Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) in Boston Terriers

Syncope is a brief loss of consciousness caused by the brain not getting enough blood for a few seconds. It is fast in, fast out. The dog goes limp or stiff, is out for a handful of seconds, then gets up looking mildly puzzled and carries on. There is rarely any warning and rarely any confusion afterward.

A seizure looks different. There is usually a build-up, then rhythmic paddling rather than limpness, often salivation or loss of bladder control, and then a recovery period of minutes to hours in which the dog is disoriented, hungry or restless. That recovery phase is the single most useful distinguishing feature for an owner.

A brachycephalic collapse is different again: it follows exertion, excitement or heat, is preceded by loud, laboured breathing, and the dog is usually blue-tinged around the gums and desperate for air rather than simply unconscious.

Film it if you can. A ten-second phone video is worth more to a cardiologist than an hour of description.

Abnormal rhythms are intermittent, which is the whole problem. A dog can have hundreds of abnormal beats a day and still produce a perfectly normal ECG during a two-minute recording in a consulting room. That is why the standard tool is a Holter monitor - a small recorder in a jacket that logs every beat for twenty-four hours while the dog goes about its ordinary day.

An echocardiogram is usually run alongside it. In ARVC the right ventricle may look dilated and thin-walled, though early cases can have a structurally normal-looking heart with a badly behaved rhythm. Blood tests rule out the metabolic causes that mimic arrhythmias.

For a Boston specifically, an airway assessment belongs in the same workup. If the collapses come after exertion and are announced by noisy breathing, a laryngeal and palate examination will often answer the question faster than a cardiac referral will. Good clinicians run both lines of enquiry rather than committing to one.