The Dizzy Ranger

1. The Dizzy Ranger Simulation Case Debriefing Material

2. Debriefing questions • What went right? • What went wrong? • How do you treat bradycardia secondary to high degree AV block? • What are the indications and contraindications for emergent pacing? • What is the proper placement of the single lumen introducer catheter for transvenous pacing? • What heart chamber are you trying to place the pacemaker? • How can you confirm proper placement and capture of the pacemaker? • Describe the cardiac manifestations of Lyme carditis. • How is Lyme carditis treated?

3. ACLS bradycardia interventions(HR <60 with symptoms) • Assess airway and breathing. • Establish IV, give O2 (continuous pulse oximetry) • Place on cardiac monitor (and obtain ECG) and check blood pressure • With signs/symptoms of poor perfusion: • Prep for trancutaneous pacing (emergent use if high degree AV block present) • Consider atropine 0.5 mg IV and repeat to a max total dose of 3mg if pacer is not ready • Consider epi (2-10 micrograms/min) or dopamine (2-10 micrograms/min) infusions if pacer not ready or is ineffective • Prepare the transvenous pacer and consider consulting cardiology

4. Recognizing high degree AV block • 2nd degree AV block • Mobitz I (Wenckebach): Progressive prolongation of the PR interval and shortening of the R-R until the QRS is dropped. • Not generally associated with a higher mortality EXCEPT in the context of acute MI • Mobitz II: Atrial beat sporadically not conducted with constant PR and R-R intervals. • Can progress to 3rd degree heart block and thus carries a higher mortality • Both can be seen with Lyme disease • 3rd degree AV block • See complete AV dissociation with the QRS being conducted at an independent rate from the atrial rate • Patient’s are generally hemodynamically unstable with bradycardia and hypotension

5. Indications for pacing in the setting of bradycardia • Symptomatic sinus node dysfunction • Sinus arrest, tachy/brady syndrome, sinus bradycardia • Second or third degree heart block • Includes Mobitz I in the setting of myocardial infarct • Symptomatic slow atrial fibrillation • New LBBB, RBBB with left axis deviation, bifascicular block, or alternating BBB in the setting of acute MI • Prior to procedures that may induce bradycardia • Malfunction of implanted pacemaker

6. Contraindications to pacing in the setting of bradycardia • No absolute contraindications • Hypothermia • Bradycardia may be manageable without pacing while awaiting rewarming • Pacing may precipitate V Fib that is difficult to convert. • Thrombolytic use: • Transcutaneous pacing may be preferred • Asymptomatic patients • Good idea to consider placing pacing pads in case of deterioration

7. Highlights for transcutaneous pacing • Consider pretreating with opiods and benzodiazepines prior to initiation • Place anterior pad at point of maximal impulses to the left chest wall • Place the posterior pad directly posterior to the anterior pad • Attach the patient to the ECG monitor and make sure both ECG leads and pacer pads are hooked up to the pacemaker • Set the presets to rate 80 and around 40-60 mA • May also start with lower amperage and increase dose until capture occurs • Confirm placement by assessing rhythm strip for consistent pacer spike followed by QRS and improvement in patient’s symptoms

8. Highlights for emergent transvenous pacing • If you have the time: • Arrange for either ultrasound to confirm placement OR • Attach the negative electrode the the V1 lead on an ECG machine • Please refer to the Pacing instructions for tips on transvenous placement • Figure 4

9. Proper location for single lumen catheter for transvenous pacing • Preferred locations are the right internal jugular vein or the left subclavian vein • These provide the straightest path to the the right heart anatomically • Check your institutions preference and cardiology preference for permanent pacemaker placement • Avoid the most likely site of permanent pacemaker placement if possible

10. Transvenous pacer: Confirmation of placement • Right ventricular placement is confirmed on ECG with LBBB pattern and LAD • Note that RBBB may indicate coronary sinus placement or septal perforation and LV pacing • Look for cannon waves present on exam of the neck veins • Listen for tricuspid insufficiency murmur due to obstruction from the catheter • Clinically assess for improvement in vitals, mentation, cardiac congestion • Obtain portable CXR radiological confirmation • May also use ultrasound to confirm that placement of the catheter in the right ventricle

11. Treatment of Lyme Carditis caused by high degree AV block • Symptomatic support including pacing if necessary • Complete heart block generally resolves within one week • Hospitalize and give IV ceftriaxone (2g IV daily for 2-4 weeks) or high-dose Penicillin G. • A combination of IV and po antibiotics should be continued for 4 weeks. • Including amoxicillin, doxycycline, and/or ceftriaxone

12. References • Field, JM; Hazinski, MF; Gilmore, D. American Heart Association’s Handbook of Emergency Cardiovascular Care for Healthcare Providers. 2005. • Roberts J.R., Hedges J.R.: Clinical Procedures in Emergency Medicine, 4th ed. Philadelphia, PA, WB Saunders, 2003, CH 15. • Bing OH, McDowell JW, Hantman J, et al: Pacemaker placement by electrocardiographic monitoring. N Eng J Med 287:651, 1972 • Goldberger E: Treatment of Cardiac Emergencies, 3rd ed. St. Louis, CV Mosby, 1982, p252. • Fish AE; Pride YB; Pinto DS: Lyme carditis. Infect Dis Clin North Am; 22(2): 275-88, vi; 2008