Arrhythmias in Pregnancy
Introduction
Which part of the elephant were they touching? As strange as it is to begin with that sentence, it could be asked of the scientists studying arrhythmias during pregnancy.
Literature on this subject comes from 3 broad sources: anecdotal reports, reports from referral centers with modestly large populations of pregnant women with structural heart disease, and reports from more general hospitals that have collected their experiences. Not surprisingly, this leads to differences in mechanisms, significance, and treatment recommendations. Although there is much we do not know, arrhythmias will not wait until we learn more. Available information does provide guidance.
Perhaps following 2 women through this article will allow the consideration of some key principles. With some concerns of entrapping the reader, they will be called our 2 women.
Two women A 29-year-old woman, not pregnant, with sudden-onset racing heart; in emergency department: blood pressure, 80/50; heart rate, 190 beats per minute and regular A 29-year-old woman, 7 months pregnant, with an identical presentation.
The arrhythmia is likely to be the same in these women. In most cases, the approach to an abnormal heart rhythm should also be the same. This article takes a particular interest in woman number 2. It is worth remembering, however, that woman number 1 could become woman number 2. The treatment decisions in women of childbearing age should always take that into consideration. A drug or procedure can affect a subsequent pregnancy. Although it could be argued that the treatment could be changed at the time a pregnancy occurs, many are unplanned and exposure to treatment or to untreated heart disease could occur when the fetus is most vulnerable.
Section snippets
Key points of arrhythmia management during pregnancy
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Document the rhythm before treatment. All treatments carry some risk to the mother and fetus, thus it is essential to know the reason for their use. The diagnostic criteria for arrhythmias are not changed by pregnancy.
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Treat hemodynamically significant rhythms early. During pregnancy, the mother's cardiovascular adaptations allow adequate blood flow to both the fetus and herself, with the uterus receiving 17% of the cardiac output at term (compared with the usual 2%) along with increased flow to
Arrhythmias are common in pregnancy and the incidence is increasing
Despite this being a time of improving care of heart disease, arrhythmias, and pregnancy, the incidence of arrhythmias is probably increasing. Two explanations are likely:
- 1.
Increasing age: Pregnancy is increasingly common in women in their thirties and forties. Aging of the heart itself may increase arrhythmias but it also results in an increased chance of an associated disease process that is likely to increase the chance of heart disease and arrhythmias. The most obvious of these are
Diagnostic testing during pregnancy
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Rhythm detection: The electrocardiogram, Holter monitoring, rhythm event monitor, and implantable loop recorder can be used as in nonpregnant patients. Standard exercise and tilt testing are appropriate if considered diagnostically useful.
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Imaging: Occasionally, imaging is important for understanding prognosis and guiding therapy. Echocardiography carries no risks to the fetus or the mother; the only concerns are general overuse, expense, and the potential misinterpretation of the changes of a
Eliminate Offending Causes
Drugs top the list, but metabolic and endocrine abnormalities (particularly hyperthyroidism given its prevalence of 0.5% in pregnancies) are additional potentially reversible causes.
Antiarrhythmic Drugs
All drugs used to treat arrhythmias cross the placenta and most are found in breast milk. There is insufficient evidence for each to be certain that they can be used safely. There is little enough information about drugs that have been available for many years that these old drugs are not clearly distinguishable
Sinus tachycardia
This most common of tachycardias by at least 1010 (author's estimate) is a common cause of tachycardia-related hospital admission during pregnancy (Fig. 2).15
The resting sinus node rate increases gradually through pregnancy by about 20 beats per minute. It rarely exceeds 100 beats per minutes. Rates faster than this are a reason to assess the electrocardiogram carefully to be certain that the rhythm is originating in the sinus node. If it is sinus tachycardia, there may be an explainable cause;
Long QT Syndrome
This syndrome is the most common arrhythmogenic repolarization abnormality syndrome in women of childbearing age.23, 24, 25, 26 Drugs are a common and potentially reversible cause. A specific genetic mutation can be defined as a cause in up to 70% of those with a congenital long QTc. Although there are at least 10 known mutations, LQTC1 occurs in about 50%, LQTC2 in about 45%, and LQTC3 in 5% with very small numbers with the other mutation. In the patients with LQT1 and LQT2, adverse cardiac
Cardiac arrest
Whatever the arrhythmia or nonarrhythmic cause, cardiopulmonary resuscitation should be performed. If it occurs in late pregnancy, tilting the abdomen/pelvis up on the left side may enhance the venous return by decreasing uterine compression of the inferior vena cava. If the pregnancy is greater than 28 weeks, an emergency cesarean section should be considered and has been performed.27
Summary
Finally, it seems the approach to our 2 women should not be all that different. Some final reminders in relation to pregnancy itself:
- 1.
Treat hemodynamically significant arrhythmias with more urgency.
- 2.
Consider risks to the fetus when choosing treatment.
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Defer radiation procedures to after delivery if possible.
References (27)
- et al.
Outcome of pregnancy in women with congenital heart disease: a literature review
J Am Coll Cardiol
(2007) - et al.
Incidence of arrhythmias in normal pregnancy and relation to palpitations, dizziness, and syncope
Am J Cardiol
(1997) - et al.
Recurrence rates of arrhythmias during pregnancy in women with previous tachyarrhythmia and impact on fetal and neonatal outcomes
Am J Cardiol
(2006) - et al.
Adenosine therapy for supraventricular tachycardia during pregnancy
Am J Cardiol
(1995) - et al.
Perinatal arrhythmias: diagnosis and management
Clin Perinatol
(2007) - et al.
Characteristics of new-onset ventricular arrhythmias in pregnancy
J Electrocardiol
(2004) - et al.
Identification of a common genetic substrate underlying postpartum cardiac events in congenital long QT syndrome
Heart Rhythm
(2004) - et al.
Does pregnancy increase cardiac risk for LQT1 patients with the KCNQ1-A341V mutation?
J Am Coll Cardiol
(2006) - et al.
Long QT syndrome and pregnancy
J Am Coll Cardiol
(2007) - Federal Register. 2008; vol. 73: p....
The pharmacokinetics of antiarrhythmic agents in pregnancy and lactation
Clin Pharmacokinet
Cardiovascular pharmacotherapeutic considerations during pregnancy and lactation
Cardiol Rev
Managing palpitations and arrhythmias during pregnancy
Heart
Cited by (19)
Arrhythmias in pregnancy: Is there anything else than just sinus tachycardia?
2024, Revista Portuguesa de CardiologiaAdverse drug reactions in pregnant women: Do they differ from those in non-pregnant women of childbearing age?
2023, TherapiesCitation Excerpt :The decrease in vascular resistance leads to a slight decrease in blood pressure, particularly in early pregnancy. Tachycardia-like arrhythmias were also relatively common in pregnant women [14], who may be more sensitive to this type of adverse reaction. Nifedipine was the drug most involved in hypotension in pregnant women, as well as in tachycardia, as well as levothyroxine.
Electrocardiographic indices and pregnancy: A focus on changes between first and third trimesters
2022, Revista Portuguesa de CardiologiaCitation Excerpt :The TP interval in the third trimester reduced significantly, which can be explained by the increased heart rate. In total, based on the literature, the incidence of cardiac arrhythmias would rise during pregnancy due to hemodynamic, autonomic, and hormonal changes and previous cardiovascular abnormalities.4,25–28 Small sample size and short-term follow up were the main limitation of the study; longer follow up from perinatal to postpartum period would be of great value.
The Utility of Leadless Atrioventricular Synchronous Pacemaker Implantation as a Novel Alternative to a Traditional Pacemaker During Pregnancy
2023, Journal of Innovations in Cardiac Rhythm ManagementAnimal Models of Cardiovascular Complications of Pregnancy
2022, Circulation ResearchDynamic and conventional electrocardiograms for diagnosing arrhythmic coronary atherosclerotic heart disease: A comparative analysis
2021, American Journal of Translational Research
Disclosures: The author has no disclosures.