title: Hemodynamic changes in left anterior descending coronary artery and anterior interventricular vein during right ventricular apical pacing: a doppler ultrasound study in open chest beagles.
abstract: OBJECTIVE
  The aim of this study was to quantify the effects of right ventricular apical pacing (RVAP) on hemodynamics in left anterior descending coronary artery (LAD) and anterior interventricular vein (AIV) contrast to baseline condition in open chest beagles using Doppler ultrasound imaging.
  
  
  METHODS
  In 6 anesthetized open chest beagles, the spectral Doppler waveforms of the middle segmental LAD and the AIV were acquired with a 5 MHz linear array transducer at baseline condition and during RVAP. The aortic pressure-time curves were recorded synchronously. The Doppler hemodynamic parameters of the LAD and AIV at both states were derived and compared.
  
  
  RESULTS
  The spectral Doppler waveforms of the LAD had a principal diastolic positive wave (Dp), which heelled by a momentary negative wave and a positive wave during early systole at baseline condition. During RVAP, an additional negative wave appeared in the LAD at late systole. The duration of the Dp shortened (227.83±12.16 ms vs 188.50±8.97 ms, P<0.001), and the acceleration of the Dp decreased (11.85±2.22 m/s(2) vs 3.54±0.42 m/s(2), P<0.001). The spectral Doppler waveforms of the AIV only had a principal positive wave (Sp) at baseline condition, but an additional diastolic negative wave appeared during RVAP. The duration of the Sp shortened (242.99±7.98 ms vs 215.38±15.44 ms, P<0.001), and the acceleration of the Sp decreased (9.61±1.93 m/s(2) vs 1.01±0.11 m/s(2), P<0.001).
  
  
  CONCLUSIONS
  Obvious hemodynamic changes in the LAD and AIV during RVAP were observed, and these abnormal flow patterns in epicardial coronary arteries and vena coronaria may be sensitive and important hints of the disturbed cardiac electrical and mechanical activity sequences.
authors.affiliation: Department of Cardiovascular Ultrasound and Non-invasive Cardiology, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, Sichuan, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Lu
authors.forename: Wenhua
authors.initials: W
authors.lastname: Li
authors.forename: Ying
authors.initials: Y
authors.lastname: Fu
authors.forename: Bin
authors.initials: B
authors.lastname: Long
authors.forename: Jie
authors.initials: J
authors.lastname: Shen
authors.forename: Li
authors.initials: L
authors.lastname: Su
authors.forename: Lixue
authors.initials: L
authors.lastname: Yin
mesh_terms: D000818:Animals; D003331:Coronary Vessels / Q000000981:diagnostic imaging* / Q000502:physiology*; D004285:Dogs; D015150:Echocardiography, Doppler; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging*; D006439:Hemodynamics; D008297:Male; D010138:Pacemaker, Artificial; D013909:Thorax; D016278:Ventricular Function, Right