Relationship between life-threatening events and electromechanical window in patients with hypertrophic cardiomyopathy: A novel parameter for risk stratification of sudden cardiac death

BACKGROUND Hypertrophic cardiomyopathy (HCM) is a leading cause of sudden cardiac death (SCD) in young individuals, largely due to ventricular arrhythmias, which may be associated with electrical disturbances from pathologic myocardial changes. OBJECTIVES The purpose of this study was to investigate electromechanical mismatches in patients with HCM and the relationship between electromechanical mismatches and life-threatening events (LTEs). METHODS We performed a retrospective review of patients (age 180 years) diagnosed with HCM. Electromechanical mismatch was evaluated using the electromechanical window (EMW), defined as the interval between the Q wave and aortic valve closure minus the QT interval. RESULTS We enrolled 458 patients (mean age 52.4 +/- 18.8 years). When the EMW of patients with HCM was compared to that of age-/sex-matched normal controls, EMW was more negative in patients with HCM than in normal controls (-51 +/- 35 ms vs 7 +/- 19 ms; P<.001). LTEs occurred in 25 patients (5.5%). EMW was more negative in patients with LTEs than in those without (-77 +/- 33 ms vs -42 +/- 31 ms; P<.001). The cutoff value of EMW to identify patients with LTEs was -54 ms, and the c-index of EMW was 0.726. EMW less than -54 ms, unexplained syncope, pediatric onset, and extreme left ventricular hypertrophy were significant risk factors for LTEs on multivariate analysis. CONCLUSION EMW was more negative in patients with HCM than in healthy individuals, and profound EMW negativity was an independent risk factor for LTEs. EMW can be useful for risk stratification of SCD in patients with HCM.

Automated summary

This study aimed to investigate electromechanical mismatches in patients with hypertrophic cardiomyopathy (HCM) and their relationship with life-threatening events (LTEs). The results showed that the electromechanical window (EMW) was more negative in HCM patients compared to normal controls, and profound EMW negativity was identified as an independent risk factor for LTEs. EMW less than -54 ms, unexplained syncope, pediatric onset, and extreme left ventricular hypertrophy were significant risk factors for LTEs. EMW can be a useful tool for risk stratification of sudden cardiac death in HCM patients.