Efficacy & safety of repeated injections of echogen for echocardiography: Improved left ventricular delineation and modest increase in myocardial contrast

Clinical applications of contrast echocardiography may include repeated administration of the agent, such as during pharmacological stress testing. To determine the safety and efficacy of repeated administration of an echocardiography contrast agent, we analyzed the patient (n = 21) responses and the transthoracic apical four-chamber and short axis image sets aefore and after the injection of EchoGen (2% dodeca-fluoropentane, Sonus Pharmaceuticals, Bothell, WA). The agent was administered in 2 separate injections (n = 42) ranging from 1-7 mL i.v (8 mL total) given 30 minutes apart. Images obtained with a 2.5 MHz transducer (Hewlett Packard 2500) operating continuously were recorded on videotape. Also, mid-diastolic frames acquired before and after EchoGen injection were stored to optical disc for analysis of myocardial intensity by Acoustic Densitometry. LV cavity opacification was achieved with all injections (full in 40/42 and intermediate in 2) with improved visualization of the boundary between endocardium and blood (at least 3 minutes). No hemodynamic effects were noted (heart rats, blood pressure, oxygen saturation). Mild, transient (less than 1 minute) side effects were reported (5/42 injections; warmth, flushing and abnormal taste). Increased myocardial contrast effect was noted in at least 10 of the 21 patients, more consistently in the septum and lateral wall (four-chamber view). Thus, repeated injections of EchoGen are safe and side effects are short-lived. Improved delineation of the LV cavity is uniformly seen and a modest myocardial contrast effect is achieved using standard imaging.