Abstract 2250: Active Cascade Screening in Primary Inherited Arrhythmia Syndromes; Does it Lead to Prophylactic Treatment?
Introduction The congenital long QT syndrome (LQTS), Brugada syndrome (BrS) and catecholaminergic polymorphic ventricular tachycardia (CPVT) are primary inherited cardiac arrhythmia syndromes which may cause syncope and sudden cardiac death in young individuals. After establishing the disease-causing DNA mutation in probands, we actively conducted cascade screening to identify relatives who are also at risk of life-threatening arrhythmias. We studied how often this led to prophylactic treatment.
Methods and Results We retrospectively collected data from our Cardiogenetics database and patient records. In 1996–2006, 118 probands with a disease causing mutation in one of the involved genes were identified and 446 relatives were tested positive for the disease causing mutation found in their family. These subjects subsequently underwent cardiologic investigation (ECG, exercise testing, Holter, ajmaline testing, echocardiography, where appropriate). We analyzed the numbers and percentages of identified carriers needing prophylactic treatment. Treatment was deemed necessary based on the results of cardiologic investigation, type of disease, previously reported properties (clinical and/or biophysical) of the mutation, familial occurrence of unexplained sudden death, and age of the subject. Treatment was initiated in 69% (197/285), 9% (5/54) and 71% (76/107) relatives in the LQTS, BrS, and CPVT families, respectively. Twenty-six carriers were lost to follow-up. Treatment included drug treatment (n=244) and implantation of pacemakers (n=26) or ICDs (n=8).
Conclusions Cascade screening in families with LQTS, BrS or CPVT, which was based on DNA mutation carriership and subsequent cardiologic investigation, resulted in immediate prophylactic treatment in a substantial proportion of carriers (278/446, 62%), although it varies significantly between the different disease entities.