# Prevalence, Spectrum, and Determinants of Cardiac Arrhythmias in the Postoperative Period Following Coronary Artery Bypass Grafting (CABG): A Prospective Observational Study

## TL;DR

This study finds that post-surgery heart rhythm problems are common after heart bypass surgery in South Asians and are linked to factors like age, BMI, and longer surgery time.

## Contribution

The study provides new insights into the prevalence and risk factors for postoperative arrhythmias in a South Asian CABG cohort.

## Key findings

- Postoperative arrhythmias occurred in 32.4% of patients, with atrial fibrillation being the most common.
- Older age, higher BMI, and longer cardiopulmonary bypass time were independent predictors of arrhythmias.
- Patients with arrhythmias had longer ICU and hospital stays and higher in-hospital mortality.

## Abstract

Introduction: Postoperative arrhythmias following coronary artery bypass grafting (CABG) are frequent and contribute to increased morbidity, prolonged hospital stay, and higher healthcare costs. Their epidemiology and determinants in South Asian populations, who exhibit a higher prevalence of metabolic and cardiovascular risk factors, remain underexplored.

Objective: To determine the prevalence, spectrum, and predictors of postoperative arrhythmias in patients undergoing isolated CABG in a South Asian cohort.

Methodology: This prospective observational study enrolled 355 patients undergoing isolated CABG at two tertiary hospitals from January 2023 to December 2024. The sample size was calculated using a single-proportion formula based on a 32.4% expected prevalence of atrial fibrillation with 95% confidence and a 5% margin of error. Patients with preexisting arrhythmias, pacemakers, or concomitant surgeries were excluded. Continuous telemetry monitoring was applied for 72 hours, followed by daily ECGs until discharge; arrhythmias were defined according to American College of Cardiology/American Heart Association (AHA/ACC) and European Society of Cardiology (ESC) criteria. Missing data (<2%) were excluded listwise. Multivariable logistic regression identified independent predictors, with odds ratios (ORs) and 95% confidence intervals (CIs) reported; p < 0.05 was considered significant.

Results: Postoperative arrhythmias occurred in 115 (32.4%) patients, most frequently atrial fibrillation (88; 24.8%), with 71.3% developing within 72 hours. Patients with arrhythmias had longer ICU stays (4.2 ± 1.8 vs. 3.1 ± 1.2 days, p < 0.001), hospital stays (9.8 ± 3.2 vs. 7.6 ± 2.4 days, p < 0.001), and higher in-hospital mortality (6.1% vs. 2.1%, p = 0.048). Independent predictors were advanced age (adjusted OR 1.08; 95% CI 1.04-1.12; p < 0.001), higher BMI (adjusted OR 1.12; 95% CI 1.02-1.23; p = 0.017), and longer cardiopulmonary bypass (CPB) time (adjusted OR 1.02; 95% CI 1.01-1.04; p = 0.005). Perioperative β-blocker or amiodarone use and interobserver variability were not systematically assessed and are acknowledged as limitations.

Conclusion: Postoperative arrhythmias, particularly atrial fibrillation, are common after CABG and significantly worsen short-term outcomes. Longer cardiopulmonary bypass duration, higher BMI, and older age independently increase risk. Given the unique cardiovascular profile of South Asian populations, focused postoperative monitoring and preventive strategies are essential to reduce arrhythmia-related complications.