Relationship between myocardial bridging and fatal ventricular arrhythmias in patients with hypertrophic cardiomyopathy: the HCM-MB study.

BACKGROUND

Myocardial bridging (MB) and hypertrophic cardiomyopathy (HCM) are associated with the risk of fatal ventricular arrhythmias (VAs). The goal of the study was to determine the relationship between MB and fatal VAs in HCM patients with implantable cardiac defibrillators (ICD).

METHODS

A total of 108 HCM patients (mean age: 46.6 ± 13.6 years; male: 73) were enrolled in this retrospective study. All patients underwent transthoracic echocardiography and coronary computed tomography angiography. Fatal VAs including sustained ventricular tachycardia and ventricular fibrillation were documented in ICD records.

RESULTS

There were documented fatal VAs in 29 (26.8%) patients during a mean follow-up time of 71.3 ± 30.9 months. Compared with the other groups, the fatal VA group had a higher incidence of the following: presence of MB (82.8 vs. 38%, p < 0.001), deep MB (62.1 vs. 6.3%, p < 0.001), very deep MB (24.1 vs. 0%, p < 0.001), long MB (65.5 vs. 11.4%, p < 0.001), presence of > 1 MB (17.2 vs. 0%, p = 0.001), and MB of the left anterior descending artery (79.3 vs. 17.7%, p < 0.001) . Sudden cardiac death (SCD) risk score (hazard ratio: 1.194; 95% CI: 1.071-1.330; p = 0.001) and presence of MB (hazard ratio: 3.815; 95% CI: 1.41-10.284; p = 0.008) were found to be independent predictors of fatal VAs in HCM patients.

CONCLUSIONS

The current data suggest that the SCD risk score and presence of MB were independent risk factors for fatal VAs in patients with HCM. In addition to conventional risk factors, the coronary anatomical course can provide clinicians with valuable information when assessing the risk of fatal VAs in HCM patients.