Left ventricular unloading with calcium antagonists.
Calcium channel blockers reduce the arterial smooth muscle tone and lower blood pressure. They may be regarded as left ventricular unloading agents. Left ventricular unloading efficacy of nifedipine (15 cases) and verapamil (14 cases) was tested in hypertensive decompensated patients, through one-month treatment period. Nifedipine persistently reduced systemic vascular resistance, mean arterial pressure, mean pulmonary wedge pressure and left ventricular diastolic diameter and improved cardiac index and velocity of circumferential fiber shortening. All of the patients had relief from dyspnea and reduction in heart size. The only side effect was ankle edema in 6 cases. Verapamil reduced systemic vascular resistance and mean arterial pressure and was not effective on mean pulmonary wedge pressure, left ventricular diastolic diameter and velocity circumferential fiber shortening. The drug was discontinued in 2 patients who developed severe dyspnea at rest after a 3-4 day continued oral treatment. Clinical symptoms and signs did not improve in the remaining subjects despite persistent pressure reduction. A less potent vasodilating action of verapamil and a prominent depression in cardiac contractility may account for the different results with the two compounds, in spite of a shared vasodilating antihypertensive effect. These findings prove that functional changes in the failing hypertensive heart may differ from one calcium blocker to another as a result of interaction and relative preponderance of influences on afterload and contractility.
D002302:Cardiac Output / Q000187:drug effects; D006332:Cardiomegaly / Q000188:drug therapy; D004341:Drug Evaluation; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D006973:Hypertension / Q000188:drug therapy / Q000503:physiopathology*; D009200:Myocardial Contraction / Q000187:drug effects; D009543:Nifedipine / Q000494:pharmacology*; D013318:Stroke Volume / Q000187:drug effects; D014655:Vascular Resistance / Q000187:drug effects; D014700:Verapamil / Q000494:pharmacology*
D014700:Verapamil; D009543:Nifedipine