Greater cardiorespiratory fitness reduces incidence of atrial fibrillation: a meta-analysis

Abstract

\n \n \n Type of funding sources: None.\n \n \n \n \xa0Atrial Fibrillation (AF) is the most common sustained cardiac arrhythmia affecting 1-2% of the global population, with the prevalence of AF increasing dramatically over the past two decades. Although low levels of cardiorespiratory fitness (CRF) and physical activity are predictive of cardiovascular disease onset and mortality, only recently has this emerged as a potential risk factor for AF.\n \n \n \n The aim of this meta-analysis was therefore to quantify the relationship between CRF, measured by a symptom limited exercise stress test, and incident AF. We hypothesised that there would be an inverse relationship between CRF and the incidence of AF.\n \n \n \n The systematic literature review was conducted using PUBMED, MEDLINE and EMBASE databases, with seven studies meeting the inclusion criteria. A random-effects meta-analysis was then used to compare the multivariate risk estimates of the lowest CRF group from each cohort with the group of the highest CRF.\n \n \n \n Data from 206,925 individuals (55.8% males) was used for analysis with a mean age of 55\u2009±\u20092.5 years and a mean follow-up period of 10.3\u2009±\u20095 years. The total number of AF events across the studies was 19,913. The overall pooled risk of AF in the high-CRF group versus the low-CRF group showed a significant lower risk of incident AF in those with high-CRF (OR: 0.52, 95% CI, 0.44-0.605, p\u2009<\u20090.001). There was evidence of statistical heterogeneity between the studies (I2\u2009=\u200981%, p\u2009<\u20090.001). AF incidence rates demonstrated an overall decline in rates across the CRF quartiles from low to high. The mean incidence rate for low-CRF was 21\u2009±\u200913.4 compared to 6.9\u2009±\u20090.7 per 1000 person-years for the high CRF group (p\u2009=\u20090.03).\n \n \n \n There is an inverse association between a lower CRF and an increased risk of AF, with a higher level of CRF protective against AF. This study highlights that low-CRF may be an additional risk factor for AF along with already other established lifestyle-based risk factors such as obesity and hypertension. Exercise interventions should be promoted as a primary prevention strategy in those at risk of developing AF with known risk factors. Future studies are warranted to identify the mechanism(s) through which improved CRF confers a reduction in AF incidence.\n Abstract Figure. AF risk between high and low-CRF\n