Community detection of long QT syndrome with a clinical registry: An alternative to ECG screening programs?

BACKGROUND long QT syndrome (LOTS) prevalence is estimated at 4 of 10,000 based on community electrocardiogram (ECG) screening, about which there is disagreement regarding efficacy, accuracy, cost-effectiveness, and practicality. Family studies of autosomal dominant conditions such as LOTS have revealed 8-9 gene-positive family members per proband. OBJECTIVE To evaluate a cardiac/genetic registry and family screening program as a toot to identify LOTS in the community. METHODS Possible LOTS probands were referred to the New Zealand Cardiac Inherited Disease service. The registry was first established in the northern region (population 2.03 million), including central Auckland (population 0.46 million). After clinical evaluation, genetic testing and family cascade screening were initiated. Genotype-positive individuals were classified as definite LOTS, and others were classified as definite or probable LOTS by clinical and ECG criteria. RESULTS One hundred twelve probands were identified (presentation: 7 sudden death, 82 cardiac event, 16 ECG abnormality, and 7 sudden death of a family member). Following cascade screening, 309 patients with LOTS were identified (248 definite and 61 probable). Two hundred twenty patients had LOTS-causing mutations identified (120 [55%] LQT1, 78 [35%] LOT2, 19 [9%] LOT3, 1 [0.5%] LOT 5, and 2 [1%] LOT7). Thus far, an average of 2.1 definitely or probably affected family members have been identified per proband. The community detection rate is 1.5 of 10,000 for the whole region and 2.2 of 10,000 in Auckland. CONCLUSIONS A high lever of community detection of LOTS is possible using a clinical registry. With adequate resourcing, this has the potential to be an effective alternative to community ECG screening.