Hemodynamic effects of nifedipine in patients with asymptomatic aortic regurgitation: evaluation by Doppler echocardiography.

Abstract

Nineteen asymptomatic patients affected by isolated chronic aortic regurgitation received 20 mg of nifedipine sublingually: the acute hemodynamic effects of nifedipine were evaluated by combined cross-sectional and Doppler echocardiography. To assess variations in the regurgitant flow volume, the flow volume across the mitral and aortic valves was calculated as the product of velocity-time integral multiplied by the orifice valve area. Flow volume across these valves represented the total stroke volume, and forward stroke volume, respectively: the regurgitant volume was obtained by calculating the difference between total and forward stroke volume. Nifedipine induced a redistribution of the two components of the total left ventricular stroke volume: regurgitant stroke volume decreased from 57 +/- 22 ml/beat to 46 +/- 21 ml/beat (P < 0.002), while forward stroke volume increased from 83 +/- 12 to 93 +/- 15 ml/beat (P < 0.0005), as a consequence of the reduction in systemic vascular resistance from 1513 +/- 378 to 1092 +/- 307 dynes.sec.cm-5 (P < 0.0001). The reduction of regurgitant volume was due to either a 24.8% decrease of the aortic-left ventricular mean pressure gradient during diastole (P < 0.008) or a 6% decrease of the diastolic time interval (P < 0.04). The effect of these acute changes on left ventricular loading was to induce a reduction in oxygen consumption which was expressed by a decrease in the double product (from 10176 +/- 1767 to 9444 +/- 1559 mmHg.beats/min; P < 0.002), in spite of a significant increase in heart rate. This study, therefore, shows the beneficial acute hemodynamic effect induced by nifedipine in asymptomatic patients affected by chronic aortic regurgitation and shows that Doppler-echocardiography is a useful instrument for the evaluation of hemodynamic changes immediately after the administration of drugs.

• Authors: F Gentile, M Ornaghi, D Esposti, M O Triulzi
• Journal: Acta cardiologica (Acta Cardiol) Vol. 48 Issue 5 Pg. 495-506 ( 1993) ISSN: 0001-5385 [Print] England
• PMID: 8284990 (Publication Type: Journal Article)

Chemical References

• Nifedipine

Topics

• Administration, Sublingual
• Adolescent
• Adult
• Aged
• Aortic Valve Insufficiency (diagnostic imaging, drug therapy)
• Blood Flow Velocity (drug effects, physiology)
• Dose-Response Relationship, Drug
• Echocardiography
• Echocardiography, Doppler (drug effects)
• Female
• Hemodynamics (drug effects, physiology)
• Humans
• Image Processing, Computer-Assisted
• Male
• Middle Aged
• Nifedipine (administration & dosage, adverse effects)