[Systolo-diastolic events in mitral stenosis]

Left ventricular contractility and relaxation in mitral stenosis are still controversial. 20 patients with pure mitral stenosis in sinus rhythm have been studied during diagnostic cardiac catheterization with high fidelity pressure and output recording at rest (R), during dynamic exercise (E), handgrip (HG), methoxamine infusion (M) and amyl nitrite inhalation (AN). - The results were as follows: Mitral valve area was 1.2 +/- 0.4 cm2 and did not change during interventions. LV end-diastolic volume were 106.3 +/- 19.6 ml and ejection fraction 66.5 +/- 3.2%. The mitral valve opening occurred irrespective of interventions 37 +/- 2 msec after left ventricular and left atrial pressure crossover. The mitral valve opening was followed by left ventricular negative pressure of -4.6 +/- 1 mm Hg, suggesting active left ventricular suction. This negative protodiastolic pressure was accentuated by the premature ventricular beat (-7.2 +/- 2.0 mm Hg), AN (-7.4 +/- 1.8 mm Hg) and M infusion (-7.4 +/- 1.2 mm Hg). Closure of the mitral valve occurred 10-15 msec after left ventricular and left atrial pressure crossover, and thus the first part of left ventricular contraction is "non-isovolumic". The LV-LA diastolic pressure gradient at R (15 +/- 7 mm Hg) rose during AN (20 +/- 7.8 mm Hg) and E (28 +/- 8 mm Hg) and remained unchanged during M (15 +/- 6 mm Hg). LV end-diastolic pressure was normal (6.5 +/- 2.4 mm Hg), unchanged during E (6.6 +/- 2.7 mm Hg), diminished during AN (3.6 +/- 1.3 mm Hg) and rose during M (16 +/- 5.8 mm Hg). The peak rate of rise of LV pressure (max dP/dt) was a little low at R (1163 +/- 236 mm Hg/sec) but rose normally on E (1860 +/- 503 mm Hg/sec) and did not change on M (1177 +/- 180 mm Hg/sec), suggesting normal systolic function.