This POTD is inspired by a septic man in Resus today who required cardioversion. If you're curious, he looked fantastic after his heart stopped going 240 beats per minute and settled in to the 90s. From NPR: “This patient was wearing a Fitbit fitness tracker that had a heart rate monitor and connected wirelessly to his smartphone. With his permission, the doctors checked the data on the phone and figured out that the episode of arrhythmia had begun only about two hours before he showed up at the ER.
"We were able to hook him up to the pads, put him to sleep, give him a little shock, and let him wake up and go home," Sacchetti says.”
ATRIAL FIBRILLATION! Rhythm Control and Cardioversion
- Atria are beating chaotically: “irregularly irregular”
- Can do rate control, rhythm control, or possibly cardioversion in the ED
- Nonpharmacologic Rhythm Control:
- Ablation by EPS
- radio frequency
- cryoballoon
- laser surgery
- Reversible causes have already been addressed (e.g. HTN, hyperthyroidism, alcoholism, heart failure, sleep apnea)
Cardioversion
- When to use: New onset a fib within 48 hrs or patient is unstable
- Contraindications: Can’t confirm it’s been less than 48 hours. In these cases, pt to be anti-coagulated for 3 weeks prior to outpatient cardioversion.
- How to do it: First sedate patient (e.g. with etomidate) and then shock at 100J—>200K—300J—360J
AF without Structural Heart Disease
- Okay in HTN without LVH
- Flecainaide or propafenone as first line
- Be wary in the elderly due to CAD (and likely structural disease)
- Others used include Amiodarone, Sotalol, Dronedarone.
- In SAFE-T and AFFIRM Trials, Amiodarone >> flecainaide, propafenone, or sotalol
AF with Structural Heart Disease
- Amiodarone, Sotalol, and Dofetilide usually first line
- CAD: Sotalol>> dronedarone, dofetilide, and amiodarone. Flecainide and propafenone are contraindicated in this population.
- LVH: Sotalol, flecainaide, propafenone may cause arrhythmia. Dronedarone or Amiodarone are options
A little bit about Amiodarone
- Low dose of 100 to 200mg po daily but can use higher doses
- Low incidence of torsades
- Made need less rate control as has beta blocker and CCB activity.
- Unfortunate toxicity
- Check LFTs, TFTs (has iodine), and Lung function
- Blue Man Syndrome (Argyria)
- Most effective
- Most likely to have long term complications
- May interfere with warfarin, thus increasing risk of stroke
- Class III Drug
- Prolong QT
- Slows Heart Rate and AV node conduction (like CCB, Beta blockers)
- Prolongs refractoriness (is that a word? It is now) via K+ and Na+ blockade
- Slows intracardiac conduction via Na+ blockade