CardioNerds ECG Challenge #6

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Question:

46 yo M is 2 days S/P minimally-invasive mitral valve repair.

Why is he complaining of intermittent neck discomfort❓

Answer

Intermittent cannon A waves account for the intermittent neck discomfort.

Learning Points:

  1. The atrial rhythm is sinus at 81/min.​
  2. The QRS complexes are accelerated junctional at 79/min, a common arrhythmia following heart surgery.​
  3. There is A-V dissociation.​
  4. When the PR interval is particularly short or the P wave follows the QRS (not seen in this tracing) the atria contract coincident with, or after the closure of the atrioventricular valves.  The resultant retrograde atrial propulsion of blood into the valveless SVC causes a pronounced pulsation in the neck veins, called a cannon A wave, that he sensed as neck discomfort.  These cannon A waves come in volleys and then disappear, only to return, until the A-V rhythm associates.​
  5. Although acute pericarditis is present and can cause discomfort, this is not intermittent neck discomfort.

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CardioNerds ECG Challenge #6