Please help me diagnosing this condition with abnormal ECG report

An 11-year-old spayed Labrador retriever is presented for vague signs of lethargy and inappetence. Physical examination reveals normal mucous membranes, normal capillary refill time, strong/bounding pulses with a slow heart rate, and a pulse rate of 50 bpm. Auscultation shows irregular heart sounds and a grade II/VI left apical systolic murmur.

Last commented 6 days ago