Author + information
- Received January 7, 2004
- Revision received April 21, 2004
- Accepted June 21, 2004
- Published online October 6, 2004.
- Robert J. Siegel, MD, FACC*,* (, )
- Valentina N. Suchkova, MD†,
- Takashi Miyamoto, MD*,
- Huai Luo, MD*,
- Raymond B. Baggs, DVM, PhD‡,
- Yoram Neuman, MD*,
- Michael Horzewski, BS*,
- Veijo Suorsa, PhD*,
- Sergio Kobal, MD*,
- Todd Thompson, BS*,
- Debra Echt, MD* and
- Charles W. Francis, MD†
- ↵*Reprint requests and correspondence:
Dr. Robert J. Siegel, Division of Cardiology, Room #5335, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, California 90048
Objectives 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 thepresence 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-Nω-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.
This study has been supported by Timi3 Systems Inc. (Santa Clara, California), of which Dr. Siegel is a consultant and stockholder.
- Received January 7, 2004.
- Revision received April 21, 2004.
- Accepted June 21, 2004.
- American College of Cardiology Foundation