Elevation of end-tidal CO2 during exercise is attenuated in patients with cardiac amyloidosis

• Published in: Heart and vessels 2024-04, Vol.39 (4), p.340-348
• Main Authors: Shibata, Atsushi, Izumiya, Yasuhiro, Yoshida, Toshitake, Tanihata, Akiko, Yamaguchi, Yumi, Kitada, Ryoko, Fukuda, Daiju
• Format: Article
• Language: English
• Subjects: Amyloidosis; Biomedical Engineering and Bioengineering; Carbon dioxide; Cardiac output; Cardiac Surgery; Cardiology; Congestive heart failure; Echocardiography; Heart failure; Medicine; Medicine & Public Health; Observational studies; Original Article; Troponin; Troponin T; Vascular Surgery
• ISSN: 0910-8327; 1615-2573
• DOI: 10.1007/s00380-023-02342-w

Reduced exercise tolerance is one of the hallmarks of patients with cardiac amyloidosis (CA), but detailed biological responses during exercise were not investigated. The purpose of this study was to compare the cardiopulmonary exercise test (CPX) parameters between CA patients and propensity-matched heart failure patients. This was a single-center, retrospective, observational study of patients diagnosed with CA. The control group was extracted by propensity score matching from patients who underwent CPX for chronic heart failure during the same period. Clinical data including assessment of biological responses during CPX were compared between the patients with CA (CA group, n  = 16) and the control group (non-CA group, n  = 16). Echocardiography suggested more impaired diastolic function in the CA group than in the non-CA group. There was no significant difference between groups in the fraction of end-tidal carbon dioxide (FETCO 2 ) at rest. However, the difference between the FETCO 2 at rest and the FETCO 2 at the respiratory compensation point (ΔFETCO 2 ) was significantly smaller in the CA group than in the non-CA group (0.40% ± 0.37% vs. 0.82% ± 0.33%; p  = 0.002). Only in the CA group, there was a significant negative correlation between the ΔFETCO 2 and the E/e’ ratio on echocardiography ( r  = − 0.521; p  = 0.039) and the serum high-sensitivity troponin T concentration ( r  = − 0.501; p  = 0.048). In conclusion, patients with CA may find it difficult to increase cardiac output during exercise due to severe diastolic dysfunction.