AGGRAVATION OF POSTCARDIOVERSION ATRIAL DYSFUNCTION BY SOTALOL

Objectives. This study determined the effect of sotalol on atrial func tion after electrical cardioversion of atrial fibrillation. Background . After electrical cardioversion of atrial fibrillation, the Doppler m itral A wave is often diminished, representing impaired atrial contrac tile function. Sotalol is an effective atrial antiarrhythmic drug with class III and beta-adrenergic blacking properties. Although the negat ive inotropic effect of sotalol on the ventricle is minimal in patient s with normal ventricular function, it may manifest negative inotropy when ventricular function is impaired. We postulated that after cardio version, when intrinsic atrial function is impaired, sotalol may have an adverse effect on the atrium. Methods. Thirty seven patients enroll ed in a randomized, double-blind study of sotalol for maintenance of s inus rhythm were studied by quantitative Doppler echocardiography with in 24 h of electrical cardioversion and, for those still in sinus rhyt hm, again at 1 month. Doppler variables (E and A wave velocities and i ntegrals) in patients receiving sotalol were compared with those in pa tients receiving placebo. Results. After electrical cardioversion, pea k A wave velocity and A wave time-velocity integral in the 20 patients receiving placebo were reduced compared with normal values. In the 17 patients receiving sotalol (median dose 320 mg twice daily) these var iables were further reduced (mean [+/-SD] peak A wave velocity 19.4 +/ - 5.5 vs. 38.4 +/- 14.7 cm/s, p < 0.001 and mean A wave Time-velocity integral 1.7 +/- 0.6 vs. 3.4 +/- 1.4 cm, p < 0.001, in sotalol- vs. pl acebo-treated patients, respectively). Early diastolic filling (E wave variables) did not differ between sotalol- and placebo-treated groups , At 1 month, five sotalol- and six placebo-treated patients remained in sinus rhythm, and A wave variables had increased for the whole grou p, with a greater increase in sotalol-treated patients. Conclusions. A fter electrical cardioversion, when atrial stunning is prominent, sota lol has a negative atrial inotropic effect, This effect may be tempora ry, as suggested by resolution at 1 month. Negative inotropic effects of antiarrhythmic drugs on the atrium should be considered in assessin g Doppler variables of left ventricular filling.