Referenced in: none

Automatically associated channels: Kv11.1 , Kv7.1

Title: Follow-up of 316 molecularly defined pediatric long-QT syndrome patients: clinical course, treatments, and side effects.

Authors: Mikael Koponen, Annukka Marjamaa, Anita Hiippala, Juha-Matti Happonen, Aki S Havulinna, Veikko Salomaa, Annukka M Lahtinen, Taina Hintsa, Matti Viitasalo, Lauri Toivonen, Kimmo Kontula, Heikki Swan

Journal, date & volume: Circ Arrhythm Electrophysiol, 2015 Aug , 8, 815-23

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/26063740

Abstract
Inherited long-QT syndrome (LQTS) is associated with risk of sudden death. We assessed the clinical course and the fulfillment of current treatment strategies in molecularly defined pediatric LQTS type 1 and (LQT1) and type 2 (LQT2) patients.Follow-up data covering a mean of 12 years were collected for 316 genotyped LQT1 and LQT2 patients aged 0 to 18 years. No arrhythmic deaths occurred during the follow-up. Finnish KCNQ1 and KCNH2 founder mutations were associated with fewer cardiac events than other KCNQ1 and KCNH2 mutations (hazard ratio [HR], 0.33; P=0.03 and HR, 0.16; P=0.01, respectively). QTc interval ≥500 ms increased the risk of cardiac events compared with QTc <470 ms (HR, 3.32; P=0.001). Treatment with β-blocker medication was associated with reduced risk of first cardiac event (HR, 0.23; P=0.001). Noncompliant LQT2 patients were more often symptomatic than compliant LQT2 patients (18% and 0%, respectively; P=0.03). Treatment with implantable cardioverter defibrillator was rare (3%) and resulted in reinterventions in 44% of cases.Severe cardiac events are uncommon in molecularly defined and appropriately treated pediatric LQTS mutation carriers. β-Blocker medication reduces the risk of cardiac events and is generally well tolerated in this age group of LQTS patients.