... 5. Myocardial disease (massive acute myocardial infarction) Chapter 021. Syncope (Part 1) Harrison's Internal Medicine > Chapter 21. Syncope Syncope: Introduction Syncope, a transient ... disorders including obstructive lesions and cardiac arrhythmias, or cerebrovascular disease (Table 21 -1). Not infrequently, however, the cause of syncope is multifactorial. Table 21-1 Causes of Syncope ... results in syncope. Normally, the pooling of blood in the lower parts of the body is prevented by (1) pressor reflexes that induce constriction of peripheral arterioles and venules, (2) reflex...