Key result
LBBB shows no increase in mortality vs other bundle branch blocks after nonischemic cardiac arrest.
Why the study?
Cardiac arrest survivors with bundle branch block and no ischemic heart disease have not been previously characterized.
Does left bundle branch block increase mortality or the need for appropriate ICD therapy in cardiac arrest survivors without ischemic heart disease compared to other bundle branch block morphologies?
Cohort (n=58)
No
Does left bundle branch block increase mortality or the need for appropriate ICD therapy in cardiac arrest survivors without ischemic heart disease compared to other bundle branch block morphologies?
In cardiac arrest survivors without ischemic heart disease, left bundle branch block is frequently associated with left ventricular systolic dysfunction at presentation but does not appear to increase medium-term mortality compared to other bundle branch block types.
Answers are grounded in this paper and cite their sources.
LBBB does not increase medium-term mortality despite lower LVEF; leaves open whether BBB subtype should guide risk stratification in non-ischemic cardiac arrest survivors.
Aims: Cardiac arrest (CA) survivors with left/right bundle branch block (LBBB/RBBB) and no ischemic heart disease (IHD) have not been previously characterized. The aim of this study was to describe heart failure, implantable cardioverter defibrillator (ICD) therapy and mortality in this population. Methods: Between 2009 and 2019 we consecutively identified all CA survivors with a consistent bundle branch block (BBB) defined as a QRS ≥ 120 ms, who had a secondary prophylactic ICD implanted. Patients with congenital and ischemic heart disease (IHD) were excluded. Results: Among 701 CA-survivors who survived to discharge and received an ICD, a total of 58 (8%) were free from IHD and had BBB; 46 (79%) had LBBB, 10 (17%) had RBBB and 2 (3%) had non-specific BBB (NSBBB). The prevalence of LBBB was 7%. Pre-arrest ECG were available in 34 (59%) patients; 20 patients (59%) had LBBB, 6 (18%) had RBBB, 2 (6%) had NSBBB, 1 had (3%) incomplete LBBB, and 4 (12%) without BBB. At discharge, patients with LBBB had a significantly lower left ventricular ejection fraction (LVEF) than patients with other types of BBB, p < 0.001. During follow-up, 7 (12%) died after a median of 3.6 years (IQR: 2.6-5.1) with no difference between BBB subtypes. Conclusion: We identified 58 CA-survivors with BBB and no IHD. The prevalence of LBBB among all CA-survivors was high, 7%. During CA hospitalization LBBB patients presented with a significantly lower LVEF than patients with other types of BBB (P < 0.001). ICD treatment and mortality did not differ between BBB subtypes during follow-up.
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Holm et al. (2023) conducted a cohort in Cardiac arrest survivors with bundle branch block and no ischemic heart disease (n=58). Left bundle branch block (LBBB) vs. Other bundle branch block morphologies (RBBB and non-specific BBB) was evaluated on All-cause mortality during follow-up (p=0.626). Among cardiac arrest survivors without ischemic heart disease, left bundle branch block did not significantly increase mortality compared to other bundle branch block types (11% vs 17%, p=0.626), despite being associated with a significantly lower ejection fraction at hospitalization.
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