Response and long-term outcomes with resynchronization therapy in atrial fibrillation
Authors: Brandao M , Goncalves Almeida J , Fonseca P , Santos E , Rosas F , Ribeiro J , Oliveira M , Goncalves H , Primo J , Fontes-Carvalho R 
Published: October 2021

Abstract

Background
Cardiac resynchronization therapy (CRT) reduces morbidity and mortality in selected patients (pts) with heart failure (HF). Pts with atrial fibrillation (AF) were excluded from major CRT trials. Studies suggested that pts with AF derive less benefit from CRT.

Purpose
To compare response and clinical outcomes after CRT in pts in AF or in sinus rhythm (SR).

Methods
Single-center retrospective study of consecutive pts submitted to CRT implantation (2007–2018). Major adverse cardiac events (MACE) included HF hospitalization or all-cause mortality. Clinical response was defined as NYHA class improvement without MACE in the 1st year of follow-up (FU). Left ventricle end-systolic volume reduction of &gt;15% during the 1st year of FU designated echocardiographic (echo) response. Survival analysis with Kaplan-Meier method and Log-rank test was performed.

Results
295 CRT pts (70.5% male, median age 68±16 years, 54.6% implanted with CRT-D) were included. 95 (32.6%) presented in AF. Pts with AF were older (72 vs 67, p=0.007), with higher prevalence of coronary disease (40.2% vs 24.2%, p=0.008), moderate to severe tricuspid regurgitation (21.7% vs 8.8%, p=0.011) and chronic kidney disease (33.0% vs 16.5%, p=0.003). AF pts had larger left atrial diameters (50.5 vs 44.6 mm, p&lt;0.001) and higher baseline N-terminal pro B-type natriuretic peptide values (6738.6 vs 3179.4 pg/ml, p=0.044). There were no differences in terms of HF etiology (p=0.242) or type of device (p=0.127). Pts with AF presented more often with secondary prevention indications for CRT-D (45.0% vs 15.7%, p&lt;0.001).
Atrioventricular junction ablation (AVJA) was performed in 14.0% of AF pts. Median percentage of biventricular pacing (BiVp) was significantly lower in AF pts (97% vs 99%, p&lt;0.001).
NYHA class improvement (79.3% vs 78.9%, p=0.930) and echo response (65.4% vs 75.2%, p=0.269) were similar between pts in AF and in SR. The rate of clinical response was lower in AF pts (52.7% vs 66.5%, p=0.036). During a median FU of 3±5 years, occurrence of MACE (Log-rank test, p&lt;0.001) and all-cause mortality (Log-rank test, p=0.011) were higher in AF pts – graph 1.
When comparing AF pts submitted to AVJA with pts in SR, clinical (62.5% vs 66.5%, p=0.816) and echo (57.1% vs 75.2%, p=0.540) response were similar.
Among pts achieving BiVp ≥98% (67.8%), no differences emerged in terms of clinical response (68.4% vs 70.5%, p=0.968) between patients in AF or in SR. Also, mortality was similar between groups (Log-rank test, p=0.214) – graph 2. MACE remained more frequent in the AF group (Log-rank test, p=0.029).

Conclusions
In this cohort, AF pts, despite having a higher comorbidity burden, showed similar NYHA class improvement and echo response to SR pts. Among pts with BiVp ≥98%, clinical response and all-cause mortality were also similar between groups. Further studies are warranted to select AF pts that benefit most from CRT.

Funding Acknowledgement
Type of funding sources: None. Graph 1Graph 2