Kazuma Rifu1, Hideki Sasanuma2, Noriya Takayama3, Naotaka Nitta4, Yukiyo Ogata5, Iwaki Akiyama6, Nobuyuki Taniguchi3. 1. Division of Gastroenterological, General and Transplant Surgery, Department of Surgery, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi, 329-0498, Japan. m03097kr@jichi.ac.jp. 2. Division of Gastroenterological, General and Transplant Surgery, Department of Surgery, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi, 329-0498, Japan. 3. Department of Clinical Laboratory Medicine, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi, 329-0498, Japan. 4. National Institute of Advanced Industrial Science and Technology, Health and Medical Research Institute, 1-2-1 Namiki, Tsukuba, Ibaraki, 305-8564, Japan. 5. Department of Cardiology, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi, 329-0498, Japan. 6. Medical Ultrasound Research Center, Doshisha University, 1-3 Tatara-miyakodani, Kyotanabe, Kyoto, 610-0321, Japan.
Abstract
PURPOSE: We previously reported that acoustic radiation force impulse (ARFI) with concomitant administration of perfluorobutane as an ultrasound contrast agent (UCA)-induced arrhythmias at a mechanical index (MI) of 1.8 or 4.0 in a rabbit model. The present study identified the location of arrhythmias with a MI < 1.8 using a new system that can transmit ARFI with B-mode imaging. METHODS: Under general anesthesia, six male Japanese white rabbits were placed in a supine position. Using this system, we targeted ARFI to the exact site of the heart. ARFI exposure with MI 0.9-1.2 was performed to the right or left ventricle of the heart 2 min after UCA injection. RESULTS: ARFI with a MI lower than previously reported to rabbit heart evoked extrasystolic waves with single UCA infusion. Arrhythmias were not observed using ARFI without UCA. Extrasystolic waves were observed significantly more frequently in the right ventricle group than in the left ventricle group, with arrhythmias showing reversed shapes. No fatal arrhythmias were observed. CONCLUSION: ARFI applied to simulate clinical conditions in rabbit heart evoked extrasystolic waves with single UCA infusion. The right ventricle group was significantly more sensitive to ARFI exposure, resulting in arrhythmias, than the left ventricle group. The shapes of PVCs that occurred in the right ventricle group and the left ventricle group were reversed. Ultrasound practitioners who use ARFI should be aware of this adverse reaction, even if the MI is below the previously determined value of 1.9.
PURPOSE: We previously reported that acoustic radiation force impulse (ARFI) with concomitant administration of perfluorobutane as an ultrasound contrast agent (UCA)-induced arrhythmias at a mechanical index (MI) of 1.8 or 4.0 in a rabbit model. The present study identified the location of arrhythmias with a MI < 1.8 using a new system that can transmit ARFI with B-mode imaging. METHODS: Under general anesthesia, six male Japanese white rabbits were placed in a supine position. Using this system, we targeted ARFI to the exact site of the heart. ARFI exposure with MI 0.9-1.2 was performed to the right or left ventricle of the heart 2 min after UCA injection. RESULTS: ARFI with a MI lower than previously reported to rabbit heart evoked extrasystolic waves with single UCA infusion. Arrhythmias were not observed using ARFI without UCA. Extrasystolic waves were observed significantly more frequently in the right ventricle group than in the left ventricle group, with arrhythmias showing reversed shapes. No fatal arrhythmias were observed. CONCLUSION: ARFI applied to simulate clinical conditions in rabbit heart evoked extrasystolic waves with single UCA infusion. The right ventricle group was significantly more sensitive to ARFI exposure, resulting in arrhythmias, than the left ventricle group. The shapes of PVCs that occurred in the right ventricle group and the left ventricle group were reversed. Ultrasound practitioners who use ARFI should be aware of this adverse reaction, even if the MI is below the previously determined value of 1.9.