Characteristics of new-onset ventricular arrhythmias in pregnancy

2023 HRS expert consensus statement on the management of arrhythmias during pregnancy

This international multidisciplinary expert consensus statement is intended to provide comprehensive guidance that can be referenced at the point of care to cardiac electrophysiologists, cardiologists, and other health care professionals, on the management of cardiac arrhythmias in pregnant patients and in fetuses. This document covers general concepts related to arrhythmias, including both brady- and tachyarrhythmias, in both the patient and the fetus during pregnancy. Recommendations are provided for optimal approaches to diagnosis and evaluation of arrhythmias; selection of invasive and noninvasive options for treatment of arrhythmias; and disease- and patient-specific considerations when risk stratifying, diagnosing, and treating arrhythmias in pregnant patients and fetuses. Gaps in knowledge and new directions for future research are also identified.

Arrhythmias in Pregnancy

Increasing maternal mortality and incidence of arrhythmias in pregnancy have been noted over the past 2 decades in the United States. Pregnancy is associated with a greater risk of arrhythmias, and patients with a history of arrhythmias are at significant risk of arrhythmia recurrence during pregnancy. The incidence of atrial fibrillation in pregnancy is rising. This review discusses the management of tachyarrhythmias and bradyarrhythmias in pregnancy, including management of cardiac arrest. Management of fetal arrhythmias are also reviewed. For patients without structural heart disease, β-blocker therapy, especially propranolol and metoprolol, and antiarrhythmic drugs, such as flecainide and sotalol, can be safely used to treat tachyarrhythmias. As a last resort, catheter ablation with minimal fluoroscopy can be performed. Device implantation can be safely performed with minimal fluoroscopy and under echocardiographic or ultrasound guidance in patients with clear indications for devices during pregnancy. Because of rising maternal mortality in the United States, which is partly driven by increasing maternal age and comorbidities, a multidisciplinary and/or integrative approach to arrhythmia management from the prepartum to the postpartum period is needed.

Impact of preeclampsia on ventricular repolarization indices

BACKGROUND

Because of cardiac hypertrophy and electrophysiological alterations associated with preeclampsia, worsening of preexisting arrhythmias or occurrence of de novo arrhythmias are common in patients with preeclampsia. Tp-e/QT and Tpe/QTc ratios are accepted as reliable indexes for predicting ventricular arrhythmias. In this study, we examined the impact of preeclampsia on ventricular repolarization indices in patients with preeclampsia by using the QT, QTc and Tp-e interval, Tp-e/QTratio, and Tp-e/QTc ratio.

METHODS

We analyzed electrocardiographic recordings of sixty pregnant women with preeclampsia and thirty age-matched healthy pregnant women. Women presenting with preeclampsia were divided into 2 groups and classified as early (gestational age < 34 weeks at clinical onset) or late (≥34 weeks) onset preeclampsia. Ventricular repolarization indices were evaluated.

RESULTS

The QT and Tp-e intervals were found to be longer in patients with earlyonset preeclampsia compared to patients with late-onset preeclampsia and helthy pregnants (377.6 ± 23 ms vs 374.3 ± 15 ms, 362 ± 15 ms & 82.6 ± 9.4 ms vs 74.0 ± 10.6 ms, 68.6 ± 10 ms). In adition, Tp-e/QT and Tp-e/QTc ratio were significantly higher in this patient population compared to others (0.21 ± 0.02 vs 0.19 ± 0.02, 0.18 ± 0.02 & 0.19 ± 0.02 vs 0.16 ± 0.02, 0.15 ± 0,02, p < 0.05 respectively).

CONCLUSION

Our data showed that preeclampsia has unfavorable effects on electrocardiographic indices of ventricular repolarization compared to healthy pregnant women. This effect is more prominent in patients with early-onset preeclampsia.

A case of mistaken arrhythmogenic identity during pregnancy

Atypical LVOT ectopy can present with an RVOT morphology on ECG and differentiation to reveal this focus is in favor of benign idiopathic ventricular ectopy over an arrhythmogenic cardiomyopathy.

The burden of premature ventricular contractions predicts adverse fetal and neonatal outcomes among pregnant women without structural heart disease: A prospective cohort study

Background

Premature ventricular contractions (PVCs) may increase during pregnancy, however, few studies have evaluated the relationship between PVCs and the pregnant outcomes.

Hypothesis

PVCs may increase the adverse fetal/neonatal outcomes in pregnant women.

Methods

Six thousand one hundred and forty‐eight pregnant women were prospectively enrolled in our center between 2017 and 2019 in the study. The average PVC burden was determined by calculating the number of PVCs in total beats. Those who had a PVC burden >0.5% were divided into two groups based on the presence or absence of adverse fetal or neonatal events. The adverse outcomes were compared between the groups to assess the impact of PVCs on pregnancy.

Results

A total of 103 (1.68%) women with a PVC burden >0.5% were recorded. Among them, 17 adverse events (12 cases) were documented, which was significantly higher than that among women without PVCs (11.65% vs. 2.93%, p < .01). The median PVC burden among pregnant women with PVCs was 2.84% (1.02%–6.1%). Furthermore, compared with that of the women without adverse events, the median PVC burden of women with adverse fetal or neonatal outcomes was significantly higher (9.02% vs. 2.30%, p < .01). Multivariate logistic regression analysis demonstrated that not the LVEF, heart rate and bigeminy, but only the PVC burden was associated with adverse fetal or neonatal outcomes among pregnant women with PVCs (OR: 1.34, 95% CI [1.11–1.61], p < .01).

Conclusions

Frequent PVCs have adverse effects on pregnancy, and the PVC burden might be an important factor associated with adverse fetal and neonatal outcomes among pregnant women with PVCs.

Management of tachyarrhythmias in pregnancy - A review

The most common arrhythmias detected during pregnancy include sinus tachycardia, sinus bradycardia, and sinus arrhythmia, identified in 0.1% of pregnancies. Isolated premature atrial or ventricular arrhythmias are observed in 0.03% of pregnancies. Arrhythmias may become more frequent during pregnancy or may manifest for the first time.

Cardiac arrhythmias secondary to hormone therapy in trans women

Introduction: With greater social acceptance and the evolution of transgender medicine as a specialty, more trans women are seeking hormone therapy (HT). Several studies have identified an increase in cardiovascular disease in trans women, however no studies have investigated the incidence of arrhythmias. Using two cases from the authors' clinic as examples, we propose that hormone therapy in trans women may increase the risk of cardiac arrhythmias. Areas covered: A literature search of sex hormones and cardiac arrhythmias was conducted. Using sex hormone studies completed in cis individuals and animal models we identified several similarities to trans women on HT. In cis men, low levels of testosterone are associated with increased rates of atrial fibrillation and right ventricular outflow tract arrhythmias. The role of estradiol remains less clear but there is evidence to suggest that the administration of exogenous estrogen may increase the rates of cardiac arrhythmias in cis women. Expert opinion: Research in the field of transgender medicine is expanding. As more trans women initiate HT, we will have a larger database from which to collect information regarding the benefits and risks of treatment, including the potential side effect of arrhythmias.

Maternal cardioautonomic responses during and following exercise throughout pregnancy

Blood pressure regulation during pregnancy is poorly understood. Cardiovagal baroreflex gain (BRG) is an important contributor to blood pressure regulation through its influence on heart rate. Heart rate fluctuations occur in response to various physiological stimuli and can be measured using heart rate variability (HRV). It is unclear how these mechanisms operate during pregnancy, particularly with regard to exercise. We examined BRG and HRV prior to, during, and following prenatal exercise. Forty-three pregnant (n = 10 first trimester (TM1), n = 17 second trimester (TM2), n = 16 third trimester (TM3)) and 20 nonpregnant (NP) women underwent an incremental peak exercise test. Beat-by-beat blood pressure (photoplethysmography) and heart rate (lead II electrocardiogram) were measured throughout. BRG (the slope of the relationship between fluctuations in systolic blood pressure and the R-R interval) and HRV (root mean square of the successive differences; RMSSD) were assessed at rest, during steady-state exercise (EX), and during active recovery. BRG decreased with gestation and was lower in the TM3 group than in the NP group (17.9 ± 6.9 ms/mm Hg vs 24.8 ± 7.4 ms/mm Hg, p = 0.017). BRG was reduced during EX in all groups. Resting HRV (RMSSD) also decreased with gestation and was lower in the TM3 group than in the NP group (29 ± 17 ms vs 48 ± 20 ms, p < 0.001). RMSSD was blunted during EX in all groups compared with rest. During active recovery, RMSSD was further blunted compared with EX in the NP group but not during pregnancy (TM1, TM2, and TM3). Compared with the nonpregnant controls, the pregnant women had lower BRG and HRV at rest, but comparable cardioautonomic control during both exercise and active recovery following peak exercise.

Supraventricular tachycardia, pregnancy, and water: A new insight in lifesaving treatment of rhythm disorders

Pregnancy may predispose to paroxysmal supraventricular tachycardia (SVT), in subjects with or without identifiable heart disease. Many physiological conditions such as autonomic nervous system changes, altered systemic hemodynamics, etc. can contribute to the onset of arrhythmias during pregnancy. Some cases reported the occurrence of arrhythmias in relation to systemic fluid variations. We report the case of a pregnant woman who experienced SVT due to fluid depletion, detected by bioimpedance vector analysis (BIVA), which was successfully treated by water repletion under tight BIVA monitoring. Emergency physicians can overcome dangerous drug administration by considering historical examination and using fast and reproducible techniques such as BIVA.

Impact of frequent premature ventricular contractions on pregnancy outcomes

OBJECTIVES

To determine cardiac and fetal/neonatal event rates among pregnant women with premature ventricular contractions (PVCs) and compare with control groups.

METHODS

Prospective case-control cohort study: 53 consecutive pregnancies in 49 women referred to the St. Paul's Hospital between 2010 and 2016 with PVC burden >1% in women without underlying cardiac disease. Maternal cardiac and fetal/neonatal outcomes were compared with two pregnant control groups: (1) supraventricular tachycardia (SVT) group of 53 women referred for a history of SVT/SVT in the current pregnancy and (2) low-risk group of 53 women with no cardiac disease.

RESULTS

The maximal PVC burden was 9.2% (range 1.1%-58.7%). Six of 53 (11%) pregnancies were complicated by a maternal cardiac event: heart failure n=1 and sustained ventricular tachycardia requiring therapy n=5 as compared with no cardiac events in both control groups. All women with an adverse event had a PVC burden >5%. Seven (13%) pregnancies were complicated by an adverse fetal and/or neonatal event and this was similar to the normal control group (5 (9%), P=0.45) and significantly less than the SVT group (16 (30%), P=0.03). The adverse fetal event was driven by small for gestational age neonates and preterm delivery.

CONCLUSIONS

In our cohort of pregnant women with a structurally normal heart and 'high' PVC burden, we found an adverse maternal event rate of 11%, and all events were successfully managed with medical therapy. The rate of adverse fetal events in the PVC group was similar to the normal control group.

Hemodynamic and Electrocardiographic Aspects of Uncomplicated Singleton Pregnancy

Pregnancy is associated with significant changes in maternal hemodynamics, which are triggered by profound systemic vasodilation and mediated through the autonomic nervous system as well as the renin-angiotensin-aldosterone system. Vascular function changes to help accommodate an increase in intravascular volume due to blood volume expansion associated with pregnancy while maintaining the efficiency of ventricular-arterial coupling and diastolic perfusion pressure. The heart undergoes physiological (eccentric) hypertrophy due to increased volume load and cardiac stroke work, whereas the functional change of the left ventricle remains controversial. There are changes in cardiac electrical activity during pregnancy which can be detected in the electrocardiogram that are not related to disease. Sympathetic activation is a common phenomenon during uncomplicated pregnancy and may be a compensatory mechanism induced by profound systemic vasodilation and a decrease in mean arterial pressure. Despite marked sympathetic activation, vasoconstrictor responsiveness is blunted during uncomplicated pregnancy. There are race and ethnic differences in maternal hemodynamic adaptations to uncomplicated pregnancy, which may be attributed to differences in socioeconomic status or in prevalence rates of cardiovascular risk factors.

Hormones and sex differences: changes in cardiac electrophysiology with pregnancy

Disruption of cardiac electrical activity resulting in palpitations and syncope is often an early symptom of pregnancy. Pregnancy is a time of dramatic and dynamic physiological and hormonal changes during which numerous demands are placed on the heart. These changes result in electrical remodelling which can be detected as changes in the electrocardiogram (ECG). This gestational remodelling is a very under-researched area. There are no systematic large studies powered to determine changes in the ECG from pre-pregnancy, through gestation, and into the postpartum period. The large variability between patients and the dynamic nature of pregnancy hampers interpretation of smaller studies, but some facts are consistent. Gestational cardiac hypertrophy and a physical shift of the heart contribute to changes in the ECG. There are also electrical changes such as an increased heart rate and lengthening of the QT interval. There is an increased susceptibility to arrhythmias during pregnancy and the postpartum period. Some changes in the ECG are clearly the result of changes in ion channel expression and behaviour, but little is known about the ionic basis for this electrical remodelling. Most information comes from animal models, and implicates changes in the delayed-rectifier channels. However, it is likely that there are additional roles for sodium channels as well as changes in calcium homoeostasis. The changes in the electrical profile of the heart during pregnancy and the postpartum period have clear implications for the safety of pregnant women, but the field remains relatively undeveloped.

Case Report of S1Q3T3 Electrocardiographic Abnormality in a Pregnant Asthmatic Patient During Acute Bronchospasm

Patient: Female, 33

Final Diagnosis: S1Q3T3 electrocardiographic abnormality in a pregnant asthmatic during acute bronchospasm

Symptoms: Cough • shortness of breath

Medication: —

Clinical Procedure: EKG

Specialty: Pulmonology

Evaluation and Management of Maternal Cardiac Arrhythmias

Pregnant women often complain of palpitations. The differential diagnosis for new-onset palpitations in pregnancy ranges from benign conditions to life-threatening arrhythmias. Maternal arrhythmias can occur in isolation or in the setting of underlying structural heart disease. Optimal management of maternal cardiac arrhythmias includes identification of the specific arrhythmia, diagnosis of comorbid conditions, and appropriate intervention. In general, management of maternal cardiac arrhythmias is similar to that of the general population. Special consideration must be given as to the effects of medications and procedures on both the mother and fetus to optimize outcomes. The importance of multidisciplinary care with cardiology, obstetrics, and anesthesia is emphasized.

Pharmacological Therapy of Tachyarrhythmias During Pregnancy

Tachyarrhythmias are the most frequently observed cardiac complications during pregnancy. The majority of these maternal and foetal arrhythmias are supraventricular tachyarrhythmias; ventricular tachyarrhythmias are rare. The use of anti-arrhythmic drugs (AADs) during pregnancy is challenging due to potential foetal teratogenic effects. Maintaining stable and effective therapeutic maternal drug levels is difficult due to haemodynamic and metabolic alterations. Pharmacological treatment of tachyarrhythmias is indicated in case of maternal haemodynamic instability or hydrops fetalis. Evidenc e regarding the efficacy and safety of AAD therapy during pregnancy is scarce and the choice of AAD should be based on individual risk assessments for both mother and foetus. This review outlines the current knowledge on the development of tachyarrhythmias during pregnancy, the indications for and considerations of pharmacological treatment and its potential side-effects.

Ventricular tachyarrhythmia during pregnancy in women with heart disease: Data from the ROPAC, a registry from the European Society of Cardiology

OBJECTIVES

To describe the incidence, onset, predictors and outcome of ventricular tachyarrhythmia (VTA) in pregnant women with heart disease.

BACKGROUND

VTA during pregnancy will cause maternal morbidity and even mortality and will have impact on fetal outcome. Insufficient data exist on the incidence and outcome of VTA in pregnancy.

METHODS AND RESULTS

From January 2007 up to October 2013, 99 hospitals in 39 countries enrolled 2966 pregnancies in women with structural heart disease. Forty-two women (1.4%) developed clinically relevant VTA during pregnancy, which occurred mainly in the third trimester (48%). NYHA class >1 before pregnancy was an independent predictor for VTA. Heart failure during pregnancy was more common in women with VTA than in women without VTA (24% vs. 12%, p=0.03) and maternal mortality was respectively 2.4% and 0.3% (p=0.15). More women with VTA delivered by Cesarean section than women without VTA (68% vs. 47%, p=0.01). Neonatal death, preterm birth (<37weeks), low birthweight (<2500g) and Apgar score <7 occurred more often in women with VTA (4.8% vs. 0.3%, p=0.01; 36% vs. 16%, p=0.001; 33% vs. 15%, p=0.001 and 25% vs. 7.3%, p=0.001, respectively).

CONCLUSIONS

VTA occurred in 1.4% of pregnant women with cardiovascular disease, mainly in the third trimester, and was associated with heart failure during pregnancy. NYHA class before pregnancy was predictive. VTA during pregnancy had clear impact on fetal outcome.

Changes in heart rate variability and QT variability during the first trimester of pregnancy

The risk of new-onset arrhythmia during pregnancy is high, presumably relating to changes in both haemodynamic and cardiac autonomic function. The ability to non-invasively assess an individual's risk of developing arrhythmia during pregnancy would therefore be clinically significant. We aimed to quantify electrocardiographic temporal characteristics during the first trimester of pregnancy and to compare these with non-pregnant controls. Ninety-nine pregnant women and sixty-three non-pregnant women underwent non-invasive cardiovascular and haemodynamic assessment during a protocol consisting of various physiological states (postural manoeurvres, light exercise and metronomic breathing). Variables measured included stroke volume, cardiac output, heart rate, heart rate variability, QT and QT variability and QTVI (a measure of the variability of QT relative to that of RR). Heart rate (p < 0.0005, p < 0.0005, p < 0.0005) and cardiac output (p = 0.043, p < 0.0005, p < 0.0005) were greater in pregnant women in all physiological states (respectively for the supine position, light exercise and metronomic breathing state), whilst stroke volume was lower in pregnancy only during the supine position (p < 0.0005). QTe (Q wave onset to T wave end) and QTa (T wave apex) were significantly shortened (p < 0.05) and QTeVI and QTaVI were increased in pregnancy in all physiological states (p < 0.0005). QT variability (p < 0.002) was greater in pregnant women during the supine position, whilst heart rate variability was reduced in pregnancy in all states (p < 0.0005). Early pregnancy is associated with substantial changes in heart rate variability, reflecting a reduction in parasympathetic tone and an increase in sympathetic activity. QTVI shifted to a less favourable value, reflecting a greater than normal amount of QT variability. QTVI appears to be a useful method for quantifying changes in QT variability relative to RR (or heart rate) variability, being sensitive not only to physiological state but also to gestational age. We support the use of non-invasive markers of cardiac electrical variability to evaluate the risk of arrhythmic events in pregnancy, and we recommend the use of multiple physiological states during the assessment protocol.

Right ventricular outflow tract tachycardia worsened during pregnancy

We report the case of a 35 years old woman without underlying heart disease who was diagnosed with a right ventricular outflow tract tachycardia worsened during pregnancy. The diagnosis of ventricular tachycardia was made early in her pregnancy course but the patient had symptoms three months earlier. Her disease course was marked by rhythmic storms during the second trimester of pregnancy that led to three hospitalizations accounting for about two weeks in total. The combination of nadolol 80 mg and flecainide tablets 150 mg improved her rhythmic storms. Radiofrequency allowed a radical cure of this ventricular tachycardia. The patient is now asymptomatic 27 months after radiofrequency treatment.

Cardiac arrhythmias in pregnancy

As more women with repaired congenital heart disease survive to their reproductive years and many other women are delaying pregnancy until later in life, a rising concern is the risk of cardiac arrhythmias during pregnancy. Naturally occurring cardiovascular changes during pregnancy increase the likelihood that a recurrence of a previously experienced cardiac arrhythmia or a de novo arrhythmia will occur. Arrhythmias should be thoroughly investigated to determine if there is a reversible etiology, and risks/benefits of treatment options should be fully explored. We discuss the approach to working up and treating various arrhythmias during pregnancy with attention to fetal and maternal risks as well as treatment of fetal arrhythmias. Acute management in stable patients includes close monitoring and intravenous pharmacologic therapy, while DC cardioversion should be used to terminate arrhythmias in hemodynamically unstable patients. Long-term management may require continued oral antiarrhythmic therapy, with particular attention to fetal safety, to prevent complications associated with arrhythmias.

Normal heart ventricular tachycardia associated with pregnancy: successful treatment with catheter ablation

BACKGROUND

Normal heart ventricular arrhythmia occurring during pregnancy has been previously described. Whilst there are established reports of catheter ablation to treat supraventricular arrhythmia during pregnancy, there are no reports of ablation to treat ventricular tachycardia.

CASE

We present the case of a 36 year old women, 31 weeks into an otherwise uncomplicated pregnancy, experiencing significant, troublesome and drug refractory tachycardia emanating from the right ventricular outflow tract.

CONCLUSION

We describe a successful radio frequency ablation in the third trimester of pregnancy.

Sex-Based Differences in Cardiac Arrhythmias, ICD Utilisation and Cardiac Resynchronisation Therapy

Many important differences in the presentation and clinical course of cardiac arrhythmias are present between men and women that should be accounted for in clinical practice. In this paper, we review published data on gender differences in cardiac excitable properties, supraventricular tachycardias, ventricular tachycardias, sudden cardiac death, and the utilisation of implantable defibrillators and cardiac resynchronisation therapy. Women have a higher heart rate at rest, and a longer QT interval than men. They further have a narrower QRS complex and lower QRS voltages on the 12-lead ECG with more often non-specific repolarisation abnormalities at rest. Supraventricular tachycardias, such as AV nodal reentrant tachycardia, are twice as frequent in women compared with men. Atrial fibrillation, however, has a 1.5-fold higher prevalence in men. The triggers for idiopathic right ventricular outflow tract tachycardia (VT) initiation are gender specific, i.e. hormonal changes play an important role in the occurrence of these VTs in women. There are clear-cut gender differences in acquired and congenital LQTS. Brugada syndrome affects men more commonly and severely than women. Sudden cardiac death is less prevalent in women at all ages and occurs 10 years later in women than in men. This may be related to the later onset of clinically manifest coronary heart disease in women. Among patients who receive ICDs and CRT devices, women appear to be under-represented, while they may benefit even more from these novel therapies.

Pregnancy and delivery in cardiac disease

Although its prevalence is relatively low in pregnant women, heart disease is the most important cause of maternal mortality. Problems may arise due to hemodynamic burden and the hypercoagulable state of pregnancy. Heart disease may be congenital or acquired. In developed countries, the former composes the biggest part of women with heart disease. Patients with unrepaired lesions, cyanotic lesions, diminished systemic ventricular function, complex congenital heart disease, left ventricular outflow tract obstruction, pulmonary hypertension, or mechanical valves are at highest risk of developing complications during pregnancy. All patients with known cardiac disease should preferably be counseled before conception. Pre-pregnancy evaluation should include risk assessment for the mother and fetus, including medication use and information on heredity of the cardiac lesion. Management of pregnancy and delivery should be planned accordingly on individual bases. The types of complications are related to the cardiac diagnosis, with arrhythmias and heart failure being most common. Treatment options should be discussed with the future parents, as they may affect both mother and child. In general, the preferred route of delivery is vaginal. The optimal care for pregnant women with heart disease requires multidisciplinary involvement and is best concentrated in tertiary centers.

Arrhythmias in pregnancy

Pregnant women have an increased risk of having the usual arrhythmias seen in women of childbearing age. Most of these are benign sinus tachycardias or bradycardias or atrial and ventricular ectopic beats. Women who have had sustained supraventricular or ventricular tachycardias before pregnancy frequently develop them during pregnancy. These arrhythmias often have enough hemodynamic significance to decrease uterine blood flow, which adds a sense of urgency for treatment. The management is similar to that of nonpregnant women, with nuances important for the protection of the developing fetus.

Emergency therapy of maternal and fetal arrhythmias during pregnancy

Atrial premature beats are frequently diagnosed during pregnancy (PR); supraventricular tachycardia (SVT) (atrial tachycardia, AV-nodal reentrant tachycardia, circus movement tachycardia) is less frequently diagnosed. For acute therapy, electrical cardioversion with 50–100 J is indicated in all unstable patients (pts). In stable SVT, the initial therapy includes vagal maneuvers to terminate tachycardias. For short-term management, when vagal maneuvers fail, intravenous adenosine is the first choice drug and may safely terminate the arrhythmia. Ventricular premature beats are also frequently present during PR and benign in most of the pts; however, malignant ventricular tachyarrhythmias (sustained ventricular tachycardia [VT], ventricular flutter [VFlut] or ventricular fibrillation [VF]) may occur. Electrical cardioversion is necessary in all pts who are in hemodynamically unstable situation with life-threatening ventricular tachyarrhythmias. In hemodynamically stable pts, initial therapy with ajmaline, procainamide or lidocaine is indicated. In pts with syncopal VT, VF, VFlut or aborted sudden death, an implantable cardioverter-defibrillator is indicated. In pts with symptomatic bradycardia, a pacemaker can be implanted using echocardiography at any stage of PR. The treatment of the pregnant patient with cardiac arrhythmias requires important modifications of the standard practice of arrhythmia management. The goal of therapy is to protect the patient and fetus through delivery, after which chronic or definitive therapy can be administered.

CARDIAC ARRHYTHMIAS DURING PREGNANCY: A CLINICAL APPROACH

Physiologic changes in maternal haemodynamics, hormones and autonomic properties contribute to arrhythmias in pregnancy. While arrhythmias most commonly occur in pregnant women with structural heart disease or those with a history of cardiac arrhythmias, they can also occur de novo in women with no documented cardiac disease.

Multiscale entropy and detrended fluctuation analysis of QT interval and heart rate variability during normal pregnancy

Pregnancy leads to physiological changes in various parameters of the cardiovascular system. The aim of this study was to investigate longitudinal changes in the structure and complexity of heart rate variability (HRV) and QT interval variability during the second half of normal gestation. We analysed 30-min high-resolution ECGs recorded monthly in 32 pregnant women, starting from the 20th week of gestation. Heart rate and QT variability were quantified using multiscale entropy (MSE) and detrended fluctuation analyses (DFA). DFA of HRV showed significantly higher scaling exponents towards the end of gestation (p<0.0001). MSE analysis showed a significant decrease in sample entropy of HRV with progressing gestation on scales 1-4 (p<0.05). MSE analysis and DFA of QT interval time series revealed structures significantly different from those of HRV with no significant alteration during the second half of gestation. In conclusion, pregnancy is associated with increases in long-term correlations and regularity of HRV, but it does not affect QT variability. The structure of QT time series is significantly different from that of RR time series, despite its close physiological dependence.

Ventricular tachycardia in pregnant patients

Ventricular tachycardia although not common, can occasionally complicate pregnancy. Its presence may indicate an underlying cardiac structural abnormality, or undiagnosed congenital arrhythmic disease. However, some pregnant patients with ventricular tachycardia have structurally normal hearts. Two cases of ventricular tachycardia in pregnant patients with structurally normal hearts are presented and an approach to diagnosis and management of such patients are discussed.

Longitudinal changes in QT interval variability and rate adaptation in pregnancies with normal and abnormal uterine perfusion

The maternal heart significantly adapts to the circulatory needs of pregnancy, but the effect of pregnancy on ventricular repolarization is poorly understood. The aim of this study was to quantify longitudinal changes in ventricular repolarization during pregnancy. Monthly electrocardiographs (ECGs) were recorded in 32 pregnant women with normal uterine perfusion and 32 pregnant women with abnormal perfusion, starting from the 20th week of gestation until 3 days postpartum. Ventricular repolarization was assessed through various QT interval variability and heart rate adaptation measures. The pregnancy outcomes of all women with normal perfusion were normal. Among pregnancies with abnormal uterine perfusion, 15 pregnancy outcomes were normal, but 17 pregnancies developed preeclampsia and/or small-for-gestational-age infants. In pregnancies with normal perfusion, the QT(c) interval was unaltered, but the QT interval-heart rate hysteresis lag was shorter and the QT interval-heart rate regression residual was higher compared with those of a control group of 10 healthy non-pregnant women. Pregnancies with abnormal uterine perfusion that developed pathological outcomes showed significantly smaller QT interval-heart rate regression residuals and a trend towards shorter QT(c) intervals compared with pregnant women with normal perfusion. In conclusion, pregnancy has a significant effect on ventricular repolarization. Pregnancies with abnormal uterine perfusion and subsequent pathological outcomes are paralleled by changes in ventricular repolarization that precede clinical symptoms.

Right ventricular outflow tract tachycardia in the parturient

Parturition is marked by physiological changes that may elicit electrocardiographic anomalies. Sustained right ventricular tachycardia is an uncommon arrhythmia that necessitates cardioversion using physical, pharmaceutical or electrical means. Patients with right ventricular tachycardia must be evaluated for right ventricular dysplasia. Long-term management of right ventricular tachycardia includes beta-adrenergic blockade and/or radio ablation of right ventricle outflow region usually below the pulmonary annuls. This report discusses the case of a 28-year-old previously healthy primigravid who experienced right ventricular outflow tract tachycardia during labor.

Acute therapy of maternal and fetal arrhythmias during pregnancy

Atrial premature beats are frequently diagnosed during pregnancy. Supraventricular tachycardia (atrial tachycardia, atrioventricular nodal reentrant tachycardia, circus movement tachycardia) is diagnosed less frequently. For acute therapy, electrical cardioversion with 50 to 100 J is indicated in all unstable patients. In stable supraventricular tachycardia, the initial therapy includes vagal maneuvers to terminate tachycardias. For short-term management, when vagal maneuvers fail, intravenous adenosine is the first choice drug and may safely terminate the arrhythmia. Ventricular premature beats are also frequently present during pregnancy and are benign in most patients; however, malignant ventricular tachyarrhythmias (sustained ventricular tachycardia, ventricular flutter, or ventricular fibrillation) may occur. Electrical cardioversion is necessary in all patients who are hemodynamically unstable with life-threatening ventricular tachyarrhythmias. In hemodynamically stable patients, initial therapy with ajmaline, procainamide, or lidocaine is indicated. In patients with syncopal ventricular tachycardia, ventricular fibrillation, ventricular flutter, or aborted sudden death, an implantable cardioverter-defibrillator is indicated. In patients with symptomatic bradycardia, a pacemaker can be implanted using echocardiography at any stage of pregnancy. The treatment of the pregnant patient with cardiac arrhythmias requires important modifications of the standard practice of arrhythmia management. The goal of therapy is to protect the patient and fetus through delivery, after which chronic or definitive therapy can be administered.

Modifying labor routines for the woman with cardiac disease

The childbearing woman with cardiac disease presents a unique challenge to healthcare providers. The physiologic adaptations that accompany pregnancy and labor predispose the woman with cardiac disease to cardiac decompensation. Ideally, these women are identified to perinatal nursing staff prior to admission to the hospital in labor or for obstetrical procedures in order to provide adequate time for review of the specific cardiac lesion and development of an interdisciplinary plan of care. This article provides a comprehensive review of typical intrapartum routines that require modification and discusses strategies for adapting labor management for the woman with cardiac disease.

Influence of Menstrual Cycle on QT Interval Dynamics

OBJECTIVES

The aim of this study was to investigate the effects of the menstrual cycle on QT interval dynamics and the autonomic tone in healthy women.

METHODS

Holter ECGs were recorded in 11 healthy women aged 18-32 years during the follicular and luteal phases of their regular menstrual cycle. The interval from QRS onset to the apex (QaT) and to the end of the T-wave (QeT), the interval between the apex and the end of the T-wave (Ta-e), and RR intervals were measured automatically in the course of 24 hours by Holter ECGs. The QeT/RR, QaT/RR, and Ta-e/RR relationships were evaluated in each subject. The autonomic tone was assessed by the serum catecholamine level at rest and heart rate variability was measured by Holter ECGs.

RESULTS

(1) The follicular and luteal phases did not differ significantly with respect to the slopes of the QeT/RR, QaT/RR, and Ta-e/RR relationships. However, QeT and QaT intervals were significantly shorter for all RR intervals in the luteal than in the follicular phase (P < 0.0001). (2) The serum progesterone concentration was significantly higher in the luteal than in the follicular phase (P < 0.001). (3) Noradrenaline was significantly higher in the luteal than in the follicular phase (P < 0.05). There was no significant difference in the follicular and luteal phases with respect to heart rate variability measurements.

CONCLUSIONS

Our results suggest that the menstrual cycle affects the QT intervals. The observed shorter QT interval during the luteal than the follicular phase may be attributable to the increase in serum progesterone and sympathetic tone.