EARLY CHANGES IN SYSTOLIC AND DIASTOLIC F UNCTION AT REST AND UNDER EXERCISE IN PATIENTS WITH HYPERTROPHIC CARDIOMYOPATHY (HOCM) AFTER MYECTOMY

Introduction: In this study systolic and diastolic function in patient s with hypertrophic obstructive cardiomyopathy (HOCM) and intractable complaints to medication were investigated before and after a mean of 7 months after myectomy. Methods: Investigations in 19 patients with H OCM included echocardiography, Swan-Ganz-thermodilution-catheter and r adionuclide-angiography. Results: Myectomy resulted in a reduction of the intraventricular gradient at rest (40.1 +/- 43.3 versus 7.6 +/- 12 .0 mm Hg, p less than or equal to 0.005) and under provocation (92.4 /- 67.1 versus 21.3 +/- 26.5 mm Hg, p less than or equal to 0.001). Ec hocardiographically determined basal septal thickness was reduced (24. 9 +/- 6.3 versus 20.1 +/- 6.8 mm; p less than or equal to 0.05) and di astolic diameter increased (40.4 +/- 5.2 versus 44.8 +/- 7.1; p less t han or equal to 0.05). Exercise tolerance increased from the maximally achieved 64.5 +/- 19.2 to 89.5 +/- 24.0 W (p less than or equal to 0. 001). Symptomatic status (NYHA) improved (1.7 +/- 1.4 versus 2.8 +/- 0 .3 (p less than or equal to 0.001). Systolic parameters showed at rest an increase in isovolumetric contraction time (65 +/- 39 versus 112 /- 50 ms, p less than or equal to 0.01), in time to peak ejection (109 +/- 40 versus Iss +/- 42 ms, p less than or equal to 0.001), and a re duced left ventricular ejection fraction (72 +/- 12 versus 64 +/- 11%, p less than or equal to 0.01). Analysis of regional ejection fraction revealed a significant reduction of ejection fraction in the basal se ptal region (p less than or equal to 0.05). Increase of global and reg ional ejection fraction under exercise was still preserved. Mean pulmo nary capillary wedge pressure was significantly reduced at rest(11.8 /- 3.8 versus 8.6 +/- 2.4 mm Hg, p less than or equal to 0.05) as well as under exercise (27.0 +/- 7.1 versus 20.4 +/- 6.8 mm Hg, p less tha n or equal to 0.01), whereas left ventricular enddiastolic volume inde x (63 +/- 19 versus 72 +/- 17 ml m(-2), p less than or equal to 0.05 ) was significantly increased. Conclusions: In patients with HOCM, mye ctomy reduces intraventricular gradient, increases exercise capacity, and is accompanied by improved diastolic function parameters, while sy stolic function parameters are generally reduced.