Document Detail

Comparison between ventricular gradient and a new descriptor of the wavefront direction of ventricular activation and recovery.
MedLine Citation:
PMID:  12018881     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: Total R T cosine (TCRT) is a new descriptor of repolarization heterogeneity that quantifies the deviation between the directions of ventricular depolarization and repolarization. It revives the old concept of ventricular gradient (VG). HYPOTHESIS: Our goal was to examine whether TCRT and VG contain nonredundant information by comparing their reaction to autonomic tests, namely, postural changes and Valsalva maneuver. METHODS: Digital 12-lead electrocardiograms were recorded in 16 patients with cardiovascular syndrome X (SX, chest pain, exercise-induced ST-depression, normal coronary arteries, 3 men, age 60 +/- 9 years) and 40 healthy volunteers (31 men, age 33 +/- 7 years) during postural changes and Valsalva maneuver. The angle (VGA) [degrees] and magnitude (VGM) [ms.mV] of VG in reconstructed XYZ leads and TCRT (average cosine of the angles between the QRS and T vectors in mathematically reconstructed three-dimensional space) were calculated. RESULTS: (mean +/- standard of the mean): In healthy subjects, VGM and TCRT decreased, whereas VGA increased in the sitting and standing compared with supine position (TCRT: 0.61 +/- 0.05,0.47 +/- 0.06,0.29 +/- 0.08, supine, sitting, and standing, p < 0.05) and during phase II Valsalva (TCRT: 0.47 +/- 0.06 vs. 0.61 +/- 0.05, p < 0.01 in supine, 0.24 +/- 0.08 vs. 0.37 +/- 0.07, p < 0.01 in standing). In patients with SX, VGM decreased in the standing position, VGA did not change significantly, while TCRT decreased only in patients without T-wave abnormalities (n = 9) (TCRT in standing and supine: 0.55 +/- 0.09 vs. 0.68 +/- 0.08, p < 0.05). VG(M) increased during Valsalva in patients with SX. Total R T cosine correlated strongly with VGA (r = -0.84, p < 0.00001) and, unlike VGM, did not correlate with heart rate. CONCLUSIONS: Ventricular gradient and TCRT contain nonredundant information. In healthy subjects, they react sensitively to autonomic provocation. In patients with SX, their reaction is attenuated, which suggests disturbance of the autonomic control of repolarization.
Velislav Batchvarov; Juan Carlos Kaski; Nikhil Parchure; Polychronis Dilaveris; Sue Brown; Azad Ghuran; Patrik Färbom; Katerina Hnatkova; A John Camm; Marek Malik
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Clinical cardiology     Volume:  25     ISSN:  0160-9289     ISO Abbreviation:  Clin Cardiol     Publication Date:  2002 May 
Date Detail:
Created Date:  2002-05-20     Completed Date:  2002-12-09     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  7903272     Medline TA:  Clin Cardiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  230-6     Citation Subset:  IM    
Department of Cardiological Sciences, St George's Hospital Medical School, London, UK.
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MeSH Terms
Case-Control Studies
Heart Conduction System / physiopathology*
Heart Ventricles / physiopathology*
Microvascular Angina / physiopathology*
Middle Aged
Posture / physiology
Sensitivity and Specificity
Signal Processing, Computer-Assisted
Valsalva Maneuver / physiology

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