Ep 112 Tachydysrhythmias with Amal Mattu and Paul Dorian

In this EM Cases main Episode 112 Tachydysrhythmias with Amal Mattu and Paul Dorian we discuss a potpurri of clinical goodies for the recognition and management of both wide and narrow complex tachydysrhythmias and answer questions such as: Which patients with stable Ventricular Tachycardia (VT) require immediate electrical cardioversion, chemical cardioversion or no cardioversion at all? Are there any algorithms that can reliably distinguish VT from SVT with aberrancy? What is the "verapamil death test"?  While procainamide may be the first line medication for stable VT based on the PROCAMIO study, what are the indications for IV amiodarone for VT? How should we best manage patients with VT who have an ICD? How can the Bix Rule help distinguish Atrial Flutter from SVT? What is the preferred medication for conversion of SVT to sinus rhythm, Adenosine or Calcium Channel Blockers (CCBs)? Why is amiodarone contraindicated in patients with WPW associated with atrial fibrillation? What are the important differences in the approach and treatment of atrial fibrillation vs. atrial flutter? How can we safely curb the high bounce-back rate of patients with atrial fibrillation who present to the ED? and many more... Podcast production &  sound design by Anton Helman; editing by Richard Hoang & Anton Helman EBM bottom line segment by Justin Morgenstern Written Summary and blog post by Shaun Mehta, edited by Anton Helman July, 2018 Cite this podcast as: Helman, A, Mattu, A, Dorion, P. Tachydysrhythmias with Amal Mattu and Paul Dorion. Emergency Medicine Cases. July, 2018. https://emergencymedicinecases.com/tachydysrhythmias/. Accessed [date].   General Approach to Tachydysrhythmias   Asking these three questions will help classify any tachydysrhythmia in most cases. 1.     Regular or irregular? 2.     Narrow or wide QRS? 3.     Are there P waves? P-QRS relationship? How many P waves for each QRS?       REGULAR IRREGULAR NARROW ST vs SVT (AVNRT, OAVRT, Aflutter 2:1) Afib vs Aflutter + variable block WIDE VT >>SVT+aberrancy HyperK, Na-blocker Afib+WPW or BBB vs PMVT Wide & regular tachydysrhythmias Ventricular Tachycardia (VT) vs SVT with aberrancy: Assume VT Wide & regular = ventricular tachycardia until proven otherwise. Clinical stability does not differentiate between VT and SVT with aberrancy. Despite multiple ECG algorithms and rules to distinguish VT from SVT with aberrancy (Brugada, Wellens, Vereckei, R wave peak time) none are better than 90% specific to identify SVT with aberrancy. No feature or combination of ECG features is 100% specific for SVT with aberrancy. Hence, using an algorithm/rule, there is a 10% chance that you will label VT as SVT with aberrancy erroneously and if you treat the patient with AV nodal blockers, cardiovascular collapse may result. There are several factors that make VT very likely: 1.     Prior MI, heart failure, recent angina and advanced age. 2.     AV dissociation (P and QRS complexes at different rates) and fusion complexes (sinus and ventricular beat coincide to produce a hybrid complex of intermediate morphology) on ECG (see images below) 3.     Pave Criteria – R-wave peak time >50ms in Lead ll 4.     Presence of 1st degree heart block on previous ECG   Arrows show AV dissociation (from Life in the Fast Lane blog) The first narrow complex is a fusion complex Remember that although advanced age makes a wide complex tachycardia...