E20 - Systematic Review and Meta-Analysis of Risk Factors for Conversion and Recurrence of Atrial Fibrillation

Abstract: Background: Both electrical and pharmacological methods for atrial fibrillation (AF) treatment are widely used. Determination of reliable prognostic factors for success and recurrence is essential to improve the therapeutic decision process.



Objective: The objective was to evaluate the impact of risk factors on the cardioversion success and recurrence rates of all the current AF treatments.



Method: After a systematic search in three international databases, studies reporting treatment of spontaneous AF in at least two horses were included and critically evaluated. A qualitative and quantitative analysis were performed.



Results: Twenty-three studies met the inclusion criteria for the analysis of the success rate and 47 for cardioversion success. The success rate estimation was 86.8% ([78.5;93.6]) for oral quinidine treatment and 96.8% ([89.1;100]) for electrical cardioversion. Horses successfully treated with quinidine were affected for a significantly shorter period than those that failed (mean difference 240, [62; 417], p-value = 0.008). Recurrence was also associated with a longer AF duration. A significant effect of cardiac disease on cardioversion success could not be demonstrated (p-value = 0.2), however, some structural and functional echocardiographic parameters were reported to influence recurrence risk (left atrial area and fractional area change). Electrical remodelling demonstrated by higher fibrillation rate was associated with both lower success and higher recurrence. No clear effect of height, weight, or age could be demonstrated.



Conclusion: Both methods for cardioversion are highly efficient but recurrence is frequent. Duration of arrhythmia, structural and electrical remodeling parameters are the most influential factors on AF conversion success and recurrence.