Department of Cardiovascular Surgery, The Jikei University School of Medicine
Ultrasound stimulation, Continuous wave, Left ventricular function, Cardiac surgery
We already reported the effect of ultrasound myocardial stimulation in isolated rat heart. In the
present study, the new model of stimulator have been developed in order to apply for cardiac surgery.
We used 12 mongrel dogs which are randomly assigned to two experimental groups. The right heart
bypass model was used in the constant mean aortic pressure (75 mmHg) and heart rate (120 beats/min.).
The change in left ventricular function was defined as percent of control in the center of mass of
SarnofT curve. In group I, ultrasound was transmitted in 20 minutes following measurement 1
(interval 1). In group II, it was transmitted in 20 minutes following measurement 2 (interval 2).
Ultrasound was transmitted with the frequency of 1.23 MHz, the intensity at 1.5 W/cm2 and
continuous wave during every early systolic phase (200 msec.) for 20 minutes. The LV function recovery
rate after interval 1 was 74.9±3.6% in group I and 61.0±3.4% in group II. After interval 2, it was
77.6±4.9% in group I, and 86.7±3.3% in group II. The significant difference was noted between
group I and group II of the LV function recovery in interval 1 (p
These data suggest that the ultrasound stimulation have a prospective effect on ischemic heart
with promising for clinical application.