RT Journal Article
SR Electronic
T1 Cardiac Presynaptic Sympathetic Nervous Function Evaluated by Cardiac PET in Patients with Chronotropic Incompetence Without Heart Failure
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 271
OP 276
DO 10.2967/jnumed.124.268638
VO 66
IS 2
A1 Goto, Toshihiko
A1 Kikuchi, Shohei
A1 Sakurai, Yomei
A1 Tsuruta, Yoshiro
A1 Mori, Kento
A1 Mizoguchi, Tatsuya
A1 Kawada, Yu
A1 Shintani, Yasuhiro
A1 Yokoi, Masashi
A1 Yamabe, Sayuri
A1 Ito, Tsuyoshi
A1 Kitada, Shuichi
A1 Fukuta, Hidekatsu
A1 Matsui, Kyoko
A1 Narita, Hitomi
A1 Nankou, Sumire
A1 Seo, Yoshihiro
YR 2025
UL http://jnm.snmjournals.org/content/66/2/271.abstract
AB Chronotropic incompetence (CTI), the inability of the heart to increase its rate with increased activity, leads to exercise intolerance and predicts overall mortality. We previously reported that cardiac β-adrenergic receptor downregulation occurs in patients with CTI without heart failure (HF), indicating postsynaptic sympathetic nervous dysfunction. However, cardiac presynaptic sympathetic nervous system function in CTI is not fully understood. Notably, 11C-hydroxyephedrine PET assesses cardiac presynaptic sympathetic nervous system function. Therefore, we investigated cardiac presynaptic sympathetic nervous system function using cardiac 11C-hydroxyephedrine PET in patients with CTI without HF. Methods: We performed cardiac PET in 13 patients with CTI without HF and 9 age-matched healthy controls using 11C-hydroxyephedrine (mean age, 75.1 ± 6.3 y; 59.1% male). The global hydroxyephedrine retention index was determined as myocardial tracer (11C-hydroxyephedrine) activity between 30 and 40 min divided by the activity input integral. CTI was defined as failing to achieve 80% of the heart rate reserve during bicycle ergometer exercise testing. Results: The clinical characteristics, including echocardiographic parameters, did not significantly differ between patients with CTI and controls. Peak heart rate was significantly lower in patients with CTI than in controls (107.0 ± 8.2 vs. 138.4 ± 13.6 beats/min, P < 0.001). The global hydroxyephedrine retention index was significantly higher in patients with CTI than in controls (0.14 ± 0.04 vs. 0.10 ± 0.05 min−1, P = 0.046). Conclusion: Hydroxyephedrine retention index was significantly higher in patients with CTI without HF than in controls. Our data suggested that impaired norepinephrine release in presynaptic sympathetic nerves contributes to the mechanism of CTI without HF.