[Contractile and relaxation reserve of the left ventricle. III. Patients with cardiomyopathy (author's transl)].

Seven of 22 patients with cardiomyopathy increased maximal rate of left ventricular pressure rise (max dP/dt) above 3200 mm Hg/s and dP/dt/P above 60/s. Relaxation reserve was normal with an increase of min dP/dt above 2400 mm Hg/s.--In 15 patients contractile and relaxation reserve was reduced. In congestive cardiomyopathy, contractility and relaxation reserve were equally reduced. Left ventricular enddiastolic pressure increased during exercise slightly or not (grade 1). Enddiastolic volume was elevated to 173 +/- 50 ml/1.73 m2 and endsystolic volume to 63 +/- 22 ml/1.73 m2; ejection fraction and mean circumferential fiber shortening were reduced (61 +/- 17%; 1.3 +/- 0.9 circ/s). In hypertrophic cardiomyopathy without obstruction, contractile and relaxation reserve and ejection phase parameters could be found to be normal. Enddiastolic pressure at rest was elevated. In severe cases, contractile and relaxation reserve were markedly reduced and enddiastolic pressure increased to a greater extent than in congestive cardiomyopathy. In addition, relaxation reserve was reduced, especially in patients with excessive hypertrophy of the myocardium. These had abnormal (grade 2) and pathological reaction to exercise: contractile and relaxation reserve were decreased and enddiastolic pressure (grade 3) increased. Left ventricular contractility was found to be almost normal in patients with hypertrophic obstructive cardiomyopathy. This was the case despite increases in enddiastolic pressure. Contractile reserve was reduced, however, in patients with excessive hypertrophy. Diastolic filling was impeded during exercise.--Measuring left ventricular function during exercise, different types of cardiomyopathy correlate with typical hemodynamic alterations.