Electrocardiographic Changes in Dogs with Degenerative Mitral Valve Disease Treated with Pimobendan: a Retrospective Study of 29 Cases

Abstract

The aim of this retrospective study was to evaluate changes in electrocardiograms (ECG) and cardiac arrhythmias in 29 dogs with degenerative mitral valve disease (DMVD) treated with pimobendan chronically. All dogs had normal ECG before pimobendan administration. The dogs were classified according to ECG after pimobendan administration into 2 groups: normal ECG (n=19) and abnormal ECG (n=10). Age, sex, breed, serum alkaline phosphatase, concurrent digoxin administration, total daily dosage of pimobendan and digoxin, duration of pimobendan administration, and ECG parameters including heart rate, P wave, PR interval, QRS complex, and QT interval were analyzed. Cardiac arrhythmias were increasingly found in the dogs treated with pimobendan in combination with digoxin. The total daily dosage of pimobendan and digoxin in the dogs with abnormal ECG was higher than in those with normal ECG (p=0.022, 0.038, respectively). In conclusion, cardiac arrhythmias can be found in dogs chronically treated with pimobendan. Therefore, caution should be taken when using pimobendan at a high dosage or in combination with digoxin.