Pregnancy outcome and management of women with an implantable cardioverter defibrillator: a single centre experience
Pregnancy outcome and management of women with an implantable cardioverter defibrillator: a single centre experience
Pia K. Schuler 2
Anna Herrey 2
Angie Pier Lambiase 3
Fiona Walker 2
Ruth Brooks 2
Donald Peebles 0
0 Department of Obstetrics, Elizabeth Garrett Anderson Hospital, UCLH , London , UK
1 UCL Institute of Child Health and Great Ormond Street Hospital for Children , London , UK
2 The Grown Up Congenital Heart Disease Unit, The Heart Hospital, University College London Hospitals (UCLH) NHS Trust , London , UK
3 Department of Electrophysiology, The Heart Hospital, University College London Hospitals (UCLH) NHS Trust , London , UK
Aims With improved survival of patients with congenital and inherited heart disease, there is now a younger cohort of patients with an implantable cardioverter defibrillator (ICD) for the prevention and treatment of ventricular dysrrhythmias. Young women with such disorders often wish to embark on pregnancy, but pregnancy outcome data for this group is sparse. We therefore evaluated pregnancy outcome in patients with heart disease and an ICD in situ. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Methods A retrospective analysis was performed on all women with an ICD in situ, who had pregnancy care provided by the and results specialist maternal cardiology service at University College London Hospitals. Data for 19 pregnancies in 14 women were collected. The underlying cardiac diagnoses were congenital heart disease (one), familial hypertrophic cardiomyopathy (eight), familial dilated cardiomyopathy (one), inherited long QT syndrome (one), and idiopathic cardiac arrest (one). Three women had moderate impairment of the left ventricular systolic function (ejection fraction ,45%), in the remainder it was normal. Nine ICD implants were for primary prevention of sudden cardiac death (64%) and five for secondary prevention (36%). Of the 19 pregnancies, 18 continued beyond 24 weeks gestation with 18 live births. In eight pregnancies there were medical or device-related complications (42.9%) as follows: arrhythmias (four) (21.1%), heart failure (two) (9.1%), ICD shocks (one) (5.3%), atrial lead fracture (one) (5.3%), and lead-related thrombus (one) (5.3%). There were no inappropriate device shocks or therapies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conclusions Women with heart disease and an ICD implant can have a good outcome during pregnancy but medical and device complications are not uncommon. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
It is now 30 years since the first implantable cardioverter
defibrillator (ICD) was used for the treatment and prevention of
lifethreatening arrhythmias (ARRs). Subsequently, the number of
device implants has increased each year,1 with 4500 implants
in 2008 in the UK alone.2 Although, the majority of implants are
in patients with acquired heart disease, the indications for ICD
implantation have expanded to include younger age groups, in
particular those with inherited and congenital heart disorders.3 For
these younger patient cohorts, survival to reproductive maturity
and beyond is now the norm,4 leading to a new and unique
group of young women with an ICD in situ who wish to embark
Pregnancy outcome for such patients is limited to case reports
and retrospective multi-centre series with small numbers.5 – 13
Moreover, the haemodynamic and electrophysiological impact of
pregnancy in these patients is also not well documented. We
therefore report our single centre experience of pregnancy
outcome in women with heart disease and an ICD implant.
All patients with heart disease and an ICD implant, under the care of
the specialist multidisciplinary maternal cardiology team at University
College London Hospitals NHS Trust (UCLH NHS Trust), between
September 2001 and October 2010, were identified from the maternal
cardiology database. The specialist team includes input from a
grown-up congenital heart disease cardiologist with device expertise,
two obstetricians, an anaesthetist, a haematologist, and clinical nurse
Follow-up during pregnancy
All patients with an ICD have their antenatal care and delivery in the
high-risk pregnancy unit at UCLH. Patients are reviewed in the
preconceptual counselling clinic where possible, or as soon as pregnancy
is confirmed. Thereafter patients are reviewed at 14 – 16 weeks
gestation and the frequency review and device interrogation is individualized
and determined by symptoms, complexity of the underlying cardiac
disorder, and ARR history. At 32 – 34 weeks a written delivery plan
is distributed electronically to all members of the specialist team,
labour ward, and to the patient by letter.
Device management during pregnancy, labour, and delivery
During the antenatal period, device parameters remain unchanged
from the non-pregnant state unless there is an indication for
reprogramming e.g. inappropriate device therapies.
The devices were programmed with a ventricular tachycardia (VT)
therapy (mean 171 – 217 per minute) and ventricular fibrillation (VF)
zone accordingly. The supraventricular tachycardia (SVT)
discriminators employed included rhythm ID for the six Guidant devices,
onset and stability algorithms for Medtronic (n ¼ 11) and
morphology/stability for the two St Jude devices.
For delivery programming is as follows:
† Vaginal delivery (VD)—device remains in full therapy mode.
† Elective caesarean section—device is programmed to ‘monitor
only’ (safe mode) to avoid electrical interference from
diathermy and re-programmed to full therapy mode immediately
Bipolar diathermy is requested for operative deliveries and a magnet is
available on labour ward and in operating theatre for use in event of
inappropriate ICD shocks (magnet placement disables ARR detection
and prevents shock delivery).
Maternal, obstetric, and neonatal outcomes were assessed. Maternal
cardiac complications including death, heart failure (HF), ARR,
thromboembolism (TE), or hospitalization for a cardiac indication
were recorded. Device therapies and complications were also
Continuous variables describing the 14 women are summarized by
mean and range. Pregnancy outcomes are summarized as percentages
within categories and confidence intervals adjusted for multiple
pregnancies within women using random effects models using M1Win v2.2.
From a total of 580 pregnancies in women with heart disease,
there were 19 pregnancies in 14 women with an ICD implant
(Table 1). The mean age at conception was 33 years (range 22 –
42 years) and the mean time interval between ICD implantation
and first pregnancy was 3.8 years (range 1 – 9 years). The
underlying cardiac diagnoses (Figure 1) were congenital heart disease
[repaired Tetralogy of Fallot (ToF)] (one), inherited heart disease
(nine) [hypertrophic cardiomyopathy (HCM) (seven), HCM with
Ross (one)], familial dilated cardiomyopathy (one), long QT
syndrome (LQTS) (three), and idiopathic VF arrest (one).
Nine device implants were for primary prevention of sudden
cardiac death (SCD) (9/14 ¼ 64%) [syncope (four), family history
SCD (four), non-sustained ventricular tachycardia (nsVT) (one)]
and five for secondary prevention (35%) [aborted cardiac arrest
(two), sustained VT (three)].
Three patients had moderate impairment of left ventricular
systolic function [ejection fraction (EF) ,45%], the remainder had
normal left ventricular (LV) systolic function.
Drug therapy was used in 18 pregnancies [95% (70, 93%)]
including beta-blockers (12, 86%), diuretics (8, 56%), aspirin (7,
50%), and low molecular weight heparin (LMWH) at therapeutic
dose (3, 35%).
Thirteen patients had transvenous endocardial leads with
prepectoral devices and one had an abdominal device with a tunnelled
transvenous endocardial lead placement. There were 3 single
ventricular lead devices and 11 dual lead (atrial and ventricular lead)
systems (Table 2, history of ICDs and ARR s).
Of the 19 pregnancies 18 pregnancies continued beyond 24 weeks
gestation resulting in 18 live births. There was one termination of
pregnancy at 10 weeks gestation for severe foetal chromosomal
abnormality. The mean gestational age at delivery was 38 weeks
(range 32 – 40 weeks). There were three pre-term deliveries
prior to 36 of 40 weeks, for symptomatic palpitations (one), left
ventricular failure (one), and spontaneous rupture of membranes
(one). The mean birth weight was 2.9 kg (range 1.6 – 3.8 kg). The
mode of delivery was per vagina (VD) in 12 [69%, confidence
interval (CI) 43, 87%] of the 17 pregnancies for which mode of delivery
was recorded (one termination, one lost to follow-up). The
remaining five were by caesarean section (CS). Three CS were
elective [breech presentation (one), symptomatic sinus tachycardia
(one), and previous CS (one)] and two were emergency sections
for failure to progress in labour with foetal distress.
Deaths—There were no maternal deaths.
Heart failure (two)—HF was precipitated in two pregnancies
(one patient). In one patient with non-obstructive hypertrophic
cardiomyopathy HF was precipitated during both her first (P1)
and second (P2) pregnancies during the second trimester (9.1%
CI 1.3, 43.5%). Her baseline LV function was impaired with EF
40 – 45% prior to both P1 and P2. It remained stable throughout
ToF, Tetralogy of Fallot; PPVI, percutaneous pulmonary valve implantation; HCM, hypertrophic cardiomyopathy; FVL, factor V Leiden; LQTS, long QT syndrome; DCM, dilated
cardiomyopathy; IVF, idiopathic VF; BB, beta-blocker; LMWH, low molecular weight heparin; ASA, aspirin 75 mg; D, diuretic. VD, vaginal delivery; IoL, induction of labour; sVD;
spontaneous vaginal delivery; CS, caesarean section; O, obstetric; C, cardiac indication; nsVT, non-sustained ventricular tachycardia; VF, ventricular fibrillation; HF, heart failure.
both pregnancies and she responded well to diuretic therapy on
both occasions, with uncomplicated induced vaginal deliveries at
36 and 37 weeks, respectively.
Thromboembolism (one)—There was one major TE complication
of ICD lead thrombus in a patient with HCM and an ICD for
primary prevention of SCD (5.3% CI 0.7, 30.3%). Biventricular
function was good but routine echocardiography [transthoracic
echocardiography (TTE)] during the second trimester identified a
13 × 15 mm thrombus attached to the ventricular lead in close
proximity to the tricuspid valve. She was treated with Dalteparin
(8500 IU bd). A thrombophilia screen diagnosed factor V Leiden
deficiency (heterozygous) and a homozygous C677T MTHFR
polymorphism. On further enquiry a positive family history of venous
thromboembolism (VTE) was identified. She remained well for
the remainder of pregnancy and the thrombus did not change in
size. She underwent elective CS at 36 weeks gestation (previous
CS). The evening dose of LMWH was omitted the day prior to
CS, prophylactic dose LMWH was re-started 5 h post-CS, and
therapeutic dosing 24 h post-operatively. One week post-partum
she presented with leg swelling and breathlessness. TTE confirmed
SR, sinus rhythm; ST, sinus tachycardia; SVT, supraventricular tachycardia; VT, ventricular tachycardia; VF, ventricular fibrillation; SR, sinus rhythm; ST, sinus tachycardia; SVT,
supraventricular tachycardia; VT, ventricular tachycardia; VF, ventricular fibrillation.
an increase in thrombus size at 41 × 18 mm with obstruction to
tricuspid valve inflow (Figure 2). She underwent urgent surgical
removal of the thrombus and ICD system (generator and leads)
via sternotomy and made an uneventful recovery.
Arrhythmia episodes, device therapies, device-related complications
There were four ARR episodes (21.1%, CI 8.1; 44.7%), Table 3.
Two episodes were symptomatic and two were detected on
device interrogation only. The symptomatic ARR s were as
follows: VF (one) and SVT (one). The patient with VF ( patient
13) had LQTS and had an appropriate device shock of 31 J at
20-week gestation. Although the ICD implant was for primary
prevention, she had been non-compliant with beta-blocker therapy
during pregnancy. There were no adverse maternal or foetal
effects and she had an uncomplicated delivery at 37-week
gestation. Of note she experienced a second appropriate ICD shock
3-month post-partum, again having been non-compliant with
betablocker treatment. There were no inappropriate device shocks or
therapies during any pregnancy or for up to 6-month post-partum.
The symptomatic SVT was in patient 5 with HCM, and it was
appropriately detected by the device without need for device
therapy. She subsequently commenced beta-blocker therapy.
There were two asymptomatic ARR episodes detected by the ICD
of sustained VT ( patient 8) and nsVT ( patient 9), respectively. The
sustained VT occurred in two salvos during the third trimester in a
patient with HCM and was detected at the time of device
interrogation prior to CS. Both salvos were successfully treated with
antitachycardia pacing (ATP). The episode of nsVT occurred in a HCM
patient in the third trimester, with appropriate device detection
One non-pacemaker-dependent patient with HCM and a
previous Ross surgery developed high atrial lead impedance in the
second trimester. An atrial lead fracture was confirmed (5.3%,
95% CI 0.7; 30.3%). The device was programmed from DDD to
VVI without further complications.
Owing to improved survival in patients with congenital and
inherited heart disease,4 there is a new and unique cohort of women
reaching reproductive age,16,17 some with an ICD in situ for the
treatment and prevention of ventricular dysrhythmias and SCD.
Published pregnancy outcome data for these patients are
minimal10,12,18 and yet their general acceptance of risk for the
experience of motherhood, means there are likely to be increasing
number of such patients. Our single centre experience
demonstrates that pregnancy outcome overall is generally good but
medical and/or device complications are frequent, occurring in 8
of the 19 pregnancies (42.9%; CI 21.4; 67.5%). The most serious
complication was a thrombotic event, with the development of a
thrombus on a ventricular lead in a patient with previously
undiagnosed thrombophillia. Arrhythmia episodes were also not
uncommon (21.1%, CI 8.1; 44.7%) especially as most device implants in
this cohort were for primary prevention; however, all ARR s
were appropriately detected and/or treated by the device and
there were no inappropriate device therapies.
With the additional pro-arrhythmic and haemodynamic changes
of pregnancy, one might expect an increased incidence of ARR
and/or device therapies in these pre-disposed patients.19 – 21 Even
in the non-pregnant state there is an appropriate ICD shock rate
of 22% over 2 years, in the congenital heart disease population,
with one study reporting an annualized shock rate of 7.7% in
adults with ToF with an ICD for primary prevention of SCD.22
Similar rates of appropriate device shocks (4% per annum) are
reported in patients with familial HCM in a population with an
ICD for primary prevention (86%).23,24 In our cohort there was
one appropriate device shock for VF in a patient with LQTS.
There were no adverse maternal effects and the foetus as
expected was unaffected (the foetal myocardium has a high
fibrillation threshold and very little shock energy is transmitted to the
foetus25,26). Our low ICD shock rate contrasts the largest
reported pregnancy series of Natale et al., where 18% (8 of 44
patients) experienced a device shock.10 This difference in shock
rate is most likely explained by the fact that in Natale’s series all
of the device implants were for secondary prevention of malignant
ARR or SCD (25 and 75%, respectively) compared with only 35%
in our own cohort. Of note there was no difference in use of
antiarrhythmics between the two series at 57 and 58%, respectively,
although perhaps a higher rate of anti-arrhythmic drug therapy
might have been expected in their higher risk cohort. Although
drugs are best avoided during pregnancy,27 many anti-arrhythmics
are FDA category B or C, and generally considered safe28,29 [with
the exception of Amiodarone and Atenolol (category D)]. The
benefit of continuing therapy therefore more often than not
outweighs risk, particularly when the indication is life-threatening
ARR. One patient in our study highlights the importance of
adjunctive beta-blocker therapy specifically in LQTS. Her ICD
implant was for primary prevention of SCD but she experienced
an appropriate device shock for sustained VT/VF on two occasions,
both of which were temporally related to non-compliance with
There were no inappropriate device shocks in our patient
cohort. This is reassuring, particularly in light of the fact that
there is a background inappropriate device discharge rate of 21%
per year in those with congenital heart disease3,30 and 5% in
patients with familial HCM23 in the non-pregnant state. Moreover
in 14 of our 19 pregnancies (74%, CI 47, 90%) there were risk
factors for inappropriate ICD shocks (,35 years old, prior
history of atrial fibrillation). Our low inappropriate shock rate
may be explained by the fact that all ARR s even if non-sustained
are treated promptly, and euvolaemia is maintained with the use
of concomitant diuretics. Diuretics were continued and or
up-titrated in four pregnancies (28%) and newly prescribed in
one pregnancy, in order to treat symptoms of dyspnea. In HCM
patients such symptoms often occur in the absence of clinically
manifest signs of pulmonary congestion but represent increasing
pulmonary venous hypertension, which responds well to small
doses of furosemide.
Lead complications31,32 occurred in two patients in our cohort
(one lead fracture and one lead thrombus; 5.3%, CI 0.7, 30.3%).
Such complications are often difficult and potentially hazardous
to treat in pregnancy.24 Lead explantation and re-implantation
has an associated procedural risk (radiation, wound infection,
tamponade), which must be carefully considered and balanced against
the risks of a conservative approach (device re-programming and
medical therapy), which may also be efficacious. Such management
decisions are case specific, but for our patient with lead fracture,
ventricular lead function was normal and device re-programming
was possible. The second more serious device-related complication
of lead thrombus is reportedly not uncommon with a 25% incidence
(detected by transoesophageal echocardiography) in one study26
but thrombi are usually small and subclinical.33– 35 Our patient had
an undiagnosed thrombophilia (Factor V Leiden deficiency) and
developed a large thrombus on the ventricular lead (Figure 2),
which increased in size despite therapeutic anti-coagulation,
eventually causing obstruction to tricuspid valve inflow. The patient had
been non-compliant with aspirin therapy but whether this treatment
alone would have prevented thrombus formation in the presence of
this inherited thrombophilia is doubtful. Her case highlights the need
for a detailed history and VTE risk assessment in all patients with
heart disease, but especially in those with intra-cardiac hardware36,37
because LMWH treatment may then be indicated.38– 40
The majority of pregnancies in our series were delivered
vaginally which is the preferred mode for the majority of women with
heart disease41 (69%, CI 42, 87%; 0.88). Of the five CS deliveries,
four were for obstetric reasons and only one for a cardiac
indication (dyspnoea and persistent sinus tachycardia). In our series
patients with an ICD implant had a planned date for delivery, which
allowed appropriate personnel to be available should the device
need to be re-programmed in the event of an operative delivery.
In the event of an emergency CS, the device remains in full
therapy mode with bipolar diathermy used for cautery. A
magnet is also available in the operating theatre for de-activating
the device in the event of inappropriate device shocks.14,15,41
The outcome of pregnancy in women with heart disease and an
ICD implant is good, but medical and or device complications
are frequent. They therefore represent a high-risk pregnancy
group who require specialist multidisciplinary team antenatal care.
We wish to thank Adam Simpson, cardiac electrophysiologist, for
help with the ICD programming evaluation.
Conflict of interest: none declared.
P.K.S. has research grants from the European Society of Cardiology and
the Swiss National Foundation.
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