title: Premature ventricular contractions during triggered imaging with ultrasound contrast.
abstract: BACKGROUND
  Premature ventricular contractions (PVCs) were observed during triggered second harmonic imaging of a contrast agent for myocardial perfusion assessment, with continuous infusion of the contrast agent. Further investigation into the relation of this phenomenon to both ultrasound energy and the contrast agent was carried out during a subsequent bolus-versus-infusion study.
  
  
  RESULTS
  Two open-label studies in healthy male volunteers were performed. The initial study was a dose-response study in 10 subjects, which compared 3 infusion rates. Each volunteer received 3 continuous infusions with different infusion rates of the contrast agent for either 10 (n = 6) or 20 (n = 4) minutes. End-systolic triggered imaging with a mechanical index (MI) of 1.5 was used throughout this part of the study. The second study compared bolus injection with a continuous infusion in 9 volunteers, with a single-dose level but different imaging modalities: end-systolic and end-diastolic triggered imaging at MIs of both 1.1 and 1.5. Spontaneous baseline PVCs were uncommon: 10 in 344 minutes (0.03 PVC/min, maximal 1 PVC/min) of baseline imaging. During end-diastolic triggering, no increase in PVCs was seen, irrespective of MI. A significant increase to 1.06 PVC/min (P <.001) was seen during end-systolic imaging with an MI of 1.5, but not with an MI of 1.1. The increase in PVC rate was dose-dependent in the initial study.
  
  
  CONCLUSIONS
  Imaging of contrast agents with high acoustic pressures can cause PVCs if end-systolic triggering is used. This effect is related to both the dose of contrast agent and acoustic pressure. It does not occur during end-diastolic triggered imaging. Precautionary measures would include using lower MIs or end-diastolic triggering.
authors.affiliation: Department of Cardiology, Academic Medical Center, Amsterdam, The Netherlands. p.a.vanderwouw@amc.uva.nl
authors.forename: P A
authors.initials: PA
authors.lastname: van Der Wouw
authors.forename: A C
authors.initials: AC
authors.lastname: Brauns
authors.forename: S E
authors.initials: SE
authors.lastname: Bailey
authors.forename: J E
authors.initials: JE
authors.lastname: Powers
authors.forename: A A
authors.initials: AA
authors.lastname: Wilde
mesh_terms: D000328:Adult; D003287:Contrast Media / Q000008:administration & dosage / Q000009:adverse effects*; D004305:Dose-Response Relationship, Drug; D004452:Echocardiography; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D014465:Ultrasonics; D018879:Ventricular Premature Complexes / Q000209:etiology*
chemical_list: D003287:Contrast Media