title: 'Nonrespiratory sinus arrhythmia' or 'heart rate alternans': comments on the article by Gratadour et al. 'Unusual sinus arrhythmia'.
authors.forename: Paulo Roberto
authors.initials: PR
authors.lastname: Benchimol-Barbosa
authors.forename: José
authors.initials: J
authors.lastname: Barbosa-Filho
mesh_terms: D001146:Arrhythmia, Sinus / Q000175:diagnosis / Q000503:physiopathology*; D004562:Electrocardiography; D006339:Heart Rate; D006801:Humans