Calcium repletion-induced arrhythmias after short periods of calcium-free perfusion in the isolated rat heart.
The occurrence of arrhythmias was studied in the "calcium-paradox" model in the isolated rat heart. Clear relationships were found between the duration of calcium-free perfusion and (a) the occurrence of calcium-free-induced electrophysiological changes, (b) the incidence and duration of subsequently induced calcium-repletion arrhythmias and (c) mechanical recovery at the end of the repletion period. The first signs of electrophysiological changes (i.e. decreased heart rate, T-wave amplitude and increased PQ-interval) and irreversible loss of myocardial recovery occurred during or after 60-90 s of calcium-free perfusion. The occurrence of calcium-repletion induced ventricular tachycardia parallelled this onset of irreversible cardiac injury. These results suggest that the process of calcium washout and subsequent sudden calcium overloading may play a role as a trigger in the pathogenesis of ventricular arrhythmias.
D000818:Animals; D001145:Arrhythmias, Cardiac / Q000209:etiology* / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D003326:Coronary Circulation; D003327:Coronary Disease / Q000150:complications; D008297:Male; D009200:Myocardial Contraction; D009206:Myocardium / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D013610:Tachycardia / Q000209:etiology
D002118:Calcium