A 9-year-old 6.3-kg (13.9-lb) sexually intact male Maltese was referred to the Cardiology Unit of the Department of Veterinary Sciences of the University of Parma because of episodes of transient loss of consciousness (T-LOC) with vocalization, limb stiffness, opisthotonus, and urine incontinence. During the preceding few months, the T-LOC episodes became more frequent and occurred during both periods of rest and exercise. Physical examination findings were unremarkable except for a grade 1/6 midsystolic cardiac murmur, which was audible over the left apex, and an irregular cardiac rhythm. Echocardiography revealed mild left ventricular systolic dysfunction and trivial mitral valve regurgitation. During the echocardiographic examination, ECG monitoring revealed respiratory sinus arrhythmia with a mean heart rate of 85 beats/min and frequent episodes of isolated second-degree atrioventricular block (AVB). On the basis of the dog's history and echocardiographic findings, Holter monitoring for a 24-hour period and clinicopathologic analyses were performed.
Leventa, MSD Animal Health S.r.l. Italia, Via Fratelli Cervi, Italy.
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