title: A novel method to capture the onset of dynamic electrocardiographic ischemic changes and its implications to arrhythmia susceptibility.
abstract: 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.
  
  
  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.
authors.affiliation: Division of Cardiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA (O.S., D.P., N.I., R.D., A.A.A.).
authors.forename: Omid
authors.initials: O
authors.lastname: Sayadi
authors.affiliation: Division of Cardiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA (O.S., D.P., N.I., R.D., A.A.A.).
authors.forename: Dheeraj
authors.initials: D
authors.lastname: Puppala
authors.affiliation: Division of Cardiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA (O.S., D.P., N.I., R.D., A.A.A.).
authors.forename: Nosheen
authors.initials: N
authors.lastname: Ishaque
authors.affiliation: Division of Cardiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA (O.S., D.P., N.I., R.D., A.A.A.).
authors.forename: Rajiv
authors.initials: R
authors.lastname: Doddamani
authors.affiliation: Cardiology Division, Emory University School of Medicine, Atlanta, GA (F.M.M.).
authors.forename: Faisal M
authors.initials: FM
authors.lastname: Merchant
authors.affiliation: Division of Cardiology, Cardiac Arrhythmia Service, Massachusetts General Hospital, Boston, MA (C.B., J.P.S., K.H., T.M.).
authors.forename: Conor
authors.initials: C
authors.lastname: Barrett
authors.affiliation: Division of Cardiology, Cardiac Arrhythmia Service, Massachusetts General Hospital, Boston, MA (C.B., J.P.S., K.H., T.M.).
authors.forename: Jagmeet P
authors.initials: JP
authors.lastname: Singh
authors.affiliation: Division of Cardiology, Cardiac Arrhythmia Service, Massachusetts General Hospital, Boston, MA (C.B., J.P.S., K.H., T.M.).
authors.forename: E Kevin
authors.initials: EK
authors.lastname: Heist
authors.affiliation: Division of Cardiology, Cardiac Arrhythmia Service, Massachusetts General Hospital, Boston, MA (C.B., J.P.S., K.H., T.M.).
authors.forename: Theofanie
authors.initials: T
authors.lastname: Mela
authors.affiliation: Biomedical Signal Interpretation & Computational Simulation (BSICoS) Group, Aragon Institute of Engineering Research, IIS Aragón, University of Zaragoza, Zaragoza, Aragon, Spain (J.P.M., P.L.) Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Zaragoza, Aragon, Spain (J.P.M., P.L.).
authors.forename: Juan Pablo
authors.initials: JP
authors.lastname: Martínez
authors.affiliation: Biomedical Signal Interpretation & Computational Simulation (BSICoS) Group, Aragon Institute of Engineering Research, IIS Aragón, University of Zaragoza, Zaragoza, Aragon, Spain (J.P.M., P.L.) Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Zaragoza, Aragon, Spain (J.P.M., P.L.).
authors.forename: Pablo
authors.initials: P
authors.lastname: Laguna
authors.affiliation: Division of Cardiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA (O.S., D.P., N.I., R.D., A.A.A.).
authors.forename: Antonis A
authors.initials: AA
authors.lastname: Armoundas
mesh_terms: D000818:Animals; D018780:Body Surface Potential Mapping / Q000379:methods*; D004195:Disease Models, Animal; D018450:Disease Progression; D042241:Early Diagnosis; D004562:Electrocardiography / Q000379:methods; D015716:Electrocardiography, Ambulatory / Q000379:methods*; D008297:Male; D017202:Myocardial Ischemia / Q000175:diagnosis*; D011897:Random Allocation; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted; D013552:Swine; D017180:Tachycardia, Ventricular / Q000175:diagnosis*; D013997:Time Factors
keywords: ECG delineation; intracardiac signals; ischemic index; myocardial infarction; wavelet transform