A wide complex tachycardia

Submitted by Van Wall M.D., Written by Pendell MeyersLet ' s go back to the basics for a common and classic scenario.A middle-aged patient presents with shortness of breath and palpitations. The patient was stable without signs of low cardiac output or distress. Her ECG is shown below (first see what you think without using the baseline): What do you think?There is a (minimally) wide complex, regular monomorphic tachycardia at a little faster than 150 bpm. I measure the QRS duration at almost exactly 120 ms. The differential would include ventricular tachycardia, any cause of narrow complex regular tachycardia plus added conduction aberrancy (such as a bundle branch block), or other causes of QRS widening like hyperkalemia or sodium channel blockade. Of course, the interpreter should always start by assuming that a wide complex monomorphic tachycardia is due to ventricular tachycardia and/or life threatening hyperkalemia, until proven otherwise.This demonstrates why it is so important to be able to recognize RBBB, LBBB, and paced rhythms (pacer spikes) so quickly. This ECG has perfect RBBB morphology, one of the rare times that we can be confident that a regular wide complex rhythm is not classic ventricular tachycardia. For more discussion on features of SVT vs. VT, see these prior posts:Wide Complex Tachycardia: Ventricular Tachycardia or Supraventricular Tachycardia with Aberrancy?Wide Complex Tachycardia and CyanosisA prior baseline showing identical RBBB morpho...

Source: Dr. Smith's ECG Blog - January 11, 2021 Category: Cardiology Authors: Pendell Source Type: blogs