Fundamental differences in electrophysiologic and electroanatomic substrate between ischemic cardiomyopathy patients with and without clinical ventricular tachycardia.

OBJECTIVES The aim of this study was to compare the electrophysiologic substrate in ischemic cardiomyopathy (ICM) patients with and without sustained monomorphic ventricular tachycardia (SMVT). BACKGROUND Despite the universal presence of potentially arrhythmogenic left ventricular (LV) scarring, it is not clear why the majority of ICM patients never develop SMVT. METHODS Detailed electroanatomic mapping of the LV endocardium was performed in 17 stable control ICM patients (16 males) without clinical SMVT. They were compared with 17 ICM patients (15 males) with spontaneous SMVT. Standard definitions of low-voltage zones and fractionated, isolated, and very late potentials were used. RESULTS There were no significant baseline differences between the groups in terms of LV diameter, ejection fraction (27% vs. 28%), infarct territory, or time from infarction. However, control patients had smaller total low-voltage area < or =1.5 mv (30% of surface area vs. 55%, p < 0.001); smaller very low-voltage area <0.5 mv (7.3% vs. 29%, p < 0.001); higher mean voltage of low-voltage zones; fewer fractionated, isolated, and very late potentials with lower density of these scar-related electrograms per unit low-voltage area; and less SMVT inducibility. Potential conducting channels within dense scar and adjacent to the mitral annulus were more frequent in SMVT patients. CONCLUSIONS Compared with ICM patients with SMVT, an otherwise similar control group demonstrated markedly smaller endocardial low-voltage zones, lower scar-related electrogram density, and fewer conducting channels with faster conduction velocity. These findings may explain why some ICM patients develop SMVT and others do not.

[1]  W. Stevenson,et al.  Characterization of the Peri-Infarct Zone by Contrast-Enhanced Cardiac Magnetic Resonance Imaging Is a Powerful Predictor of Post–Myocardial Infarction Mortality , 2006, Circulation.

[2]  D. Wilber,et al.  Catheter ablation of the mitral isthmus for ventricular tachycardia associated with inferior infarction. , 1995, Circulation.

[3]  E. Negri,et al.  Incidence and short-term prognosis of late sustained ventricular tachycardia after myocardial infarction: results of the Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico (GISSI-3) Data Base. , 2001, American heart journal.

[4]  Gerhard Hindricks,et al.  Catheter Ablation of Ventricular Tachycardia in Remote Myocardial Infarction: , 2003, Journal of cardiovascular electrophysiology.

[5]  Mercedes Ortiz,et al.  Ablation of electrograms with an isolated, delayed component as treatment of unmappable monomorphic ventricular tachycardias in patients with structural heart disease. , 2003, Journal of the American College of Cardiology.

[6]  Mercedes Ortiz,et al.  Tachycardia-Related Channel in the Scar Tissue in Patients With Sustained Monomorphic Ventricular Tachycardias: Influence of the Voltage Scar Definition , 2004, Circulation.

[7]  F. Marchlinski,et al.  Linear ablation lesions for control of unmappable ventricular tachycardia in patients with ischemic and nonischemic cardiomyopathy. , 2000, Circulation.

[8]  W. Stevenson,et al.  Catheter Ablation in Patients With Multiple and Unstable Ventricular Tachycardias After Myocardial Infarction: Short Ablation Lines Guided by Reentry Circuit Isthmuses and Sinus Rhythm Mapping , 2001, Circulation.

[9]  Warren M. Jackman,et al.  Irrigated Radiofrequency Catheter Ablation Guided by Electroanatomic Mapping for Recurrent Ventricular Tachycardia After Myocardial Infarction: The Multicenter Thermocool Ventricular Tachycardia Ablation Trial , 2008, Circulation.

[10]  S M Dillon,et al.  Electroanatomic left ventricular mapping in the porcine model of healed anterior myocardial infarction. Correlation with intracardiac echocardiography and pathological analysis. , 1999, Circulation.

[11]  J M de Bakker,et al.  Reentry as a cause of ventricular tachycardia in patients with chronic ischemic heart disease: electrophysiologic and anatomic correlation. , 1988, Circulation.

[12]  J A Vassallo,et al.  Effect of subendocardial resection on sinus rhythm endocardial electrogram abnormalities. , 1995, Circulation.

[13]  Frank Bogun,et al.  Isolated potentials during sinus rhythm and pace-mapping within scars as guides for ablation of post-infarction ventricular tachycardia. , 2006, Journal of the American College of Cardiology.

[14]  J. Ruskin,et al.  Short-term results of substrate mapping and radiofrequency ablation of ischemic ventricular tachycardia using a saline-irrigated catheter. , 2003, Journal of the American College of Cardiology.

[15]  R. Ideker,et al.  Quantitative analysis of myocardial infarct structure in patients with ventricular tachycardia. , 1986, Circulation.

[16]  David O. Martin,et al.  Relationship Between Successful Ablation Sites and the Scar Border Zone Defined by Substrate Mapping for Ventricular Tachycardia Post‐Myocardial Infarction , 2005, Journal of cardiovascular electrophysiology.

[17]  Douglas L Packer,et al.  Amiodarone or an implantable cardioverter-defibrillator for congestive heart failure. , 2005, The New England journal of medicine.

[18]  D. Lin,et al.  Anatomic characterization of endocardial substrate for hemodynamically stable reentrant ventricular tachycardia: identification of endocardial conducting channels. , 2006, Heart rhythm.

[19]  William H. Maisel,et al.  Catheter Ablation in Patients With Multiple and Unstable Ventricular Tachycardias After Myocardial Infarction Short Ablation Lines Guided by Reentry Circuit Isthmuses and Sinus Rhythm Mapping , 2002 .

[20]  W. Stevenson,et al.  Preferential Locations for Critical Reentry Circuit Sites Causing Ventricular Tachycardia After Inferior Wall Myocardial Infarction , 1997, Journal of cardiovascular electrophysiology.

[21]  Capelle,et al.  Slow conduction in the infarcted human heart. 'Zigzag' course of activation. , 1993, Circulation.

[22]  I Wiener,et al.  Determinants of Ventricular Tachycardia in Patients with Ventricular Aneurysms: Results of Intraoperative Epicardial and Endocardial Mapping , 1982, Circulation.

[23]  J A Vassallo,et al.  Endocardial catheter mapping in patients in sinus rhythm: relationship to underlying heart disease and ventricular arrhythmias. , 1986, Circulation.