Published Online
on October 14, 2002

A more recent version of this article appeared on November 5, 2002

This Article Full Text (PDF) All Versions of this Article: 106/19/2473    most recent 01.CIR.0000036369.16112.7Dv1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Viitasalo, M. Articles by Scheinman, M. M. Search for Related Content PubMed PubMed Citation Articles by Viitasalo, M. Articles by Scheinman, M. M. Related Collections Electrocardiology Arrhythmias, clinical electrophysiology, drugs

Submitted on May 23, 2002
Revised on August 20, 2002
Accepted on August 21, 2002

Ambulatory Electrocardiographic Evidence of Transmural Dispersion of Repolarization in Patients With Long-QT Syndrome Type 1 and 2

Matti Viitasalo MD^*, Lasse Oikarinen MD, Heikki Swan MD, Heikki Väänänen MSc, Kathy Glatter MD, Päivi J. Laitinen MSc, Kimmo Kontula MD, Hal V. Barron MD, PhD, Lauri Toivonen MD, and Melvin M. Scheinman MD

From the Department of Medicine, Cardiac Electrophysiology, University of California, San Francisco (M.V., K.G., H.V.B., M.M.S.); the Department of Medicine, Helsinki University Hospital, Helsinki, Finland (M.V., L.O., H.S., P.J.L., K.K., L.T.); and the Laboratory of Biomedical Engineering, Helsinki University of Technology, Espoo, Finland (H.V.).

^* To whom correspondence should be addressed. E-mail: matti.viitasalo{at}hus.fi.

Background—Transmural dispersion of repolarization (TDR) may be related to the genesis of torsade de pointes (TdP) in patients with the long-QT (LQT) syndrome. Experimentally, LQT2 models show increased TDR compared with LQT1, and ß-adrenergic stimulation increases TDR in both models. Clinically, LQT1 patients experience symptoms at elevated heart rates, but LQT2 patients do so at lower rates. The interval from T-wave peak to T-wave end (TPE interval) is the clinical counterpart of TDR. We explored the relationship of TPE interval to heart rate and to the presence of symptoms in patients with LQT1 and LQT2.

Methods and Results—We reviewed Holter recordings from 90 genotyped subjects, 31 with LQT1, 28 with LQT2, and 31 from unaffected family members, to record TPE intervals by use of an automated computerized program. The median TPE interval was greater in LQT2 (112±5 ms) than LQT1 (91±2 ms) or unaffected (86±3 ms) patients (P<0.001 for all group comparisons), and the maximal TPE values differed as well. LQT1 patients showed abrupt increases in TPE values at RR intervals from 600 to 900 ms, but LQT2 patients did so at RR intervals from 600 to 1400 ms (longest RR studied). Asymptomatic and symptomatic patients showed similar TDRs.

Conclusions—TDR is greater in LQT2 than in LQT1 patients. LQT1 patients showed a capacity to increase TDR at elevated heart rates, but LQT2 patients did so at a much wider rate range. The magnitude of TDR is not related to a history of TdP.

Key words: arrhythmia • electrocardiography • long-QT syndrome • torsade de pointes

This article has been cited by other articles:

				E. Ghelfi, C. R. Rhoden, G. A. Wellenius, J. Lawrence, and B. Gonzalez-Flecha Cardiac Oxidative Stress and Electrophysiological Changes in Rats Exposed to Concentrated Ambient Particles are Mediated by TRP-Dependent Pulmonary Reflexes Toxicol. Sci., April 1, 2008; 102(2): 328 - 336. [Abstract] [Full Text] [PDF]

				M. Viitasalo, L. Oikarinen, H. Swan, H. Vaananen, J. Jarvenpaa, H. Hietanen, J. Karjalainen, and L. Toivonen Effects of Beta-Blocker Therapy on Ventricular Repolarization Documented by 24-h Electrocardiography in Patients With Type 1 Long-QT Syndrome J. Am. Coll. Cardiol., August 15, 2006; 48(4): 747 - 753. [Abstract] [Full Text] [PDF]

				M. Viitasalo, L. Oikarinen, H. Swan, K. A. Glatter, H. Vaananen, H. Fodstad, N. Chiamvimonvat, K. Kontula, L. Toivonen, and M. M. Scheinman Ratio of Late to Early T-Wave Peak Amplitude in 24-h Electrocardiographic Recordings as Indicator of Symptom History in Patients With Long-QT Syndrome Types 1 and 2 J. Am. Coll. Cardiol., January 3, 2006; 47(1): 112 - 120. [Abstract] [Full Text] [PDF]

				M. Viitasalo, L. Oikarinen, H. Swan, K. A. Glatter, H. Vaananen, H. Fodstad, N. Chiamvimonvat, K. Kontula, L. Toivonen, and M. M. Scheinman Ratio of Late to Early T-Wave Peak Amplitude in 24-h Electrocardiographic Recordings as Indicator of Symptom History in Patients With Long-QT Syndrome Types 1 and 2 J. Am. Coll. Cardiol., December 13, 2005; (2005) j.jacc.2005.07.068v1. [Abstract] [Full Text] [PDF]