Persistent atrial standstill in a cat

Abstract

A domestic shorthaired cat was presented with a 1-month history of cardiomegaly and recurrent chylothorax. The heart rate was 130 beats/min and no P waves were present on a surface electrocardiogram. Thoracic radiographs and an echocardiogram demonstrated severe biatrial dilatation, pleural effusion and restrictive pleural disease. Permanent atrial standstill was suspected. Pleurocentesis was performed and therapy was started with enalapril, frusemide and aspirin. Intracardiac electrograms revealed no atrial activity, and atrial pacing failed to elicit atrial or ventricular depolarisations. The patient was euthanased. Necropsy showed severe atrial wall thinning with marked cardiocyte loss. Persistent atrial standstill is a rare disease in the cat. Clinical signs may have been due to loss of atrial function, ventricular diastolic dysfunction, bradycardia, neurohormonal activation and reduced atrial natriuretic peptide plasma concentrations.

Indications for permanent pacing in dogs and cats

“…Persistent atrial standstill has been also described in cats, and the definitive diagnosis was made using electrophysiological study and histological examination. The histopathological findings were consistent with loss of atrial cardiomyocytes, in which remaining cells were separated by residual atrial collagenous connective tissue and fat [87].…”

ECG of the Month

“…2,4,5 Hyperkalemia is the most common cause of transient atrial standstill and is reversible if the primary disease is identified and treated. 2,3 Permanent atrial standstill is a condition typically associated with severe end-stage cardiomyopathy or atrial myopathy.…”

Prevalência das arritmas cardíacas e distúrbios de condução em cães e gatos em Botucatu, Brasil (2003-2007)

“…Supraventricular and ventricular tachycardia were reported in cats with hyperkalemia 12,26 and cardiac disease 25 . One case of persistent atrial standstill not related with hyperkalemia is presented in the literature 9 . A study reported 50 cats with atrial fibrillation that was detected when signs of decompensated cardiac disease were evident, but also was commonly identified as an incidental finding 10 .…”