Aims: Hypertrophic cardiomyopathy (HCM) is the leading cause of sudden cardiac death in young adults. Current risk markers for this heterogeneous disease lack performance and, thus, new approaches are needed. This study aimed to improve risk assessment in HCM patients through the development of new electrocardiogram (ECG)-based markers focused on QRS and T wave morphologies.
Methods: 2-lead (V5 and aVF) ambulatory Holter ECG signals of 79 HCM patients were analyzed. Patients were divided into high-risk (16 patients) and low-risk (63 patients) groups depending on whether they developed non-sustained ventricular tachycardia and syncope during follow-up. We proposed a novel marker based on the ratio between R and S/Q wave areas, ranging from 1 (predominant R waveform) to -1 (S waveform). Analogously, we proposed to compute Tr, ranging from 1 (positive T wave) to -1 (inverted T wave). Mean values of both markers were analyzed in the most stable 30 minutes during the night period.
Results: QRSr in lead aVF showed significant differences between high- and low-risk groups (p=0.01). The high-risk group predominantly exhibited positive QRS waveforms in lead aVF, while the low-risk group showed rS or S waveforms. In lead V5, no differences in QRSr were observed between the two groups, with both mainly displaying R waveforms. Tr in lead aVF was significantly different between the groups (p=0.03), with a larger proportion of patients in the high-risk group presenting T wave inversion (TWI): 56% vs 22%. In lead V5, TWI was more prevalent in the high-risk group (62% vs 43%), but Tr differences were not significant.
Conclusion: The proposed markers QRSr and Tr highlight the importance of QRS and T wave morphology for risk stratification in HCM patients. Our findings also reveal the potential of aVF for risk stratification.