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...

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BACKGROUND The clinical course and the precipitating risk factors in the congenital long QT syndrome (LQTS) are genotype specific. OBJECTIVES The goal of this study was to develop a computer algorithm allowing for electrocardiogram (ECG)-based identification and differentiation of LQT1 and LQT2 carriers. METHODS Twelve-lead ECG Holter monitor recordings were acquired in 49 LQT1 carriers, 25...

Patients with the long QT syndrome (LQTS) suffer from cardiac arrhythmias that can lead to abrupt loss of consciousness and sudden death, already in young individuals. Thus, an early diagnosis of LQTS is essential for patients and their family members. So far, six genes (KCNQ1, HERG, SCN5A, ANK2, KCNE1, KCNE2) have been demonstrated to be involved in the development of LQTS. Since this syndrome...

The sudden infant death syndrome (SIDS) is defined as sudden death in infants, unexpected by history, for which no cause is found at autopsy . The peak rate of SIDS occurs between and 3 months of life, and it is uncommon before 1 month and after 6 months (1) . Survivors of episodes that seem to be life threatening (apparent life-threatening events) are usually called near-miss for SIDS, or simp...

Diagnosing a congenital long QT syndrome (LQTS) is straightforward when a prolonged QT is present in a patient with arrhythmia-related symptoms and documented torsade de pointes.1 More often, however, a clear-cut diagnosis is not possible because: (1) QT-related arrhythmias are only rarely documented (except for patients with arrhythmic storms), and cannot be reliably and safely provoked. (2) A...

Background—Women with congenital long-QT syndrome experience an increased risk for cardiac events after the onset of adolescence that is more pronounced among carriers of the LQT2 genotype. We hypothesized that the hormonal changes associated with menopause may affect clinical risk in this population. Methods and Results—We used a repeated-events analysis to evaluate the risk for recurrent sync...

The 3-O-sulfotransferase (3-OST) family catalyzes rare modifications of glycosaminoglycan chains on heparan sulfate proteoglycans, yet their biological functions are largely unknown. Knockdown of 3-OST-7 in zebrafish uncouples cardiac ventricular contraction from normal calcium cycling and electrophysiology by reducing tropomyosin4 (tpm4) expression. Normal 3-OST-7 activity prevents the expansi...

Background—Genetic testing can diagnose long-QT syndrome (LQTS) in asymptomatic relatives of patients with an identified mutation; however, it is costly and subject to availability. The accuracy of a simple algorithm that incorporates resting and exercise ECG parameters for screening LQTS in asymptomatic relatives was evaluated, with genetic testing as the gold standard. Methods and Results—Asy...