Abstract 4122: What is the Effect of Amiodarone on Cardiac Memory? A Prospective Cohort Study
Post pacing induced T-wave inversion after resumption of normal ventricular activation is known as cardiac memory. Animal studies have shown that the transient outward current Ikto and L-type calcium channels are altered in cardiac memory. We hypothesize that pacing induced cardiac memory is modified by amiodarone due to its I kto and L-type calcium channel blocking effects. We conducted a prospective cohort evaluation of paced patients at a single institution. Patients were excluded if they were pacemaker dependant or had underlying bundle branch block. All eligible patients had a pacemaker-inhibited standard 12-lead electrocardiogram after informed consent and collection of basic demographic information. Patients who were receiving amiodarone (n=11) at the time of pacemaker interrogation were compared to a control group of patients that were not taking amiodarone (n=28). Cardiac memory was deemed to be present if T-wave inversions were observed in any pre-cordial or inferior lead (V1-V6, II, III, and AVF). Univariate statistics were used to compare both the incidence of cardiac memory and the mean number of cardiac memory leads. Seven patients receiving and 27 patients not receiving amiodarone exhibited cardiac memory (63.6% vs. 96.4%; p=0.02†). (See Table⇓) In addition, patients receiving amiodarone had cardiac memory observed in significantly fewer pre-cordial or inferior leads (2.91 vs. 5.18; p=0.02†) Amiodarone appears to be associated with attenuation of pacing induced cardiac memory.