A retrospective evaluation of transthoracic biphasic electrical cardioversion for atrial fibrillation in dogs.
OBJECTIVE
To evaluate safety, efficacy, and clinical usefulness of biphasic transthoracic cardioversion for management of dogs with atrial fibrillation (AF).


BACKGROUND
In dogs AF is usually managed with heart rate control rather than by restoration of sinus rhythm (SR). However, restoration of SR has potential advantages of improving cardiac output and reducing ventricular filling pressures, and biphasic cardioversion provides an improved benefit/risk ratio compared to traditional monophasic cardioversion.


METHODS
Retrospective analysis of data from 39 dogs with spontaneous AF managed with biphasic transthoracic cardioversion was done. Conversion characteristics, adverse effects, and duration of SR were evaluated. Effects of heart disease and pretreatment with amiodarone on success of cardioversion and on duration of SR were also evaluated.


RESULTS
Restoration of SR was achieved in 36 of 39 dogs (92.3%). Presence of heart disease or atrial enlargement had no effect on cardioversion characteristics or ability to restore SR. Median duration of SR following cardioversion and treatment with amiodarone was 120 days. Dogs with lone AF remained in SR longer than those with heart disease.


CONCLUSIONS
Biphasic cardioversion is safe and effective. Although duration of SR varied, a majority of dogs remained in SR long enough to benefit.
Bright
Janice M
JM
The Department of Clinical Sciences, Colorado State University, 300 W. Drake Road, Fort Collins, CO 80523-1620, USA.
Martin
Julie M
JM
Mama
Khursheed
K