Ad. Demir et al., Effects of atrial pacing on QT dispersion in patients with coronary arterydisease without angina pectoris and ST segment depression, ANGIOLOGY, 52(6), 2001, pp. 393-398
The aim of this study was to investigate QT dispersion during atrial pacing
in patients with coronary artery disease (CAD) without clinical ischemia,
such as angina pectoris and ST segment depression. Thirteen patients with n
ormal coronary arteries and 42 patients with CAD (12 with single-vessel, 16
with two-vessel and 14 with three-vessel disease) having no angina pectori
s or ST segment depression during atrial pacing with maximum rate of 120/mi
nute were enrolled in the study. Twelve-lead surface ECGs were recorded at
100 mm/second paper speed before pacing, at maximum pacing rate, and during
the recovery period for measurement of QT interval parameters.
Corrected QTd (QTcd) increased from 43.4 +/- 8.1 to 49.3 +/-9.5 ms (p<0.05)
in the control group, from 46.1<plus/minus>8.1 to 74.3 +/-7.7 ms (p< 0.000
1) in the single-vessel disease group, from 48.5 +10.4 to 93.8<plus/minus>2
2.1 ms in the two-vessel disease group (p < 0.0001), and from 49.7<plus/min
us>13.6 to 128.5 +/- 31 ms (p< 0.0001) in the three-vessel disease group at
peak atrial pacing period. A positive correlation was found between the se
verity of CAD and QTcd (r= 0.49, p < 0.0001). It was found that pacing-indu
ced QTc dispersion identifies coronary disease extent, even when there is n
o ST depression or T wave inversion during pacing.