Predictors of Left Atrial Thrombus and Short-Term Recurrence of Arrhythmia in Patients Undergoing Electrical Cardioversion for Atrial Fibrillation, a Single-Centre Experience

Background: Systemic thromboembolism is a serious complication of electrical cardioversion. Even in the absence of such complications there exists a significant rate of arrhythmia recurrence post cardioversion. Aims: The aim of this study was to identify factors that may aid clinicians in identifying those patients at increased risk of atrial thrombus formation and short-term arrhythmia recurrence. Methods: One-hundred and twelve patients were retrospectively identified across a 2.5 year period as having undergone electrical cardioversion at the Gold Coast University Hospital for atrial fibrillation or atrial flutter. Demographic, clinical and echocardiogram data was analysed to identify potential predictors of thrombus, unsuccessful cardioversion and arrhythmia recurrence. Results: Cardioversion was successful in 87.6% of patients. Cardioversion was more successful initially in males (p<0.01) and those with reduced atrial volume (p<0.01) and higher left ventricular ejection fraction (p<0.01). Arrhythmia recurrence within 3 months occurred in 57.7% of patients. Recurrence was more likely in those with congestive heart failure (p<0.05) and a longer pre-cardioversion duration of arrhythmia (p<0.05). Spontaneous echo contrast was observed in 3 (2.6%) of patients, whilst left atrial thrombus was observed in 7 (6.2%) of patients. Potential predictors of thrombus were congestive heart failure (p<0.05) and increased left atrial volume (p<0.01). Conclusions: This retrospective study identified a number of factors that may useful in the clinical setting in predicting cardioversion success, both initially and short-term, in addition to predicting thrombus formation.