Impact of intraventricular conduction delay on coronary haemodynamics: a study with intracoronary Doppler in patients with bundle branch blocks and normal coronary arteries.
OBJECTIVE
The impact of right bundle branch block (RBBB) and left bundle branch block (LBBB) on myocardial perfusion is not completely understood as data are often blurred by underlying cardiac disease. The present study investigates whether conduction delays per se affect coronary perfusion-an indirect measure of myocardial oxygen demand.


RESULTS
Intracoronary Doppler and ultrasound were performed in 8 patients with RBBB, 10 patients with LBBB, and 10 control subjects. All patients had angiographically normal coronary arteries and normal left ventricular function. Baseline (bAPV) and adenosine-induced hyperaemic average flow velocity and coronary flow velocity reserve (CFVR) were measured in left anterior descending arteries. Intravascular ultrasound showed no difference in lumen cross-sectional area and plaque burden between groups. Patients with RBBB and LBBB had higher bAPV values than controls (19.0 +/- 4.9, 21.9 +/- 5.1, and 14.6 +/- 2.4 cm/s, respectively; ANOVA P = 0.003). There was no difference between patients with LBBB and RBBB compared with controls in CFVR (2.8 +/- 0.5, 3.0 +/- 1.0, and 3.4 +/- 0.7, respectively; ANOVA P = 0.21).


CONCLUSIONS
Bundle branch blocks, in particular LBBB, are associated with an increased coronary flow velocity, which indicates enhanced myocardial oxygen demand on the basis of mechanoenergetic disturbance. This may contribute to the unfavourable outcome of patients with intraventricular conduction delay.
Wieneke
Heinrich
H
Department of Cardiology, University Duisburg-EssenHufelandstr. 55, D-45122 Essen Germany. heinrich.wieneke@uni-esen.de
Sattler
Katherine
K
von Birgelen
Clemens
C
Böse
Dirk
D
Haude
Michael
M
Rechenberg
Wolfram
W
Sack
Stefan
S
Dagres
Nikolaos
N
Erbel
Raimund
R
D000241:Adenosine / Q000494:pharmacology; D001783:Blood Flow Velocity; D002037:Bundle-Branch Block / Q000000981:diagnostic imaging / Q000378:metabolism / Q000503:physiopathology*; D003326:Coronary Circulation; D003331:Coronary Vessels / Q000000981:diagnostic imaging; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D006940:Hyperemia; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D018084:Ultrasonography, Interventional; D014665:Vasodilator Agents / Q000494:pharmacology; D016277:Ventricular Function, Left
D014665:Vasodilator Agents; D000241:Adenosine; D010100:Oxygen