Snapshot A 17-year-old girl presents to the emergency room with lightheadedness and palpitation. Her pulse is 250/min and she is hemodynamically stable. An electrocardiogram shows an antidromic atrioventricular reentrant tachycardia. She is given procainamide with a resolution of the arrhythmia. Now in sinus rhythm, she is found to have a widened QRS, delta wave, and shortened PR interval on the electrocardiogram. Introduction Clinical definition login to view 1 more bullet Associated conditions login to view 2 more bullets Epidemiology Risk factors login to view 1 more bullet Etiology Can be familial Pathogenesis login to view 6 more bullets Presentation Symptoms login to view 7 more bullets Physical exam login to view 1 more bullet Studies Electrocardiogram (ECG) login to view 4 more bullets Making the diagnosis login to view 1 more bullet Differential Myocardial infarction login to view 2 more bullets Bundle branch block login to view 2 more bullets Treatment Management approach login to view 1 more bullet Medical login to view 7 more bullets Non-operative login to view 6 more bullets Complications Sudden cardiac death Prognosis Can present with the following arrhythmias login to view 9 more bullets