RT Journal Article SR Electronic T1 123I-MIBG Myocardial Scintigraphy in Patients with “Takotsubo” Cardiomyopathy JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 1121 OP 1127 VO 45 IS 7 A1 Yoshihiro J. Akashi A1 Kiyoshi Nakazawa A1 Masayoshi Sakakibara A1 Fumihiko Miyake A1 Haruki Musha A1 Kaoru Sasaka YR 2004 UL http://jnm.snmjournals.org/content/45/7/1121.abstract AB The clinical characteristics of reversible left ventricular dysfunction due to “takotsubo” cardiomyopathy have been described, but the origin of this condition remains unclear. This study investigated 123I-metaiodobenzlguanidine (123I-MIBG) myocardial scintigraphy in patients with takotsubo cardiomyopathy. Methods: Eight consecutive patients with takotsubo cardiomyopathy were studied. Left ventricular wall motion was monitored by echocardiography until wall motion normalized. 123I-MIBG myocardial scintigrams were performed within 3 d of admission (0 mo) and after the improvement of left ventricular dysfunction (3 mo). Early images were obtained at 30 min after radioisotope injection and delayed images were obtained after 4 h. The heart-to-mediastinum ratio (H/M ratio) and the washout rate were calculated. Results: The mean left ventricular ejection fraction improved significantly (from 42.8% ± 8.7% to 66.5% ± 7.9%; P < 0.0001) and normalized after 19.4 ± 5.4 hospital days. The early H/M ratio was significantly higher than the late ratio at 0 mo (2.16 ± 0.25 vs. 1.89 ± 0.24, respectively; P < 0.05), but not at 3 mo. The washout rate was significantly greater at 0 mo than at 3 mo (39.1% ± 10.2% vs. 25.4% ± 6.3%, respectively; P < 0.05). Conclusion: In patients with takotsubo cardiomyopathy, initial 123I-MIBG myocardial scintigraphy depicted a unique pattern of ventricular asynergy and indicated the existence of cardiac sympathetic hyperactivity, although coronary blood flow was maintained. These findings strongly suggest that takotsubo cardiomyopathy could be caused by neurogenic myocardial stunning.