Postoperative Arrhythmias after open heart surgery: incidence, risk factors and therapeutic management among patients at Jakaya Kikwete cardiac institute, Dar es salaam, Tanzania

Abstract

ABSTRACT Background: Arrhythmias are a major cause of morbidity and mortality following heart surgery and are a fairly common complication. It has been discovered that the percentage of heart failure patients who simultaneously have post-cardiac surgery arrhythmia ranges between 10 and 57%. Despite the apparent maturity of the cardiac procedure, risks and postoperative consequences, there is scarce data in developing countries. Postoperative arrhythmias can lead to complications and negatively impact patient recovery following open heart surgery. Understanding the incidence and associated factors is essential for targeted intervention and improved patient outcomes. Objective: This study aimed to assess the incidence, factors associated with arrhythmias, therapeutic management and treatment outcomes among patients undergoing open heart surgery at Jakaya Kikwete Cardiac Institute (JKCI) in Dar es Salaam, Tanzania. Methods: A prospective observation study involving 100 post-cardiac surgery patients who meet the specified criteria was conducted from March to May 2024 at the JKCI in Dar es Salaam. Patients were selected consecutively until the sample size was reached then followed for the four (4) consecutive days post-surgery. Post-cardiac surgery arrhythmias were diagnosed with electrocardiography (ECG) monitoring and confirmed with ECG re-examinations, data were collected using case report form (CRF) that contained three sections. The first section included demographic information and preoperative variables e.g. obesity, impaired renal function, the second section included clinical information and operative variables like the types of cardiac surgery, cardiopulmonary bypass time, and the third section included information on post cardiac surgery e.g. occurrence of postoperative arrhythmia, the types of arrhythmias, management of arrhythmia, complication of postoperative arrhythmia. Data were then analyzed by SPSS version 23. A p-value of < 0.05 for the association between dependent and independent variables were considered statistically significant.

Results: Out of 100 participants in the study, Of the participants, 52 (52.0%) had a previous history of arrhythmia before admission, 96 (96.0%) had rheumatic heart disease, and 26 (26.0%) had pre-operative arrhythmia during admission of which 18 (69.2%) had ventricular tachycardia and the remaining had atrial fibrillation. Hypertension was present in 78 (78.0%), smoking in 15 (15.0%), COPD in 7 (7.0%), and diabetes in 35 (35.0%). Normal weight was seen in 57 (57.0%), overweight in 36 (36.0%), and underweight in the remainder. The majority underwent valve replacement 55 (55.0%), with 23 (23.0%) having CABG. The study found that 54 (54.0%) of patients undergoing open heart surgery at Jakaya Kikwete Cardiac Institute developed postoperative arrhythmias, with sinus tachycardia 36 (66.7%) and atrial fibrillation 32 (59.2%) being the most common types. Significant factors associated with these arrhythmias included higher BMI (ARR 1.72, p=0.038), a history of arrhythmia (ARR 1.25, p=0.045), pre-operative arrhythmia (risk ratio 7.19, p=0.011), and hemodynamic instability (risk ratio 4.41, p=0.004). Treatment modalities included cardiac membrane stabilizers (69.2%), hydration fluids (69.2%), beta-blockers (61.5%), and anticoagulants (59.0%). The outcomes revealed that 59 (59.0%) of patients experienced hemodynamic instability, 33 (33.0%) had extended hospital stays, and 33 (33.0%) faced bleeding complications, with a very low mortality rate of 1 (1.0%). Conclusion: This study highlights the urgent need to address postoperative arrhythmias following open heart surgery, with a notable incidence observed among patients. Key factors associated with arrhythmias include higher BMI and a history of pre-operative arrhythmia. While pharmacological interventions were commonly used, treatment outcomes were generally positive, though complications such as prolonged hospital stays, and bleeding were noted. The low mortality rate underscores the effectiveness of current management practices but continued focus on optimizing arrhythmia management is essential.