Atrial fibrillation in cats: 50 cases (1979-2002)

• Published in: Journal of the American Veterinary Medical Association Vol. 225; no. 2; pp. 256 - 260
• Main Authors: Cote, E, Harpster, N.K, Laste, N.J, MacDonald, K.A, Kittleson, M.D, Bond, B.R, Barrett, K.A, Ettinger, S.J, Atkins, C.E
• Format: Journal Article
• Language: English
• Published: United States 15-07-2004
• Subjects: Age Factors; Animals; Atrial Fibrillation - diagnosis; Atrial Fibrillation - drug therapy; Atrial Fibrillation - mortality; Atrial Fibrillation - veterinary; Cat Diseases - diagnosis; Cat Diseases - drug therapy; Cat Diseases - mortality; Cats; Diagnosis, Differential; Electrocardiography - veterinary; Female; Heart - anatomy & histology; Heart Defects, Congenital - diagnosis; Heart Defects, Congenital - drug therapy; Heart Defects, Congenital - mortality; Heart Defects, Congenital - veterinary; Male; Retrospective Studies; Sex Factors; Survival Analysis; Treatment Outcome
• ISSN: 0003-1488; 1943-569X
• DOI: 10.2460/javma.2004.225.256

To determine signalment, clinical signs, diagnostic findings, treatment, and outcome for cats with atrial fibrillation (AF).
Retrospective study.
50 cats.
Medical records of cats that met criteria for a diagnosis of AF (ECG consisting of at least 2 leads, clear absence of P waves, supraventricular rhythm, and convincingly irregularly irregular rhythm) and had undergone echocardiography were reviewed.
There were 41 males (37 castrated) and 9 females (7 spayed). Forty-one were of mixed breeding; 9 were purebred. Mean +/- SD age was 10.2 +/- 3.7 years. The most common chief complaints were dyspnea, aortic thromboembolism, and lethargy. In 11 cats, AF was an incidental finding. Mean +/- SD ventricular rate was 223 +/- 36 beats/min. The most common echocardiographic abnormalities were restrictive or unclassified cardiomyopathy (n = 19), concentric left ventricular hypertrophy (18), and dilated cardiomyopathy (6). Mean +/- SD left atrial-to-aortic diameter ratio (n = 39) was 2.55 +/- 0.80. The most common thoracic radiographic findings were cardiomegaly, pleural effusion, and pulmonary edema. Median survival time (n = 24) was 165 days (range, 0 to 1,095 days). Eight of 24 cats lived for > or = 1 year after a diagnosis of AF was made.
Results suggest that AF occurs primarily in older adult male cats with structural heart disease severe enough to lead to atrial enlargement. Atrial fibrillation in these cats was most commonly first detected when signs of decompensated cardiac disease were evident, but also was commonly identified as an incidental finding.