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Assessment of prolonged QT and JT intervals in ventricular conduction defects.

TitleAssessment of prolonged QT and JT intervals in ventricular conduction defects.
Publication TypeJournal Article
Year of Publication2004
AuthorsRautaharju, PM, Zhang, Z-M, Prineas, R, Heiss, G
JournalAm J Cardiol
Volume93
Issue8
Pagination1017-21
Date Published2004 Apr 15
ISSN0002-9149
KeywordsAdult, Aged, Aged, 80 and over, Arrhythmias, Cardiac, Bundle-Branch Block, Electrocardiography, Female, Heart Ventricles, Humans, Male, Middle Aged
Abstract<p>The JT interval or Bazett's QTc - QRS has been advocated for detection of prolonged repolarization in ventricular conduction defects (VCDs). However, the use of neither JT nor QTc - QRS has been validated, and normal limits for rate-adjusted JT have not been established for VCDs or for normal ventricular conduction. Functional relations among RR, JT, and QT intervals were evaluated in 11,739 adult men and women with normal ventricular conduction and in 1,251 subjects with major VCD. The results showed that JT adjustment obtained as QTc - QRS retained a strong residual correlation with ventricular rate (r = 0.54), making its use ill-advised. In contrast, QT adjustment as a linear function of the RR interval for VCD as QT(RR,QRS) = QT - 155 x (60/heart rate - 1) - 0.93 x (QRS - 139) + k, with k = -22 ms for men and -34 ms for women, removed the rate dependence and produced upper 2% and 5% normal limits at 460 and 450 ms, respectively, which are identical to those in normal conduction. As an alternative, equally effective linear JT adjustment formulas were derived, including newly required normal standards. Thus, detection of prolonged repolarization in VCD requires the use of the JT interval or a bivariate model for QT with RR and QRS intervals as covariates.</p>
DOI10.1016/j.amjcard.2003.12.055
Alternate JournalAm J Cardiol
PubMed ID15081446
Grant ListN01-HC-15103 / HC / NHLBI NIH HHS / United States
N01-HC-35129 / HC / NHLBI NIH HHS / United States
N01-HC-55015 / HC / NHLBI NIH HHS / United States
N01-HC-55016 / HC / NHLBI NIH HHS / United States
N01-HC-55018 / HC / NHLBI NIH HHS / United States
N01-HC-55022 / HC / NHLBI NIH HHS / United States
N01-HC-85079 / HC / NHLBI NIH HHS / United States
N01-HC-85086 / HC / NHLBI NIH HHS / United States