Ultrasound energy improves myocardial perfusion in the presence of coronary occlusion.
OBJECTIVE
We evaluated whether ultrasound improves myocardial tissue perfusion in 14 animals with coronary artery occlusion.


BACKGROUND
A recent study demonstrated that low-frequency ultrasound improves tissue perfusion in the rabbit ischemic limb, but there are no data on ultrasound enhancement of myocardial perfusion.


METHODS
Fourteen animals (9 dogs, 5 pigs) underwent thoracotomy and occlusion of a diagonal branch of the left anterior descending coronary artery. Myocardial tissue perfusion units (TPUs) and pH were measured before coronary occlusion, after occlusion, and after direct exposure of the ischemic myocardium in the presence of fixed occlusion to low-frequency ultrasound (27 kHz).


RESULTS
The TPU decreased from 100.9 +/- 13 at baseline to 71.1 +/- 13 (p < 0.01) after 60 min occlusion but rose by 19.7% to 85.1 +/- 8 (p < 0.01) after ultrasound exposure for 60 min. After 60-min coronary occlusion, myocardial pH fell from 7.43 +/- 14 to 7.05 +/- 0.15 (p < 0.01) but then improved to normal (7.46 +/- 0.32) after ultrasound for 60 min. Administration of L-Nomega-nitro-arginine methyl esther (L-NAME), an inhibitor of nitric oxide synthase, before ultrasound exposure, blocked improvement in myocardial tissue perfusion and pH by ultrasound. Quantitative histomorphology showed a significant increase in the capillary area of myocardium exposed to ultrasound versus non-exposed myocardium (16.2 +/- 7.9 vs. 8.2 +/- 2.1, p < 0.02).


CONCLUSIONS
Low-frequency, low-intensity ultrasound improves myocardial tissue perfusion and pH in the presence of a fixed coronary artery occlusion.
Division of Cardiology, Cedars-Sinai Medical Center, Los Angeles, California 90048, USA. siegel@cshs.org <siegel@cshs.org>
Robert J
RJ
Siegel
Valentina N
VN
Suchkova
Takashi
T
Miyamoto
Huai
H
Luo
Raymond B
RB
Baggs
Yoram
Y
Neuman
Michael
M
Horzewski
Veijo
V
Suorsa
Sergio
S
Kobal
Todd
T
Thompson
Debra
D
Echt
Charles W
CW
Francis
D000818:Animals; D003251:Constriction, Pathologic; D003331:Coronary Vessels / Q000473:pathology*; D004285:Dogs; D004791:Enzyme Inhibitors / Q000009:adverse effects; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging* / Q000209:etiology / Q000473:pathology*; D019331:NG-Nitroarginine Methyl Ester / Q000009:adverse effects; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D013552:Swine; D013997:Time Factors; D014463:Ultrasonography
D004791:Enzyme Inhibitors; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester