In the Irish Wolfhound breed, regular annual heart evaluations or workups consisting of electrocardiography (ECG or EKG), echocardiograms, and an ambulatory heart monitor (ECG), e.g., Holter Monitor are essential and indispensable...Why use a Holter monitor if an ECG and Echocardiogram detect no ventricular arrhythmias (abnormal heart rhythms)?....