PT - JOURNAL ARTICLE AU - Kimio Nishisato AU - Akiyoshi Hashimoto AU - Tomoaki Nakata AU - Takahiro Doi AU - Hitomi Yamamoto AU - Daigo Nagahara AU - Shinya Shimoshige AU - Satoshi Yuda AU - Kazufumi Tsuchihashi AU - Kazuaki Shimamoto TI - Impaired Cardiac Sympathetic Innervation and Myocardial Perfusion Are Related to Lethal Arrhythmia: Quantification of Cardiac Tracers in Patients with ICDs AID - 10.2967/jnumed.110.074971 DP - 2010 Aug 01 TA - Journal of Nuclear Medicine PG - 1241--1249 VI - 51 IP - 8 4099 - http://jnm.snmjournals.org/content/51/8/1241.short 4100 - http://jnm.snmjournals.org/content/51/8/1241.full SO - J Nucl Med2010 Aug 01; 51 AB - Despite widespread prophylactic use of implantable cardioverter defibrillator (ICD) therapy, sudden cardiac death and refractory arrhythmia events are still important clinical issues to be overcome. We examined whether the impairment of cardiac sympathetic innervation and myocardial perfusion is responsible for lethal arrhythmic events and has prognostic value by comparing conventional clinical indices. Methods: In consecutive ICDs implanted in 60 patients, cardiac uptake of 123I-metaiodobenzylguanidine and 99mTc-tetrofosmin at rest was quantified, and then patients were prospectively followed with endpoints of appropriate ICD shocks or cardiac death. Cardiac metaiodobenzylguanidine activity was quantified as a heart-to-mediastinum ratio (HMR), and impaired tetrofosmin uptake was graded as a summed score (SS) using a computerized technique with a percentage of tracer uptake. Results: During a mean 29-mo interval, ICD shock was documented in 30 patients (50%); 3 cardiac deaths were also observed in this group of patients. Patients with ICD shocks had a significantly smaller HMR and a greater SS than did those without (1.73 ± 0.34 vs. 2.06 ± 0.46, P = 0.003, and 18.0 ± 16.2 vs. 5.7 ± 4.4, P = 0.001, respectively). Kaplan–Meier analysis showed that patients who had both an HMR of 1.90 or less and an SS of 12 or greater had a significantly greater ICD discharge rate than did those who had both an HMR greater than 1.90 and an SS less than 12 (94% vs. 18%, P < 0.005) (log rank, 15.14; P < 0.0005). Multivariate analysis with a Cox model identified the greatest Wald χ2 of 6.454 and a hazard ratio of 3.857 (P = 0.011) when an HMR of 1.9 or less and tetrofosmin SS of 12 or greater were combined. Conclusion: Impairment of cardiac sympathetic innervation and myocardial perfusion is related to lethal arrhythmic events leading to sudden death, and the combined assessment of these can identify patients for whom prophylactic ICD use has the greatest potential.