Guess what? It’s an election year! You are excited. And nervous. And kind of sick of the nonstop new coverage. In fact, you are having palpitations watching these candidates gore out each others’ figurative hearts and roast them over a public pit of shame, name-calling, and general stupidity.
But still… Will it be Hillary? Will it be Bernie? Will it be Trump?!? You start to feel these funny palpitations, almost like your heart is stopping for a moment when you think about each candidate. When you think about Trump you briefly syncopize. Is this normal??
Probably.
But why don’t we take a look at your cardiac rhythm:
What rhythm is this?
Third degree heart block – AKA COMPLETE heart block. You have loss of AV conduction, so your atria are doing their thing, and an escape pacemaker (either from the AV junction or purkinje fibers) lets your ventricles do their own thing. If the escape pacemaker, which does not respond to autonomic stimulation, does not keep up sufficient cardiac output, then you syncopize… or maybe even die.
That is right, you’ve heard so many politicians vying for votes and splashing petty insults and accusations on one another that your heart has broken and can’t keep up. Or, it’s like your atria are Republicans, and your ventricles are Democrats, and the two just cannot cooperate.
What are important causes of this rhythm?
Basically, anything that knocks out the AV node or the His bundle:
- Ischemia: Inferior or anterior MI
- AV nodal blocking drugs: Ca-channel blockers, beta-blockers, digoxin, etc
- Infiltrative diseases: Amyloid, sarcoid, hemochromatosis, hypothyroidism
- Autoimmune/Infection: Lyme disease, Chagas disease, rheumatic fever, TB, lupus, etc
- Lev disease and Lenegre disease (fibrosis of proximal bundles or His-Purkinje system, respectively)
- Trump’s gigantic Mexican-financed border wall
What do you want to do immediately?
ABCs! IV, O2, Monitor!
Ok, of course, typical political response. But THEN what do you want to do immediately?
Make sure transcutaneous pacer pads are attached and ready!
What are the general indications for cardiac pacing? What meds can you try first in this case?
- Unstable bradycardia / bradyarrythmia (like complete heart block or Mobitz II) – Try atropine first. It often won’t work but should be attempted before electrocution.
- Bradycardia-dependent Torsades de Pointes – Pacing will increase heart rate and reduce risk of recurrence
- Sick sinus syndrome with sinus pauses > 3 seconds.Â
You have pacer pads on, and cardiology is heading over after they finish up with the STEMI code next door. You decide that although you feel symptomatic from the bradycardia, you really don't want to be externally shocked with these transcutaneous pads and atropine did not work. What can you do now to control your rhythm?
Transvenous pacing! One of our procedural gems in the ED. Â You grab your kit, get yourself sterile and get ready to party.
What vessel are you going to catheterize and why?
-Right internal jugular vein – this offers the most direct access into the right atrium. Â Left subclavian is second choice.
I can walk you through all of the steps but check out this video instead. There are all the same steps as a regular IJ central line, but it’s a single lumen catheter sized specifically for the pacer wires (a cordis is not the appropriate size). Once secured, you will feed the pacer wire through and attach to the external pacer box. An continuous ECG and/or bedside ultrasonography can assist with proper placement of the wire.
References
- Martindale JL, Brown DFM. Rapid Interpretation of ECGs in Emergency Medicine. Philadelphia, PA: Lippincott Williams and Wilkins; 2012.
- Piktel JS. Chapter 22. Cardiac Rhythm Disturbances. In: Tintinalli JE, Stapczynski J, Ma O, Cline DM, Cydulka RK, Meckler GD, T. eds. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 7e. New York, NY: McGraw-Hill; 2011
- Lim S, Venkataraman A, Teo W. Chapter 35. Cardiac Pacing. In: Tintinalli JE, Stapczynski J, Ma O, Cline DM, Cydulka RK, Meckler GD, T. eds. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 7e. New York, NY: McGraw-Hill; 2011.
- Jeremy Fernando. “Temporary Transvenous Cardiac Pacing.” Life in the Fast Lane Blog. http://lifeinthefastlane.com/ccc/temporary-transvenous-cardiac-pacing/
- Edward Burns. “Av Block: Third Degree (complete heart block)” Life in the Fast Lane Blog. http://lifeinthefastlane.com/ecg-library/basics/complete-heart-block/ Â
Special thanks to Dr. Willis
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Kylie Birnbaum
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1 Comment
iandesouza · April 22, 2016 at 1:47 am
Nice post, Birnbaum. Remember that transcutaneous pacing is painful and a reasonable alternative (equally recommended in ACLS) is vasoactive medication: dopamine, epinephrine, and isoproterenol (for bradycardia-dependent ventricular tachydyshrythmias).
OVERDRIVE pacing for unstable tachydysrhythmias cannot be performed effectively with transcutaneous or transvenous pacing because the pacers are incapable of generating sufficiently high ventricular rates. It is almost always performed in the electrophysiology laboratory.