Autonomic Function Analysis in Patients with Chronic Heart Failure with Reduced and Preserved Ejection Fraction

Raphael Martins de Abreu1, Beatrice Cairo2, Vlasta Bari2, Giulia Paglione3, Beatrice De Maria4, Francesco Bandera5, Massimo Francesco Piepoli6, Alberto Porta2
1LUNEX University of Applied Sciences, 2Department of Biomedical Sciences for Health, University of Milan, 3Clinical Research Service, IRCCS Policlinico San Donato, San Donato Milanese, Milan, Italy, 4IRCCS Istituti Clinici Scientifici Maugeri, Milan, 5Department of Cardiothoracic, Vascular Anesthesia and Intensive Care, IRCCS Policlinico San Donato, San Donato Milanese, Milan, Italy; Cardiac Rehabilitation and Heart Failure Unit, Cardiology University Department, Scientific Institute for Research, Hospitalization and Healthcare MultiMedica, Sesto San Giovanni, Milan, Italy, 6Department of Biomedical Sciences for Health, University of Milan, Milan, Italy; Clinical Cardiology, IRCSS Policlinico San Donato, San Donato Milanese, Milan, Italy


Abstract

Chronic heart failure (CHF) is a syndrome in which the heart fails to pump enough blood to meet the body's needs. It is classified into two phenotypes: CHF with preserved ejection fraction (HFpEF) and reduced ejection fraction (HFrEF). HFpEF and HFrEF are associated with distinct pathophysiological mechanisms. CHF disrupts autonomic control, and cardiorespiratory coupling (CRC) has emerged as a tool to quantify these changes. CRC quantifies the dynamic interactions between heart period (HP) and respiration (RESP). The assessment of CRC offers insights beyond traditional univariate markers, such as the high frequency (HF) power of HP variability (HFaHP) and the power of variability of the time interval between Q-wave onset and T-wave end (QT) in the low frequency (LF) band (LFaQT). In this study, we analyzed HFaHP, LFaQT, and CRC strength in 29 subjects belonging to three gender-balanced groups (HFrEF: n=10, 62±11 yrs; HFpEF: n=9, 56±14 yrs; healthy controls, CTRL: n=10, 58±9 yrs). CRC was estimated computing the squared coherence in the HF band between HP and RESP (K2)between RESP on HP at the respiratory rate. Compared to HFrEF in the HFpEF group, K2 and HFaHP were reduced (0.80±0.16 vs 0.46±0.22 and 158±80 ms2 vs 113±94 ms2 respectively) and LFaQT was increased (48±55 ms2 vs 143±109 ms2). Markers in CRTL group were more similar to HFrEF. These results suggest compensatory autonomic mechanisms that help maintain proper cardiac function, with these responses depending on the CHF phenotype