Objective. The purpose of this study was to determine the type of arrhythmias induced with therapeutic versus diagnostic transthoracic low-frequency ultrasound (TLFUS) transducers in the presence of intravenous microbubbles. Methods. Intravenous perfluorocarbon-exposed sonicated dextrose albumin (PESDA) microbubbles were infused or given as a bolus injection while TLFUS was applied in the standard parasternal and apical views with either a 1-MHz therapeutic ultrasound transducer or high-mechanical-index diagnostic ultrasound (1.7 MHz). Results. Significantly more ectopy was produced by the therapeutic transducer, especially at higher-intensity settings in the continuous wave mode after bolus injections of PESDA (P < .001 compared with lower intensities and lower continuous infusion rates). Six patients (15%) had either clinical supraventricular tachycardia or nonsustained ventricular tachycardia after intravenous PESDA with therapeutic TLFUS. In comparison, diagnostic high-mechanical-index ultrasound produced only isolated ventricular ectopy and no sustained ventricular arrhythmias. Conclusions. Intravenously injected microbubbles and low-frequency therapeutic transducers operating at longer duty cycles and wide beam widths have the capability of eliciting clinically important arrhythmias in patients at high risk for such events.
- Ultrasound contrast
ASJC Scopus subject areas
- Radiological and Ultrasound Technology
- Radiology Nuclear Medicine and imaging