HRVFIT2 study database
The aim of this study was to verify the superiority of high-intensity interval training (HIIT) to enhance parasympathetic activity, cardiorespiratory fitness and cardiac function when compared to moderate intensity continuous training (MICT) in a short and intense cardiac rehabilitation program (RP). Methods: This is a prospective, monocentric, evaluator-blinded, randomized (1 :1) study with a two arm parallel group design. 31 voluntary chronic heart failure (CHF) patients (LVEF < 45 %) were included either to MICT (n=15) or HIIT group (n=16) for a short RP (27 ± 4 days). They underwent, at entry and at the end of the study, a 24-hour ECG recording, an echocardiography and a cardiopulmonary exercise test. Results: The High-Frequency power (HFnu, %) measured with HRV increased in HIIT group (from 21.2 to 26.4 %, p<0.001) but remained unchanged in MICT group (from 23.1 to 21.9 %, p=0.444) with significant inter-group difference: p=0.003. Resting heart rate (24-h Holter ECG) decreased significantly in both groups (from 68.2 to 64.6 bpm and from 66.0 to 63.5 bpm for MICT and HIIT respectively, without inter-group difference: p=0.578). No difference in premature ventricular contractions was observed between groups. V̇O2peak improvement was greater after HIIT when compared to MICT (+21 % vs +5% respectively, p=0.009). LVEF only improved in HIIT group (from 36.2 to 39.5 %, p=0.034).