955-54 Adjunctive Techniques Enable Myocardial Opacification by Intravenous Injection of Reduced Doses of QW3600 (EchoGen ® )

QW3600 (EG) is a new perflourocarbon (dodecaflouropentane) ultrasonic contrast agent capable of producing myocardial opacification by IV injection. However, the doses required for myocardial visualization have sometimes been associated with transient hemodynamic changes. Therefore, we evaluated the ability of pretreatment with: (1) antihistamines and corticosteroids to eliminate hypersensitivity and thus reduce hemodynamic changes; and (2) administration of coronary vasodilators to enhance myocardial intensity. We performed 2–D echo in the short axis parasternal view in 10 closed chest ventilated dogs in whom LV, Ao and pulmonary artery catheters enabled direct assessment of hemodynamics. All animals were given benadryl 1 mg/kg and Solu-Mediol 1 mg/kg approximately one hour prior to the study. Subsequently, a 0.5 cc/kg EchoGen®injection was repeated. Contrast intensity was quantified by a 0.3 cm2region of interest positioned in the midventricular wall and peak videointensity (PVI) was measured in gray levels. Results *= p l 0.01 for EG vs DIP + EG. HR FA (S) FA (D) LV PA PVI BASE 145 ± 23 172 ± 14 120 ± 7 165 ± 12 122 ± 6 23 ± 18 EG 150 ± 24 163 ± 13 114 ± 7 159 ± 13 28 ± 10 69 ± 50 DIP 142 ± 19 171 ± 14 114 ± 15 162 ± 23 24 ± 3 33 ± 21 DIP + EG 145 ± 23 156 ± 31 99 ± 21 145 ± 32 32 ± 4 110 ± 41 Thus, combination of antihistamine-steriod pretreatment and dipyridamole vasodilation enables enhanced visualization of myocardial perfusion by reduced doses of EG without significant hemodynamic effects. This approach may be of value in achieving myocardial opacification in patients with EG without incurring side effects.