How to interpret EKGs better than you document a rash: Syncope Part 1

• Prevalence: 0.7 to 1.7 per 10,000

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:

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

• 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

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!)

• 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.