(Circulation. 1997;96:2808-2812.)
© 1997 American Heart Association, Inc.
Articles |
From the Department of Cardiology (A.N., M.J.G., K.N.), Duke University Medical Center, and the Durham Veterans Administration Medical Center, Durham, NC; University of Michigan Medical Center (T.D.) (Ann Arbor); and University of Kentucky (A.N.) (Lexington).
Correspondence to Andrea Natale, MD, University of Kentucky, Division of Cardiovascular Medicine, Kentucky Clinic, Room L-543, Lexington, KY 40536-0284.
| Abstract |
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Methods and Results A multicenter retrospective analysis was performed on women with an ICD who became pregnant. Data were collected on 44 patients. The mean age and ejection fraction at the time of the initial ICD implant were 25.6±4.9 years and 49.8±9.7%, respectively. The mean follow-up after the ICD implant was 4.8±2.8 years. Forty-two women had abdominally implanted generators, and 2 had a prepectoral device. Thirty had epicardial lead sensing systems, and 14 had transvenous. Thirty-six (82%) experienced no complications, and 8 (18%) had a medical or device-related complication. The ICD-related problems included tenderness at the ICD pocket scar (2 patients), generator migration (1), and pericarditis secondary to the epicardial patches (1). Medical complications were pulmonary embolism (1), therapeutic abortion (1), worsening hyperthyroidism (1), congestive heart failure (1), and weight loss (1). Thirty-seven women delivered vaginally, and 7 underwent cesarean section. Thirty-nine babies were born healthy, 1 was stillborn, 2 were small for gestational age, 1 had transient hypoglycemia, and 1 woman had a therapeutic abortion unrelated to the ICD. During pregnancy, 33 women received no ICD therapy, 8 had 1 shock, 1 had 5 discharges, 1 had 11 shocks, and 1 had 5 shocks. The total number of shocks during pregnancy ranged from 0 to 11, with an average of 0.66±1.9 discharges. Five women had 7 additional pregnancies without an ICD shock.
Conclusions The mere presence of an ICD should not defer a women from becoming pregnant unless she has an underlying structural cardiac disease that is considered a contraindication. Pregnancy does not increase the risk of major ICD-related complications or result in a high number of ICD discharges.
Key Words: defibrillation death, sudden morbidity women
| Introduction |
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1% of all
pregnancies,1 only a small portion of these are
represented by women with arrhythmias. The effects
of various pharmacological agents to treat arrhythmias during
pregnancy has been evaluated2 ; however, little is known
regarding the outcome of pregnancy in women with ICDs. In fact, only
two cases have been reported of women with ICDs who have successfully
completed a pregnancy.3 4 Given this, no general
guidelines or recommendations are available for physicians to offer
patients with ICDs who want to become pregnant. The purpose of this study was to evaluate a large cohort of women who had had an ICD implanted because of a malignant ventricular arrhythmia to determine whether pregnancy was associated with an increased risk of maternal and fetal complications, an increased number of ICD discharges, and a higher risk of lead- and generator-related complications. A multicenter joint project was therefore undertaken to address these issues.
| Methods |
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Data were collected in the form of questionnaire completed by the treating electrophysiologist or other designated health care personnel. The information that was requested was age and ejection fraction at time of initial ICD implantation and current age and ejection fraction; indication for ICD implantation; other cardiac and medical disorders; device information (generator model, implant position, lead sensing system [transvenous versus epicardial, number of generator and lead replacements]); total number of pregnancies and number of pregnancies with an ICD in place; time of device implantation in relationship to pregnancies; mode of delivery; device status at time of delivery; maternal and fetal complications; number of ICD firings during each pregnancy, delivery, and 24- to 48-hour postpartum period; total number of ICD discharges in a lifetime; and antiarrhythmic medication taken before and during pregnancy.
The number of ICD discharges in a lifetime does not include shocks given during device testing or pregnancy. Similarly, in the calculation of the total number of shocks received during pregnancy, the discharges administered when an ICD was implanted or a generator was replaced during pregnancy were not included. However, shocks given for device testing during pregnancy were included in the assessment of the safety of ICD firing on fetal outcome.
Each ICD was implanted according to the standard practice of the electrophysiologist performing the procedure; follow-up was also according to local practice. Each pregnancy was considered high risk, and care was provided by both the obstetrician and electrophysiologist accordingly.
Data are presented as mean±SD. The
2
test was used to determine the statistical significance between
proportions.
| Results |
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Defibrillators
A wide range of ICDs were implanted in this population,
including those from CPI (models 1500, 1520, 1550, 1600, PRX 1700,
AID-BR), Ventritex (model V100), Medtronic (models 7217B, Jewel 7219D,
7216) and Teletronics (model 4203). The total number of generator
replacements averaged 1.9±1.2 and ranged from one to six. Only 2
patients had the generator implanted in the prepectoral position
(patients 10 and 37); all others were located in the abdomen. Thirty
patients had epicardial lead sensing systems, and 14 had transvenous
lead systems.
Device and Lead Complications During and After Pregnancy
Two patients (patients 18 and 28) reported mild tenderness
at the ICD pocket scar as the abdomen expanded; 2 patients experienced
migration of the generator onto the iliac bone (patient 30) during
pregnancy and into the left lower abdominal quadrant (patient 42)
nearly 3 years after the pregnancy; and 1 patient had pericarditis
attributed to the epicardial patches (patient 17). No generator erosion
or lead fractures were reported during pregnancy or the postpregnancy
mean follow-up of 2.4±1.2 years.
Pregnancy
The total number of pregnancies after ICD implantation by 1 woman
ranged from one to three, with the majority (39 patients) having had
only one pregnancy. With reference to the first pregnancy after ICD
implantation, 36 women (82%) had an uneventful experience, and 8
(18%) had a medical or device-related complication. In terms of the
medical complications, 1 had a pulmonary embolism during the
fifth month of pregnancy (patient 2); 1 had an induced therapeutic
abortion, unrelated to the presence of the ICD or an arrhythmia
(patient 4); 1 developed worsening signs and symptoms of preexisting
hyperthyroidism, resulting in tachyarrhythmias that
abated after adjustment of her thyroid medication (patient 30); 1 with
a history of a cardiomyopathy developed congestive
heart failure with a reduction in her EF, all of which resolved after
delivery (patient 21); and the patient with severe coronary
artery disease had a 9-lb weight loss (patient 20). In addition, 2
women had the ICD implanted while pregnant (patients 6 and 15), and 1
had the generator replaced during the fifth month because it was at the
end of life (patient 17).
Thirty-seven women delivered vaginally, and 7 underwent cesarean section. The indications for cesarean section included cephalic disproportion (patient 6), fetal distress (patient 24), repetitive variable heart rate decelerations (patient 22), oligohydramnios (patient 17), severe coronary artery disease such that labor or induction was thought to be too stressful (patient 20), failed induction (patient 34), and unknown (patient 5). The device was on during delivery in 28 women and was off in 16 patients. In only 1 of the women who had a cesarean section, the device was left on; in all others, it was turned off.
Fetal Outcome
Regarding fetal outcome after the first pregnancy, 37 babies
were born healthy; 2 others were born healthy but with long-QT syndrome
and are doing well on ß-blocker therapy (mothers 10 and 12); 1 was
stillborn due to umbilical cord strangulation, but it was known that
the heartbeat was absent the day before delivery (mother 15); 2 were
small for gestational age, which was thought to be secondary to
antiarrhythmic therapy (mothers 24 and 41); 1 had transient
hypoglycemia due to sotalol the mother had been taking (mother 17); and
1 woman had a therapeutic abortion (patient 4). Among the 11 women
experiencing shocks during pregnancy, 9 babies were born healthy, 1 was
stillborn (mother 15) and proven to be healthy after the last ICD
shock, and 1 had transient hypoglycemia thought to be secondary to
sotalol therapy.
Subsequent Pregnancies
Five women had seven additional pregnancies. Three women had an
uncomplicated second pregnancy and delivered healthy children (patients
15, 16, and 43). The patient who had an abortion during the first
pregnancy became pregnant two additional times (patient 4). The second
was complicated by nausea, vomiting, and weight loss secondary to
amiodarone. At 5 weeks before the estimated date of delivery,
she experienced spontaneous rupture of the membranes and delivered the
baby. The child had a ventricular septal defect and
experienced transient sinus bradycardia after birth attributed to the
amiodarone. Her third pregnancy resulted in a spontaneous
abortion unrelated to the presence of the ICD or an arrhythmia.
The remaining patient also had two additional pregnancies (patient 7).
The second was uncomplicated, and the baby was born healthy; the third
pregnancy ended in a miscarriage, but this was unrelated to the ICD or
an arrhythmia. No ICD discharges occurred during any of these
subsequent pregnancies.
ICD Discharges
During the first pregnancy, 33 women experienced no ICD
discharge, 8 received a single shock (patients 2, 6, 8, 11, 14, 17, 21,
and 35); 1 experienced 5 firings in response to new onset atrial
fibrillation (patient 15); and 2 had 11 and 5 discharges, respectively,
for monomorphic ventricular tachycardia
(patients 20 and 44). The latter were the patients with severe
coronary artery disease and dilated
cardiomyopathy. In 3 women, 1 of the ICD shocks
received during pregnancy was for device testing at the time of ICD
implantation (patients 6 and 14) or generator replacement (patient 17).
During delivery, in the women in whom the ICD remained active, none
received any shocks. External defibrillation was not required in the 16
in whom the ICD was turned off. In the 24- to 48-hour period after
delivery, 1 patient experienced an ICD discharge for
ventricular fibrillation (patient 8); all others had no
firings. Overall, the total number of ICD discharges during pregnancy
ranged from none to 11, with an average of 0.66±1.9 shocks (0.07 shock
per month). The total number of discharges in a lifetime for this
population ranged from none to 42, with a mean of 3.1±6.7 shocks.
Given an average follow-up period of 4.8 years minus the 9 months of
pregnancy, this averages to 0.79 shock per year (0.06 shock per
month).
Antiarrhythmic Therapy
Thirty-one women had been on one or more antiarrhythmic
medications before becoming pregnant, and 14 had never taken any
pharmacological therapeutics. During pregnancy, 25 women took
antiarrhythmic drugs, and 19 took none. The therapies used included
ß-blocker alone (16 patients), ß-blocker and digoxin (4),
ß-blocker and mexiletine (1), quinidine and digoxin (1), sotalol (2),
and amiodarone (1). Two of the women on ß-blocker therapy
took it for only a brief duration of their pregnancy (patients 30 and
31). As shown in the Table
, for women on antiarrhythmic medications
while pregnant, either the mother or the fetus experienced additional
medical complications. The complications that could be attributed to
the antiarrhythmic therapy included weight loss by the mother (patient
4), ventricular septal defect and sinus bradycardia of the
baby (patient 4), spontaneous abortion during pregnancy number 3
(patient 4), oligohydramnios and transient fetal hypoglycemia (patient
17), variable fetal heart rate deceleration (patient 22), fetal
distress (patient 24), and small fetal size (patients 24 and
41).
| Discussion |
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A second major concern has been that of lead fracture, which could conceivably occur with either the epicardial or transvenous systems. As the diaphragm elevates and the abdominal girth expands secondary to fetal growth, stress increases on the epicardial or transvenous system. In addition, the contractions associated with labor are intense enough to affect the muscles located in the upper torso and shoulder and therefore could apply stress particularly to the transvenous system. Despite this, however, no lead fractures were reported, not even in the 14 patients with a transvenous system.
Women who are otherwise healthy may experience an increased incidence of supraventricular tachycardias during pregnancy,6 most of which are due to reentrant mechanisms.7 The same can apply to ventricular tachycardia, which may be triggered during pregnancy as a result of hemodynamic changes and autonomic nervous system alterations8 9 In our cohort in whom there was an underlying electrical disorder or structural cardiac disease before pregnancy, it might be expected that the patients would experience an increased number of ventricular arrhythmias and hence more frequent ICD firings due to the stress of the pregnancy. However, no increase in ICD discharges compared with baseline occurred in this population when reviewed collectively. When assessed on an individual basis, only 3 women experienced more shocks during their pregnancy compared with their nonpregnant state. The first was the woman with new-onset atrial fibrillation. Since the implant of the ICD, she had five shocks while pregnant as a result of inappropriate discharging of the device for the atrial arrhythmia. The remaining 2 were patients with severe structural heart disease who had a total of 15 and 13 firings, 11 and 5 of which were for monomorphic ventricular tachycardia during pregnancy. It is possible that the diffuse electrical disorder present in the majority of patients in this study is probably less affected by the physiological changes of pregnancy and could explain why an increased number of ICD firings did not occur.
Surprisingly, the hormonal and autonomic changes and the strong uterine contractions during delivery did not precipitate any arrhythmias or ICD firings. In this respect, even though the status (on/off) of the ICD at the time of delivery appears to have no effect on the overall outcome, we recommend leaving the device "on" during vaginal deliveries. After all, if an arrhythmia develops, more prompt therapeutic intervention can be delivered than that by external defibrillation. Certainly, in the case of the cesarean section, the device must be "off" because cautery is involved.
As far as the safety of the fetus is concerned, recurrence of ventricular tachycardia could be dangerous because it may result in hypotension and hypoperfusion and the energy of the ICD shock could be shunted to the fetal heart, with unpredictable effects. However, in the 11 women in whom ICD therapy was delivered, no adverse fetal outcomes were evident as a result of the discharges. It is conceivable that hemodynamic changes are only transient due to the rapid termination of ventricular tachyarrhythmias by the ICD. In addition, it is unlikely that ICD firings could cause life-threatening fetal arrhythmias given that the fetal heart has a high fibrillation threshold and that the amount of current reaching the uterus should be small because therapy from internal defibrillation is very directed.10
Although it is undesirable for any woman to take medication while pregnant, 25 (56%) of the patients in this study were on antiarrhythmic therapy. This, however, is not surprising considering this patient population is more ill given their various underlying electrical and structural heart disease. Of interest, more patients on antiarrhythmic drugs experienced one or more medical complications during their pregnancy or the fetus suffered some minor adverse outcome. Whether these women were simply more ill and therefore more likely to suffer complications during pregnancy cannot be excluded. It may be advisable to consider and attempt discontinuing any antiarrhythmic medication that the patient may be taking before or during the pregnancy to avoid these adverse effects.
Conclusions
To our knowledge, this is the largest clinical series reported on
pregnancy outcomes in ICD recipients. Based on our results with 44
patients, the presence of an ICD poses negligible risks to a pregnant
woman or her fetus. Therefore, it seems unreasonable to prohibit
pregnancy in patients with an ICD unless the decision is based on the
underlying cardiac status and severity of the structural heart disease.
Such patients should be made aware of the clinical experience to date,
which will help them to reach an informed decision regarding pregnancy.
If vaginal delivery is anticipated, the ICD should remain active as it
poses no additional risks and can provide therapy quickly if needed.
The number of women reaching childbearing years and desiring to have
children after ICD implantation will continue to increase. This
analysis should provide useful guidelines for counseling women
with preexisting ICDs about their prospects for a successful pregnancy
and the effect of pregnancy on their underlying rhythm disorder.
| Footnotes |
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| Appendix 1 |
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Received February 27, 1997; revision received June 5, 1997; accepted June 19, 1997.
| References |
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