Journal ArticleDOI
Cardiovascular action of verapamil in the dog with particular reference to myocardial contractility and atrioventricular conduction
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It is suggested that clinical doses of verapamil cause peripheral vasodilation which leads to a sympathetic reflex induced increase in heart rate and myocardial contractility and this effect was partly mediated through cholinergic stimulation and partly through a direct depression on atrioventricular conduction.Abstract:
Verapamil (Isoptin®) caused a dose-dependent peripheral vasodilation, increase in myocardial contractility, and tachycardia in the anaesthetized dog. Propranolol pre-treatment blocked the cardiac stimulation following verapamil but the vasodilation was unaltered. Inflation of a thoracic aortic balloon prevented the fall in intravascular pressure and reduced the tachycardia and positive inotropic responses. These experiments suggest that clinical doses of verapamil cause peripheral vasodilation which leads to a sympathetic reflex induced increase in heart rate and myocardial contractility. Verapamil also had a direct myocardial depressant action which became evident at doses above the range used clinically. The drug increased the PR interval in conscious dogs for up to 60 minutes. This effect was partly mediated through cholinergic stimulation and partly through a direct depression on atrioventricular conduction.read more
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Journal ArticleDOI
Verapamil: A Review of its Pharmacological Properties and Therapeutic Use
TL;DR: Experimental and clinical data suggest that verapamil will become an important and safe addition to existing drug regimens, especially as an agent of choice for the short-term treatment of most cases of paroxysmal supraventricular tachycardias and in the maintenance of sinus rhythm following cardioversion of atrial fibrillation.
Journal ArticleDOI
New antiarrhythmic agents: amiodarone, aprindine, disopyramide, ethmozin, mexiletine, tocainide, verapamil.
Douglas P. Zipes,Paul J. Troup +1 more
TL;DR: The present status, clinical experience, side effects, clinical pharmacology and electrophysiologic actions of seven new antiarrhythmic agents are reviewed.
Journal ArticleDOI
Wide Complex Tachycardia: Misdiagnosis and Outcome After Emergent Therapy
TL;DR: The extent and consequence of misdiagnosis of wide complex tachycardia (QRS, 120 ms or more; heart rate, 100 or more beats/min) presenting emergently were assessed and Verapamil is commonly administered in these circumstances and is frequently associated with a poor outcome.
Journal ArticleDOI
Influence of severity of ventricular dysfunction on hemodynamic responses to intravenously administered verapamil in ischemic heart disease
Christopher Y.C. Chew,Christopher Y.C. Chew,Harvey S. Hecht,Harvey S. Hecht,John T. Collett,John T. Collett,R.G. McAllister,Bramah N. Singh,Bramah N. Singh +8 more
TL;DR: In patients with cardiac disease having a mild to moderate decrease in left ventricular ejection fraction accompanied by a normal or mildly elevated mean pulmonary capillary wedge pressure, the intrinsic depressant effect of verapamil is offset almost entirely by its potent vasodilator proporties.
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