cardiovascular disorders
Mitral Valve Prolapse (MVP)
Symptoms and Signs of Mitral Valve Prolapse
Most patients with mitral valve prolapse are asymptomatic. Some experience nonspecific symptoms (eg, chest pain, dyspnea, palpitations, dizziness, near syncope, migraines, anxiety) thought to be due to poorly defined associated abnormalities in adrenergic signaling and sensitivity rather than to mitral valve pathology. In about one third of patients, emotional stress precipitates palpitations, which may be a symptom of benign arrhythmias ( Atrial premature beats , paroxysmal atrial tachycardia, Occasionally, patients present with Mitral Regurgitation . Rarely, patients present with Other physical findings associated with but not diagnostic of MVP include hypomastia, pectus excavatum, hypokyphosis (eg, straight back syndrome), and a narrow anteroposterior chest diameter. Crisp mid-systolic click Typically, mitral valve prolapse causes no visible or palpable cardiac signs. MVP alone often causes a crisp mid-systolic click as the subvalvular apparatus abruptly tightens. The click is heard best with the diaphragm of the stethoscope over the left apex when the patient is in the left lateral decubitus position. MVP with MR causes a click with a late-systolic MR murmur. The click moves closer to the first heart sound (S1) with maneuvers that decrease left ventricle (LV) size (eg, sitting, standing, Valsalva maneuver); the same maneuvers cause an MR murmur to appear or become louder and last longer. These effects occur because decreasing LV size causes papillary muscles and chordae tendineae to pull together more centrally beneath the valve, resulting in quicker, more forceful prolapse with earlier, more severe regurgitation. Conversely, squatting or isometric handgrip delays the S1 click and shortens the MR murmur. The systolic click may be confused with the click of congenital aortic stenosis; the latter may be distinguished because it occurs very early in systole and does not move with postural or LV volume changes. Other findings include a systolic honk or whoop, thought to be caused by valvular leaflet vibration; these findings are usually transient and may vary with respiratory phase. An early diastolic opening snap caused by return of the prolapsed valve to its normal position is rarely heard. In some patients, especially children, the findings of MVP may be more noticeable after exertion. 