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Henry Ford Hospital Medical Journal

Abstract

Sound within the pulmonary artery was measured in 24 patients to determine if right ventricular failure modifies the amplitude of the pulmonary component of the second sound (P2). The amplitude of P2 in eight patients with right ventricular failure secondary to pulmonary hypertension (2610 ± 370 dynes/cm2) did not differ from P2 in eight patients with pulmonary hypertension not accompanied by right ventricular failure (3120 ± 710 dynes/cm2). In both groups, the amplitude of P2 exceeded control subjects (520 ± 70 dynes/cm2) (P < .001 and P < .01, respectively). The maximal rate of development of the pressure gradient across the closed pulmonary valve was higher in patients with right ventricular failure (580 ± 100 mm Hg/sec) than in control subjects (150 ± 30 mm Hg/sec) (P < .001) and maximal negative dp/dt was also higher in patients with failure (750 ± 70 mm Hg/sec vs 190 ± 20 mm Hg/sec) (P < .001). The maximal rate of change of the diastolic pressure gradient correlated linearly with maximal negative dp/dt (r=.89). These observations indicate that P2 is accentuated in patients with right ventricular failure secondary to pulmonary hypertension. The accentuation results from the augmented rate of development of the diastolic pressure gradient, which reflects an augmented right ventricular negative dp/dt. Therefore, an accentuated P2 remains valid as a clinical sign of pulmonary hypertension whether or not right ventricular failure occurs.

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