1. Centro Cardiologico Monzino, Istituto di Ricerca e Cura a Carattere Scientifico, Milan, Italy
2. Department of Clinical Sciences and Community Health, Cardiovascular Section, University of Milan, Milan, Italy
3. Laboratory for the Analysis of Cardio-Respiratory Signals, Istituti Clinici Scientifici Maugeri, IRCCS, Divisione di Cardiologia Riabilitativa, Veruno, Italy
4. Life Science Institute, Sant’Anna School of Advanced Studies, Pisa, Italy; and
5. Fondazione Toscana Gabriele Monasterio, Pisa, Italy