Cardiac and Respiratory Function With Non-invasive Ventilation

To assess patients with hypercapnic respiratory failure using echocardiography,cardiac output measurements and markers of neural respiratory drive (EMGpara) prior to, during and after non-invasive ventilation (NIV) initiation, and to follow the patients for 3 months. The investigators hypothesize that the improvement in cardiac function and/or respiratory mechanics over time are associated with ongoing improvements in oxygenation, quality of life and exercise capacity.