Pediatric noncompaction patients with high spatial QRS-T angles are at increased risk for ventricular tachycardia

Noncompaction cardiomyopathy (NCCM) patients may develop sustained ventricular arrhythmias (VA). Currently no known electrocardiogram (ECG) parameter has demonstrated predictive value for VA development. The spatial QRS-T angle has demonstrated ability to identify VA in other cardiomyopathy populations.

A total of 39 patients with NCCM, defined by compact to non-compact ratio of >2.3 by magnetic resonance imaging, were assessed. The first ECG taken at time of MRI was assessed utilizing the heart rate, the QRS duration (QRSd), the corrected QT interval (QTc), and the spatial QRS-T angle (SPQRS-T angle, three-dimensional angle between the QRS and T-wave vectors) were assessed.

Eight patients developed VA (20.5%). Median time to event was 3 months (95% CI 1.0 to 24.0 months). There were no significant differences between baseline ejection fraction or fractional shortening. Baseline median heart rate, spatial QRS-T angles, and indexed left ventricular end-diastolic volumes were all significantly higher in patients with VA development (p-value <0.05). Only heart rate and the SPQRS-T angle had significant univariate hazard ratios (HR) for VA at 1.031/beat per minute (1.001-1.071) and at a cut-off of 147 degrees the SPQRS-T angle gave a hazard ratio of HR of 5.773 (95% CI 1.161 to 28.702). The multivariate hazard ratio was only significant for the SPQRS-T angle, 1.031/degree (1.001-1.066). Survival analysis by Kaplan-Meier yielded a significant difference at a cutoff of 147 degrees.

The SPQRS-T angle identified those at risk for VA development. Future studies are warranted with larger populations of noncompaction patients.