Abstract
BACKGROUND: QRS duration has been recognized as a risk factor for ventricular arrhythmias in hypertrophic cardiomyopathy (HCM), but its role in reflecting left ventricular (LV) function and morphology is unknown. We aimed to investigate the relationship between QRS duration and strain values in hypertrophic nonobstructive cardiomyopathy (HNCM) and hypertrophic obstructive cardiomyopathy (HOCM). METHODS: A total of 45 HNCM patients and 81 HOCM patients with preserved ejection fraction were retrospectively enrolled in this study. The QRS duration was measured using standard 12-lead electrocardiograms. LV global and segmental strain analyses were performed using cardiac magnetic resonance feature tracking. RESULTS: The QRS duration correlated with global circumferential (GCS, r=0.386, P=0.013), radial (GRS, r=-0.374, P=0.016) and longitudinal (GLS, r=0.3462, P=0.026) strain in HNCM patients, whereas it was correlated with GCS (r=0.253, P=0.036) and GRS (r=-0.257, P=0.033) in HOCM patients. In patients with a QRS duration ≥110 ms, the global radial peak strain (PS, 30.69%±12.74% vs. 17.03%±8.74%, P=0.003), peak systolic strain rate (PSSR, 1.96±0.92 vs. 1.07±0.47 s(-1), P=0.006) and peak diastolic strain rate (PDSR, -1.71±0.78 vs. -0.90±0.49 s(-1), P=0.004) were impaired in HNCM patients, and the circumferential PS (-18.44%±3.65% vs. -15.88%±3.65%, P=0.006), PSSR (-1.10±0.21 vs. -0.95±0.19 s(-1), P=0.004) and PDSR (0.85±0.28 vs. 0.71±0.20 s(-1), P=0.020) were decreased in HOCM patients. LV deformation and strain impairments occurred from the apex to the basal and mainly involved the apical segments in HNCM patients with prolonged QRS duration. In addition, the basal inferoseptal segmental circumferential strain and strain rate were reduced in HOCM patients with prolonged QRS duration. CONCLUSIONS: The QRS duration increases with global and segmental impairments in both HNCM and HOCM patients. Prolonged QRS duration may serve as an indicator of apical deformation in HNCM patients and as an indicator of mid-wall involvement in HOCM patients.