# Rhythm control benefits left ventricular function compared with rate control in patients with atrial fibrillation: A computational study

## TL;DR

This study shows that rhythm control improves heart function more than rate control in patients with atrial fibrillation.

## Contribution

The study computationally compares the effects of rhythm and rate control on left ventricular function in atrial fibrillation.

## Key findings

- Rhythm control improved left ventricular ejection fraction more than pharmacologic rate control.
- Paced and pharmacologic rate control had similar effects on ventricular function.
- Atrial contraction had no benefit when heart rate was irregular.

## Abstract

Atrial fibrillation (AF) alters heart rate, rhythm regularity, and atrial contraction, which may contribute to an increased risk of heart failure. Although rate and rhythm control target different aspects of these disturbances, their specific effects on left ventricular (LV) function remain unclear.

The purpose of this study was to predict the independent and combined contribution of heart rate, rhythm regularity, and atrial contraction to LV function in patients with AF.

We predicted LV ejection fraction (EF) and stroke volume (SV) in 10 whole-heart patient-specific models of patients with AF while varying heart rate, rhythm regularity, and effectiveness of atrial contraction.

AF was modeled as a fast, irregular heart rate with no atrial contraction. Pharmacologic and paced rate control were modeled as a slow irregular and regular heart rate without atrial contraction, respectively, whereas rhythm control had a slow, regular heart rate with atrial contraction.

Rhythm control resulted in a greater improvement than pharmacological rate control in LVEF compared with AF (+5.1% ± 0.4% vs +2.8% ± 0.3%, P < .01). Paced rate control was equivalent to pharmacologic rate control in terms of LVEF (+2.6% ± 0.4% vs +2.8% ± 0.3%). Atrial contraction did not improve ventricular function in the presence of an irregular heart rate (pharmacologic rate: +2.8% ± 0.3% vs rhythm with irregular heart rate: +2.7% ± 0.3%).

Rhythm control provides superior improvements in LV function compared with rate control. However, restoring sinus rhythm may yield limited benefits to LV function when atrial contraction is ineffective or when heart rate is irregular.