Breathing Exercise Against Dyspnoea in Heart Failure Patients to Improve Chemosensitivity

The registry criteria, word for word

What the trial wants to find out

An exaggerated ventilatory response (minute ventilation, V̇E) to exercise relative to exhaled carbon dioxide (V̇CO2) is common in heart failure (HF) patients with reduced as well as preserved left ventricular ejection fraction (HFrEF, HFpEF). Severity of this exaggerated response is associated with poor prognosis. This response may be triggered by pulmonary congestion and peripheral muscle myopathy. A vicious circle is fuelled by hypersensitivity of chemoreceptors to hypercapnia and sympathetic nervous hyperactivity, resulting in hyperventilation (low PaCO2). Low PaCO2 is predictive of mortality in these patients. PaCO2 can be increased acutely, e.g. by apnoea. Also, nasal breathing has been found to reduce the V̇E/V̇CO2 slope during exercise compared to oral breathing. Three previous slow breathing studies in HFrEF patients have had encouraging results with regard to reducing sympathetic activity, reflected in lowered arterial (pulmonary) blood pressure and increased EF. The investigators hypothesise that a 12-week training with nasal slow breathing followed by end-expiratory apnoea based on education, centre-based introduction and home-based 15 min/day breathing training will be effective at reducing the exaggerated ventilatory response to exercise. A total of 68 patients with stable HF seen at the HF clinics of the Inselspital (34 HFrEF, 34 HFpEF) will be randomised to the breathing intervention or usual care. Primary outcome will be V̇E/V̇CO2 slope at 12 weeks. If breathing training successfully ameliorates the exaggerated ventilatory response and perception of dyspnea during exercise, it offers an attractive tele-health based add-on therapy that may add to or even amplify the beneficial effects of exercise training.

The 2 groups in the trial

• Breathing trainingTreatment being tested

  The respiratory pattern modulation training is performed at home for 12 weeks twice daily for 15 min per session and consists of three components: 1) education on abnormal ventilation in heart failure, the effect of ventilation on PaCO2 and the autonomous nervous system, and chemoreceptor sensitivity; 2) 1-3 sessions of guided and monitored face-to-face training with slow nasal abdominal breathing and intermittent apnoea supported by the Healer vest (L.I.F.E., Milan, Italy) measuring electrocardiogram (ECG), and chest excursions at the level of the xiphoid, thoracic manubrium, and abdomen; 3) independent home-based apnoea training supported by hand-outs, videos and weekly phone calls to monitor progress and adherence, answer questions and encourage further progression with duration of breath-hold.

• ControlNo study treatment, for comparison

  The control group receives standard of care. They perform the study measurements before and after the intervention period of 12 weeks. They are offered to perform the breathing training after study completion.