Genotype- and mutation site-specific QT adaptation during exercise, recovery, and postural changes in children with long-QT syndrome.

Genotype and Mutation Site Specific QT Adaptation during Exercise, Recovery and Postural Changes in Children with LQTS Running title: Aziz et al.; Exercise Stress Testing in Pediatric LQTS Patients

Rate adaptation of QT intervals during and after exercise in children with congenital long QT syndrome.

OBJECTIVES To improve the diagnostic criteria of the congenital long QT syndrome in borderline cases we examined rate adaptation of ventricular repolarization phases during exercise and subsequent recovery in children with the long QT syndrome and controls. METHODS Nineteen children with definite long QT syndrome and 19 healthy controls underwent exercise testing. QT intervals were measured t...

Utility of treadmill testing in identification and genotype prediction in long-QT syndrome.

BACKGROUND The clinical diagnosis of long-QT syndrome (LQTS) remains challenging when ECG abnormalities are borderline or intermittent. Despite issues with access, cost, and heterogeneity of LQTS mutations, genetic testing remains the diagnostic gold standard for diagnosis of LQTS. We sought to develop a provocative testing strategy to unmask the LQTS phenotype and relate this to the results of...

The relationship between Tonic-Clonic sizures in children and increased time of ventricular repolarization

Background: Long QT syndrome (LQTS) is a disorder in which electrical cardiac ventricular repolarization is impaired. It results in an increased risk of an irregular heartbeat which can result in palpitations, fainting, drowning, or sudden death. Long QT Syndrome may present as tonic-clonic seizure or a seizure-like disorder. By taking a superficial electrocardiogram (ECG) and proper diagnosis,...

Abnormal repolarization dynamics revealed in exercise test in long QT syndrome mutation carriers with normal resting QT interval.

AIMS The identification of affected family members with long QT syndrome (LQTS) is often difficult due to their normal-or only marginally lengthened-QT interval duration. We examined whether physical exercise test could increase the ability to detect the mutation carrier status in phenotypically normal LQTS family members. METHODS AND RESULTS Sixty-six subjects were included: 15 were carriers...