Dec 11, 2020
Dr. Jeremy Berberian joins EMRA*Cast with Alex Kaminsky to delve deeper into the pathophysiology and electrical findings associated with diagnoses such as WPW, Brugada and ARVD.
Lumps and Bumps: Can't-Miss Diagnoses in Syncope
Host: Alex Kaminsky
Guest: Jeremy Berberian, MD
- Associate Director of Resident Education, ChristianaCare
- Editor-in-chief: EMRA EKG Guide, EMRA Ortho Guide, and the upcoming Emergency ECGs: Case-Based Review and Interpretations, with Amal Mattu and William Brady
- Faculty editor: EM Resident Monthly ECG Challenge
- Creator: ECG Greeting Cards©, a collaboration with MPP and JerBer Productions
EPISODE OVERVIEW
Residents are well-programmed to recognize
cardiovascular emergencies such as STEMIs at a glance. However,
during a busy shift it can be easy to overlook dysrhythmias and
other electrophysiologic urgencies and emergencies. Syncope is a
prime example of a chief complaint that may be uncovered with an
EKG alone -- however, syncopal emergencies are often subtle and
nuanced. Dr. Berberian joins EMRA*Cast with Alex Kaminsky to delve
deeper into the pathophysiology and electrical findings associated
with diagnoses such as WPW, Brugada, ARVD and more.
KEY POINTS
Wolff-Parkinson-White (WPW)
Prevalence: 0.7 to 1.7 per 10000
Overview
Accessory Pathway Connecting the atria to the
ventricle. In some instances, this can cause the accessory pathway
to travel FASTER than through the AV node.
- Orthodromic (Narrow): Travels down the AV node (can bypass)
- Antidromic (Wide): Bypasses AV node and UP the his-purkinje system.
Courtesy of CardioNetworks: Free use image
Key Features:
Image: Courtesy of EMRA EKG Guide
- Short PR (less than 120ms)
- “Delta” wave -- which is a “slurring” of the QRS complex
- QRS might be “a little” wide (still <120ms)
- Often secondary ST-T wave changes.
Most common presentation is SVT. But also can present as atrial fibrillation.
Treatment
Orthodromic
(Narrow): Treat
like SVT
Key Point: Procainamide is the most safe chemical cardioversion in WPW as it does not directly affect the AV node. Use of AV-nodal blockers in WPW (including Amiodarone) increases the risk of VT/VF.
***Blocking the AV node in a WPW patient in Atrial Fibrillation can precipitate bad ventricular rhythms. If you see A-fib GREATER than 220 minus age -- consider WPW.***
Antidromic (Wide): Treat Like V-Tach
Brugada Syndrome
Prevalence: 5 in 10,000. Traditionally taught
more common in Southeast Asian populations.
Overview
Sodium Channelopathy, which can lead to
unstable dysrhythmias and ultimately cardiac death
Key Features
Diagnosis is made both by EKG and clinical criteria
Images: Courtesy of EMRA EKG Guide
Type 1:
- “Coved” ST-Elevation >2mm with a negatively deflected T in right precordial leads (V1-V3)
- Potentially diagnostic as isolated EKG finding.
Type 2:
- ST elevation in right precordial leads (V1-V3) with a “saddleback.” Within the STE.
- Not completely diagnostic but concerning fr workup.
Clinical Criteria (EKG Findings PLUS one or more):
- SYNCOPE
- Nocturnal Agonal Respirations
-
- Brugada gets WORSE with parasympathetic stimuli.
- Family member with known Type 1
- Observed/Documented VT/VF
- Sudden cardiac death in family member <45 (Take that history!)
Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy (ARVD)
Prevalence: Unknown, likely more than we thought. Mean age is 31. Also we don't have great clinical criteria to full encompass this -- yet. Multiple genes linked to disease process. Variable inheritance patterns.
Overview
Fibro-Fatty infiltration of the myocardium that
replaces good "conductive" tissue with fibrinous infiltrates.
Think: "Kinda like cirrhosis of the heart."
Causes paroxysmal ventricular rhythms. Can present as CHF.
Key Features
Image: Courtesy of EMRA EKG Guide
- Epsilon wave -- AKA "The Ditzle or Nubbin" (only in 30% of patients)
- T-wave inversions in right precordial leads (V1-V3) -- (85% of patients)
- Long S-wave repolarization delay >55ms (in 95% of patients)
- Slightly prolonged QRS >110ms (Right precordial leads)
- VT looks more like a Left-bundle morphology -- Appreciate that AFTER the patient is out of VT.
Key Resources: *If needed and/or different than references*
- EMRA EKG Guide
- Clinical Policy: Critical Issues in the Evaluation and Management of Adult Patients Presenting to the Emergency Department with Syncope: Huff J.S., Decker W.W., Quinn J.V., Perron A.D., Napoli A.M., Peeters S., Jagoda A.S.( 2007) Annals of Emergency Medicine, 49 (4) , pp. 431-444.
- Epidemiological profile of Wolff-Parkinson-White syndrome in a general population younger than 50 years of age in an era of radiofrequency catheter ablation. Lu C.-W., Wu M.-H., Chen H.-C., Kao F.-Y., Huang S.-K. (2014) International Journal of Cardiology, 174 (3) , pp. 530-534.
- Reference, G. (2019). Brugada syndrome. [online] Genetics Home Reference. Available at: https://ghr.nlm.nih.gov/condition/brugada-syndrome#statistics [Accessed 14 Feb. 2019].
- McNally E, MacLeod H, Dellefave-Castillo L. Arrhythmogenic Right Ventricular Cardiomyopathy. 2005 Apr 18 [Updated 2017 May 25]. In: Adam MP, Ardinger HH, Pagon RA, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2019. Available from: https://www.ncbi.nlm.nih.gov/books/NBK1131/