Maximal rate of fall of left ventricular pressure in cardiomyopathy and constrictive pericarditis.

The maximal rate of fall of left ventricular pressure (peak negative dp/dt) was measured in 4 patients with congestive cardiomyopathy (primary myocardial disease), in 5 patients with constrictive pericarditis and in 3 controls. Measurements were made at rest, with leg raising, after a bolus of 6 mug intravenous isoprenaline, and in patients with constrictive pericarditis during pulsus paradoxus. Peak negative dp/dt was 1810 +/- 234 mmHg/sec in controls; it was reduced in patients with constrictive pericarditis (1337 +/- 514 mmHg/sec) and greatly decreased in patients with congestive cardiomyopathy (812 +/- 190 mmHg/sec). There was close linear correlation between resting peak positive and peak negative dp/dt and there was little change with leg raising. Isoprenaline caused an increase in peak positive dp/dt, but there was only a small change in peak negative dp/dt. In patients with constrictive pericarditis, peak negative dp/dt varied during pulsus paradoxus: the linear relationship to peak positive dp/dt was maintained throughout the respiratory cycle. Peak negative dp/dt may be a useful index of myocardial function.