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Digital pulse plethysmography as a non-invasive method for predicting drug-induced changes in left ventricular
E Stengele1, F Winkler, D Trenk
1Department of Clinical Pharmacology, Herz-Zentrum, Bad Krozingen, Germany.
European Journal of Clinical Pharmacology
|January 1, 1996
Summary
Nitroglycerin, not nifedipine, alters digital pulse wave contour, suggesting these changes reflect left ventricular (LV) preload reduction, not just afterload. This study differentiates nitrate actions in coronary artery disease patients.
Area of Science:
- Cardiovascular Pharmacology
- Hemodynamics
- Clinical Medicine
Background:
- Organic nitrates are known to alter digital pulse wave contour.
- The precise hemodynamic mechanism (left ventricular preload vs. afterload reduction) behind these contour changes remains unclear.
Purpose of the Study:
- To differentiate the effects of nitroglycerin and nifedipine on pulse wave contour.
- To determine if observed pulse wave changes are due to left ventricular preload or afterload reduction.
Main Methods:
- 20 coronary artery disease patients received equieffective doses of nitroglycerin or nifedipine.
- Measured aortic and digital pulse wave contours, blood pressure (Riva Rocci), and heart rate.
- Analyzed the a/b ratio of pressure curves.
Main Results:
- Both drugs decreased systolic blood pressure; only nifedipine significantly decreased diastolic blood pressure.
- Heart rate increased with both nitroglycerin and nifedipine.
- The a/b ratio of the digital pulse curve increased significantly after nitroglycerin but not nifedipine.
- Nitroglycerin reduces LV preload and afterload, while nifedipine primarily reduces afterload.
Conclusions:
- Reduced afterload alone does not explain the characteristic peripheral pulse wave contour changes seen with organic nitrates.
- Changes in the a/b ratio of the digital pulse curve are likely indicative of left ventricular preload reduction.