Author + information
- Received October 19, 2009
- Revision received January 5, 2010
- Accepted January 11, 2010
- Published online May 25, 2010.
- Shiro Nakahara, MD, PhD,
- Roderick Tung, MD,
- Rafael J. Ramirez, PhD,
- Yoav Michowitz, MD,
- Marmar Vaseghi, MD,
- Eric Buch, MD,
- Jean Gima, RN, MN, NP,
- Isaac Wiener, MD,
- Aman Mahajan, MD, PhD,
- Noel G. Boyle, MD, PhD and
- Kalyanam Shivkumar, MD, PhD⁎ ()
- ↵⁎Reprint requests and correspondence:
Dr. Kalyanam Shivkumar, UCLA Cardiac Arrhythmia Center, A2-237 CHS, 10833 Le Conte Avenue, Los Angeles, California 90095-1679
Objectives The purpose of this study was to compare the characteristics and prevalence of late potentials (LP) in patients with nonischemic cardiomyopathy (NICM) and ischemic cardiomyopathy (ICM) etiologies and evaluate their value as targets for catheter ablation.
Background LP are frequently found in post-myocardial infarction scars and are useful ablation targets. The relative prevalence and characteristics of LP in patients with NICM is not well understood.
Methods Thirty-three patients with structural heart disease (NICM, n = 16; ICM, n = 17) referred for catheter ablation of ventricular tachycardia were studied. Electroanatomic mapping was performed endocardially (n = 33) and epicardially (n = 19). The LP were defined as low voltage electrograms (<1.5 mV) with onset after the QRS interval. Very late potentials (vLP) were defined as electrograms with onset >100 ms after the QRS.
Results We sampled an average of 564 ± 449 points and 726 ± 483 points in the left ventricle endocardium and epicardium, respectively. Mean total low voltage area in patients with ICM was 101 ± 55 cm2and 56 ± 33 cm2, endocardial and epicardial, respectively, compared with NICM of 55 ± 41 cm2and 53 ± 28 cm2, respectively. Within the total low voltage area, vLP were observed more frequently in ICM than in NICM in endocardium (4.1% vs. 1.3%; p = 0.0003) and epicardium (4.3% vs. 2.1%, p = 0.035). An LP-targeted ablation strategy was effective in ICM patients (82% nonrecurrence at 12 ± 10 months of follow-up), whereas NICM patients had less favorable outcomes (50% at 15 ± 13 months of follow-up).
Conclusions The contribution of scar to the electrophysiological abnormalities targeted for ablation of unstable ventricular tachycardia differs between ICM and NICM. An approach incorporating LP ablation and pace-mapping had limited success in patients with NICM compared with ICM, and alternative ablation strategies should be considered.
Supported by the National Heart, Lung, and Blood Institute(R01-HL084261and R01-HL067647to Dr. Shivkumar). Dr. Shivkumar's institution has received support from St. Jude Medicaland Biosense Webster; this support is unrelated to the current study. Drs. Nakahara and Tung contributed equally to this work.
- Received October 19, 2009.
- Revision received January 5, 2010.
- Accepted January 11, 2010.
- American College of Cardiology Foundation