Open AccessProvocative Testing in Children with Suspect Congenital Long QT Syndrome
Author(s) -
Berul Charles I.,
Sweeten Tammy L.,
Hill Sharon L.,
Vetter Victoria L.
Publication year - 1998
Publication title -
annals of noninvasive electrocardiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.494
H-Index - 48
eISSN - 1542-474X
pISSN - 1082-720X
DOI - 10.1111/j.1542-474x.1998.tb00023.x
Subject(s) - medicine , long qt syndrome , cardiology , catecholaminergic polymorphic ventricular tachycardia , qt interval , electrocardiography , ryanodine receptor 2 , ryanodine receptor , calcium
Objectives This study was designed to evaluate several alternative ECG measurements and provocative tests in order to identify markers for children with suspect congenital long QT syndrome (LQTS). Background A single QT c measurement on a resting ECG does not identify all children with LQTS. Alternative ECG measurements have been established for identification of LQTS patients, with varied degrees of accuracy. Additionally, findings of QT prolongation during exercise or catecholaminergic stimulation have been suggested as indicators for the presence of LQTS and associated arrhythmias. Methods The ECGs from 40 children with suspect congenital LQTS were compared with 1000 gender and age matched control patients. Complete exercise ECG studies were performed on 32 of the 40 suspect LQTS patients and compared with 29 controls. ECGs recorded during isoproterenol infusion were obtained in 9 suspect LQTS patients and compared with 44 matched control subjects. Results During exercise, the QT c was mildly prolonged in both groups, without a similar increase in JT c , suggesting prolongation of depolarization time. QT and JT dispersion shortened with exercise in control subjects, but not in the suspect LQTS patients. During isoproterenol infusion, the QT c and JT c are prolonged in the suspect LQTS group, without an increase in the control patients. Conclusions We describe the ECG findings with provocative testing in patients in whom there is a clinical suspicion of LQTS, yet have a normal or borderline QT c . Exercise or isoproterenol may aid in identification of patients with congenital long QT syndrome.