Inflammation, mitochondrial dysfunction and physical performance: a possible association in older patients with persistent atrial fibrillation-the results of a preliminary study

Background: Atrial fibrillation (AF) is associated with chronic inflammation, a hallmark of ageing process. The aim of this study was to determine interleukin-6 (IL-6)-associated variables, also exploring acylcarnitines, expression of mitochondrial abnormalities. Methods: We evaluated 22 controls and 50 patients with persistent AF. IL-6 and acylcarnitines were measured with ELISA kits and mass spectrometry techniques. Results: IL-6 concentration (mean: 3.9 ± 3.1 pg/mL) was lower in controls and increased in AF patients, especially with heart failure. The CHA2DS2-VASc, the MMSE and the SPPB scores were 3.8 ± 1.6, 28 ± 2 and 9.4 ± 2.1. Thirteen acylcanitines correlated with IL-6. At multivariable analysis, IL-6 was directly associated with C4-OH-a short-chain acylcarnitine, fibrinogen and alanine aminotransferase values, and with hyperuricemia. An inverse association existed with calcium concentration and SPPB score. Conclusions: In older AF patients, IL-6 correlated with acylcarnitines and lower physical performance. Alterations in energy production, reduced physical function and inflammation could contribute to frailty development.