Elsevier

Cardiology Clinics

Volume 30, Issue 3, August 2012, Pages 425-434
Cardiology Clinics

Arrhythmias in Pregnancy

https://doi.org/10.1016/j.ccl.2012.04.002Get rights and content

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

  1. 1.

    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

  2. 2.

    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

  • 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.

  • 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

  • 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.

  • 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.

  • 3.

    Defer radiation procedures to after delivery if possible.

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    Managing palpitations and arrhythmias during pregnancy

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    • Adverse drug reactions in pregnant women: Do they differ from those in non-pregnant women of childbearing age?

      2023, Therapies
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      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

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      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.

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    Disclosures: The author has no disclosures.

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