Case records of the Massachusetts General Hospital. Weekly clinicopathological exercises. Case 7-1981

Abnormal chordal insertion: a cause of mitral valve prolapse

Although the morphology of mitral valve prolapse (MVP) has been described, abnormalities of chordal arrangement and insertion have not been emphasized. We retrospectively reviewed 23 surgically-excised MVP and 10 control mitral valves removed at necropsy. Two-dimensional echocardiograms (2DE) were available in 10 MVP and in six additional controls. 2DE accurately assessed the length of anterior leaflet (AL) and posterior leaflet (PL) of the mitral valve (3.2 +/- 0.7 cm and 2.2 +/- 0.6 cm, respectively) as compared to morphologic measurements (3.0 +/- 0.4 cm and 2.1 +/- 0.4 cm, respectively). However, annular diameter as assessed by echocardiography was significantly less (4.6 +/- 0.7 cm) than that derived by morphologic measurements of annular circumference (AC) (5.3 +/- 0.7 cm). The AL and PL lengths and the mitral anuli were significantly larger in patients with MVP as compared to controls (p less than 0.01) when assessed both by 2DE and by morphology. The ratio of the maximum distance of chordal separation/AC was 0.11 +/- 0.04 in MVP and 0.13 +/- 0.02 in controls (p less than 0.05). Chordal divisions were increased in MVP (4.2) compared to controls (3.1, p less than 0.01). The most striking morphologic feature of MVP was abnormal chordal insertion and a random, unpredictable pattern of chordal distribution. We postulate that abnormal chordal architecture may be responsible for unequal stress on the valve leaflets and may thus lead to MVP.

Flail mitral valve syndrome: comparison with chronic mitral regurgitation of other etiologies

Thirty-nine patients with symptomatic severe mitral regurgitation (MR) were studied by cardiac catheterization and two-dimensional echocardiography (2DE) prior to mitral valve replacement. A flail mitral valve was found at surgery in 23 patients (group 1); 16 patients had intact chordae tendineae (chronic MR, group 2). No difference was found between groups 1 and 2 with regard to hemodynamic findings. Left atrial volumes in end systole (LAESV) and end diastole (LAEDV) were determined by 2DE from apical four- and two-chamber views with the use of a biplane area-length method and a light pen system. The LAESV and LAEDV measured 116 +/- 66 ml and 56 +/- 48 ml, respectively, in group 1, as compared with 185 +/- 101 ml and 105 +/- 62 ml in group 2 (p less than 0.025). Ten patients from group 1 with LAESV less than or equal to 100 ml (group 1A) were compared to the remaining 13 patients with LAESV greater than 100 ml (group 1B). Patients in group 1A had significantly smaller left ventricular volume and higher mean pulmonary wedge pressure, pulmonary artery, and left ventricular end-diastolic pressure compared to patients in groups 1B and 2 (p less than 0.05). Thus, a subset group of patients with flail mitral leaflets and smaller LAESV has hemodynamic features of acute MR, whereas the remainder with larger LAESV are indistinguishable from patients with chronic MR.

The Mitral Valve Prolapse Syndrome in Athletes

In brief The mitral valve prolapse syndrome is prevalent in apparently normal people, including athletes. Symptoms, when present, range from chest pain and palpitations to anxiety neurosis. The typical finding on auscultation of the heart is a midsystolic click and/or a mid-to-late systolic high-frequency murmur. Cardiac arrhythmias are common and often do not require therapy. The exercise ECG shows ST segment depression in up to one fourth of patients. When drug therapy is necessary, beta blockers are usually selected. The overall prognosis is excellent. Sudden death, infectious endocarditis, and cerebral thromboembolic events are relatively rare.