Atrioventricular Blocks

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    79 year old male with fatigue.

    79 year old male with fatigue.

    Questions

    Question 1: What are possible causes of the patient's fatigue?

    Question 2: What is the location of block for the "dropped" P waves in this patient?

    Key Findings

    -Sinus rhythm

    -2nd degree AV block type I (Mobitz I)

    -Low voltage

    Coding for Boards

    -Sinus rhythm

    -Av block, second degree-Mobitz type II (Wenckebach)

    -Low voltage, limb leads

    Answers

    Question 1: Conduction System Disease, Excessive doses of AV nodal blocking agents, and Hypothyroidism.

    Question 2: Usually P waves fail to conduct in the AV node during periods of Wenckebach. This is probably true for this patient. However, the last non-donducted P wave falls before the T wave and could have potentially blocked in the ventricular myocardium (ventricular refractory period).