Exertional syncope suggests cardiac outflow tract obstruction, mainly due to aortic stenosis. This syncope reflects cerebral ischemia caused by the simultaneous dilatation of peripheral vessels due to the inability to increase cardiac output during exertion. Prolonged syncope can cause seizures. Hypovolemia and positive inotropic drugs (e.g., digitalis) can worsen outflow tract obstruction in patients with hypertrophic obstructive cardiomyopathy, and syncope may occur suddenly. Syncope often occurs immediately after exercise and is caused by decreased venous return, reduced left atrial pressure, and reduced ventricular filling. Cardiac arrhythmias may also play a role. Abnormal function after heart valve replacement may also be a cause. Exertional syncope can also result from other causes of outflow tract obstruction (e.g., pulmonary vascular obstruction or pulmonary hypertension due to pulmonary embolism), as well as from decreased left ventricular filling or pericardial tamponade due to decreased left ventricular compliance, or obstructed venous return (e.g., severe pulmonary hypertension or tricuspid stenosis, intracardiac mucinous aneurysm). Mucinous tumors can cause postural syncope due to obstruction of the mitral valve opening by a tipped left atrial mucinous tumor. Coughing and urination can cause syncope due to decreased venous return. Syncope can also occur during Valsalva maneuvers, where increased intrathoracic pressure restricts venous return, resulting in decreased cardiac output and a decrease in systemic arterial pressure. What are the possible causes of exertional syncope? 1, Cardiac outflow tract obstruction, aortic valve stenosis. 2.Decreased venous return, reduced left atrial pressure and reduced ventricular filling. 3, Abnormal function after heart valve replacement may also be the cause. 4.Other causes of outflow tract obstruction (such as pulmonary vascular obstruction or pulmonary hypertension due to pulmonary embolism), as well as left ventricular underfilling or pericardial tamponade due to decreased left ventricular compliance, or obstructed venous return (such as severe pulmonary hypertension or tricuspid stenosis, intracardiac mucinous aneurysm).