The influence of agent delivery mode on cardiomyocyte injury induced by myocardial contrast echocardiography in rats

Bioeffects induced in rat hearts by the interaction of ultrasound with contrast agent gas bodies depends on user controlled parameters. This study examined the influence of contrast agent delivery mode on cardiomyocyte injury. Hairless rats were anesthetized and mounted vertically in a water bath. Evans blue dye was injected as stain for cardiomyocyte injury. The contrast agent (Definity, Amersham Health Inc., Princeton NJ) was diluted in saline and injected IV at 20 or 80 μL/kg either as bolus or continuous infusion. Echocardiography was performed with a GE Vingmed System V in a short axis view with 1:4 or 1:16 ECG triggering at 1.5 MHz for 5 or 20 min. The peak rarefactional pressure amplitude (PRPA) was 2.0 MPa. Fluorescent stained cells were scored on frozen sections of heart samples obtained 24 hr after scanning. Five min infusion led to 3.4 times (P