Document Detail

Dynamics and rate-dependence of the spatial angle between ventricular depolarization and repolarization wave fronts during exercise ECG.
MedLine Citation:
PMID:  20645970     Owner:  NLM     Status:  In-Process    
BACKGROUND: QRS/T angle and the cosine of the angle between QRS and T-wave vectors (TCRT), measured from standard 12-lead electrocardiogram (ECG), have been used in risk stratification of patients. This study assessed the possible rate dependence of these variables during exercise ECG in healthy subjects. METHODS: Forty healthy volunteers, 20 men and 20 women, aged 34.6 +/- 3.4, underwent an exercise ECG testing. Twelve-lead ECG was recorded from each test subject and the spatial QRS/T angle and TCRT were automatically analyzed in a beat-to-beat manner with custom-made software. The individual TCRT/RR and QRST/RR patterns were fitted with seven different regression models, including a linear model and six nonlinear models. RESULTS: TCRT and QRS/T angle showed a significant rate dependence, with decreased values at higher heart rates (HR). In individual subjects, the second-degree polynomic model was the best regression model for TCRT/RR and QRST/RR slopes. It provided the best fit for both exercise and recovery. The overall TCRT/RR and QRST/RR slopes were similar between men and women during exercise and recovery. However, women had predominantly higher TCRT and QRS/T values. With respect to time, the dynamics of TCRT differed significantly between men and women; with a steeper exercise slope in women (women, -0.04/min vs -0.02/min in men, P < 0.0001). In addition, evident hysteresis was observed in the TCRT/RR slopes; with higher TCRT values during exercise. CONCLUSIONS: The individual patterns of TCRT and QRS/T angle are affected by HR and gender. Delayed rate adaptation creates hysteresis in the TCRT/RR slopes.
Tuomas Kenttä; Mari Karsikas; Antti Kiviniemi; Mikko Tulppo; Tapio Seppänen; Heikki V Huikuri
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Annals of noninvasive electrocardiology : the official journal of the International Society for Holter and Noninvasive Electrocardiology, Inc     Volume:  15     ISSN:  1542-474X     ISO Abbreviation:  Ann Noninvasive Electrocardiol     Publication Date:  2010 Jul 
Date Detail:
Created Date:  2010-07-21     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9607443     Medline TA:  Ann Noninvasive Electrocardiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  264-75     Citation Subset:  IM    
Institute of Clinical Medicine, University of Oulu, Finland.
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