values may be available. Otherwise, these techniques have a clear tendency to signifi cantly overestimate the degree of pulmonary hypertension during pregnancy and may incorrectly diagnose the presence of pulmonary hypertension in up to 32% of cases when compared with cardiac catheterization [43] . If any question exists regarding the presence of pulmonary Table 20.6 Management and outcome of pregnant women with Eisenmenger ’ s syndrome ( n = 73). Maternal survival Maternal mortality Number (%) 47 (64%) 26 (36%) Age (years) 26.4 ± 4.8 24.9 ± 4.5 Hospital admission (weeks of pregnancy) 26.7 ± 6.5 31.4 ± 5.9 Toxemia of pregnancy 2 (4%) 3 (12%) Delivery (weeks of pregnancy) 35.1 ± 3.5 34.4 ± 4.4 Vaginal delivery 27 (57%) 11 (48%) Operative delivery 20 (43%) 12 (52%) Monitoring Non - invasive, not reported 24 (51%) 15 (63%) Invasive SAP and/or CVP 23 (49%) 9 (37%) Invasive PAP 8 (17%) 6 (25%) Anesthesia/analgesia Not reported 13 (28%) 5 (22%) Regional techniques 22 (47%) 8 (35%) General anesthesia 12 (25%) 7 (30%) Local anesthesia/analgesia 0 3 (13%) Oxytocic drugs 14 (30%) 4 (17%) Antithrombotic therapy 28 (60%) 12 (46%) Neonatal survival 43 (96%) * 20 (77%) Maternal death, days postpartum – 5 (0 – 30) Data presented are mean value; ± SD, number (%) of patients, or median (range). * In two cases neonatal outcome was not reported. Three patients died before delivery and 23 died after delivery. CI, confi dence interval; CVP, central venous pressure; PAP, pulmonary artery pressure; SAP, systemic arterial pressure. (From Weiss BM, Zemp L, Burkhardt S, Hess O. Outcome of pulmonary vascular disease in pregnancy: a systemic overview from 1978 through 1996. J Am Coll Cardio 1998;31:1650 – 1657.) Cardiac Disease 263 functional right ventricle beyond the apically displaced tricuspid valve provides effective forward pulmonary blood fl ow. However, at times the functional right ventricle may be extremely small and barely able to produce enough forward pulmonary fl ow to sustain adequate blood pressure. Those women who reach childbearing years may have either the acyanotic or cyanotic form of Ebstein ’ s anomaly. Since pulmonary hypertension is not seen in this anomaly, as noted, the cyanosis is determined by the degree of right to left shunting across the patent foramen ovale from tri- cuspid regurgitation. Fetal prematurity, loss and low birth weight are more common in the cynanotic form of Ebstein ’ s anomaly, refl ecting this fi nding. It is extremely unusual for the non - cyanotic form of Ebstein ’ s anomaly to convert to a cyanotic form once patients have reached maturity. However, this is dependent upon the degree of tricuspid regurgitation and the functional capacity of the non - atrialized portion of the right ventricle. Therefore, evaluation of oxygen and volume status is an impor- tant consideration during gestation, labor and delivery. Paroxysmal atrial arrhythmias have been reported to occur in up to one - third of non - pregnant women with Ebstein ’ s anomaly and represent a potential concern during pregnancy. The Wolff – Parkinson – White syndrome is an arrhythymia classically associ- ated with Ebstein ’ s anomaly and may represent a risk factor for excessively rapid ventricular rates in response to the increased incidence of atrial arrhythmias that are associated with Ebstein ’ s anomaly [56] . Despite these concerns, in a review of 111 pregnancies in 44 women, no serious maternal complications were noted. Seventy - six per cent of pregnancies ended in live births, with a 6% inci- dence of congenital heart disease in the offspring of these women [55] . Coarctation of the a orta Coarctation of the aorta accounts for approximately 10% of all congenital cardiac disease. The most common site of coarctation is usually at the origin of the left subclavian artery. Associated anomalies of the aorta and left heart, including VSD and PDA, are common, as are intracranial aneurysms in the circle of Willis [57] . Coarctation is often asymptomatic. Its presence is suggested by hypertension confi ned to the upper extremities, although Goodwin [58] cites data suggesting a generalized increase in peripheral resistance throughout the body. Resting cardiac output may be increased; however, increased left atrial pressure with exercise suggests occult left ventricular dysfunction. Aneurysms also may develop below the coarctation or involve the intercostal arteries and may lead to rupture. In addition, ruptures without prior aneurysm formation have been reported [59] . Over 150 patients with uncorrected and corrected coarctation of the aorta have been reported during pregnancy, with maternal mortality ranging from 0% to 17% [25,59,60] . In a 1940 review of 200 pregnant women with coarctation of the aorta, Mendelson [61] reported 14 maternal deaths and recommended routine abortion and sterilization for these patients. Deaths in this series were from aortic dissection and rupture, congestive heart failure, branch can be quite diffi cult in the presence of markedly elevated pulmonary pressures. These patients require ICU monitoring, and are increased risk of pulmonary artery rupture, pulmonary infarction, and dysrhythmia. They also require suspension of any oral anticoagulation before placement,with increased risk of pul- monary artery thrombosis. Many now believe the risk of this technique far outweighs the its benefi ts in patients with cyanotic heart disease [48] and its use is rare. In many cases, pulse oxim- etry may offer appropriate guidance in the intrapartum manage- ment of these patients without the need for and/or the associated risks of, pulmonary artery catheterization. Because the primary concern in such patients is the avoidance of hypotension, any attempt at preload reduction (i.e. diuresis) must be undertaken with great caution, even in the face of initial fl uid overload. We prefer to manage such patients on the “ wet ” side, maintaining a preload margin of safety against unexpected blood loss, even at the expense of mild pulmonary edema. Recently, the use of inhaled nitric oxide and intravenous prostacyclin therapy have shown promise as potentially helpful agents in reducing the pul- monary vascular resistance while relatively sparing the systemic vascular resistance [49,50] . Anesthesia for patients with pulmonary hypertension is con- troversial. Theoretically, conduction anesthesia, with its accom- panying risk of hypotension, should be avoided. However, there are several reports of its successful use in patients with pulmonary hypertension of different etiologies [51,52] . The use of epidural or intrathecal morphine sulfate, a technique devoid of effect on systemic BP, represents perhaps the best approach to anesthetic management of these diffi cult patients. Although the AHA recommendations for antibiotic prophy- laxis to prevent endocarditis have been extensively revised, the recommendations regarding cyanotic congenital heart disease have not. Endocarditis prophylaxis continues to be recommended for cyanotic congenital heart disease [28] . Ebstein ’ s a nomaly Because it accounts for less than 1% of all congenital cardiac disease, Ebstein ’ s anomaly is uncommonly encountered during pregnancy [53 – 55] . This anomaly consists of apical displacement of the tricuspid valve into the right ventricle, sometimes markedly so, with secondary tricuspid regurgitation of varying degrees, and enlargement of the right atrium by incorporation of the right ventricle situated above the tricuspid valve (the so called “ atrial- ized right ventricle ” ). A patent foramen ovale may be present in the interatrial septum and thus these patients may have non - cyanotic or cyanotic form of the anomaly. The presence or absence of cyanosis and hemodynamic consequences of Ebstein anomaly result from the degree of displacement of the tricuspid valve leafl ets and extent of atrialization of the right ventricle. The severity of tricuspid regurgitation and hence shunting across the patent foramen ovale depends on the extent of leafl et displace- ment, ranging from mild regurgitation with minimal displace- ment to severe tricuspid regurgitation with more apical displacement and atrialization of the right ventricle. Usually the Chapter 20 264 unproven, to decrease the force of left ventricular ejection into the aorta and to reduce aortic wall stress. Despite these concerns, most patients with a successfully repaired coarctation of the aorta have a relatively unremarkable pregnancy. Saidi, et al [63] fol- lowed 18 pregnancies in women who had undergone a successful repair of their aortic coarctations. All 18 women had uneventful pregnancies. Interestingly, the incidence of pre - eclampsia in this series was no different than that reported in the normal popula- tion. Maternal risk, however, is clearly increased if pre - eclampsia develops [66] . In a recent retrospective study of 100 women [65] , a higher incidence of hypertension and pre - eclampsia was found in women who had previously had a repair of coarctation of the aorta. Interestingly, 80% had had end - to - end surgical resection at a median age of 6 years, 13% had required interven- tion for recoarctation and 30% were noted to have hypertension at the time of the review. This supports the contention that chil- dren often outgrow their initial surgery and that hypertension is quite common even after successful repair of coarctation of the aorta. In the presence of aortic or intervertebral aneurysm, known as aneurysm of the circle of Willis, or associated cardiac lesions, the risk of death may approach 15%; therefore, termination of preg- nancy should be strongly considered. Tetralogy of Fallot Tetralogy of Fallot refers to four key anatomic features which lead to cyanosis: VSD, overriding aorta, right ventricular hypertrophy, and pulmonary stenosis. In the United States, most cases of tetral- ogy of Fallot are corrected during infancy or childhood. Most of the women with this condition at childbearing age have had it surgically corrected but many have residual lesions such as ongoing VSD through a VSD patch, pulmonary insuffi ciency of varying degrees with right heart enlargement, prosthetic pulmo- nary valve, residual right ventricular outfl ow tract obstruction, or a combination of these. A few will have only had palliative pro- cedures and are cyanotic [67] . Rarely do they present in the cyanotic state without any prior surgical correction. Several published reports attest to the relatively successful outcome of pregnancy in patients with totally or partially cor- rected tetralogy of Fallot [66,68] . For the totally corrected patient, pregnancy outcome is similar to that of the general population. For those with residual lesions including mild pulmonic and/or tricuspid regurgitation, mild pulmonary stenosis, or small VSD patch leak, the maternal and fetal risk is minimal. If there is sig- nifi cant right heart enlargement from residual pulmonary insuf- fi ciency, right ventricular outfl ow obstruction or pulmonic stenosis, the risk is higher for development of arrhythmias or heart failure during pregnancy. However, these patients still can be managed successfully if they fi rst present during pregnancy. Women with uncorrected tetralogy of Fallot do not fare as well. In a review of 55 pregnancies in 46 patients, there were no mater- nal deaths among nine patients with correction of this lesion before pregnancy; in patients with an uncorrected lesion, however, maternal mortality has traditionally ranged from 4% to 15%, cerebral vascular accidents, and bacterial endocarditis. Six of the 14 deaths occurred in women with associated lesions. In contrast to this dismal prognosis, a more recent series by Deal and Wooley [60] reported 83 pregnancies in 23 women with uncomplicated coarctation of the aorta. All were NYHA class I or II before preg- nancy. In these women, there were no maternal deaths or perma- nent cardiovascular complications. In one review, aortic rupture was more likely to occur in the third trimester, before labor and delivery [62] . More recent reviews have also supported the fi nding that improved surgical and percutaneous techniques, medical therapy for hypertension, and improvement in the management of these women during pregnancy have resulted in more favor- able maternal outcomes [63 – 65] . Thus, it appears that today, patients with coarctation of the aorta uncomplicated by aneurysmal dilation or hemodynamically signifi cant associated cardiac lesions who enter pregnancy as class I or II have a good prognosis and a minimal risk of complications or death. Even if uncorrected, uncomplicated coarctation has historically carried with it a risk of maternal mortality of only 3 – 4% [58] . These unrepaired patients should be considered for repair of their coarctation after the postpartum period is con- cluded and before contemplation of a next pregnancy. Those pregnant women who have uncontrolled symptomatic hyperten- sion attributable to coarctation despite maximal medical therapy should have a stent placed at the coarctation site. This procedure is 90% successful with < 20 mmHg residual gradient. The risk of fetal irradiation is low compared to the high maternal risk of death from heart failure, arrhythmia, dissection, stroke, and myo- cardial infarction. The fetal risk can further be reduced by involv- ing a radiation physicist from the hospital who can help calculate the radiation dose based on the distance of the X - ray tube from the mother ’ s abdomen, by shielding the mother ’ s abdomen with lead (both anterior and posterior), and by performing the proce- dure after the second trimester. Surgical intervention for coarcta- tion of the aorta in a pregnant woman is not ideal. For those with previously surgically repaired coarctation of the aorta, the maternal outcome appears good [63,65] . Surgical repair of the coarctation, often accomplished in early childhood, usually results in long - term normalization of blood pressure. However, those who have surgeries done at an early age require ongoing surveillance since the site of surgical intervention does not typically “ grow ” with the child and further intervention may be necessary for redevelopment of hypertension, aneurysm at the site of the surgical repair, or other issues related to the repair. Percutaneous catheter - based interventional techniques for treat- ment of coarctation are also being widely used as well, for man- agement of both children and older patients. Weakness in the aortic wall, both proximal and distal to the repair, is histologically similar (cystic medial necrosis) to the aortic weakness exhibited in Marfan syndrome and bicuspid aortic valve. This abnormality can be amplifi ed during pregnancy. For women who have unre- paired coarctation of the aorta, who have residual coarctation after surgical or interventional therapy, or who have a residual gradient, β - blockade therapy seems reasonable, although Cardiac Disease 265 For those in whom the diagnosis is established, both maternal outcome and pregnancy is generally well tolerated with NYHA class I or II symptoms [70] . It is still diffi cult to quantify RV function due to the lack of a suitable control group for compari- son, and because of the dependence on shape assumptions and loading conditions of the commonly used systolic indices. Nevertheless, those with severe AV valve regurgitation or severely depressed morphologic RV function should be counseled against pregnancy regardless of functional class. Lessons being learned from those who have had atrial switch operations for D - TGA (see below) and similar systemic arterial RV functional issues may be of help in this group of patients. D - transposition ( D - TGA ) D - transposition or complete transposition of the great vessels is incompatible with prolonged life after birth. In this condition, the transposed aorta is connected to the RV and the pulmonary artery to the LV. The atria and ventricles are not transposed so that systemic venous return to the RV is ejected into the aorta. This defect requires urgent surgical palliation and then subse- quent complete repair. The fi rst complete repair involved the “ atrial switch ” operation. Both the Mustard and Senning opera- tions in the late 1950s and early 1960s revolutionized the manage- ment of babies with D - TGA and became the treatment of choice. In this operation, the systemic venous fl ow from the RA is redi- rected into the LV and PA, while the systemic arterial fl ow is redirected from the pulmonary veins into the morphologic RV to the aorta. Since the morphologic RV serves as the systemic arterial ventricle, similar issues arise to those seen with L - TGA, and the key to long - term outcome is the fate of the RV. In addi- tion, because of the extensive surgical intervention to the atria in redirection of fl ow, signifi cant arrhythmias have been described in both types of surgeries. This procedure has been largely aban- doned in favor of the arterial switch begun in the 1980s [71] because of these concerns. This procedure appears to reduce the late morbidity rates that have been described with the atrial repairs [72,73] . Women that have had successful arterial switch procedures are now entering reproductive ages. The arterial switch procedure is done within days of birth. Both great arteries are transected and reanastomosed above the sinuses of Valsalva, and the coronary arteries are translocated. The native pulmonary valve becomes the systemic outfl ow valve, and the anatomic pul- monary root is subjected to systemic blood pressure. The native valves are not touched. Short - and midterm follow - up of these patients have shown coronary artery narrowing, pulmonary artery stenosis, neoaortic valve aortic insuffi ciency, and neoaortic root dilation [74,75] The risk of pregnancy in patients with D - transposition who have had the Mustard or Senning procedure is related to the severity of any heart failure present, the degree of AV valve regur- gitation, the degree of resultant pulmonary hypertension and the presence of arrhythmias. A series of pregnant patients who were followed subsequent to the Mustard (atrial switch) operation reported 12 of 15 live births and no maternal deaths [76] . In a with a 30% fetal mortality due to hypoxia [66,69] . In patients with uncorrected VSD and right ventricular outfl ow tract obstruc- tion or pulmonic stenosis, the decline in SVR that accompanies pregnancy can lead to worsening of the right to left shunt. This condition can be aggravated further by systemic hypotension as a result of peripartum blood loss. A poor prognosis for successful pregnancy has been related to several prepregnancy parameters, including a hemoglobin exceeding 20 g/dL, a history of syncope or congestive failure, electrocardiographic evidence of right ven- tricular strain, cardiomegaly, right ventricular pressure in excess of 120 mmHg, and peripheral oxygen saturation below 85%. Women who present with a palliative shunt procedure only from childhood may be cyanotic and/or have pulmonary hypertension with the same attendant problems as outlined in the section on pulmonary hypertension/Eisenmenger ’ s syndrome. If they are found to have this problem they should be discouraged from attempting or continuing pregnancy. Transposition of the g reat v essels Transposition of the great vessels consists of two types: • L - transposition; the so - called congenitally corrected transposi- tion of the great arteries • D - transposition: the complete transposition. L - transposition ( L - TGA ) In L - transposition, or congenitally corrected transposition, the great arteries are transposed. This accounts for less than 1% of all congenital cardiac defects. In this defect, the atria and ventricles are also transposed. Hence there is a double discordance of the atrial - ventricular and ventricular - arterial connections. The right ventricle is attached to the aorta and acts as the systemic arterial ventricle receiving oxygenated blood from the lungs and left atrium. The morphologic left ventricle is attached to the pulmo- nary artery and acts as the systemic venous ventricle receiving venous blood from the right atrium, IVC and SVC. Although the morphologic right ventricle is not designed to accommodate sys- temic arterial pressures, it may accommodate this pressure well for years. Ventricular dysfunction and AV valve regurgitation are recognized and important complications of patients with L - TGA but this may present slowly and insidiously and does not happen in all L - TGA patients. Although RV dilation is common, few develop evidence of symptomatic heart failure. Serial studies do not indicate that there is an inevitable progressive downward and progressive deterioration of function with time. Heart failure symptoms are typical, as one would expect, with pulmonary edema, increasing pulmonary pressures and decreased forward systemic arterial output. This condition is detected later in life usually when the morphologic right ventricle can no longer accommodate systemic arterial pressures or the AV valve becomes regurgitant and symptoms of shortness of breath, palpitations, and arrhythmia become manifest. Disconcertingly, the diagnostic anatomic features of this congenital defect may be missed on echocardiography by adult cardiologists not trained in congenital heart disease. Chapter 20 266 Functional s ingle v entricle and Fontan p rocedure Some of the anomalies described as a functional single ventricle that will ultimately undergo staged reconstructive procedures resulting in a “ Fontan circulation ” are tricuspid atresia, hypoplas- tic left heart, double - inlet left ventricle, and some variations of double - outlet right ventricle. Given the variety of lesions and the infrequency of this procedure, data on pregnancy outcomes after Fontan operation are limited [82,83] . In the small numbers reported in the United States, no maternal deaths have occurred. Pregnancies in these patients have been associated with an increased incidence of spontaneous abortions, however. In a small survey from the Netherlands, 10 pregnancies in 6 women were associated with a 50% miscarriage rate and one aborted ectopic pregnancy. In the four live births, NYHA class deteriora- tion, atrial fi brillation and premature delivery were reported. There were no maternal deaths. Thus, at this early stage, although maternal death does not appear to be prominent in patients who have undergone a Fontan repair with their specifi c underlying congenital lesion and who have elected to proceed with preg- nancy, there appears to be a substantial risk for spontaneous abortion, as well as other signifi cant obstetric and cardiac issues. Fetal c onsiderations Perinatal outcome in patients with cyanotic congenital cardiac disease correlates best with hematocrit; successful outcome in patients with a hematocrit exceeding 65% or hemoglobin exceed- ing 20 g/dL is unlikely. Presbitero and associates [13] described outcome in 96 pregnancies complicated by cyanotic congenital heart disease. Patients with Eisenmenger ’ s syndrome were excluded from this analysis. Although only one maternal death was seen (from endocarditis 2 months postpartum), the preg- nancy loss rate was 51%. Functional class III or IV, hemoglobin greater than 20 g/dL, and a prepregnancy oxygen saturation less than 85% all were associated with a high risk for poor pregnancy outcome. Such patients have an increased risk of spontaneous abortion, intrauterine growth restriction, and stillbirth. Maternal P a O 2 below 70 mmHg results in decreased fetal oxygen saturation; thus, P a O 2 should be kept above this level during pregnancy, labor, and delivery. In the presence of maternal cardiovascular disease, the growth - restricted fetus is especially sensitive to intra- partum hypoxia, and fetal decompensation may occur more rapidly [7,84] . During the antepartum period, serial antepartum sonography for the detection of growth restriction and antepar- tum fetal heart rate testing are recommended in any patient with signifi cant cardiac disease. Fetal activity counting also may be of value in patients with severe disease [85] . In a series of six patients with cyanotic cardiac disease, every pregnancy was eventually delivered secondary to fetal, rather than maternal, deterioration [86] . Of equal concern in patients with congenital heart disease is the risk of fetal congenital cardiac anomalies. This risk appears to be of the order of 5%, although one older study suggested that similar series of seven patients with transposition having under- gone the Mustard procedure, no maternal deaths were reported [77] . In one case, however, pregnancy termination was necessary due to maternal deterioration. In the largest series described thus far, using a retrospective nationwide registry in the Netherlands, outcomes of 70 women with D - transposition and Mustard or Senning operations were reported [78] . Forty - two were childless of whom 35 wished to bear children in the future. Of the 28 patients who completed 49 pregnancies, all were in NYHA class I or II before pregnancy. There was clinical deterioration in NYHA in one - third of pregnancies and development of clinically signifi cant arrhythmias in 20% of these pregnancies. No maternal deaths occurred. The cardiac issues were manageable. However, there was a high incidence of obstetric complications. The authors indicated that in contrast to what is generally assumed, pregnancy is not always well tolerated in these patients. They also estimate that approximately 4500 women with this congenital lesion and surgical procedure will enter childbearing age in the USA over the next few years. Women who have had the Jatene (arterial switch) procedure are only now entering their childbearing years. There has been a case report, cited frequently, of a successful pregnancy and deliv- ery in a patient with D - transposition and arterial switch [79] . Pulmonic s tenosis Pulmonic stenosis is a common congenital defect. Although obstruction can be valvular, supravalvular, or subvalvular, the degree of obstruction, rather than its site, is the principal deter- minant of clinical performance [8] . Maternal well - being is rarely signifi cantly affected by pulmonic stenosis. Even 30 years ago, a compilation (totaling 106 pregnancies) of three series of patients with pulmonic stenosis revealed no maternal deaths [25 – 27] . With severe stenosis, right heart failure can occur; fortunately, this is usually less clinically severe than is the left heart failure associated with mitral or aortic valve lesions. Symptoms of dyspnea, angina, syncope or presyncope can occur in those with markedly stentotic lesions. Severe pulmonic stenosis is defi ned by a peak valvular gradient of more than 80 mmHg. Because this degree of obstruction imposes a signifi cant load on the right ventricle, patients with severe pulmonic stenosis usually benefi t from balloon valvuloplasty even in the absence of symptoms. In these women with severe pulmonic stenosis, pregnancy may be associated with increased risk during labor, delivery, and the puerperium. The fi rst balloon valvuloplast was performed in 1982. Balloon valvuloplasty in pregnancy has since been per- formed successfully and with relatively low complication rates [80] . The incidence of fetal congenital heart disease in patients with pulmonic valve stenosis appears to be approximately 20%, with a 55% concordance rate [81] . Aortic s tenosis Congenital and rheumatic aortic valvular disease are important causes of aortic stenosis. The impact of aortic stenosis on preg- nancy will be discussed in Acquired cardiac lesions. Cardiac Disease 267 and pedal edema mimic the symptoms of valvular heart disease making the clinical diagnosis diffi cult. Jugular venous distention, brisk and collapsing pulses, and a diffuse and laterally displaced left ventricular impulse, all normal physiologic adaptations to pregnancy, further confound the clinical assessment. On auscul- tation of the normal heart during pregnancy, it is not unusual to hear an accentuated fi rst heart sound (S1) or a systolic fl ow murmur that peaks in midsystole and is best appreciated along the left sternal border. A third heart sound (S3), a fourth heart sound (S4), or a diastolic murmur are uncommon in normal pregnancy and require an echocardiographic assessment. Doppler echocardiography in normal pregnancy refl ects the physiologic consequences of the increased intravascular volume and blood fl ow on the cardiac chambers and valves. There is an increase in the left ventricular end - diastolic dimension and a decrease in the left ventricular end - systolic dimension represent- ing an increase in both the stroke volume and ejection fraction. The aortic root dimension, as well as the mitral and tricuspid annuli, are slightly increased. The left ventricular mass increases by as much as 30% with minimal changes in wall thickness [91] . Flow velocities across the aortic valve are minimally increased but rarely exceed 1.5 m/s by Doppler assessment. Campos et al. [92] studied 18 pregnant women longitudinally throughout preg- nancy utilizing Doppler echocardiogram. Mild valvular regurgi- tation was detected consistently throughout pregnancy. Aortic regurgitation was rarely detected; however, mitral (0 – 28%) tricuspid (39 – 94%), and pulmonic regurgitation (22 – 94%) were found to increase substantially from early to late gestation. Table 20.7 reviews the effect of pregnancy on the clinical and echocar- diographic fi ndings associated with cardiac valvular abnormali- ties [81] . Acquired valvular lesions generally are rheumatic in origin, although endocarditis secondary to intravenous drug abuse may the actual risk may be as high as 10%, or even higher in women whose congenital lesion involves ventricular outfl ow obstruction [13,81,87,88] (see Figure 20.3 ). In such patients, fetal echocar- diography is indicated for prenatal diagnosis of congenital cardiac defects [89] . Of special interest is that affected fetuses appear to be concordant for the maternal lesion in approximately 50% of cases. The genetics and embryologic development of congenital cardiac defects have been reviewed by Clark [90] . Acquired c ardiac l esions Many common complaints associated with normal pregnancy including dyspnea, fatigue, orthopnea, palpitations, presyncope Figure 20.3 Echocardiographic image of a fetus at 19 weeks in a mother with a ventricular septal defect (VSD). A similar VSD is demonstrated in this fetus. Table 20.7 The effect of pregnancy on the clinical and echocardiographic fi ndings associated with cardiac valvular abnormalities. Heart sounds Murmur Other Doppler echocardiography Aortic stenosis (AS) Diminished or single S2 – unchanged Increase in intensity and duration Systolic ejection click unchanged Increase in Doppler gradient; AVA unchanged Aortic insuffi ciency (AI) Diminished S2 – unchanged Decreased or unchanged Wide pulse pressure – increased or unchanged LV dimensions may increase secondary to pregnancy not AI Mitral stenosis (MS) Loud 1 – increased; P2 – increased Increased decrease or unchanged S2 – OS interval gradient, decrease in pressure half - time and increase in calculated MVA Increase in Doppler Mitral regurgitation (MR) Diminished S1 – unchanged Decreased or unchanged S3 – unchanged to pregnancy not MR LV dimensions may increase secondary Pulmonic stenosis (PS) Diminished P2 – unchanged Increase in intensity and duration Systolic ejection click unchanged Increase in Doppler gradient Pulmonic insuffi ciency (PI) Diminished P2 – unchanged Decreased or unchanged N/A secondary to pregnancy not PI RV dimensions may increase Tricuspid stenosis (TS) N/A Increased N/A N/A Tricuspid regurgitation (TR) N/A unchanged Decreased or secondary to pregnancy not TR N/A RV dimensions may increase AVA, arteriovenous anastomosis; LV, left ventricle; MVA, mitral valve anastomosis; RV, right ventricle. Chapter 20 268 diagnosis of mitral stenosis will be discovered for the fi rst time during pregnancy, illustrating what is frequently referred to as “ occult ” mitral stenosis. The hemodynamic changes accompany- ing normal pregnancy may represent the fi rst time the patient ’ s cardiovascular system has been signifi cantly stressed. These patients may present with “ acute ” pulmonary edema and/or atrial fi brillation as the initial diagnostic clue to the presence of mitral stenosis. When clinical symptoms persist despite attentive medical management, interventional therapy may be prudent. Percutaneous balloon mitral valvuloplasty during pregnancy has become increasingly prevalent. More than 100 pregnant women have undergone percutaneous balloon mitral valvuloplasty without periprocedural maternal or fetal mortality. Multiple case reports [95 – 97] and case series [98 – 105] support the relative safety of this procedure during pregnancy. Procedural complica- tions include cardiac tamponade, maternal arrhythmias, tran- sient uterine contractions, and systemic thromboembolism. Transesophageal echocardiography can be used as the sole imaging modality, thereby eliminating the undesired radiation exposure associated with fl uoroscopy. Cardiac output in patients with mitral stenosis is largely depen- dent on two factors. First, these patients are dependent on ade- quate diastolic fi lling time. Thus, while in most patients tachycardia is a clinical sign of underlying hemodynamic instabil- ity, in patients with mitral stenosis, the tachycardia itself, regard- less of etiology, may contribute signifi cantly to hemodynamic decompensation. During labor, such tachycardia may accompany the exertion of pushing or be secondary to pain or anxiety. Such a patient may exhibit a rapid and dramatic fall in cardiac output and BP in response to tachycardia. This fall compromises mater- nal as well as fetal well - being. To avoid hazardous tachycardia, the physician should consider intravenous β - blocker therapy for any patient with severe mitral stenosis who enters labor with a pulse exceeding 90 – 100 bpm. A short acting β - blocker, such as esmolol, is ideal in that minute - to - minute heart rate control can be achieved without the undesired prolonged beat - blockade that is associated with more conventional agents such as propranolol. Another consideration is use of intravenous calcium channel blocking agents such as diltiazem with which the cardiologists and nursing personnel are generally familiar and for which administration is easier. In patients who are not initially tachy- cardic, acute control of tachycardia with an intravenous β - blocking agent is only rarely necessary [42] . A second important consideration in patients with mitral ste- nosis is left ventricular preload. In the presence of mitral stenosis, pulmonary capillary wedge pressure is not an accurate refl ection of left ventricular fi lling pressures. Such patients often require high - normal or elevated pulmonary capillary wedge pressures to maintain adequate ventricular fi lling pressure and cardiac output. Any preload manipulation (i.e. diuresis), therefore, must be undertaken with extreme caution and careful attention to main- tenance of cardiac output. Potentially dangerous intrapartum fl uctuations in cardiac output can be minimized by using epidural anesthesia [106] ; occasionally occur, especially with right heart lesions. During pregnancy, maternal morbidity and mortality with such lesions result from congestive failure with pulmonary edema or arrhyth- mias. Szekely et al. [93] found the risk of pulmonary edema in pregnant patients with rheumatic heart disease to increase with increasing age and with increasing length of gestation. The onset of atrial fi brillation during pregnancy carries with it a higher risk of right and left ventricular failure (63%) than does fi brillation with onset before gestation (22%). In addition, the risk of sys- temic embolization after the onset of atrial fi brillation during pregnancy appears to exceed that associated with onset in the non - pregnant state. In counseling the patient with severe rheu- matic cardiac disease on the advisability of initiating or continu- ing pregnancy, the physician must also consider the long - term prognosis of the underlying disease. Chesley [94] followed 134 women who had functionally severe rheumatic heart disease and who had completed pregnancy for up to 44 years. He reported a mortality of 6.3% per year but concluded that in patients who survived the gestation, maternal life expectancy was not short- ened by pregnancy. Thus, in general, pregnancy does not appear to introduce long - term sequelae for patients who survive the pregnancy [44] . Pulmonic and t ricuspid l esions Isolated right - sided valvular lesions of rheumatic origin are uncommon; however, such lesions are seen with increased fre- quency in intravenous drug abusers, where they are secondary to valvular endocarditis. Pregnancy - associated hypervolemia is far less likely to be symptomatic with right - sided lesions than with those involving the mitral or aortic valves. In a review of 77 maternal cardiac deaths, Hibbard [27] reported no deaths associ- ated with isolated right - sided lesions. In a more recent review, congestive heart failure occurred in only 2.8% of women with pulmonic stenosis [87] . Even following complete tricuspid val- vectomy for endocarditis, pregnancy, labor, and delivery are gen- erally well tolerated. Cautious fl uid administration is the mainstay of labor and delivery management in such patients. In general, invasive hemodynamic monitoring during labor and delivery is not necessary. Mitral s tenosis Mitral stenosis is the most common rheumatic valvular lesion encountered during pregnancy [42] . It can occur as an isolated lesion or in conjunction with aortic or right - sided lesions. When mitral stenosis is signifi cant (valve area < 1.0 cm 2 ) the principal hemodynamic aberration involves a left ventricular diastolic fi lling obstruction, resulting in a relatively fi xed cardiac output. Marked increases in cardiac output accompany normal preg- nancy, labor, and delivery. If the pregnant patient is unable to accommodate such volume fl uctuations, atrial arrhythmias and/ or pulmonary edema may result. Ideally it is best to treat signifi cant mitral stenosis before preg- nancy with balloon and/or surgical commissurotomy. Often the . antepartum bed rest and meticulous prenatal care. Intrapartum management principles include laboring in the lateral position; the use of epidural anesthesia, which will minimize intrapartum. endocarditis: Patients with highest risk of adverse outcomes from endocarditis. 1. Prosthetic cardiac valves (mechanical, bioprosthetic, homograft) 2. Previous history of infective endocarditis. fetus is especially sensitive to intra- partum hypoxia, and fetal decompensation may occur more rapidly [7,84] . During the antepartum period, serial antepartum sonography for the detection of