Anesthetic Management of Cardiac Rhythm

ManagementDevices

N746: Summer 2014Jennifer Ranieri

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

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

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)

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

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

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

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?

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

Preoperative Management Cont…

• Determine is CRMD should be reprogrammed• Asynchronous pacing mode• Disabling of special algorithms (ex: rate

adaptive functions)• Suspend anti-tachyarrhythmia functions

IntraoperativeManagement

• 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

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

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

IntraoperativeMonitoring

• 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

PostoperativeManagement

• 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

Unique ProcedureConsiderations

• 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

Unique ProcedureConsiderations

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

Summary Algorithm

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 (5th 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.