Tsuyoshi Matsunaka, Presenter: Nothing to Disclose

Aiko Mori, Abstract Co-Author: Nothing to Disclose

Masamichi Tanaka, Abstract Co-Author: Nothing to Disclose

Eiki Hirose, Abstract Co-Author: Nothing to Disclose

Hideyuki Saeki, Abstract Co-Author: Nothing to Disclose

Shinichi Hiramatsu, Abstract Co-Author: Nothing to Disclose

Makoto Suzuki, Abstract Co-Author: Nothing to Disclose

Yukio Kazatani, Abstract Co-Author: Nothing to Disclose

Katsuhiko Ninomiya, Abstract Co-Author: Nothing to Disclose

Yuji Matsumoto, Abstract Co-Author: Nothing to Disclose

Sumiko Sato, Abstract Co-Author: Nothing to Disclose

Yasushi Koyama MD,PhD, Abstract Co-Author: Nothing to Disclose

Akiyoshi Ogimoto, Abstract Co-Author: Nothing to Disclose

Makoto Ohshita, Abstract Co-Author: Nothing to Disclose

Jitsuo Higaki MD, Abstract Co-Author: Nothing to Disclose

Jiro Komatsu, Abstract Co-Author: Nothing to Disclose

Hideo Kawakami, Abstract Co-Author: Nothing to Disclose

Hiroshi Matsuoka, Abstract Co-Author: Nothing to Disclose

Masao Miyagawa MD,PhD, Abstract Co-Author: Nothing to Disclose

Kenichi Kashihara MD, PhD, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

Sudden and unexpected death has been recognized as the most devastating and often unpredictable complication in the patients with hyoertrophic cardiomyopathy (HCM). We hypothesized that the distribution of myocardial fibrosis by MRI is predictive of fetal arrhythmia in patients with HCM.

Seventy-four patients with HCM were examined with 1.5T MR system. Cine, myocardial perfusion and Delayed-enhanced MRI (DE-MRI) were performed. Percent delayed-enhancement (DE) and ejection fraction (EF) were measured. Percent DE were calculated from the following equation; %DE=delayed enhancement area / total myocardium area.

DE was found in 56 patients (76%) in patients with HCM. EF in patients with DE (59.7±8.8%) were significantly smaller than those of patients without DE (63.2±16.0%, p=0.0479). We found significant negative correlations between EF and %DE (r=-0.445, p＜0.0001). During follow-up of 1256±193 days, 8 patients (11%) occurred ventricular tachycardia and 7 of them had showed DE. Implantable cardioverter defibrillators were implanted in 4 patients. Four patients died of sudden death and 2 patients died of heart failure. All of them had showed DE and 5 of them had showed perfusion defect in myocardial perfusion MRI. A 41-year-old male died of ventricular fibrillation and underwent autopsy, histological examination showed severe myocardial fibrosis at the insertion points of the right ventricle to the interventricular septum. MRI had showed DE and perfusion defect at the same point about 5 years ago. All patients without DE have been alive.

Myocardial perfusion and DE-MRI are useful methods for the early diagnosis of myocardial fibrosis as a substrate for fatal arrhythmia and may identify high-risk patient with HCM.

Myocardial fibrosis detected by myocardial perfusion and DE-MRI may be a novel risk factor for sudden death in patient with HCM.

Matsunaka, T, Mori, A, Tanaka, M, Hirose, E, Saeki, H, Hiramatsu, S, Suzuki, M, Kazatani, Y, Ninomiya, K, Matsumoto, Y, Sato, S, Koyama, Y, Ogimoto, A, Ohshita, M, Higaki, J, Komatsu, J, Kawakami, H, Matsuoka, H, Miyagawa, M, Kashihara, K, et al, , Clinical Impact of Cardiac Magnetic Resonance on Risk Factor for Fatal Arrhythmia in Patients with Hypertrophic Cardiomyopathy.  Radiological Society of North America 2006 Scientific Assembly and Annual Meeting, November 26 - December 1, 2006 ,Chicago IL. http://archive.rsna.org/2006/4441311.html