Role of calcium-blocking agents in treatment of cardiac arrhythmias related to myocardial ischemia.
Potential antiarrhythmic effects of calcium (slow-channel)-blocking drugs ca be indirect or direct. The indirect effect would affect ischemia-induced arrhythmias by improving myocardial perfusion or decreasing myocardial oxygen consumption. The direct effect would affect the electrical activity of the sinoatrial (SA) and atrioventricular (AV) nodes and any type of cardiac fibers depolarized to a level at which the slow inward current becomes activated. Although myocardial ischemia could become a setting of slow-channel-dependent conduction or automaticity, or both, there is no conclusive evidence that slow-channel-blocking drugs suppress ischemia-induced ventricular arrhythmias. Thus the principal usefulness of slow-channel-blocking drugs may be expected in the treatment of supraventricular arrhythmias and in the prevention of arrhythmogenic ischemia.
D000818:Animals; D001145:Arrhythmias, Cardiac / Q000188:drug therapy / Q000209:etiology* / Q000503:physiopathology; D001794:Blood Pressure / Q000187:drug effects; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000627:therapeutic use*; D002302:Cardiac Output / Q000187:drug effects; D002417:Cattle; D003327:Coronary Disease / Q000150:complications*; D004285:Dogs; D006801:Humans; D007473:Ion Channels / Q000187:drug effects; D009206:Myocardium / Q000378:metabolism; D010101:Oxygen Consumption; D011690:Purkinje Fibers / Q000502:physiology; D014655:Vascular Resistance / Q000187:drug effects; D014700:Verapamil / Q000627:therapeutic use*
D002121:Calcium Channel Blockers; D007473:Ion Channels; D014700:Verapamil; D002118:Calcium