before
instillation.
Three
patients
did not have
the severe
local “¿burning―
pain that occurred with our original
group of patients. It is our belief that if the aiphapro
@
dine is not routinely given, it should be at the bedside
and be given immediately
to those who do complain of
pain. Caution should be observed in the dosages of both
the morphine sulfate and the alphaprodine
hydrochlor
ide in patients with known metastatic hepatic involve
ment or with cirrhosis. One patient
hepatic disease and cirrhosis needed
chloride
(NARCAN)
which occurred
with metastatic
naloxone hydro
to reverse a respiratory
after the alphaprodine
arrest
was given. So I
and revealed no deviation from the manufacturer's
ifications.
Duration
spec
was 0.50 to 0.52 msec, and ampli
bide was from 100 to 250 my in each case. These
remained constant even though the rate changed (pa
tients 2 and 6).
Significant
(greater
than 3
increases in
pacing rate occurred in 50 percent (six) of these 12
pacemakers within six months of the date of implanta
tion, and five of the six exhibited these changes at the
time of the first follow-up visit at four months. One
patient showed an increase from 74 beats per minute at
12 weeks to 77 beats per minute at 24 weeks. All of the
suggest that in these patients a smaller dose of morphine
remaining patients have shown an increase in rate of
sulfate
approximately
routinely.
be given
and
If it is given,
the alphaprodine
then
a narcotic
not be given
antagonist
should
be readily available.
Howard
W. Wallach,
M.D.
Chief Medical Resident
Washington Hospi@a1Center, Washington, DC
2 beats
per minute
(3 percent)
. After
the
initial clinic visit, one patient died of related cardiac
disease. Table 1 shows the increase in rate for each
patient. Patient 6 became symptomatic with chest pain
while her rate was 78 to 79 beats per minute. The
discomfort
subsided
spontaneously
as the rate
decreased.
DiscussioN
Pacemaker Rate Increase
Unexpected
changes
in rate
can
occur
with
alarming
consequences if one is not fully aware of all of the meth
To the Editor:
ods now available for clinical surveillance
of pacemakers.2
The early complete analysis of certain data in a pace
maker clinic has identified an excessive increase in rate
The current model of Medtronic pacemaker
in a significant number of Medtronic
ers (model595l;
Xytron).
pulse duration, and drop in amplitude with battery
failure. Because of the absence of these factors, we
believed that we were dealing with an exaggerated rate
unipolar
pacemak
METhODS
A schedule of follow-up clinic visits was established. This
included physical examination
and electrocardiographic
osciloscopic
wave-form
analysis.
and
RESULTS
Wave-form
analysis was performed
at each clinic visit
designed
to exhibit
a decrease
(5951 ) is
prolongation
of
drift3 and that replacement
was not necessary. It is
obvious that a downward drift to below the level present
at implantation
would represent a change of significant
magnitude and indicate prompt pacemaker replacement
unless
one
is aware
of an
initial
rate
increase.
Many
variables must be utilized in making the decision for
pacemaker change to ensure maximal efficiency,@'@
avoid unnecessary surgery, and particularly avoid unex
pected pacemaker failure or exhaustion.
Robert
Table 1—Patients' Characteristics and Rate Increase
L. Richardson,
M.D.,
F.C.C.P.
Dawood Siroospour, M.D.
at Time of Each Evaluation
(yr),
PatientAge
Race, SexFollow-up,weeksRate
(percent)170,W,F182(3)212,W,M12
in rate,
and James W. Pate, M.D., F.C.C.P.
Department
of Surgery, College of Medicine
University of Tennessee,
Memphis
Change,
beats per minute
REFERENCES
241(1)
4(6)375,W,F124(6)489,B,M182(3)537,W,F162(3)656,W,F12
13
6(8)
15
5(7)
187(10)
3(4)772,B,F142(3)878,B,M162(3)959,B,F165(7)106,
1 Furman S, Parker B, Escher DJW: Transtelephone
pace
maker clinic. J Thorac Cardiovasc Surg 61 :827-834, 1971
2 Parsonnet V, Myers GH, Gilbert L, et al: Review: Follow
up of implanted pacemakers. Am Heart J 87:642-653,
1974
3 Readers ask. Medtronic News 5:4-5, 1975
4 Furman
S, Escher DJW, Parker B, et al: Electronic
analy
sis for pacemaker failure. Ann Thorac Surg 8:57-65, 1969
M166(8)1158,B,F53(4)1218,B,F50
B,
5 Parsonnet V, Myers GH, Gilbert L, et al: A clinic for long
term pulse generator surveillance. In Samet P (ed) : Car
diac Pacing. New York, Grune and Stratton, mc, 1973,
pp 201-221
CHEST,70: 3, SEPTEMBER,
1976
COMMUNICATIONS
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