FREQUENCY OF ARRHYTHMIA IN POST-OPERATIVE PATIENTS OF CONGENITAL HEART DISEASES

Congenital heart diseases (CHDs) are among the most common congenital abnormalities worldwide and remain a major cause of morbidity and mortality in pediatric patients. These defects include acyanotic lesions such as atrial septal defect, ventricular septal defect, and patent ductus arteriosus, as well as cyanotic lesions including tetralogy of Fallot and transposition of the great arteries. The global prevalence of CHDs is estimated to be 8–10 per 1000 live births, making them a significant public health concern that often requires early surgical intervention. Improvements in pediatric cardiology, cardiopulmonary bypass (CPB) techniques, anesthesia, and postoperative intensive care have significantly increased the survival rate of children undergoing congenital heart surgery.

/Despite advancements in surgical management, postoperative complications continue to affect clinical outcomes, among which cardiac arrhythmias are particularly important. Postoperative arrhythmias may occur due to surgical trauma, myocardial ischemia, inflammation, electrolyte imbalance, hypothermia, or injury to the cardiac conduction system during corrective procedures. These rhythm disturbances range from transient benign arrhythmias to potentially life-threatening conditions such as junctional ectopic tachycardia, atrioventricular block, atrial flutter, atrial fibrillation, and ventricular arrhythmias.

 The incidence of postoperative arrhythmias following congenital heart surgery has been reported between 10% and 50%, depending on the complexity of the congenital defect and surgical procedure. Complex intracardiac repairs, prolonged CPB duration, and extended aortic cross-clamp times are considered important risk factors for postoperative conduction abnormalities. Junctional ectopic tachycardia is one of the most frequently reported arrhythmias in pediatric cardiac surgery and may result in significant hemodynamic instability and prolonged intensive care unit stay if not identified and managed promptly.

 Postoperative arrhythmias can adversely affect patient recovery by reducing cardiac output, prolonging mechanical ventilation, increasing intensive care and hospital stay, and increasing healthcare costs. Severe arrhythmias may lead to low cardiac output syndrome, heart failure, thromboembolic complications, or sudden cardiac death. Therefore, early recognition and continuous cardiac monitoring during the postoperative period are essential to improve patient outcomes and reduce morbidity and mortality associated with congenital heart surgery.

 Although several international studies have evaluated postoperative arrhythmias in congenital heart disease patients, limited local data are available in Pakistan regarding their frequency and associated perioperative factors. Differences in patient demographics, healthcare facilities, surgical expertise, and postoperative management may influence clinical outcomes in the local population. Therefore, local evidence is necessary to better understand the burden and pattern of postoperative arrhythmias in pediatric cardiac surgery patients.

The objective of this study was to determine the frequency of postoperative arrhythmias in pediatric patients undergoing congenital heart surgery and to evaluate their association with perioperative factors including cardiopulmonary bypass time, aortic cross-clamp time, and type of congenital heart surgery.

This descriptive cross-sectional study was conducted in the Department of Cardiac Surgery at Sharif Medical City Hospital, Lahore, over a period of four months. The study included pediatric patients diagnosed with congenital heart diseases (CHDs) who underwent corrective or palliative cardiac surgery and received postoperative care in the Cardiac Surgical Intensive Care Unit (CSICU). Patients were enrolled through non-probability consecutive sampling. A total of 99 patients were included in the study. The sample size was calculated using the single population proportion formula based on a previously reported postoperative arrhythmia frequency of 20.4%, with a 95% confidence level and 8% margin of error.

Patients diagnosed with CHDs through echocardiography and operative records, who underwent congenital heart surgery and had continuous postoperative electrocardiographic (ECG) monitoring, were included in the study. Patients with previous cardiac surgery, preexisting pacemakers, severe multisystem disease, mechanical circulatory support, or incomplete perioperative records were excluded.

 Data were collected using a structured proforma that included demographic characteristics, preoperative investigations, intraoperative variables, and postoperative outpe, and intraoperative hypothermia temperature. Continuous ECG monitoring was performed during the postoperative period to detect arrhythmias within the first 72 hours after surgery. Additional clinical parameters including hemodynamic stability, duration of mechanical ventilation, intensive care unit stay, hospital stay, and laboratory investigations such as serum electrolytes, troponin levels, creatinine, and renal function tests were also assessed. Preoperative and postoperative echocardiography was performed to evaluate cardiac function and identify residual defects or postoperative complications.

 The primary outcome variable was the occurrence of postoperative arrhythmia, while secondary outcomes included the type of arrhythmia and associated postoperative complications. Statistical analysis was performed using Statistical Package for Social Sciences (SPSS) version 26.0 (IBM Corp., Armonk, NY, USA). Descriptive statistics were used to summarize demographic and clinical variables. Categorical variables were presented as frequencies and percentages, while continuous variables were expressed as mean ± standard deviation. Associations between categorical variables and postoperative arrhythmias were analyzed using the chi-square test. A p-value of <0.05 was considered statistically significant.

Giant congenital melanocytic nevi (GCMN) represent a rare This study demonstrated a high frequency of postoperative arrhythmias in pediatric patients undergoing congenital heart surgery, with arrhythmias occurring in 66.7% of patients. Junctional ectopic tachycardia and complete heart block were the most commonly observed arrhythmias, which is consistent with previous studies in pediatric cardiac surgery.

 Prolonged cardiopulmonary bypass (CPB) time and aortic cross-clamp time showed significant associations with postoperative arrhythmias, suggesting that longer ischemic and perfusion durations increase myocardial stress and electrical instability. Complex procedures such as Tetralogy of Fallot, transposition of the great arteries, and TAPVC repair demonstrated a higher frequency of arrhythmias compared to simpler surgeries.

 Hypothermia temperature was also significantly associated with arrhythmia development, with moderate and deep hypothermia linked to different arrhythmia patterns. Logistic regression analysis identified type of surgery, hypothermia, and gender as independent predictors of postoperative arrhythmia.

The study was limited by its single-center design, relatively small sample size, and lack of long-term follow-up. Despite these limitations, the findings provide important local data regarding postoperative arrhythmia in pediatric congenital heart surgery patients and highlight the importance of perioperative monitoring and optimization of surgical factors to  improve patient outcomes.

Postoperative arrhythmias are frequent complications in pediatric patients undergoing congenital heart surgery. Prolonged cardiopulmonary bypass time, aortic cross-clamp time, hypothermia, and complex surgical procedures were significantly associated with arrhythmia development. These findings emphasize the importance of careful perioperative monitoring and optimization of surgical factors to improve postoperative outcomes.

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