title: [The hemodynamic effect of dobutamine stress on myocardial bridging-mural coronary artery].
abstract: OBJECTIVE
  Patient with myocardial bridging (MB) usually has a benign prognosis, but some MB patients might experience myocardial ischemia, infarction and sudden cardiac death, especially during active physical activities. The purpose of the study was to study the stress-induced blood flow changes of the mural coronary artery in MB patients determined by intracoronary Doppler.
  
  
  METHODS
  In 8 patients with MB, the basic average peak velocity (bAPV), hyperemic average peak velocity (hAPV) of blood flow, coronary flow reverse (CFR) proximal and distal to the mural coronary artery were measured before and during intravenously dobutamine (10 microg kg-1 min-1, then add 10 microg kg-1 min-1 at 3 min interval till 40 microg kg-1 min-1) by intracoronary Doppler.
  
  
  RESULTS
  The baseline mural coronary diameter reduction was (51.7+/-21.4)% and significantly increased to (90.0+/-12.7)% (P<0.01) during dobutamine infusion. bAPV on the segments proximal and distal to the mural coronary artery significantly increased from (19.83+/-5.84) cm/s and (20.75+/-4.91) cm/s to (31.52+/-10.93) cm/s and (30.46+/-9.01) cm/s (all P<0.05 vs. baseline) respectively post dobutamine infusion. CFR measured at proximal and distal to myocardial bridging also significantly decreased from (2.91+/-0.62) and (2.46+/-0.82) to (2.17+/-0.66) and (1.83+/-0.51) (all P<0.01).
  
  
  CONCLUSIONS
  Stress can significantly increase the compression of intramural coronary artery and reduce CFR on coronary segments both proximal and distal to the MB. Thus, active exercise might induce myocardial ischemia in patients with myocardial bridging.
authors.affiliation: Department of Cardiology, The First People's Hospital of Zhenjiang, Zhenjiang 212002, China.
authors.forename: Guo-hui
authors.initials: GH
authors.lastname: Zhang
authors.forename: Jun-fang
authors.initials: JF
authors.lastname: Guo
authors.forename: Ya
authors.initials: Y
authors.lastname: Zhen
authors.forename: Wei-dong
authors.initials: WD
authors.lastname: Li
authors.forename: Zhong-hua
authors.initials: ZH
authors.lastname: Bao
authors.forename: Hong
authors.initials: H
authors.lastname: Jiang
authors.forename: Ju-ying
authors.initials: JY
authors.lastname: Qian
authors.forename: Bing
authors.initials: B
authors.lastname: Fan
authors.forename: Jun-bo
authors.initials: JB
authors.lastname: Ge
mesh_terms: D001783:Blood Flow Velocity; D002316:Cardiotonic Agents / Q000494:pharmacology*; D003326:Coronary Circulation / Q000187:drug effects*; D003330:Coronary Vessel Anomalies / Q000503:physiopathology*; D003331:Coronary Vessels / Q000187:drug effects; D004280:Dobutamine / Q000494:pharmacology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged
chemical_list: D002316:Cardiotonic Agents; D004280:Dobutamine