Electromechanical Window and Spontaneous Ventricular Tachyarrhythmias in Takotsubo Syndrome

Abstract

QT interval prolongation is common in patients hospitalized with Takotsubo syndrome (TTS), however, only a minority experience ventricular tachyarrhythmias. Our aim was to characterize the electromechanical window (EMW) in patients with TTS and to evaluate its association with ventricular tachyarrhythmias. We preformed aretrospective analysis of 84 patients hospitalized with TTS in the Tel-Aviv Medical Center between 2013 and 2022. All patients underwent a comprehensive echocardiographic evaluation and the EMW was calculated by subtracting the QT interval from the QRS onset to the aortic valve closure obtained from a continuous-wave Doppler for the same beat. Of the 84 patients with TTS, 74 (88%) were female and the mean age was 70 ± 11 years. The mean left ventricular ejection fraction was 42 ± 8%. The EMW was negative in 81 patients (96%), and the mean EMW was -69 ± 50 ms. Ventricular tachyarrhythmias occurred in 7 patients (8%). The EMW of patients who experienced ventricular tachyarrhythmias was more negative than patients who did not (-133 ± 23 ms vs -63 ± 48 ms, p = 0.001). In the univariate analysis, EMW and QT were associated with ventricular tachyarrhythmias (univariate odds ratio [OR]EMW1.03, 95% confidence interval [CI] 1.01 to 1.05, p = 0.003 and univariate ORQTc1.02, 95% CI 1.01 to 1.03, p = 0.02); however, only EMW remained significant in the multivariate analysis (OREMW1.03 95% CI 1.03 to 1.05, p = 0.023). EMW was more effective than corrected QT interval in identifying patients who had ventricular tachyarrhythmias (AUCEMW: 0.89, 95% CI 0.82 to 0.97 vs AUCQTc0.77, 95% CI 0.61 to 0.93, p = 0.02), and a cut-off value of -108 ms was predictive of ventricular tachyarrhythmias with a sensitivity of 86% and a specificity of 79%. In conclusion, EMW is negative in patients with TTS and is associated with increased risk for ventricular tachyarrhythmias. The role of EMW in the risk stratification of patients with TTS warrants further investigation.