Central hemodynamic responses during acute high-intensity interval exercise and moderate continuous exercise in patients with heart failure

Abstract

The aim of this study was to compare the acute hemodynamic responses during high-intensity intermittent exercise (HIIE) session compared with moderate-intensity continuous exercise (MICE) session in patients with heart failure and reduced ejection fraction (HFREF). Thirteen patients with HFREF (age, 59 ± 6 years; left ventricular ejection fraction, 27% ± 6%; New York Heart Association class I to III) were randomly assigned to a single session of HIIE (2 × 8 min) corresponding to 30 s at 100% of peak power output (PPO) and 30 s passive recovery intervals or to a MICE (22 min) at 60% of PPO. Gas exchange and central hemodynamic parameters (cardiac bioimpedance) were measured continuously during exercise. Oxygen uptake, stroke volume (SV), cardiac output (CO), and arterio-venous difference (C(a-v)O(2)) were compared. Mean oxygen uptake and ventilation were lower during HIIE vs. MICE. CO, SV, and C(a-v)O(2)) were not different between MICE and HIIE. Optimized HIIE was well tolerated (similar perceived exertion) and no significant ventricular arrhythmias and (or) abnormal blood pressure responses occurred during HIEE session. Compared with MICE, optimized HIIE elicited similar central hemodynamic and C(a-v)O(2) responses in HFREF patients with lower oxygen uptake and ventilation. HIIE may be an efficient exercise training modality in patients with HFREF.

Cardiovascular and hemodynamic responses on dryland vs. immersed cycling

“…Calibration of the Cosmed flow module was accomplished by introducing a calibrated volume of air at several flow rates with a 3-liter pump. 13 Gas analyzers were calibrated before each test using a standard certified commercial gas preparation (O 2 : 16%; CO 2 : 5%) according to manufacturer's specifications and previous published methodology. 1,13 Data were measured every four respiratory cycles during testing and then were averaged every 15 s for minute ventilation (VE, in L min −1 BTPS), oxygen uptake (VO 2 , in L min −1 , STPD), carbon dioxide production (VCO 2 , in L min −1 STPD).…”

“…13 Gas analyzers were calibrated before each test using a standard certified commercial gas preparation (O 2 : 16%; CO 2 : 5%) according to manufacturer's specifications and previous published methodology. 1,13 Data were measured every four respiratory cycles during testing and then were averaged every 15 s for minute ventilation (VE, in L min −1 BTPS), oxygen uptake (VO 2 , in L min −1 , STPD), carbon dioxide production (VCO 2 , in L min −1 STPD). 1 Maximal exercise tests on IE and DE lasted until the attainment of one of the two primary maximal criteria: (1) a plateau ofVE despite an increase in cadence, (2) R.E.R.…”

“…Data were averaged every 15 consecutive heartbeats 13 for cardiac output (in L min −1 ), stroke volume (in mL), heart rate (in beats min −1 ), ejection fraction (in %), end-diastolic and systolic volume (in mL), contractility index (in arbitrary units) and systemic vascular resistance (in dynes s −1 cm −5 ). The use of this noninvasive technique during dry and immersed exercise in adults has been previously published.…”

“…The use of this noninvasive technique during dry and immersed exercise in adults has been previously published. 3,13,16 Ejection fraction was calculated according to the Capan formula: EF (%) = 0.84 − (0.64 × pre-ejection time)/ventricular ejection time. 17 Contractility index (CTI) was calculated according to the following formula CTI (arbitrary unit) = dZ/dT max .…”

“…17 Arteriovenous difference (C(a-v)O 2 ) was calculated according to the Fick principle: C(a-v)O 2 =VO 2 /Q . 13 Blood pressure measurement was done manually on the upper arm, with a sphygmomanometer (WelchAllyn, USA) at the elbow crease over the brachial artery, according to recommended guidelines. 18 Results are presented as mean ± standard deviation except where otherwise indicated.…”