title: Ultrasound exposure (mechanical index 1.8) with acoustic radiation force impulse evokes extrasystolic waves in rabbit heart under concomitant administration of an ultrasound contrast agent.
abstract: OBJECTIVE
  Acoustic radiation force impulse (ARFI) is a modality for elasticity imaging of various organs using shear waves. In some situations, the heart is a candidate for elasticity evaluation with ARFI. Additionally, an ultrasound contrast agent (UCA) provides information on the blood flow conditions of the cardiac muscle. This study aimed to evaluate ARFI's effect on the heart concomitantly with UCA administration (i.e., perfluorobutane).
  
  
  METHODS
  Ultrasound with ARFI was applied to the hearts of male Japanese white rabbits (n = 3) using a single-element focused transducer with or without UCA administration. They were exposed to ultrasound for 0.3 ms with a mechanical index (MI) of 1.8. UCA was administered in two ways: a single (bolus) injection or drip infusion. Electrocardiograms were recorded to identify arrhythmias during ultrasound exposure.
  
  
  RESULTS
  Extrasystolic waves were observed following ultrasound exposure with drip infusion of UCA. Life-threatening arrhythmia was not observed. The frequency of the extra waves ranged from 4.2 to 59.6 %. With bolus infusion, extra waves were not observed.
  
  
  CONCLUSIONS
  Arrhythmogenicity was observed during ultrasound (MI 1.8) with ARFI and concomitant administration of UCA in rabbits. Although the bolus administration of UCA was similar to its clinical use, which may not cause extra cardiac excitation, cardiac ultrasound examinations with ARFI should be carefully performed, particularly with concomitant use of UCA.
authors.affiliation: Department of Surgery, Jichi Medical University, School of Medicine, 3311-1 Yakushiji, Shimotsuke, Tochigi, 329-0498, Japan. ynao-i@mub.biglobe.ne.jp.
authors.forename: Yasunao
authors.initials: Y
authors.lastname: Ishiguro
authors.affiliation: Human Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, Japan.
authors.forename: Naotaka
authors.initials: N
authors.lastname: Nitta
authors.affiliation: Department of Clinical Laboratory Medicine, Jichi Medical University, School of Medicine, Shimotsuke, Tochigi, Japan.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Taniguchi
authors.affiliation: Medical Ultrasound Research Center, Doshisha University, Kyotanabe, Kyoto, Japan.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Akai
authors.affiliation: Department of Clinical Laboratory Medicine, Jichi Medical University, School of Medicine, Shimotsuke, Tochigi, Japan.
authors.forename: Noriya
authors.initials: N
authors.lastname: Takakayama
authors.affiliation: Department of Surgery, Jichi Medical University, School of Medicine, 3311-1 Yakushiji, Shimotsuke, Tochigi, 329-0498, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Sasanuma
authors.affiliation: Division of Cardiovascular Medicine, Department of Medicine, Jichi Medical University, School of Medicine, Shimotsuke, Tochigi, Japan.
authors.forename: Yukiyo
authors.initials: Y
authors.lastname: Ogata
authors.affiliation: Department of Surgery, Jichi Medical University, School of Medicine, 3311-1 Yakushiji, Shimotsuke, Tochigi, 329-0498, Japan.
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Yasuda
authors.affiliation: Medical Ultrasound Research Center, Doshisha University, Kyotanabe, Kyoto, Japan.
authors.forename: Iwaki
authors.initials: I
authors.lastname: Akiyama
mesh_terms: D000818:Animals; D001145:Arrhythmias, Cardiac / Q000209:etiology* / Q000503:physiopathology; D003287:Contrast Media / Q000008:administration & dosage*; D004452:Echocardiography / Q000009:adverse effects* / Q000295:instrumentation / Q000379:methods*; D054459:Elasticity Imaging Techniques / Q000009:adverse effects* / Q000295:instrumentation / Q000379:methods*; D004562:Electrocardiography; D006321:Heart / Q000503:physiopathology; D008297:Male; D011817:Rabbits; D012039:Regional Blood Flow
chemical_list: D003287:Contrast Media
keywords: Acoustic radiation force; Arrhythmia; Heart; Rabbit; Ultrasound contrast agent