Preanesthetic Evaluation of Pacemakers 101 David A. Cross, M.D. Department of Anesthesiology Scott and White Memorial Hospital and Clinic Associate Professor, Anesthesiology TX A&M Health Sciences Center Temple, TX SHAZAM!!

Preanesthetic Evaluation of Pacemakers 101 ASA Practice Advisory: Anesthesiology 2005;203:186.

Preanesthetic Evaluation of Pacemakers 101 For information regarding a specific pacemaker during or after interrogation, go to: and download their FREE “Pacemaker and ICD Encyclopedia” into your handheld. Both Palm OS and Windows versions are there.

Preanesthetic Evaluation of Pacemakers 101 Why do we care? After all, the pacemaker is working fine and has been for…for…well… for how long now?? AHA!! Could that be a problem??

Preanesthetic Evaluation of Pacemakers 101 Why ignore the pacemaker? “Too much trouble, and, besides…” “Been doing it this way for 20+ years… and…” “I don’t believe in…” “Nothing ever happens…” “Not my problem, it’s cardiology’s problem.”…and we all know cardiology will bail us out anytime, anywhere, on demand!

Preanesthetic Evaluation of Pacemakers 101 Let me remind you what part of your anatomy is prominently exposed when your head is buried in the sand!

Indications Levels of Evidence Level I – solid medical evidence or general agreement that the procedure or treatment is beneficial, useful, and effective Level II – conflicting evidence or divergence of opinion regarding a procedure’s or treatment’s usefulness and / or efficacy Level III – evidence or general agreement that a procedure or treatment is not useful and in some cases may be harmful.

Indications Level I Neurogenic syncope caused by light carotid stimulation Symptomatic 2 nd or 3 rd degree A-V block Asymptomatic 3 rd degree A-V block with HRs 40 or below Fascicular blocks with intermittent symptomatic 3 rd degree block or Type II 2 nd degree block with or without symptoms

Indications Level I (con’t) Sinus node dysfunction with documented bouts of symptomatic bradycardia Cardiomyopathy with symptomatic bouts of AV node dysfunction or AV blocks with symptomatic bradycardias

Indications Level II Asymptomatic 2 nd degree or 3 rd degree with HR > 40 Sinus node dysfunction with HR > 40 Dilated cardiomyopathy with EF 130 ms, and Class 3-4 CHF

Indications Atrial Fibrillation: ?? VVI with history of ventricular bradycardia ?? DDDR with rate set at rate high enough to try and inhibit the occurrence of AF. Evidence suggestive of longer bouts of NSR and fewer embolic phenomena. May have DDDR set to VVIR with a mode switch.

Preanesthetic Evaluation of Pacemakers 101 We’re concerned about five broad intra-operative possibilities regarding the pacemaker: 1) Will it quit during surgery? 2) Will the patient die if it quits? 3) Will the pacemaker cause a dysrhythmia? 4) Will the patient get shocked if he / she has an ICD? 5) Will the ICD cause a dysrhythmia?

Preanesthetic Evaluation of Pacemakers 101 So, we need to know: 1) What kind of pacemaker does the patient have? 2) To what mode it is set? 3) Is it functioning properly? 4) Does it need to be reset to a different mode for surgery? 5) Is it likely to stop functioning during surgery?

Preanesthetic Evaluation of Pacemakers 101 6) What is the patient’s underlying rhythm? 7) Is there an ICD? 8) Does the ICD need to be inhibited or turned off? 9) What is the magnet response of the pacemaker? 10) Will a magnet be needed or will it help?

Types of Pacemakers Many types, but at S&W, mostly two types, with an occasional third. 1) St. Jude 2) Medtronic 3) Guidant (Boston Scientific) (see these rarely) If the pacemaker was put in at S&W before a couple of years ago, it is most likely a Medtronic. More recently, it may be a St. Jude. We occasionally see Guidants placed elsewhere.

How To Tell the Type 1) Take a chance—pick an interrogator. If it senses the pacemaker, that’s the brand. Won’t hurt the pacemaker if you try to interrogate it with the wrong interrogator. It just won’t sense it. 2) Take a Chest X-ray. Every brand has an X-ray identifiable marker for its brand of pacemaker.

Preanesthetic Evaluation Presently, we only have two interrogators available to us in the OR area: St. Jude and Medtronic. If neither of these will interrogate the pacemaker, you’ll have to call the pacemaker clinic ( / ) to do the interrogation. Some pacemakers are wireless, and the interrogator will ask you to remove the magnet head to interrogate.

Pacemaker Nomenclature IIIIIIIVV Chamber Paced Chamber Sensed Response to Sensing Rate Modulation, Programmability Anti- tachycardia Features A=AtriumA=AtriumT=Triggered P=Simple Rate and Output P=Pacing V=VentV=VentI=Inhibited M=Multi- programmable S=Shock D=DualD=DualD=Dual R=Rate Adaptive D=Dual O=NoneO=NoneO=None C=Communicating (telemetry) O=None

Defibrillator Nomenclature Position I Position II Position III Position IV (or use pacemaker code) Shock Chamber Antitachycardia Pacing Chambers Tachycardia Detection Antibradycardia Pacing Chambers O=noneO=none E =Electrical O=none A=AtrialA=Atrial H =Hemodyn. A=Atrial V=VentricleV=VentricleV=Ventricle D=DualD=DualD=Dual

Pacemaker Nomenclature Examples: VOO – ventricle asynchronously paced at set rate. VVI – Ventricle paced, Ventricle sensed, pacing inhibited if sensed. VVIR – Ventricle paced, Ventricle sensed, pacing inhibited if sensed, rate response to exercise.

Pacemaker Nomenclature DOO – asynchronous Atrio-Ventricular pacing at preset rate. DDD – Atrium and Ventricle synchronously paced, both sensed, pacing triggered in each chamber if underlying pacer not detected DDDR – as above, with rate responsiveness to exercise.

Rate-variable…how? Most will detect respiratory rate variability and vary the heart rate in response to an increase in ventilatory rate. Suggested by some to increase the programmed HR in the pacemaker for surgery to compensate for metabolic demand.

Pacemaker Mode Problems with asynchronous mode pacing: Works against atria and a-v valve opening Lowers cardiac output unless: in AF 3 rd degree block with a VERY slow vent rate.

Intraoperative Monitoring Always have the monitor setup set to “Monitor,” and not “ESU,” so you can see the pacing spike. May cause problems if there is undue interference in the room, or when the surgeon uses a unipolar electrocautery.

The Interrogation Device Data Device – Patient Interaction Data Patient Data

The Interrogation

Intraoperative Problems Electrocautery Can reprogram the pacemaker Can inhibit the pacemaker Can cause an ICD to perform tachytherapy Can cause pacemaker damage (very rare) Can induce VF Can cause a rise in capture threshold by causing a burn at the site of lead implantation (rare)

Problematic Solutions Magnets are useful, but not utopian! Many pacemakers will respond by resetting to an “OO” mode with a magnet at a HR acceptable (65-85). NOT ALL….that’s why you need to download the “Pacemaker Encyclopedia.”

Problematic Solutions Magnet rate response in an “OO” mode dependent on brand and battery life. Magnets will cause most DDDs to convert to DOO at about 85 with a BOL (beginning of life) battery, and to VOO at a rate of about 65 at ERI (effective replacement interval) is reached to conserve power. Manufacturer variability…download the encyclopedia!

Problematic Solutions Useful to put a magnet on the patient’s pacemaker IF: Pacemaker dependent Surgeon won’t or can’t use a bipolar ESU Cannot place the pad distal to the unipolar ESU Closer than the general “6-inch” rule. There is NO ICD

Problematic Solutions Magnet potentially harmful IF: The patient’s underlying rhythm is very close to the pacemaker’s setting. If you reprogram the pacemaker to an “OO” mode, you might cause a pacemaker stimulus at the wrong point on the patient’s cycle and induce VT or VF. There is an ICD. All ICDs are inhibited by the magnet (Guidant problem), but no pacemakers with ICDs are affected by the magnet.

Problematic Solutions If the patient’s underlying rhythm is close to the pacemaker’s set rhythm, leave the pacemaker alone. If it’s inhibited, it won’t matter. Consider placing external pacemaker electrodes just in case.

Problematic Solutions Alternatively, reprogram pacemaker to AAI with the output very low so it doesn’t capture. Problematic if patient’s underlying rhythm becomes severely bradycardic intraoperatively.

Problematic Solutions As a general rule, disable or turn off all ICDs prior to surgery by reprogramming or by using a magnet. Can read ESU as VF and shock patient. Hurts like hell if patient awake, and can cause real VT, VF, or Torsade des Pointes if happens on the wrong part of the patient’s underlying cycle.

Problematic Solutions Many ICDs have built-in VOO pacemakers. If the patient has no pacemaker implanted, the built-in ICD pacemaker will become active in the event that a shock is delivered and the patient goes into asystole. Rate is usually minimal, at about 40 or so.

Problematic Solutions Guidant ICDs – CAREFUL!! 1) Some Guidants were installed with the magnet response switch turned OFF. Placing a magnet on the ICD may not turn off the ICD. 2) How to tell? The tell-tale beeping sound

Problematic Solutions Most Guidant ICDs have a very low volume ‘beeping’ sound in conjunction with the HR. If you place a magnet over the ICD for 90 sec or so, you will hear the tone convert to a constant tone IF the ICD has been effectively disabled by the magnet. You can then remove the magnet and it’ll stay disabled. At the end of the case, do the reverse. The magnet will restore the beeping sound after about 90 sec IF the ICD has been re-enabled. You can then remove the magnet.

Problematic Solutions If you have: 1) a sensing pacemaker and ICD, 2) the patient is pacemaker dependent, and 3) there is no way to prevent the ESU current from going across the pacemaker, it must be reprogrammed to the ICD off, and the pacemaker to an “OO” mode.

Other Surgery-related Problems Lithotripsy Keep the generator out of shock path ECT Convert to non-sensing mode, unless set close to patient’s underlying rhythm Nerve Stimulator, TENS Watch placement with regard to generator MRI Absolute contraindication to MRI

CASES

Cases 72 year-old male with DDDR pacemaker pacing at 74/min. Patient’s underlying rhythm is sinus at 68/min. Patient is to have a left carotid endarterectomy.

Cases 68 year old male with DDDR pacemaker and ICD to have a mediastinoscopy, bronchoscopy, and possible right upper lobectomy. Patient is pacemaker dependent with no underlying ventricular rate during the pacemaker test inhibition (2 sec).

Cases 55 year old female having a left hip replacement. She has chronic atrial fibrillation with a VVI pacemaker in place pacing at 70 / min. Her underlying rhythm is AF with an irregularly irregular ventricular response rate of

Cases 82 year old man with a 10% EF to undergo CABG. He has a DDIR biventricular pacemaker in. His underlying rhythm is AF with no detectable ventricular activity for the duration of pacemaker inhibition on testing.

Cases 75 year old woman in atrial fibrillation with a DDIR pacemaker functioning as a VVIR at 60 / min to undergo a Maze Procedure for her AF and CABG.

Preanesthetic Evaluation of Pacemakers 101 QUESTIONS??