The role of temperature on the development of oscillatory afterpotentials and triggered activity.

Increasing evidence suggests that calcium dependent oscillatory afterpotentials (OAP) may play a pivotal role in the genesis of reperfusion-induced arrhythmias. Many factors may influence the vulnerability of the heart to reperfusion arrhythmias, some of which may possibly affect the development of OAP. Since intramyocardial temperature changes during ischemia and reperfusion, it may be speculated that the rapid rewarming of the ischemic area during reperfusion favors the development of associated arrhythmias. We thought it important to examine the effects of sudden changes in temperature on OAP and subsequent triggered activity. Evidence is presented that raising the bath temperature from 34 degrees C to 37 degrees C causes a transient increase above the control level of the OAP amplitude, and that if the OAP is large enough to reach the threshold a triggered rhythm ensues. These results suggest that sudden rewarming of calcium overloaded cell (as it happens during reperfusion of the ischemic myocardium) may favor the development of abnormal automaticity due to OAP.