A novel method to capture the onset of dynamic electrocardiographic ischemic changes and its implications to arrhythmia susceptibility

Background-this study investigates the hypothesis that morphologic analysis of intracardiac electrograms provides a sensitive approach to detect acute myocardial infarction or myocardial infarction-induced arrhythmia susceptibility. large proportions of irreversible myocardial injury and fatal ventricular tachyarrhythmias occur in the first hour after coronary occlusion; therefore,early detection of acute myocardial infarction may improve clinical outcomes. methods and results-we developed a method that uses the wavelet transform to delineate electrocardiographic signals,and we have devised an index to quantify the ischemia-induced changes in these signals. we recorded body-surface and intracardiac electrograms at baseline and following myocardial infarction in 24 swine. statistically significant ischemia-induced changes after the initiation of occlusion compared with baseline were detectable within 30 seconds in intracardiac left ventricle (p<0.0016) and right ventricle-coronary sinus (p<0.0011) leads,60 seconds in coronary sinus leads (p<0.0002),90 seconds in right ventricle leads (p<0.0020),and 360 seconds in body-surface electrocardiographic signals (p<0.0022). intracardiac leads exhibited a higher probability of detecting ischemia-induced changes than body-surface leads (p<0.0381),and the right ventricle-coronary sinus configuration provided the highest sensitivity (96%). the 24-hour ecg recordings showed that the ischemic index is statistically significantly increased compared with baseline in lead i,avr,and all precordial leads (p<0.0388). finally,we showed that the ischemic index in intracardiac electrograms is significantly increased preceding ventricular tachyarrhythmic events (p<0.0360). conclusions-we present a novel method that is capable of detecting ischemia-induced changes in intracardiac electrograms as early as 30 seconds following myocardial infarction or as early as 12 minutes preceding tachyarrhythmic events. © 2014 the authors. published on behalf of the american heart association,inc.,by wiley blackwell.