[Hemodynamically-induced syncope]

Hemodynamic syncope is caused by an impediment to a necessary increase of the cardiac output; therefore, hemodynamic syncopes most often occur during or shortly after exercise. However, a syncope at rest does not exclude a hemodynamic cause. Moreover, arrhythmias which may directly lead to syncope or accentuate the hemodynamic impediment are often present in cardiac diseases causing hemodynamic syncope. Hemodynamic syncopes are responsible for 2 to 3% of all syncopes leading to medical evaluation. Of these, more than half are caused by aortic stenosis and about one quarter by pulmonary embolism. Other reasons are rare. Hypertrophic cardiomyopathy is more often associated with arrhythmic than with hemodynamic syncope. Syncope in primary pulmonary hypertension is often preceded by dizziness, epigastric distress and faintness. Since the medical therapy may lead to hemodynamic deterioration, it must be started under invasive observation. Primary tumors of the heart are rare; secondary cardiac neoplasms are 6 to 40 times more common. Myxoma is the most common primary tumor of the heart. It is important to promptly undertake surgery in order to improve prognosis. Various other diseases may provoke hemodynamic syncope; however, other symptoms are by far more common.