Thank you to John for presenting the case of a patient with complete heart block who went into acute heart failure due to their complete heart block and subsequent bradycardia. Thanks also to Luke for being our expert discussant.
Indications for Temporary Pacing in Bradycardia:
- Recall that in ACLS, indications for entering the bradycardia algorithm for treatment include:
- Acute altered mental status
- Signs of shock
- Ischemic chest discomfort
- Acute heart failure
- In Bradycardia, first steps are to try atropine, and if this is ineffective, proceed to transcutaneous pacing (especially if unstable), dopamine infusion, or epinephrine infusion
- If you are thinking of transcutaneous pacing, you should also be calling Cardiology consult and think about getting transvenous pacing in the works because no one wants to be shocked 60-90 times per minute for days awaiting permanent pacemaker placement!
Heart Block Pearls and When to Worry:
- Look at an old EKG to see what their underlying conduction system looks like:
- Does the person have 1st degree AV block?
- Do they have a RBBB or LBBB?
- Is there left anterior fascicular block? Is there a left posterior fascicular block?
- The more conductive disease, the more worried you should be that they are going to (or have already) progressed to complete heart block
- Look for Mobitz Type II (stable PR interval with dropped QRS complexes)
- Remember that this means that there is a very sick AV node and that conduction is NOT happening
- If there is AV dissociation and there is a NARROW complex, trying medications (atropine, dopamine, epinephrine) is not completely unreasonable as there may not be COMPLETE heart block, but they could have high-grade AV block that will benefit from meds (or just exercise). BUT, even narrow complex can still be infranodal disease that wil not respond to meds, so considering pacing early is important.
- If there is AV dissociation and there is a WIDE complex escape rhythm, the lesion is DEFINITELY below the AV node and His-Purkinje system. Thus, trying medications will NOT work
- These people NEED transvenous pacing until they can get a permanent pacemaker placed