FIG 35.23 Doppler echocardiography of pulmonary arterial flow in the early postoperative course following corrective surgery in tetralogy of Fallot shows antegrade flow occurring in diastole coincident with atrial systole, thus shortening the duration of pulmonary regurgitation This pattern is considered the hallmark of isolated right ventricular restriction (From Cullen S The right ventricle in tetralogy of Fallot: the early postoperative period In Redington A, et al, editors The Right Heart in Congenital Heart Disease Bristol, UK: GMM Publishing, 1998.) Late Outcomes of Intervention An important paper published in 1993 reviewed the late survival and outcomes of surgical repair of TOF.33 Actuarial survival was overall at 86% among patients surviving 30 days after complete repair compared with 96% in the control population Further analysis showed rates of survival after 30 years of 90%, 93%, and 91% in patients undergoing surgery younger than the age of 5 years, from 5 to 7 years, and at 8 to 11 years, respectively Of patients who were 12 years of age or older at the time of operation, only 76% were alive compared with 93% in controls Although reflecting a success story in terms of modification of the natural history of the disease, it became clear and increasingly the case that the late mortality after definitive repair will far exceed the early postoperative risk Consequently the past decade or so has seen a shift toward improved understanding of the determinants of late outcomes, with concentration on the adverse effects of pulmonary incompetence, which was previously considered to be a benign side effect of relief of the obstructed right ventricular outflow tract Physical Response to Correction Following successful repair, almost all children rapidly catch up in terms of their height and weight They grow faster than their peers, and height and weight are normal 5 years after repair Murmurs frequently persist after operation, usually but not always related to mild residual subpulmonary obstruction or to acquired pulmonary incompetence The typical auscultatory findings on follow-up are a single second sound, an ejection systolic murmur in the second or third left intercostal space, and a slightly delayed diastolic decrescendo murmur If the pulmonary valve has been preserved, the second sound may be split If subvalvar obstruction is completely relieved without a patch across the ventriculopulmonary junction, there may be no murmurs Presence of an ejection systolic murmur may complicate assessment of other problems, such as a residual ventricular septal defect, although cross-sectional echocardiography with Doppler studies easily allows quantification of residual intracardiac anomalies In patients who have undergone a staged surgical approach with a preceding systemic-to-pulmonary anastomosis, reappearance of a continuous systolic-diastolic murmur may be the first symptom of a recanalized anastomosis Those patients have a high risk for acquiring endocarditis, so elective closure in the catheter laboratory is recommended.34 Apart from a right aortic arch, when present, the chest radiograph may return to normal, but some will have a bulge over the upper left heart border as a consequence of patching the outflow tract Cardiomegaly evolves with longer duration of follow-up and largely reflects right-sided dilation The electrocardiogram will often show right bundle branch block, with the duration of the QRS complex lengthening in response to dilation of the right heart Pulmonary incompetence (PI) is found by echo-Doppler examination in between three-fifths and nine-tenths of patients postoperatively Pulmonary insufficiency is well tolerated for the first few years but may result in a chronically dilated right ventricle Patients with isolated congenital PI are known to remain asymptomatic for up to 20 years, but thereafter freedom from symptoms decline rapidly with time.35 Symptoms include effort intolerance, right-sided failure, arrhythmias, and sudden death Chronic pulmonary regurgitation may also adversely affect exercise performance and right ventricular function Early studies assessing pulmonary PI using pressurevolume loops36 showed a linear relationship between PI and right ventricular volumes, and reduced maximal consumption of oxygen during exercise in those with the more severe amount of PI.37 Today PI is measured directly and accurately by cardiac MRI Results using this approach have reinforced the earlier data regarding the adverse effects of pulmonary incompetence on functional performance and disturbances of conduction Before dwelling in more detail on the arrhythmia problems and their relationship to hemodynamic disturbances, it is of note that, in the long term, the consequences of chronic PI may be modified by the diastolic properties of the right ventricle.38 Restrictive right ventricular physiology, found in some patients early after operation (Fig 35.23), is correlated with beneficial rather than adverse hemodynamic consequences when it persists on long-term follow-up Exercise tolerance is enhanced, the heart does not enlarge despite pulmonary regurgitation, and intraventricular conduction disturbances, as reflected by the QRS prolongation, may be less.38 In this respect, it should also be noted that the presence of peripheral pulmonary stenosis will increase the amount of pulmonary incompetence following surgery.39 In the context of the mechanical dysfunction of the right ventricle, it is increasingly appreciated that additional left ventricular dysfunction seems to coexist in many patients with tetralogy The right ventricle is anatomically integrated with the left ventricle through subepicardial bundle of aggregated myocytes that run from the free wall of the right ventricle to the anterior wall of the left ventricle Moreover, the ventricles share the septum and are enclosed in the same pericardial cavity The interaction of the two ventricles results in alterations of both diastolic and systolic function.40 Experimental research has demonstrated that part of the external mechanical work generated by the right ventricle is a direct consequence of left ventricular contraction or contraction of shared myocytes.41 Patients late after repair show a reasonably strong linear relationship between right and left ventricular ejection fractions.42 Left ventricular dysfunction is also known to be a risk factor for sudden death late after repair of tetralogy,43 with experimental research showing that acute dilation of the right heart can modify left ventricular performance by a direct effect on load-independent indexes of systolic performance.44 Thus right ventricular dilation may significantly affect left ventricular systolic function.45 In addition, progressive right ventricular enlargement and worsening right bundle branch block may result in increasing ventricular dyssynchrony Indeed, patients with the longest delay between the onsets of contraction of the two ventricles had worse exercise performance and a higher incidence of ventricular arrhythmia.46 Pacing the right ventricle may also improve synchronicity of right