A 47-year-old man with abdominal pain and heart rates approaching 300 bpm

 Written by Pendell MeyersA 47-year-old man with known WPW syndrome presented to the ED complaining of left abdominal pain, diarrhea, and chills. He denied palpitations, but is found to have a heart rate of 170 bpm at triage. He states that he occasionally has episodes of tachycardia which usually lasts about 1 hour, which he was instructed to " ride out at home unless they persist. "  Other than his heart rate, his other vitals were within normal limits, and the patient did not show any signs of compromised cardiac output or distress.Here is his initial ECG:What do you think?The ECG shows an irregularly irregular polymorphic tachycardia at approximately 186 bpm. Occasional beats are conducted with narrow, normal morphology, but most are conducted aberrantly with a nonspecific intraventricular conduction delay pattern, which is not actually very wide despite the abnormal conduction. While most of the abnormally conducted beats have the same morphology, the morphology becomes more polymorphic when the rate increases, as seen twice during this ECG, with lead V1 best demonstrating significantly different morphology between QRS complexes. Several beats are conducted at approximately 300 msec after the previous beat, which is extremely unlikely to be the result of a normal AV node conduction.Because it is irregularly irregular, polymorphic, and has R-R intervals approaching less than 300 msec, the diagnosis is atrial fibrillation with WPW (also called pre-excited atrial ...
Source: Dr. Smith's ECG Blog - Category: Cardiology Authors: Source Type: blogs