Emergency Medical Services (EMS) Agency
ECG OF THE MONTH – June 2020
Paramedics respond to a 68-year old female after a syncopal episode while at a restaurant.
ECG obtained from LITFL.com
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Rate: ~40 bpm
Rhythm: Sinus rhythm, p wave preceding each QRS, additional P wave without QRS complex
ST Segment Elevation >1mm
In 2 or more contiguous
Reciprocal Changes: N/A
This ECG demonstrates a 2nd degree, Mobitz II heart block. This type of heart block occurs when there is failure to conduct electrical impulses below the AV node within the His-Purkinje system. It is typically due to structural damage to the cardiac conduction system due to a myocardial infarction, scarring, or other causes for cardiac cell damage that can occur over time. Other causes include, cardiac surgery, and systemic inflammatory conditions (lupus, sarcoidosis, Lyme disease).
Note that there is a “dropped” QRS complex after every other p wave (2:1 block because for every 2 p-waves, only one QRS complex is generated).
Figure 1. Note that the p-waves are generated regularly at about 80bpm, but the QRS complex only occurs every other beat at a rate of about 40 bpm.
Patients with a 2nd degree Mobitz II heart block are at higher risk to become symptomatic due to severe bradycardia or even progression to a complete heart block. These patients will require hospital admission for monitoring and eventual pacemaker placement.
This patient presented with a syncopal episode and should be managed in accordance with TP-1233 – Syncope/Near Syncope as well as TP-1212 – Cardiac Dysrhythmia, Bradycardia. Base Contact is required because the syncopal episode constitutes symptomatic bradycardia. The 12-lead does not otherwise show a STEMI, so the patients would be transported to the MAR.
Author: Denise Whitfield, MD, MBA