Trials of new device for treating heart failure show no improvement in survival

14th April 2016

Trials of a new device to help people with heart failure show it is safe and well tolerated, but compared to drug treatments alone, it does not improve survival or reduce worsening chronic heart failure.

The international study, which included eight hospitals in the UK, investigated the benefits of the CardioFit system which stimulates the vagus nerve. This is the longest cranial nerve, extending from the brainstem to the stomach by way of multiple organs including the heart and lungs.  It forms part of the involuntary nervous system, and its role includes keeping the heart rate constant.

Results of the INOVATE HF trial were reported at the American College of Cardiology 2016 scientific sessions and online in the Journal of the American College of Cardiology.

The treatment failed to improve outcomes in people with long lasting NYHA class 111 heart failure (those comfortable at rest but with marked limitation of their physical activity) and reduced pumping of the heart. 

But the device, fitted under the skin in the upper chest, led to significant improvements in exercise capacity, symptoms and quality of life, but the influence of the placebo effect cannot be excluded because both patients and physicians were aware of treatment assignment, Dr Michael Gold, from the Medical University of South Carolina, Charleston reported to the conference.

Dr Gold said future research should focus on better ways to stimulate the vagus nerve and on the search for subgroups of patients who might get greater benefit from the treatment.

Animal studies have shown that vagus nerve stimulation can boost cardiac function and reduce mortality and inflammation, and a non-randomised pilot study of the technology used in the current trial showed improvements in quality of life and heart function.

In heart failure there is an imbalance in how the brain helps control the heart through two branches of the nervous system.  The sympathetic branch activates the fight or flight response during stress, increasing the heart rate and blood pressure.  The parasympathetic branch has a calming effect on the heart through signals carried from the brain to the heart by the vagus nerve.

In heart failure the sympathetic branch is in overdrive and the parasympathetic branch is underactive. 

The CardioFit device is designed to increase the effect of the parasympathetic branch to help bring better balance to the heart.

Source: Gold MR, Van Veldhuisen DJ, Hauptman PJ, et al. Vagus nerve stimulation for the treatment of heart failure: the INOVATE-HF trial. J Am Coll Cardiol. 2016.

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