 Interaction
Between Minute Ventilation Rate-Adaptive Pacemakers and Cardiac Monitoring
and Diagnostic Equipment
(You are encouraged to copy and distribute this letter)
October 14, 1998
Dear Colleague:
This is to alert you that minute ventilation rate-adaptive implantable
pacemakers can occasionally interact with certain cardiac monitoring and
diagnostic equipment, causing the pacemakers to pace at their maximum
programmed rate. Minute ventilation rate-adaptive pacemakers currently
marketed include Telectronics’ (St. Jude Medical) META and Tempo
series, Medtronic’s Legend Plus and Kappa 400 series, and ELA Medical’s
Chorus RM and Opus RM series.
Reports
Over the past year, several incidents have been reported in the medical
literature in which minute ventilation rate-adaptive pacemakers paced
at their maximum rate when patients were connected to cardiac monitoring
and diagnostic equipment.1-3 None of these instances resulted
in a patient death or injury (pacing returned to normal when the monitors
were disconnected from patients). However, we are concerned that this
unexpected rise in the pacing rate could be misdiagnosed as clinically
significant tachycardia, resulting in unnecessary therapy, or that patients
with compromised cardiac reserve (e.g., with unstable angina or myocardial
infarction) may poorly tolerate the higher pacing rates.
Cause of problem
Minute ventilation is sensed in rate-adaptive pacemakers by a technology
known as bioelectric impedance measurement (BIM). Many medical devices
in addition to pacemakers use this technology. When one of these devices
is used on a patient with an active, minute ventilation rate-adaptive
pacemaker, the pacemaker may erroneously interpret the mixture of BIM
signals created in the patient, resulting in an elevated pacing rate.
Examples of commonly used devices that may use BIM technology and thus
could affect minute ventilation pacemaker rates are cardiac monitors,
echocardiograph equipment, apnea monitors, respiration monitors, and external
defibrillators.
Recommendations
The following precautions should be taken into consideration for patients
with minute ventilation rate-adaptive pacemakers:
1. Deactivate minute ventilation sensor. When treating
a patient with an implanted minute ventilation rate-adaptive pacemaker,
be aware that an increase in the cardiac rate may be due to interaction
between the pacemaker and another medical device attached to the patient.
Consider changing the operating mode of the pacemaker to a minute ventilation
insensitive mode before performing the procedure. Consult the pacemaker
manufacturer’s instructions for this.
2. Select appropriate maximum pacing rate. Since interference
is most likely to cause serious effects if the pacemaker is programmed
at a maximum rate not tolerated by the patient, be sure to periodically
check that the set maximum rate is still appropriate for the patient during
pacemaker follow-up visits.
3. Inform appropriate pacemaker patients (or their families) of the
potential for this interaction. They would then be aware of the potential
for unexpected rises in the pacing rate when the patient undergoes medical
procedures that use BIM devices.
Reporting adverse events
FDA is interested in obtaining data on malfunctions and adverse events
involving minute ventilation rate-adaptive pacemakers and other BIM devices.
Practitioners who are employed by health care facilities that are subject
to FDA's user facility reporting requirements should follow the reporting
procedures established by their facility. All other practitioners may
submit these reports directly to MedWatch, FDA's voluntary reporting program.
The reports can be submitted by phone at 800-FDA-1088, by fax at 800-FDA-0178,
by internet at www.fda.gov/medwatch (under "How to Report",
"Reporting by Health Professionals"), or by mail to: MedWatch,
FDA, HF-2, 5600 Fishers Lane, Rockville, MD 20857.
Getting more information
If you have any questions regarding this letter, please contact Lily
Ng, Office of Surveillance and Biometrics, CDRH, FDA, 1350 Piccard Drive,
Mail Stop HFZ-510, Rockville, MD 20850; by fax at (301) 594-2968; or by
e-mail at lxn@cdrh.fda.gov.
All of FDA's medical device postmarket safety notifications can be found
on the World Wide Web at http://www.fda.gov/cdrh/safety.html.
Postmarket safety notifications can also be obtained through e-mail on
the day they are released by subscribing to our list server. To subscribe,
visit: http://service.govdelivery.com/service/subscribe.html?code=USFDACDRH_10
Additional information safety information is available at www.fda.gov/medwatch/safety.htm.
|
Sincerely yours,
D. Bruce Burlington, M.D.
Director,
Center for Devices and Radiological Health |
References
1. Wallden J, Gupta A, and Carlsen H-O. Supraventricular tachycardia
induced by Datex patient monitoring system. Anesth Analg 1998; 86(6):
1339.
2. Chew EW, Trougher RH, Kuchar DL, and Thorburn CW. Inappropriate rate
change in minute ventilation rate responsive pacemakers due to interference
by cardiac monitors. PACE 1997; 20 (Part 1): 276-82.
3. Heartweb@webaxis.com
|
