December 12, 2009Circulation Arrhythmia and Electrophysiology267 citations
ECG Criteria to Identify Epicardial Ventricular Tachycardia in Nonischemic Cardiomyopathy
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Key Result
A q wave in lead I (QWL1) identified epicardial origin in pace maps significantly more often than endocardial origin (91% vs 4%, P<0.001), yielding 88% sensitivity and 88% specificity.
Study Design
Type
Observational (n=25)
Structured PICO
Can specific ECG criteria identify the epicardial origin of ventricular tachycardia in patients with nonischemic cardiomyopathy?
P
Population
14 patients with nonischemic cardiomyopathy (study population) and an 11-patient validation cohort
I
Intervention
ECG criteria (4-step algorithm including q wave in lead I, q waves in inferior leads, pseudo-delta wave >=75 ms, and maximum deflection index >=0.59)
O
Outcome
Ability to identify epicardial versus endocardial origin of ventricular tachycardiasurrogate
Morphological ECG features, particularly a 4-step algorithm including q wave in lead I, can accurately identify basal-superior/lateral epicardial VTs in nonischemic cardiomyopathy.
Main Result
Absolute Event Rate: 91% vs 4%
p-value: p=<0.001
Abstract
BACKGROUND: ECG criteria identifying epicardial (EPI) origin for ventricular tachycardia (VT) in nonischemic cardiomyopathy have not been determined. Endocardial (ENDO) and EPI basal left ventricle fibrosis characterizes the VT substrate. METHODS AND RESULTS: We assessed the QRS from 102 basal-superior/lateral EPI and 67 comparable ENDO pace maps in 14 patients with nonischemic cardiomyopathy. Pace mapping focused on low bipolar voltage areas. Published morphology criteria: q wave in lead I (QWLI) and no q waves in inferior leads and interval criteria: pseudo-delta wave > or =34 ms, intrinsicoid deflection time > or =85 ms, shortest RS complex > or =121 ms, and maximum deflection index > or =0.55 were assessed for ability to identify EPI origin. Sixteen EPI and 8 ENDO of the 34 mapped VTs (71%) in the study population and 14 EPI and 7 ENDO VTs from an 11-patient validation cohort were localized to basal-superior/lateral left ventricle and corroborated pacing data. A QWL1 was seen in EPI but not ENDO pace maps (91% versus 4%; P or =75 ms, maximum deflection index > or =0.59, and QWL1) having > or =95% specificity and > or =20% sensitivity in identifying EPI/ENDO origin for pace maps. This 4-step algorithm identified the origin in 109 of 115 pace maps (95%), 21 of 24 VTs (88%) in the study population, and 19 of 21 VTs (90%) in validation cohort. CONCLUSIONS: Morphological ECG features that describe the initial QRS vector can help identify basal-superior/lateral EPI VTs in nonischemic cardiomyopathy.
Cite This Study
Vallès et al. (2009) conducted an observational in Nonischemic cardiomyopathy with ventricular tachycardia (n=25). ECG criteria (q wave in lead I) vs. Endocardial origin was evaluated on Presence of q wave in lead I (QWL1) in pace maps (p=<0.001). A q wave in lead I (QWL1) identified epicardial origin in pace maps significantly more often than endocardial origin (91% vs 4%, P<0.001), yielding 88% sensitivity and 88% specificity.