Technologies

Low amplitude QRS peaks predict ventricular tachyarrhythmias in patients with cardiomyopathy: Refining risk stratification using quantitative QRS morphology analysis

Cardiomyopathy patients are at risk of sudden death, typically from heterogeneous myocardial scarring that alters normal electrical activation patterns and promotes lethal reentrant ventricular arrhythmias. Identifying high risk patients who will derive survival benefit from defibrillator therapy remains challenging, and traditional QRS metrics have not been reliable. Quantification of low amplitude QRS peaks (QRSp) on the electrocardiogram (ECG) can provide an index of abnormal conduction, thereby defining arrhythmogenic myocardial substrate.

QRSp is measured from high resolution digital 12-lead-ECGs recordings. Using our proprietary algorithm, QRSp is quantified for each ECG lead based on the total number of low amplitude deflections that deviated from the respective naive QRS template. In a large prospective clinical validation study, QRSp independently predicted ventricular arrhythmic events in patients with cardiomyopathy, such that the risk increased 2-fold for each QRSp detected. The sensitivity and negative predictive value of QRSp≥2.25 in detecting arrhythmic events was 100% and 100%, respectively.

When compared to traditional QRS metrics, such as QRS duration, QRSp had significantly greater sensitivity and negative predictive value. Thus, QRSp has the potential to improve sudden death risk stratification and patient selection for prophylactic defibrillator therapy.