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Individualized corrected QT interval is superior to QT interval corrected using the Bazett formula in predicting mutation carriage in families with long QT syndrome

Tijdschriftbijdrage - Tijdschriftartikel

BACKGROUND Long QT syndrome (LQTS) is characterized by reduced penetrance and variable QT prolongation over time, resulting in an estimate of 25% carriers of a pathogenic mutation with a normal corrected QT (QTc) interval on the resting electrocardiogram (ECG). OBJECTIVE The purpose of this study was to test the hypothesis that an individualized corrected QT interval derived from 24-hour Holter data more accurately predicts carriage of a pathogenic LQTS mutation than did QT derived from a standard 12-lead ECG and corrected using the Bazett formula (QTcinterval). METHODS Carriers of a pathogenic LQTS mutation and their genotype-negative family members who had both resting ECG and Holter recordings available were included. Automated and manual measurements of QTc were performed. QTi was derived from 24-hour Holter recordings and defined as the QT value at the intersection of an RR interval of 1000ms, with the linear regression line fitted through QT-RR data points of each individual patient. RESULTS In total, 69 patients with LQTS (23 long QT type1, 39 long QT type2 and 7 long QT type3) and 55 controls were selected. Demographic characteristics were comparable. A comparison of the receiver operating characteristic curves indicates that the test added diagnostic value compared to manual measurement (P = .02) or automated measurement (P = .005). The diagnostic accuracy of manually measured QTc using conventional cutoff criteria was 72%, while it was 92% using a sex-independent QTi cutoff of 445ms. This was caused by a 39% increase in sensitivity without compromising the specificity. CONCLUSION QTi derived from Holter recordings is superior to conventional QTc measured from a standard 12-lead ECG in predicting the mutation carrier state in families with LQTS.
Tijdschrift: Heart Rhythm
ISSN: 1547-5271
Issue: 3
Volume: 14
Pagina's: 376 - 382
Jaar van publicatie:2017
BOF-keylabel:ja
IOF-keylabel:ja
BOF-publication weight:2
CSS-citation score:1
Authors from:Hospital, Higher Education
Toegankelijkheid:Closed