© 1993 by European Society of Cardiology
Copyright © 1993, European Society of Cardiology
Comparative assessment of regional left atrial perfusion by laser Doppler and radionuclide microsphere techniques
University of Cincinnati Medical Center, Department of Internal Medicine, Division of Cardiology, 231 Bethesda Avenue, Cincinnati, OH 45267-0542, USA: B D Hoit, R A Walsh, Y Shao, M Gabel; Department of Pharmacology and Cell Biophysics, University of Cincinnati Medical Center: R Millard.
Correspondence to Dr Hoit.
Objective: The aim was to study the relation between left atrial microcirculatory flux, using laser Doppler flowmetry (LDF), and blood flow, using radiolabelled microspheres (MS). Methods: Studies were done in five anaesthetised dogs. LDF probes were sewn to the appendage and body of the left atrium. Radionuclide spheres (15 µm) were used to quantitate blood flow at baseline, and during atrial pacing at 3.5 Hz, atrial fibrillation, and intravenous adenosine infusion (1 mg·kg–1·min–1). Results: In the left atrial body, both MS and LDF perfusion increased significantly during pacing and adenosine infusion; only LDF registered significant increases during atrial fibrillation. In the left atrial appendage, MS flow failed to increase significantly with any intervention and LDF perfusion increased significantly only during atrial fibrillation. There was a significant but weak correlation (r=0.36, p<0.05) between LDF and MS when data from all sample sites (n=40) were compared, but good correlation when only baseline and pacing data were compared (r=0.72, p=0.0004, n=20). In four additional dogs with heart failure [mean left atrial pressure 25.3(SD 7.4) mm Hg] produced by three weeks of rapid right ventricular pacing, flux values at baseline were increased significantly compared to control dogs and the responses registered by LDF to pacing, atrial fibrillation, and adenosine infusion were attenuated markedly. Conclusions: (1) Microcirculatory flux detected by LDF can identify the direction, and to a lesser extent, the magnitude of changes in regional atrial perfusion; and (2) LDF may be useful in identifying abnormalities of vasodilator reserve that accompany chronic left atrial myocardial dysfunction.
Cardiovascular Research 1993;27:508-514
KEYWORDS microcirculation; left atrium; atrial tibrillation; laser Doppler; radiolabelled microspheres; heart failure
The authors would like to acknowledge the secretarial skills of Norma Burns and thank Doug Collins, Transonics Systems Inc, and Robert Leonard, Medtronic Inc, for providing equipment for this study. The work was supported in part by NIH grants to RAW and RWM and by a grant-in-aid from The American Heart Association, Ohio Affiliate, to BDH.