Premium
Limb Lead Interchange in Thorough QT/QTc Studies
Author(s) -
Salvi Vaibhav,
Karnad Dilip R.,
Panicker Gopi Krishna,
Kothari Snehal,
Hingorani Pooja,
Natekar Mili,
Mahajan Vaibhav,
Narula Dhiraj
Publication year - 2011
Publication title -
the journal of clinical pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.92
H-Index - 116
eISSN - 1552-4604
pISSN - 0091-2700
DOI - 10.1177/0091270010383857
Subject(s) - qt interval , precordial examination , medicine , lead (geology) , electrocardiography , cardiology , long qt syndrome , holter monitor , geomorphology , geology
The investigators analyzed 85 133 electrocardiograms (ECGs) recorded in 484 subjects from 5 thorough QT/QTc studies (3 using Holter devices, 2 using 12‐lead ECGs) for inadvertent limb lead interchanges using a dedicated quality control process in a central ECG laboratory. Limb lead interchanges were present in 2919 (3.4%) ECGs in 17.9% of subjects and were more frequent with Holter devices (7.5% vs 0.8%, P < .0001), where leads remain connected for prolonged periods, affecting data from several time points. Left arm—left leg interchange was seen in 54% of 12‐lead ECGs and right arm—left arm interchange in 38%. The ECG device itself could identify 21.7% of interchanges, whereas experienced readers blinded to subject and visit identified 79% of interchanges; 21% of interchanges were identified only during the quality control process. If correctly identified, QT measurement could be performed in a precordial lead. If undiagnosed, incorrect QT interval measurements and morphological diagnosis may confound results.