Identifying and Reducing Risk in Familial Long QT Syndrome

Abstract

Although knowledge of molecular genetics in cardiac inherited diseases (CID) has changed dramatically in recent years, the detection and clinical management of these conditions have changed little. Aims To focus on four key clinical areas relating primarily to familial long QT syndrome; (1) the family history in detection, (2) Holter recordings in detection and risk stratification, (3) adherence to betablocker therapy and (4) the side effects of left cardiac sympathetic denervation. Methods Patients enrolled with the New Zealand Cardiac Inherited Disease Registry were eligible for inclusion. Case notes were reviewed, electronic records audited and Holter monitors, ECGs and patient surveys conducted. Findings Taking a multigenerational family history increases detection of cardiac inherited diseases but is done poorly amongst general cardiology teams. Measurements of repolarisation on Holter monitors are highly repeatable, reflect disease status and clinical risk better than the initial ECG, and indicate those at low risk of symptoms and cardiac arrest. Beta-blocker adherence is suboptimal in half the Auckland LQTS population. Morbidity and patient satisfaction are both very high following left cardiac sympathetic denervation for LQTS and catecholaminergic polymorphic ventricular tachycardia. Conclusions The detection of CIDs and risk stratification and treatment of LQTS can be improved through refinements of clinically available tools. The cardiac sympathectomy is well tolerated despite side effects. Further research is needed to improve adherence to beta-blocker therapy.