title: [When the QRS becomes narrow].
authors.forename: P
authors.initials: P
authors.lastname: Della Bella
mesh_terms: D004562:Electrocardiography; D006801:Humans; D011226:Pre-Excitation Syndromes / Q000175:diagnosis*; D013617:Tachycardia, Supraventricular / Q000175:diagnosis* / Q000503:physiopathology / Q000628:therapy