Arrhythmogenic Right Ventricular Cardiomyopathy
Dr Robert Hamilton
Cardiac Genetics Clinic (416-813-5850)
The Hospital for Sick Children, Toronto
Submitted January 2007
Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an increasingly recognized disorder associated with life-threatening arrhythmias and sudden death in young adults. ARVC may be present in as many as 1/1000 people, although more traditional estimates are from 1/1667 to 1/5000.
In the past, ARVC was most often diagnosed when the heart was examined after the sudden death of individual in their 20’s or 30’s. Such hearts demonstrated fat and scarring replacing heart muscle in the wall of the right pumping chamber. Increasingly, ARVC is now being diagnosed during life in patients presenting with heart arrhythmias or episodes of fainting, often associated with activity. Because the right pumping chamber has a complex shape, lies directly under the breastbone and is surrounded some normal fat, it is often difficult to see or recognize the small changes that occur in the cavity and wall of this pumping chamber in affected people. Similarly, ECG’s in such patients often appear relatively normal unless specific measurements or special kinds of ECG’s are performed. ARVC often requires multiple abnormalities to be identified on several tests in order to make a firm diagnosis. Fortunately, the process of diagnosis has been helped by the definition of ARVC Task Force Criteria by an expert consensus committee of the European Society of Cardiology in 1994.
ARVC diagnosis is now moving into an era of potential genetic diagnosis. Multiple gene locations associated with ARVC have been identified. So far, a common feature is that these gene mutations change proteins that hold heart muscle cells together at their ends. Some genes are available for clinical testing through out-of-country laboratories, with funding for this testing assessed by provincial health ministries on a case-by-case basis. Other gene testing is also performed in research laboratories. Currently (2007), genes are only identified for between 15 and 50% of patients with ARVC.
Symptoms and Assessment: The most common symptoms among adults with ARVC are palpitations, syncope and sudden death. Children likely present with similar symptoms, although sudden death is less common. Among patients who died with typical ARVC, only 10% of deaths occurred before age 19, but 50% occurred before age 35. Among children assessed for ARVC, patients rarely met ARVC Task force criteria before age 8 years, and the rare deaths that occurred were after age 12 years.
Electrocardiogram (ECG): ECG features of ARVC in adults, when carefully measured, can be identified in 75 to 84%, and are usually quite specific (not found in unaffected individuals). The Signal-Averaged ECG (SAECG