Ability of Terminal QRS Notching to Distinguish Benign from Malignant Electrocardiographic Forms of Early Repolarization

• Published in: The American journal of cardiology Vol. 104; no. 10; pp. 1402 - 1406
• Main Authors: Merchant, Faisal M., MD, Noseworthy, Peter A., MD, Weiner, Rory B., MD, Singh, Sheldon M., MD, Ruskin, Jeremy N., MD, Reddy, Vivek Y., MD
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 15.11.2009; Elsevier; Elsevier Limited
• Subjects: Adult; Biological and medical sciences; Cardiac arrhythmia; Cardiology; Cardiology. Vascular system; Cardiovascular; Cardiovascular disease; Case-Control Studies; Defibrillators; Defibrillators, Implantable; Electrocardiography; Female; Follow-Up Studies; Heart; Humans; Male; Medical records; Medical sciences; Retrospective Studies; Tachycardia, Ventricular - physiopathology; Tachycardia, Ventricular - therapy; Ventricular Fibrillation - physiopathology; Ventricular Fibrillation - therapy; Electrodiagnosis; Repolarization; QRS interval; Electrocardiography; Early; Circulatory system; Malignant tumor; Cardiology; Terminal; Cancer
• ISSN: 0002-9149; 1879-1913
• DOI: 10.1016/j.amjcard.2009.06.062

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 ≥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.