Myocardial contrast echocardiography (MCE) with triggered ultrasound does not cause premature ventricular complexes: Evidence from PB127 MCE studies

Previous studies suggest that myocardial contrast echocardiography using high mechanical index triggered ultrasound can be associated with increased frequency of the premature ventricular complex (PVC). However, this association has not been systematically examined. PB127 (Point Biomedical Corp, San Carlos, Calif) is a novel microsphere designed for evaluation of myocardial perfusion with ultrasound. PB127 myocardial contrast echocardiography was performed with triggered harmonic power Doppler in early/mid diastole (mechanical index less than or equal to 1.0). A total of 71 patients (cohort A) were studied at rest and another 64 (cohort B, age 62 +/- 12.6 years) were allocated to stress. Continuous electrocardigraphy was recorded. The study evaluated premature ventricular complex frequency at baseline, during, and after infusion of PB127 (dose < 0.175 mg/kg, < 60-minute duration). Proportions of triggered and non-triggered intervals associated with premature ventricular complex were determined. PVC frequency did not increase with PB127 infusion in either cohort (P = .572, P = .263). Proportion of triggered intervals after QRS associated with PVC was similar to proportion of untriggered intervals in cohort A (P > .999) and was lower than untriggered intervals (P = .001) in B, suggesting that triggers do not cause PVC. PB127 does not cause increase PVC frequency during or after imaging with triggered ultrasound at mechanical index of 1.