Resistance Exercise With Blood Flow Restriction by Vascular Occlusion on Myocardial Function in Heart Failure With Reduced Ejection Fraction

Exercise is essential in cardiac rehabilitation for heart failure patients.Aerobic training and resistance training are both recommended. Resistance training improves muscle mass and strength and also improves the remodeling of cardiac function, thus reducing exercise intolerance in these patients. However, to obtain these adaptations, resistance training must be done at moderate to high intensities, which cannot always be sustained by the most fragile and deconditioned patients, such as those with reduced ejection fraction (Heart failure with reduced Ejection Fraction). Blood flow restriction (BFR) by vascular occlusion training is an interesting alternative to conventional resistance training for these deconditioned patients. Preclinical and clinical studies have shown that, for low-intensity regimens, resistance training and blood flow restriction by vascular occlusion improves muscle strength and left ventricular function, unlike resistance training alone. Tissue hypoxemia, initiated by vascular occlusion and exacerbated by maintenance of exercise, is a key element in the peripheral adaptations documented in blood flow restriction, triggering a cascade of signaling pathways involving neurohumoral factors in particular, with effects both locally (i.e. striated skeletal muscle) and remotely, on the myocardium among others. The feasibility and safety of blood flow restriction in heart failure patients has been well demonstrated. Left ventricle ejection fraction remains a very global functional index, with poor reproducibility influenced by cardiac load conditions, making it impossible to draw any conclusions as to possible improvements in myocardial function, linked to changes in intrinsic tissue decontractility/relaxation properties. New cardiac imaging techniques like Speckle Tracking Echography have made it possible to assess the effects of blood flow resistance on myocardial function but so far no studies have used these tools to compare the effects of BFR+resistance training and resistance training alone on myocardial function in heart failure patients. It is suggested that resistance training combined with blood flow resistance could further improve cardiac and muscular function compared with resistance training alone, by activating neurohumoral mediators, like certain micro ribonucleic acids.

Physical exercise is an essential part of cardiac rehabilitation for heart failure patients. In addition to aerobic training, resistance training is now recommended by scientific societies. Clinical studies report that resistance training contributes not only to peripheral reconditioning, with improved muscle mass and strength, but also to central reconditioning, with improved remodeling and cardiac function, thus reducing the exercise intolerance of heart failure patients. These favorable adaptations are achieved, however, on condition that RT is performed at moderate to high intensities (e.g. \>75-80% of maximal repetition), intensities that cannot always be sustained by the most fragile and deconditioned patients, such as those with heart failure with reduced ejection fraction. The guidelines recommend intensities of 40% or less of repetition maximum. Blood flow restriction (BFR) by vascular occlusion training is an interesting alternative to conventional resistance training, particularly for these most deconditioned patients. Preclinical and clinical studies have clearly established that for low-intensity regimens (around 40% of maximal repetition, an intensity well tolerated by the most fragile patients), resistance training+BFR improves muscle strength and left ventricular function, unlike resistance training alone. Tissue hypoxemia, initiated by vascular occlusion and exacerbated by maintenance of exercise, is a key element in the peripheral adaptations documented in BFR, triggering the activation of a cascade of signaling pathways involving neurohumoral factors in particular, with effects both locally (i.e. striated skeletal muscle) and remotely, on the myocardium among others. The feasibility and safety (i.e. no reported adverse events) of BFR in heart failure patients has been well demonstrated. Left ventricular ejection fraction remains a very global functional index, with poor reproducibility and influenced by cardiac load conditions, making it impossible to draw any conclusions as to possible improvements in myocardial function, linked to changes in intrinsic tissue decontractility/relaxation properties. Innovative cardiac imaging techniques, such as Speckle Tracking Echography, now enable a detailed assessment of the effects of BFR on myocardial function. However, no study has yet used these tools to compare the effects of BFR+resistance training and resistance training alone on myocardial function in heart failure with reduced ejection patients. It is hypothetically suggested that resistance training combined with BFR could further improve cardiac and muscular function compared with resistance training alone, thanks to the activation of neurohumoral mediators, such as certain micro ribonucleic acids.