Right bundle branch block and ventricular septal fibrosis in patients with hypertrophic cardiomyopathy.

BACKGROUND

Right bundle branch block (RBBB) is associated with ventricular septal fibrosis in patients with hypertrophic cardiomyopathy (HCM) after alcohol septal ablation, but little data are available in HCM patients without a history of septal ablation.

METHODS

Magnetic resonance late gadolinium enhancement (LGE) was performed in 59 HCM patients with no history of alcohol septal ablation. The location and extent of LGE were examined in relation to electrocardiographic features including RBBB.

RESULTS

LGE volume was higher in 7 HCM patients with RBBB (7.3±7.4g/cm) than in patients without RBBB (2.9±7.4g/cm, p=0.016). LGE volume was positively correlated to QRS duration of RBBB (correlation coefficient=0.93, p=0.023). The diagnostic value of RBBB was highly specific for the detection of LGE in the ventricular septum, with sensitivity 21% and specificity 94%.

CONCLUSIONS

The presence of RBBB may be a simple marker for detecting ventricular septal fibrosis in HCM patients who had no history of alcohol septal ablation. Further studies are necessary to confirm our findings.