Heart-Stopping Syncope

Today we presented a case of syncope 2/2 to age-related degeneration of the conducting system leading to complete heart block. We first went through a framework for Syncope (taken from Dr. Eric Strong’s awesome lecture series)

Definition: Syncope is defined as a transient, self-limited loss of consciousness with an inability to maintain postural tone that is followed by spontaneous recovery.

DDxSyncope.PNG

Source: https://www.youtube.com/watch?v=iJ6g5rsQKaM&t=343s

We then emphasized the importance of choosing wisely in the workup of syncope. All patients with syncope should receive the following:

  • A spectacular history
  • A splendid physical examination
  • An EKG
  • Orthostatic vital signs

Depending on the above, target your further testing accordingly

Remember, it’s the cardiogenic syncope that is highly concerning and so the San Francisco Syncope Rule can be useful in deciding who is safe to discharge…BUT, as a recent paper reported, the sensitivity of clinical judgement for adverse outcomes secondary to a syncope is higher than decision making rules. Therefore, if something doesn’t feel right, trust your instincts!

Our patient was found to have complete heart block on an EKG and we reviewed the three major classifications for its etiology:

  1. Known Pathologic
    • Ischemia
    • Myocarditis (i.e lyme)
    • Infiltrative cardiomyopathy (amyloidosis, sarcoidosis
  2. Iatrogenic
    • Medication-related
    • Post-cardiac surgery
    • Post catheter ablation
    • Post TAVR
  3. Idiopathic Progressive Cardiac Conduction Disease (>50% of cases)
    • thought to be secondary to age-related degeneration of the conduction system

Finally, we discussed management of complete heart block:

  • Atropine use should be avoided since it is likely ineffective (since the block is likely below the AV node) and more importantly it delays more effective treatment
  • Electrical & Medication options (either epinephrine OR dopamine) should be considered
  • Unless the cause is immediately reversible, patients will generally need a transvenous pacemaker and then a permanent pacemaker
If you made it this far in the post, congratulations. As a reward, do note that the framework for syncope actually has a mnemonic embedded within it (ROCS) 🙂

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