Acute echocardiographic effects of sotalol on ventricular systolic function in dogs with ventricular arrhythmias

Background: Sotalol is a commonly used antiarrhythmic drug that may alter ventricular function. Objective: To determine the effect of sotalol on echocardiographic indices of ventricular systolic function in dogs with ventricular arrhythmias. Animals: Thirty-five client-owned dogs with ventricular arrhythmias. Methods: Dogs with ventricular arrhythmias (n = 27) had an echocardiogram and 5-minute ECG performed at baseline and 2-4 hours post-sotalol (2-2.5 mg/kg PO once). Eight additional dogs underwent the same protocol but did not receive sotalol (within-day variability controls). Left ventricular (LV) internal dimension at end-systole normalized to bodyweight (LVIDs_N), LV ejection fraction (LV EF), LV shortening area, LV fractional shortening, tricuspid annular plane systolic excursion (TAPSE), and right ventricular systolic myocardial velocity were evaluated as indices of systolic function. Results: All indices except TAPSE had mild decreases in systolic function post-sotalol (all P ≤.0007) compared with baseline but only the percent change in LVIDs_N and LV EF were significantly (P ≤.0079) different from the percent change of the same indices in control dogs. Sinus heart rate, ventricular premature complexes/5-minutes, and arrhythmia grade also were decreased post-sotalol (all P ≤.01) compared with baseline when assessed by a 5-minutes ECG. No dog experienced an adverse event post-sotalol, including dogs with systolic dysfunction or atrial enlargement. Conclusions and Clinical Importance: A single dose of sotalol may cause a mild decrease in LV systolic function in dogs with ventricular arrhythmias. Sotalol appears to be well tolerated, even in dogs with atrial enlargement or systolic dysfunction.