Ability of terminal QRS notching to distinguish benign from malignant electrocardiographic forms of early repolarization.
Recent studies have suggested that early repolarization (ER) might be associated with up to 1/3 of idiopathic ventricular tachycardia/ventricular fibrillation (VT/VF) cases ("malignant" ER). We sought to identify electrocardiographic features to distinguish benign from malignant variants of ER. We reviewed the medical records for implantable-cardioverter defibrillators implanted at a single institution (1988 to 2008) to identify cases of idiopathic VT/VF. The electrocardiograms were scored for ER, defined as a >or=0.1-mV elevation of the QRS-ST junction manifesting as J-point slurring or notching in 2 contiguous leads. We also identified a cohort of 200 healthy age- and gender-matched controls with electrocardiographic findings previously identified as normal ER ("benign" ER cohort). Of 1,224 consecutive implantable-cardioverter defibrillator implants, we identified 39 cases of idiopathic VT/VF. Of the 39 cases, 9 (23%) demonstrated ER. During a mean follow-up of 7.2 +/- 4.6 years, the combined end point of appropriate implantable-cardioverter defibrillator shocks or all-cause mortality occurred less frequently in cases of idiopathic VT/VF with ER than in those without ER (11% vs 30%, odds ratio 0.29, 95% confidence interval 0.03 to 2.69, p = 0.40). A comparison of the electrocardiograms between those with malignant ER and controls demonstrated that QRS notching was significantly more prevalent among cases when present in leads V4 (44% vs 5%, p = 0.001) and V5 (44% vs 8%, p = 0.006), with a similar trend in lead V6 (33% vs 5%, p = 0.013). In conclusion, left precordial terminal QRS notching is more prevalent in malignant variants of ER than in benign cases. These findings could have important implications for risk stratification of patients with ER.
Merchant
Faisal M
FM
Cardiology Division, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA.
Noseworthy
Peter A
PA
Weiner
Rory B
RB
Singh
Sheldon M
SM
Ruskin
Jeremy N
JN
Reddy
Vivek Y
VY
D000328:Adult; D016022:Case-Control Studies; D017147:Defibrillators, Implantable; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D012189:Retrospective Studies; D017180:Tachycardia, Ventricular / Q000503:physiopathology* / Q000628:therapy; D014693:Ventricular Fibrillation / Q000503:physiopathology* / Q000628:therapy