Effect of chronic pressure overload on the maximal rate of pressure fall of the right ventricle.

The maximal rate of fall in right ventricular pressure (negative dp/dt) was evaluated in 34 patients. Eight had normal pulmonary arterial pressure. Seventeen had pulmonary arterial hypertension, and nine had pulmonary arterial hypertension with right ventricular failure. The right ventricular maximal negative dp/dt in patients with normal pulmonary arterial pressure was 170 +/- 20 mm Hg/sec. In patients with pulmonary arterial hypertension not accompanied by right ventricular failure, this value was 670 +/- 60 mm Hg/sec; and in patients with right ventricular failure, it was also 670 +/- 60 mm Hg/sec. This was higher than in control subjects (P less than 0.001). The maximal positive dp/dt was also higher in patients with pulmonary hypertension, regardless of the presence of right ventricular failure. Right ventricular maximal negative dp/dt correlated with right ventricular maximal positive dp/dt (r = 0.72). Right ventricular maximal negative dp/dt in patients who were not in right ventricular failure correlated linearly with pulmonary arterial systolic pressure (r = 0.83) and pulmonary arterial diastolic pressure (r = 0.83). At any level of pulmonary arterial systolic pressure, right ventricular maximal negative dp/dt in patients with right ventricular failure was lower than in patients with the same level of pulmonary arterial hypertension who were not in failure. These observations indicate that right ventricular maximal negative dp/dt is dependent on load. Even in the presence of right ventricular failure, right ventricular maximal negative dp/dt exceeded values in control subjects.