title: [Electric alternans of QRS: its electrophysiologic significance in narrow QRS supraventricular paroxysmal tachycardia].
abstract: The results of 22 patient's transesophageal electrophysiologic studies were analyzed to value the meaning of QRS alternans during narrow QRS tachycardia. Standard ECG showed ventricular pre-excitation in eight patients. QRS alternans were in six of them: heart rate was included between 230 and 374 m/sec (301.8 +/- 42 m/sec); in the remaining 16 patients, heart rate was included between 240 and 450 m/sec (350.0 +/- 42 m/sec). Our findings suggest that QRS alternans is related to the rate of tachycardia rather than to the presence of an accessory pathway.
authors: I Facoltà di Medicina e Chirurgia, Cattedra di Cardiologia, Università degli Studi di Napoli Federico II, Napoli.
authors: L
authors: L
authors: Santangelo
authors: M S
authors: MS
authors: Mayer
authors: F
authors: F
authors: Marsico
authors: C
authors: C
authors: Nave
authors: A
authors: A
authors: Prisco
authors: A
authors: A
authors: Catizone
mesh_terms: D000328:Adult; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate; D006352:Heart Ventricles / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D013614:Tachycardia, Paroxysmal / Q000175:diagnosis / Q000503:physiopathology*; D013617:Tachycardia, Supraventricular / Q000175:diagnosis / Q000503:physiopathology*
vernacular_title: Alternanza elettrica del QRS: suo significato elettrofisiologico nelle TPSV a QRS stretto.