Open AccessComparison between ventricular gradient and a new descriptor of the wavefront direction of ventricular activation and recovery
Author(s) -
Batchvarov Velislav,
Kaski Juan Carlos,
Parchure Nikhil,
Dilaveris Polychronis,
Brown Sue,
Ghuran Azad,
Färbom Patrik,
Hnatkova Katerina,
Camm A. John,
Malik Marek
Publication year - 2002
Publication title -
clinical cardiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.263
H-Index - 72
eISSN - 1932-8737
pISSN - 0160-9289
DOI - 10.1002/clc.4950250507
Subject(s) - medicine , cardiology , wavefront , optics , physics
Abstract 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 (VG A ) [°] and magnitude (VG M ) [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, VG M decreased in the standing position, VG A 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 VG A (r = –0.84, p< 0.00001) and, unlike VG M , did not correlate with heart rate. Conclusions : Ventricular gradient and TCRT contain non‐redundant 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.