PT  - JOURNAL ARTICLE
AU  - Toshihiko Goto
AU  - Shohei Kikuchi
AU  - Kento Mori
AU  - Takafumi Nakayama
AU  - Hidekatsu Fukuta
AU  - Yoshihiro Seo
AU  - Hitomi Narita
AU  - Akihiko Iida
AU  - Nobuyuki Ohte
TI  - Cardiac Beta-Adrenergic Receptor Downregulation, Evaluated by Cardiac Positron Emission Tomography, in Chronotropic Incompetence
AID  - 10.2967/jnumed.120.253419
DP  - 2020 Dec 01
TA  - Journal of Nuclear Medicine
PG  - jnumed.120.253419
4099  - http://jnm.snmjournals.org/content/early/2020/12/18/jnumed.120.253419.short
4100  - http://jnm.snmjournals.org/content/early/2020/12/18/jnumed.120.253419.full
AB  - The mechanism of chronotropic incompetence (CI), which has been associated with autonomic dysfunction, has not been elucidated in patients without heart failure (HF). Methods: Cardiac positron emission tomography using 11C-CGP12177 was performed to investigate the cardiac beta-adrenergic receptor density (β-ARD) in 13 patients with CI without HF and six healthy controls. The maximum number of available specific 11C-CGP12177 binding sites per gram of tissue was calculated in regions of interest using an established graphical method. Results: Peak heart rate was significantly lower in CI patients than in controls (116.9 ± 11.0 vs. 154.8 ± 14.4 beats/min, p < 0.001). β-ARD of the total myocardium was significantly lower in CI patients than in controls (4.3 ± 1.7 vs. 7.0 ± 1.7 pmol/mL, p = 0.005). Conclusion: Beta-adrenergic receptor downregulation was demonstrated in patients with CI without HF. Decreased β-ARD is a common feature in patients with CI, with or without HF.