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Evaluation of the QT interval in patients with drug‐induced QT prolongation and torsades de pointes
Author(s) -
Krisai Philipp,
Vlachos Konstantinos,
Ramirez F. Daniel,
Nakatani Yosuke,
Nakashima Takashi,
Takagi Takamitsu,
Kamakura Tsukasa,
Surget Elodie,
André Clémentine,
Cheniti Ghassen,
Welte Nicolas,
Chauvel Rémi,
Tixier Romain,
Duchateau Josselin,
Pambrun Thomas,
Derval Nicolas,
Hocini Mélèze,
Jaïs Pierre,
Haïssaguerre Michel,
Sacher Frédéric
Publication year - 2020
Publication title -
journal of cardiovascular electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.193
H-Index - 138
eISSN - 1540-8167
pISSN - 1045-3873
DOI - 10.1111/jce.14687
Subject(s) - medicine , torsades de pointes , qt interval , cardiology , long qt syndrome , t wave , electrocardiography
Abstract Background Data on the optimal location of the electrocardiogram (ECG) leads for the diagnosis of drug‐induced long QT syndrome (diLQTS) with torsades de pointes (TdP) are lacking. Methods We systematically reviewed the literature for the ECGs of patients with diLQTS and subsequent TdP. We assessed T wave morphology in each lead and measured the longest QT interval in the limb and chest leads in a standardized fashion. Results Of 84 patients, 61.9% were female and the mean age was 58.8 years. QTc was significantly longer in chest versus limb leads (mean ( SD ) 671 (102) vs. 655 (97) ms, p = .02). Using only limb leads for QT interpretation, 18 (21.4%) ECGs were noninterpretable: 10 (11.9%) due to too flat T waves, 7 (8.3%) due to frequent, early PVCs and 1 (1.2%) due to too low ECG recording quality. In the chest leads, ECGs were noninterpretable in nine (10.7%) patients: six (7.1%) due to frequent, early PVCs, one (1.2%) due to insufficient ECG quality, two (2.4%) due to missing chest leads but none due to too flat T waves. The most common T wave morphologies in the limb leads were flat (51.0%), broad (14.3%), and late peaking (12.6%) T waves. Corresponding chest lead morphologies were inverted (35.5%), flat (19.6%), and biphasic (15.2%) T waves. Conclusions Our results indicate that QT evaluation by limb leads only underestimates the incidence of diLQTS experiencing TdP and favors the screening using both limb and chest lead ECG.