Abstract 19804: The Spatial QRS-T Angle Predicts Ventricular Arrhythmias in Patients With Hypertrophic Cardiomyopathy

Abstract

Introduction: The spatial peaks QRS-T (SPQRS-T) angle has been shown to differentiate hypertrophic cardiomyopathy (HCM) patients from controls. The SPQRS-T angle has also demonstrated ventricular arrhythmia risk stratification in those with ischemic heart disease. Hypothesis: We hypothesize that the spatial QRS-T angle will differentiate HCM patients with ventricular arrhythmias (VA’s) from those without VA’s. Methods: A retrospective study of HCM patients (maximum septal or posterior wall thickness of 15mm or greater) was performed. Corrected QT interval (QTc), QRS duration (QRSd) and spatial peaks QRS-T angles (SPQRS-T angle) were assessed on patients with VA’s (>5 consecutive beats) and those without VA’s. Significance, positive/negative predictive values and relative risks were calculated. Results: ECG results from 100 HCM patients (32.7 ±17.2 years) were assessed. Twenty patients with VA’s were identified. The QTc differentiated those with VA’s from those without VA’s with values of 440.7±48.1ms and 472.0±43.4ms, respectively (pvalue= 0.013). QTc positive and negative predictive values (PPV and NPV) were 10% and 70.0%, respectively with relative risk (RR) of 0.4 (95% CI 0.2 to 1.0). The SPQRS-T differentiated those with VA’s from those without VA’s, 108.2±45.9 versus 144.0±26.7 degrees (p value<0.001) with PPV and NPV’s of 36.7% 96.1%, respectively with RR of 2.3 (95% CI 1.8 to 3.5). QRSd values did not significantly differ. When those with congestive heart failure (CHF) or VA were compared to HCM patients without VA or CHF, the spatial peaks QRS-T angle PPV, NPV and RR were 42.9%, 96.1% and 2.5 (95% CI 1.8 to 3.5), respectively. Conclusion: In our HCM cohort, the SPQRS-T angle and the QTc differentiate HCM with VA’s from those without VA’s. The SPQRS-T angle best differentiated patients with VA’s from those without VA’s with highest predictive values and relative risk.