THE SYMPTOMS, when present, are generally those of left ventricular outflow obstruction, namely, dyspnea, syncope, angina, and palpitations. It is not uncommon to see a patient for evaluation of a murmur detected during a routine examination.
Clinical Features
Dyspnea.—
Effort dyspnea and paroxysmal nocturnal dyspnea constitute the most common symptoms and represent evidence of pulmonary congestion. Because elevations in pulmonary venous and left atrial pressures occur in the face of a hyperdynamic, hypercontractile left ventricle, these must necessarily be attributed to reduced compliance of the ventricle. In some patients, especially those with volume overload, frank pulmonary edema may be noted.
Syncope and Dizziness.—
Frank syncope and dizziness short of loss of consciousness (presyncope) are common. These are generally effort related although not predictably so.The frequency of the episodes is highly variable. The exact mechanism is obscure; however, it is probably related to reflex vasodilation and hypotension induced by stretching