Effect of atenolol on heart rate, arrhythmias, blood pressure, and dynamic left ventricular outflow tract obstruction in cats with subclinical hypertrophic cardiomyopathy.

Abstract

OBJECTIVE:

To investigate the negative chronotropic, antiarrhythmic, and obstruction-relieving effects of atenolol in cats with subclinical hypertrophic cardiomyopathy (HCM).

ANIMALS:

Seventeen cats with HCM.

METHODS:

Results for echocardiography, electrocardiography, Doppler blood pressure, and 24 h Holter monitoring were compared in cats before and 2-4 weeks after atenolol therapy (6.25-12.5 mg PO q 12 h).

RESULTS:

The left ventricular outflow tract maximum velocity (LVOT Vmax) decreased after atenolol administration (mean Vmax pre-treatment 3.3 m/s ± 1.8 m/s; post-treatment 1.6 m/s ± 1.0 m/s, p < 0.0001). Heart rate (HR) decreased after atenolol for all HR modalities. The total number of ventricular origin complexes (TotVent) and ventricular premature complexes (VPCs) decreased after atenolol. The VPCs decreased from a geometric mean of 61 complexes/24 h (range, 11-620 complexes/24 h) to 15 complexes/24 h (range, 1-1625 complexes/24 h) (p < 0.0001). Murmur grade decreased after atenolol from a median grade of 3/6 to 2/6 (p < 0.0001). The systolic blood pressure did not change (mean pre-treatment 130 mmHg ± 16 mmHg, mean post-treatment 123 mmHg ± 20 mmHg, p = 0.2).

CONCLUSION:

Atenolol decreases HR, murmur grade, and LVOT obstruction, and to a lesser degree, frequency of ventricular ectopy, in cats with subclinical HCM. Further studies are needed to determine if sudden cardiac death or long-term outcome is influenced by atenolol administration.

• Authors: Bethany L Jackson, Darcy B Adin, Linda B Lehmkuhl
• Journal: Journal of veterinary cardiology : the official journal of the European Society of Veterinary Cardiology (J Vet Cardiol) Vol. 17 Suppl 1 Pg. S296-305 (Dec 2015) ISSN: 1875-0834 [Electronic] Netherlands
• PMID: 26776587 (Publication Type: Clinical Trial, Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2015 Elsevier B.V. All rights reserved.

Chemical References

• Anti-Arrhythmia Agents
• Atenolol

Topics

• Animals
• Anti-Arrhythmia Agents (therapeutic use)
• Arrhythmias, Cardiac (drug therapy, veterinary)
• Atenolol (therapeutic use)
• Blood Pressure (drug effects)
• Cardiomyopathy, Hypertrophic (drug therapy, veterinary)
• Cat Diseases (drug therapy)
• Cats
• Female
• Heart Rate (drug effects)
• Male
• Ventricular Outflow Obstruction (drug therapy)