Ventricular arrhythmias in horses: 21 cases (1984-1989)

Johanna M. Reimer From the Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, New Bolton Center, 382 W Street Rd, Kennett Square, PA 19348.

Search for other papers by Johanna M. Reimer in
Current site
Google Scholar
PubMed
Close
 VMD
,
Virginia B. Reef From the Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, New Bolton Center, 382 W Street Rd, Kennett Square, PA 19348.

Search for other papers by Virginia B. Reef in
Current site
Google Scholar
PubMed
Close
 DVM
, and
Raymond W. Sweeney From the Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, New Bolton Center, 382 W Street Rd, Kennett Square, PA 19348.

Search for other papers by Raymond W. Sweeney in
Current site
Google Scholar
PubMed
Close
 VMD

Click on author name to view affiliation information

Summary

Ventricular premature depolarizations (vpd) were identified in 21 horses in which unexplained tachycardia or an arrhythmia was detected on auscultation. Horses were categorized into 3 groups on the basis of ecg findings. Seven horses had uniform isolated vpd (group 1); 7 horses had repetitive uniform vpd at a rate <100 vpd/min (group 2); and 7 horses had either multiform vpd, R-on-T, or ≥ 100 vpd/min (group 3). Concurrent systemic disease was identified in 12 horses, 7 of which had gastrointestinal tract disorders. Serum cardiac isoenzyme activities were high in 6 (2 from each group) of 13 horses in which they were measured. Serum electrolyte concentrations were normal in all but 1 of 11 horses in which they were measured.

Antiarrhythmic drugs were given to 9 horses (all of which were in group 2 or group 3), 6 of which converted to sinus rhythm. Two horses that had R-on-T in the ECG died shortly after initiation of antiarrhythmic treatment. An accelerated idioventricular rhythm persisted in 1 horse for at least 8 months and failed to respond to antiarrhythmic drugs. Ventricular premature depolarizations resolved or decreased considerably in frequency in 11 horses without the administration of antiarrhythmic agents. Treatment in these horses included therapy for any underlying systemic disease, corticosteroids, nonsteroidal antiinflammatory drugs, or stall rest. The remaining horse was euthanatized several hours after hospitalization.

Five horses died or were euthanatized either during hospitalization or several months after being discharged. Myocardial lesions were identified at necropsy in 2 horses.

Summary

Ventricular premature depolarizations (vpd) were identified in 21 horses in which unexplained tachycardia or an arrhythmia was detected on auscultation. Horses were categorized into 3 groups on the basis of ecg findings. Seven horses had uniform isolated vpd (group 1); 7 horses had repetitive uniform vpd at a rate <100 vpd/min (group 2); and 7 horses had either multiform vpd, R-on-T, or ≥ 100 vpd/min (group 3). Concurrent systemic disease was identified in 12 horses, 7 of which had gastrointestinal tract disorders. Serum cardiac isoenzyme activities were high in 6 (2 from each group) of 13 horses in which they were measured. Serum electrolyte concentrations were normal in all but 1 of 11 horses in which they were measured.

Antiarrhythmic drugs were given to 9 horses (all of which were in group 2 or group 3), 6 of which converted to sinus rhythm. Two horses that had R-on-T in the ECG died shortly after initiation of antiarrhythmic treatment. An accelerated idioventricular rhythm persisted in 1 horse for at least 8 months and failed to respond to antiarrhythmic drugs. Ventricular premature depolarizations resolved or decreased considerably in frequency in 11 horses without the administration of antiarrhythmic agents. Treatment in these horses included therapy for any underlying systemic disease, corticosteroids, nonsteroidal antiinflammatory drugs, or stall rest. The remaining horse was euthanatized several hours after hospitalization.

Five horses died or were euthanatized either during hospitalization or several months after being discharged. Myocardial lesions were identified at necropsy in 2 horses.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 294 294 59
PDF Downloads 48 48 7
Advertisement