May 2002
Volume 66 |
Number 5
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WHAT'S NEW IN…
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| Perioperative Pacemaker –
ICD Management |
Mark F. Trankina, M.D.
Few areas in clinical medicine have been more dependent upon
and more affected by advances in engineering technology than cardiac
pacing. In the more than 40 years since the first implantation
of a pacing system, there has been a significant change not only
in pulse generators and leads but also in the indications for
pacing,1 pacing modalities, implantation
techniques and follow-up of patients with implanted pacing devices.
Today approximately 200,000 permanent pacemakers and 60,000 implantable
cardioverter defibrillators (ICD) are implanted each year in the
United States.2 With the advent of
more complex devices such as the new biventricular pacemakers,
even greater numbers of patients will receive devices. Left ventricular
or biventricular pacing can improve systolic function in patients
with dilated cardiomyopathy and intraventricular conduction delay
by resynchronizing contraction 3-5
pacemaker, and ICD recalls and safety alerts occur frequently
and continue to increase in frequency.6
All of this places an ever-growing burden upon the anesthesiologist
to properly manage these technologies during the perioperative
period, a period that still involves pacemaker-related morbidity
and mortality.7-9
Perioperative Management of Patients With Permanent Pacemakers
Preoperative evaluation: Patients with permanent pacemakers
typically have significant heart disease and should be evaluated
in the usual fashion for medical problems. Approximately 40 percent
of these patients have significant coronary artery disease, 56
percent are hypertensive and 20 percent have insulin-dependent
diabetes.10 Several anesthesiologists
have advocated preoperative and postoperative interrogation of
these devices.11-13 A recent American
College of Cardiology/American Heart Association (ACC/AHA) guidelines
update clearly recommends the same if at all possible.2
Presently there is no universal programmer available, and each
generator manufacturer therefore requires a unique unit.
Type of pacemaker generator (i.e., unipolar or bipolar, programmable)
and indication for pacemaker placement should be elucidated. Knowledge
of the pre-existing dysrhythmia is important to anticipate potential
therapy should the generator fail during the anesthetic. The patient
should be questioned whether symptoms similar to those prior to
placement of the pacemaker, such as dizziness or fainting, have
returned. The North American Society of Pacing and Electrophysiology
(NASPE) recommends transtelephonic checks every 12 weeks. NASPE
further recommends an office pacemaker interrogation every 12
months.
Electrocautery
Electrocautery, which emits radiofrequency energy, has the potential
to cause transient or permanent changes in pacemaker function.
The most common problem is inhibition of the pacemaker (ventricular
oversensing). As long as the electromagnetic interference (EMI),
which is defined as an adverse change in the normal function of
a device caused by electromagnetic energy, from the cautery is
brief, it should be of little concern in most patients. Yet if
the inhibition is continuous, most pacemakers will revert to a
"noise mode" and pace asynchronously. This also rarely
leads to difficulty. If cautery is to be used extensively, consideration
should be given to reprogramming the generator to an asynchronous
mode preoperatively to avoid intermittent inhibition. Conversion
to an asynchronous mode, though, does not prevent circuit damage
from electrocautery.14 Magnets, which
activate a reed switch in the generator, also can be used to convert
many generators to an asynchronous mode.
Unfortunately, many programmable pacemakers are affected in an
unpredictable fashion by EMI and should probably be evaluated
on an individual basis. Hayes et al. in 1987, found that 21 percent
of patients exposed to monopolar electrocautery during various
types of surgery had their pacemaker reprogram to the back-up
mode.15
Measures to decrease susceptibility to EMI in the operating theater
include: 1) the use of bipolar cautery versus unipolar cautery
when possible, 2) receiving plate placement as remote from the
generator as possible, 3) the pacing generator/lead axis not being
in the line between the operative site and the receiving plate,2,
10 4) utilization of the lowest current
and the shortest burst of electrocautery possible, 5) shielding
the generator from beams of therapeutic ionizing radiation that
can damage generator circuits11
and 6) careful use of nerve stimulators so that lead placement
is away from the generator.16 Diagnostic
X-ray does not interfere with pacemaker function.
If electrocautery is to be used, a magnet should be available
but not necessarily placed on the patient unless the exact response
of the pacemaker is known (call manufacturer). Adverse responses
to prophylactic magnet placement perioperatively have been reported,
including increased sensitivity of the generator to reprogramming,
hemodynamic instability due to pacing asynchronously at a program
rate slower than the intrinsic rate and discontinuation of pacing.
If a generator reprograms as a result of EMI, magnet placement
can be attempted in the hope that the generator will be converted
to asynchronous mode (reed closure). Once a magnet is placed on
a generator, the magnet should be left on the generator until
a programmer is available since a new program can manifest itself
upon removal of the magnet.
Magnetic resonance imaging (MRI), upon initial exposure, will
lead to reed switch closure in most generators. The radiofrequency
portion of the test does not seem to reprogram many units, but
some available generators will attempt to pace at the pulse period,
i.e., as high as 3,000 beats per minute. It is prudent to avoid
exposure of all permanent generators to MRI.17
Rate Modulation
Rate-modulating generators have been developed and have been shown
to increase work capacity.18 Presently
many types of physiologic sensors are undergoing investigation.
Table 1 lists the sensors under investigation, all of which can
be affected by the anesthesiologist during an anesthetic. Inappropriate
heart-rate increases during electrocautery continue to be reported.8
Rate-adaptive therapy should be disabled during the preoperative
interrogation. 2, 13,
17
ICD
Approximately 350,000 Americans die each year from sudden cardiac
arrest.19 Prophylactic antidysrhythmic
drug therapy has not been as successful as hoped in controlling
ventricular tachycardia and fibrillation.20
The ICD has emerged as a practical and effective means of controlling
these lethal dysrhythmias in patients in whom medical therapy
has failed.21 Several large studies
have shown significant efficacy of the ICD versus class III antiarrhythmic
drugs.22 A recent meta-analysis of
these trials concluded that there is a 28-percent reduction in
the relative risk of death with the ICD, which is due almost entirely
to a 50-percent reduction in arrhythmic death.23
In this analysis, patients with left ventricular ejection fraction
less than 35 percent derived significantly more benefit from ICD
therapy than those with better-preserved left ventricular function.
Modern devices are used in patients with coronary artery disease,
left ventricular dysfunction, nonsustained ventricular tachycardia
and inducible ventricular tachycardia. Dual-chamber ICDs have
become increasingly sophisticated with rate-adaptive sensors.
Biventricular pacing is being combined with ICD function in patients
with heart failure and systolic dysfunction.24
The response of these newer units during the perioperative period
is unknown.
EMI also can interfere with the ICD and can lead to inappropriate
discharge and/or reprogramming. Both the ACC/AHA guidelines2
and a recent comprehensive review17
recommend discontinuation of therapy during EMI. This does not
alter susceptibility to device damage by EMI. Care must be used
with magnets around the generator because they can activate or
deactivate the unit or initiate a magnet test depending on the
programming of the individual unit.21,
25 Therapy should be reactivated and the
device checked before leaving the operating room/ postanesthesia
care unit. "Atrioverter" units for atrial fibrillation
are presently under investigation and have shown some success.26,
27 Management of these devices should
parallel that of the ICD.
In summary, patients receiving pacemaker and/or ICD therapy continue
to challenge the anesthesiologist. The extraordinary growth in
pacemaker technology even challenges the skills of the electrophysiologist.
Excellent reviews of pacemakers and their use for arrhythmias
are available.13,17,25,28,
29, With proper understanding of pacemaker
function and thorough preoperative evaluation, smooth perioperative
care can be anticipated. The anesthesiologist should be aware
of the new ACC/AHA guidelines for perioperative management.2
References are available from the ASA Executive Office or on
the ASA Web site < www.ASAhq.org/NEWSLETTERS/homepage.html
>.
References:
1. Bryce M, Spielman SR, Greenspan AM, Kotler
MN. Evolving indications for permanent pacemakers. Ann Intern
Med. 2001; 134:1130-1141.
2. Eagle KA, Berger PB, Calkins H, et al. ACC/AHA
guideline update for perioperative cardiovascular evaluation for
noncardiac surgery ĉ executive summary: A report of the American
College of Cardiology/American Heart Association Task Force on
Practice Guidelines (Committee to Update the 1996 Guidelines on
Perioperative Cardiovascular Evaluation for Noncardiac Surgery).
J Am Coll Cardiol. 2002; 39(3):542-553.
3. Nelson GS, Berger RD, Fetics BJ, et al. Left
ventricular or biventricular pacing improves cardiac function
at diminished energy cost in patients with dilated cardiomyopathy
and left bundle-branch block. Circulation. 2000; 102: 3053-3059.
4. Conti JB. Biventricular pacing therapy for
congestive heart failure: A review of the literature. Cardiol
Rev. 2001; 9:217-226.
5. Breithardt OA, Stellbrink C, Franke A, et
al. Acute effects of cardiac resynchronization therapy on left
ventricular Doppler indices in patients with congestive heart
failure. Am Heart J. 2002; 143(1):34-44.
6. Maisel WH, Sweeney MO, Stevenson WG, et al.
Recalls and safety alerts involving pacemakers and implantable
cardioverter-defibrillator generators. JAMA. 2001; 286(7):793-799.
7. Werner P, Charbit B, Samain E, et al. Interference
between a dual-chamber pacemaker and argon electrocautery device
during hepatectomy. Ann Fr Anesth Reanim. 2001; 20:716-719.
8. Wong DT, Middleton W. Electrocautery-induced
tachycardia in a rate-responsive pacemaker. Anesthesiology. 2001;
94:710-711.
9. Rozner MA, Nishman RJ. Pacemaker-driven tachycardia
revisited. Anesth Analg. 1999; 88:965.
10. Trankina MF, Black S, Gibby G. Pacemakers:
Perioperative evaluation, management and complications. Anesthesiology.
2000; 93(abstract) A1193.
11. Levine PA, Balady GJ, Lazar HL, et al. Electrocautery
and pacemakers: Management of the paced patient subject to electrocautery.
Ann Thorac Surg. 1986; 41(3):313-317.
12. Zaidan JR. Pacemakers. IARS Review Course
Lectures. 1998:164-170.
13. Rozner MA, Trankina MF. Intrathoracic gadgets:
Update on pacemakers and implantable cardioverter defibrillators.
Refresher Courses in Anesthesiology. American Society of Anesthesiologists.
2000; 28:183-199.
14. Mangar D, Atlas GM, Kane PB. Electrocautery-induced
pacemaker malfunction during surgery. Can J Anaesth. 1991; 38:616-618.
15. Hayes DL, Trusty JM, Christiansen JR. A
prospective study of electrocauteryıs effect on pacemaker function.
PACE.Pacing. Clin.Electrophysiol. 1987; 10:442.
16. Ducey JP, Fincher CW, Baysinger CL. Therapeutic
suppression of a permanent ventricular pacemaker using a peripheral
nerve stimulator. Anesthesiology. 1991; 75:533-536.
17. Atlee JL, Bernstein AD. Cardiac rhythm management
devices (part II): Perioperative management. Anesthesiology. 2001;
95:1492-1506.
18. Barold SS, Barold HS. Contemporary issues
in rate-adaptive pacing. Clin Cardiol. 1997; 20:726-729.
19. American Heart Association. 2001 Heart and
Stroke Statistical Update. 2000. Dallas, TX: American Heart Association.
20. Ruskin JN. The cardiac arrhythmia suppression
trial (CAST). N Engl J Med. 1989; 321:386-388
21. Saksena S, Tullo NG, Krol RB, Mauro AM.
Initial clinical experience with endocardial defibrillation using
an implantable cardioverter/defibrillator with a triple-electrode
system. Arch Intern Med. 1989; 149:2333-2339.
22. A comparison of antiarrhythmic-drug therapy
with implantable defibrillators in patients resuscitated from
near-fatal ventricular arrhythmias. The Antiarrhythmics versus
Implantable Defibrillators (AVID) Investigators. N Engl J Med.
1997; 337:1576-1583.
23. Connolly SJ, Hallstrom AP, Cappato R, et
al. Meta-analysis of the implantable cardioverter defibrillator
secondary prevention trials. AVID, CASH and CIDS studies. Antiarrhythmics
vs. Implantable Defibrillator study. Cardiac Arrest Study Hamburg.
Canadian Implantable Defibrillatory Study. Eur Heart J. 2000;
21(24):2071-2078.
24. Kuhlkamp V, The InSync 7272 ICD World Wide
Investigators. Initial experience with an implantable cardioverter-defibrillator
incorporating cardiac resynchronization therapy. J Am Coll Cardiol.
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25. Atlee JL, ed. Management of Patients with
Pacemakers or ICD Devices, Arrhythmias and Pacemakers. In: Practical
Management for Anesthesia and Critical Care Medicine. Philadelphia:
W.B. Saunders. 1996:293-329.
26. Saksena S, Prakash A, Mangeon L. Clinical
efficacy and safety of atrial defibrillation using biphasic shocks
and current nonthoracotomy endocardial lead configurations. Am
J Cardiol. 1995; 76:913-921.
27. Adler SW, Wolpert C, Warman EN, et al. Efficacy
of pacing therapies for treating atrial tachyarrhythmias in patients
with ventricular arrhythmias receiving a dual-chamber implantable
cardioverter defibrillator. Circulation. 2001; 104:887-892.
28. Atlee JL, ed. Overview of Mechanisms for
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Anesthesiology. 2001; 95:1265-1280.
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Mark
F. Trankina, M.D., is Associate Professor, Department of Anesthesiology,
Division of Cardiothoracic Anesthesia, University of Alabama
at Birmingham, Birmingham, Alabama. |
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