1. Anesthetic Management of Cardiac Rhythm Management Devices N746: Summer 2014 Jennifer Ranieri

2. Cardiac Rhythm Management Devices (CRMD) Pacemakers Automatic Internal Cardioverter Defibrillators (AICDs) +500,000 individuals in the US have pacemakers or AICDS 115,000 new devices implanted each year

3. Pacemakers Utilized for treatment of Bradycardia AV block Sinus node dysfunction Dysrhythmias Device consists of Leads Delivers current to depolarize myocardium Anode Completes electrical circuit Pulse generator Contains computer and battery to last 6-10 years

4. Pacemaker Classification I: Chamber Paced O- None A- Atrium V- Ventricle D- Dual (atria and ventricle) II: Chamber Sensed O- None A- Atrium V- Ventricle D- Dual (atria and ventricle) III. Response to sensing O- None T- Triggered I- Inhibited D- Dual (both triggered and inhibited IV: Programmability and Rate Responsiveness O- None R- Rate Responsive or rate modulation V. Multisite pacing or antiarrhythmic function O- None A- Atria V- Ventricle D- Dual (atria and ventricle) Last two functions commonly omitted Generic Pacemaker Code (NBG*): NASPE/BPEG Revised (2002)

5. Implanted Cardioverter Defibrillators Indicated for Patients s/p ventricular fibrillation or cardiac arrest Decreased ventricular function following MI LVEF <35% regardless of etiology Patients with dilated, hypertrophic, arrhythmogenic cardiomyopathies AICDs bypass the delays experienced before receiving defibrillation High long-term survival rates

6. Implanted Cardioverter Defibrillators Cont… Two basic parts: Lead electrode Detects arrhythmias Delivers defibrillating shocks 10-15 seconds after detecting arrhythmia Cardiac pacing* Pulse generator Battery to deliver 120 shocks and last 3-6 years Computer microprocessor Contain algorithms to detect VF an VT All AICDs are pacers, but not all pacers are AICDS! Anti-tachycardic pacing

7. Preoperative Management Establish whether patient has CRMD Patient interview: why was it inserted? Did symptoms improve? Physical exam (scars, palpation of device) Review of medical records EKG, CXR Cardiology notes Establish type of CRMD Manufacturer’s card: what kind of device is it? CXR studies if no other data available Supplemental resources Manufacturer’s database Pacemaker clinic records Consult with cardiologist

8. Preoperative Management Cont… Determine whether patient is CRMD dependent for antibradycardia pacing function Verbal history Evaluation that shows no spontaneous ventricular activity when pacemaking function of CRMD is VVI paced mode at the lowest rate *BONUS QUESTION: What is VVI?

9. Preoperative Management Cont… Determine device function Ideally assessed with comprehensive evaluation of the device Date of last interrogation Adequate battery life If this is not possible, then one MUST confirm if pacing impulses are present to create a paced beat Device must produce mechanical systole with pacemaker impulse Consult with cardiologist or CRMD service may be required as reprogramming may be required for surgery

10. Preoperative Management Cont… Determine is CRMD should be reprogrammed Asynchronous pacing mode Disabling of special algorithms (ex: rate adaptive functions) Suspend anti-tachyarrhythmia functions

11. Intraoperative Management Determine if electromagnetic inference (EMI) is likely to occur during procedure and take steps to minimize EMI Why does this matter? Ask surgeon to consider bipolar cautery or ultrasound (harmonic) scalpel to minimize potential for effects of EMI on pulse generator or leads Do you know the difference between unipolar and bipolar? Request short bursts of cautery with low energy setting Grounding pad should be as far from the pacemaker as possible External pacing and defibrillator supplies readily available Position pads as far away from pulse generator as possible, A-P preferable

12. Asynchronous Mode If EMI is likely to occur, asynchronous mode should be initiated, often by playing magnet over pacer Asynchronous mode: pacemaker function at predetermined ventricular paced rate without rate responsiveness in atria or ventricle Magnet rate and response determined by manufacturer What is the letter abbreviation for asynchronous? However, some models do not reliably convert to asynchronous with magnet Magnet may reprogram pacemaker inadvertently Do NOT place magnet over all pacemakers! One goal of preoperative evaluation is to determine if magnet use is appropriate

13. Magnet on AICD Use extreme caution when placing a magnet over an AICD as this suspends the anti- tachycardia function Some AICDs can become permanently disabled by magnet function

14. Intraoperative Monitoring Continuous EKG monitoring ASA Task Force Practice Advisory recommends continuous peripheral pulse monitoring Pulse palpation, auscultation of heart sounds, intra-arterial pressure tracing, ultrasound peripheral pulse monitoring, pulse oximetry

15. Postoperative Management Interrogate and restore pacemaker or AICD function, device should be reprogrammed to appropriate settings if necessary Consult with cardiology or CRMD services if needed Restore AICD to anti-tachycardia settings Cardiac rate and rhythm should continued to be monitored through the postoperative period Back-up pacing and cardioversion/defibrillation equipment should be immediately accessible

16. Unique Procedure Considerations Lithotripsy Surgeon must avoid lithotripsy beam near generator Lithotripsy may trigger on R-wave, consider disabling atrial pacing Disable AICD prior to ESWL, reactivate immediately following procedure Radiofrequency Ablation Surgeon must avoid contact between ablation catheter and pulse generator and leads

17. Unique Procedure Considerations Cont… ECT Consult with physician, cardiologist, CRMD manufacturer or service Consider ECT has significant cardiac risks Radiation Can safely be performed in patients with CRMD May need to relocated CRMD out of radiation field MRI Contraindicated in patients with CRMD

18. Summary Algorithm

19. References American Society of Anesthesiologists Committee on Standards and Practice Parameters. (2011). Practice advisory for the perioperative management of patients with cardiac implantable electronic devices: pacemakers and implantable cardioverter-defibrillators. Anesthesiology, 5(2), 247-261. Barash, P. G., Cullen, B. F., & Stoelting, R. K. (2009). Clinical anesthesia (6th ed.). Philadelphia: Lippincott Williams & Wilkin Butterworth, J., Mackey, D. & Wasnick, J. (2013). Morgan & Mikhail’s clinical anesthesiology (5 th ed.). New York, NY: McGraw Hill. Madigan et al. (1999). Surgical management of the patient with an implanted cardiac device implications of electromagnetic interference. Annals of Surgery, 230(5), 639–647. Nagelhout, J., Plaus, K. (2014). Nurse anesthesia. St. Louis, MO. Elsevier Saunders.