Impact of left bundle branch block in Takotsubo Syndrome

Background: Left bundle branch block (LBBB) causes left ventricular dyssynchrony, and its presence with concomitant left ventricular dysfunction has been proven to play a synergistic role, worsening ventricular function. Our study seeks to further explore the association between LBBB and various in-hospital outcomes in patients with takotsubo syndrome (TTS).

Methods: The national inpatient sample was queried from 2016 to 2019 to identify all admissions with a primary diagnosis of TTS. International classification of diseases, tenth revision codes were used to divide patients based on the presence or absence of LBBB. Multivariate regression analysis was performed to assess the effect of LBBB among all the pre-specified outcomes.

Results: A total of 26,615 admissions were included in the analysis. Admissions with LBBB were more likely to be older (72.2 vs. 66.2 years) and have a higher burden of comorbidities. The presence of a LBBB was associated with ventricular arrhythmias (OR = 1.97, 95% CI 1.08-3.61, p = 0.028) but not with sudden cardiac arrest (SCA), acute heart failure, cardiogenic shock, and all-cause intra-hospital mortality.

Conclusions: Intraventricular dyssynchrony appears to play a significant role in ventricular arrhythmogenesis and SCA, as several trials have demonstrated that cardiac resynchronization therapy alone without defibrillator function reduces the rate of ventricular arrhythmias and SCA in patients with heart failure with systolic dysfunction and a widened QRS complex. The most likely mechanism of arrhythmia development in TTS is related to the elevated plasma levels of catecholamines and their proarrhythmic effects in the ventricular myocardium.