Fundamental differences in electrophysiologic and electroanatomic substrate between ischemic cardiomyopathy patients with and without clinical ventricular tachycardia
Haqqani HM et al. – Compared with ischemic cardiomyopathy (ICM) pts with sustained monomorphic ventricular tachycardia (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 pts develop SMVT. Methods- Study to compare electrophysiologic substrate in ICM pts with/without SMVT
Results- Detailed electroanatomic mapping of left ventricular (LV) endocardium in 17 stable control ICM pts (16 males) without clinical SMVT
- Comparison with 17 ICM pts (15 males) with spontaneous SMVT
- Standard definitions of low-voltage zones and fractionated, isolated, and very late potentials
- No significant baseline differences between groups in terms of LV diameter, ejection fraction (27% vs 28%), infarct territory, or time from infarction
- Control pts had smaller total low-voltage area ≤1.5 mv (30% of surface area vs 55%); smaller very low-voltage area <0.5 mv (7.3% vs. 29%); 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 more frequent in SMVT pts
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