Transplacental cardioversion of fetal supraventricular tachycardia with procainamide

Cardiac arrhythmias during pregnancy

OPINION STATEMENT

This article reviews the appropriate evaluation and management of cardiac arrhythmias in the pregnant patient. Any treatment strategy in this patient population has the inherent potential to adversely affect the health of the unborn child. As such, there is no room for empiric therapy in these patients. Adequate arrhythmia documentation is paramount, preferably by noninvasive means. The decision to treat should be based on symptom severity and the risk to both mother and fetus posed by potentially recurring arrhythmia episodes throughout the pregnancy. Minimal symptoms in the setting of a structurally normal heart call for a conservative approach. Less is better. If pharmacologic therapy is justified, drugs with historically demonstrated safety profiles in pregnancy should be tried first. The safety profiles of virtually all drugs used to treat cardiac arrhythmias during human pregnancy are based solely on an accumulation of past clinical experience. Newer antiarrhythmics therefore carry a largely unknown risk. Most inherent rhythm disorders manifest long before a woman reaches childbearing age. Women with previously diagnosed arrhythmias frequently experience a recurrence or worsening of their arrhythmia during the pregnancy. Counseling of these individuals and perhaps preemptive treatment by means such as arrhythmia ablation prior to a planned pregnancy would seem optimal.

Prenatal management of urogenital disorders

Antenatal sonography has markedly increased the detection of urogenital anomalies, including those conditions that lead to significant morbidity and mortality. Prenatal intervention is feasible to arrest and sometimes reverse the sequelae of bladder outlet obstruction but not necessarily renal damage. Myelomeningoceles, the most severe form of spina bifida, can be corrected in utero, with improvements in hydrocephalus seen along with a decreased incidence of ventricular shunting postnatally. Medical therapy to prevent virilization associated with congenital adrenal hyperplasia has been successful, with improved ability to detect its presence prenatally now possible. As further techniques evolve to correct underlying disease processes, it becomes important to critically assess the therapies, particularly with long-term outcome data.

Cardiovascular pharmacotherapeutic considerations during pregnancy and lactation

Cardiovascular drugs are often used in pregnancy for the treatment of maternal and fetal conditions. Mothers could also require continued postpartum drug therapy. Most cardiovascular drugs taken by pregnant women can cross the placenta and therefore expose the developing embryo and fetus to their pharmacologic and teratogenic effects. These effects are influenced by the intrinsic pharmacokinetic properties of a given drug as well as by the complex physiological changes occurring during pregnancy. Many drugs are also transferred into human milk and therefore can potentially have adverse effects on the nursing infant. This 2-part article summarizes some of the available literature concerning the risks and benefits of using various cardiovascular drugs and drug classes during pregnancy and lactation. Included in the discussion are cardiac glycosides, antiarrhythmic drugs, drugs used to treat both acute and chronic hypertension, cholesterol-lowering agents, anticoagulants, thrombolytics, and antiplatelet drugs.

Management of fetal tachyarrhythmias

Fetal tachyarrhythmias are an important cause of fetal morbidity and mortality. The majority of fetal tachyarrhythmias are due to atrioventricular reentrant type of supraventricular tachycardia and atrial flutter. Fetal echocardiography remains the main tool of diagnosing and discerning the mechanism of tachyarrhythmia. The goals of therapy for fetal arrhythmias are to restore sinus rhythm, resolve heart failure, and postpone delivery before term. Although there is no anonymity in the approach to the drug treatment of fetal tachycardia, digoxin is the most commonly employed first-line antiarrhythmic drug for supraventricular tachycardia. In digoxin nonresponders, flecainide ( digoxin) controls tachyarrhythmia with high conversion rate. A combination of digoxin and sotalol has proved effective therapy for atrial flutter, but the proarrhythmic side effect of sotalol on the fetus has been a concern. Amiodarone has emerged as a second-line treatment after digoxin failure in nonhydropic fetuses and the most effective treatment for drug-refractory fetal tachycardia accompanied by hydrops. Both the fetus and mother should be closely monitored for the response and adverse effect of the treatment. The antiarrhythmic treatment for supraventricular tachycardia should be continued after birth and during infancy due to the high incidence of postnatal recurrence.

Prenatal management of urogenital disorders

Antenatal sonography has increased the detection of urogenital anomalies markedly, including conditions that lead to significant morbidity and mortality. Prenatal intervention is feasible to arrest and sometimes reverse the sequelae of bladder-outlet obstruction, but not necessarily renal damage. Myelomeningoceles, the most severe form of spina bifida,can be corrected in utero, with improvements in hydrocephalus and a decreased incidence of ventricular shunting postnatally. Medical therapy to prevent virilization associated with congenital adrenal hyperplasia has been successful, with improved ability to detect its presence prenatally. As techniques evolve to correct underlying disease processes,it becomes important to assess the therapies critically, particularly with long-term outcome data.

Drug treatment of fetal tachycardias

The pharmacological treatment of fetal tachycardia (FT) has been described in various publications. We present a study reviewing the necessity for treatment of FT, the regimens of drugs used in the last two decades and their mode of administration. The absence of reliable predictors of fetal hydrops (FH) has led most centers to initiate treatment as soon as the diagnosis of FT has been established, although a small minority advocate nonintervention. As the primary form of pharmacological intervention, oral maternal transplacental therapy is generally preferred. Digoxin is the most common drug used to treat FT; however, effectiveness remains a point of discussion. After digoxin, sotalol seems to be the most promising agent, specifically in atrial flutter and nonhydropic supraventricular tachycardia (SVT). Flecainide is a very effective drug in the treatment of fetal SVT, although concerns about possible pro-arrhythmic effects have limited its use. Amiodarone has been described favorably, but is frequently excluded due to its poor tolerability. Verapamil is contraindicated as it may increase mortality. Conclusions on other less frequently used drugs cannot be drawn. In severely hydropic fetuses and/or therapy-resistant FT, direct fetal therapy is sometimes initiated. To minimize the number of invasive procedures, fetal intramuscular or intraperitoneal injections that provide a more sustained release are preferred. Based on these data we propose a drug protocol of sotalol 160 mg twice daily orally, increased to a maximum of 480 mg daily. Whenever sinus rhythm is not achieved, the addition of digoxin 0.25 mg three times daily is recommended, increased to a maximum of 0.5 mg three times daily. Only in SVT complicated by FH, either maternal digoxin 1 to 2mg IV in 24 hours, and subsequently 0.5 to 1 mg/day IV, or flecainide 200 to 400 mg/day orally is proposed. Initiating direct fetal therapy may follow failure of transplacental therapy.

Outcome of fetuses with heart disease diagnosed in utero

OBJECTIVE

To review the outcomes of 193 fetuses with cardiac abnormalities detected by echocardiography.

METHODS

A total of 422 fetuses between 16 and 41 gestational weeks, referred to paediatric cardiologists for detailed echocardiography, were included in this study.

RESULTS

Structural heart defects were found in 55 (28%), isolated arrhythmia in 105 (54%), and other non-structural abnormalities (dilated cardiomyopathy, hypertrophic cardiomyopathy, aneurysm of the foramen ovale, isolated pericardial effusion or echogenic foci) in 33 (17%) of 193 fetuses. Total mortality was 26%. The prognosis was poor in fetuses with structural heart defects; 37 of 55 cases (67%) died in utero or postnatally. Chromosomal abnormality was associated with structural heart defect in 38% of fetuses, of whom 38% died. Among fetuses with isolated arrhythmia survival was 95%. Poor outcome was associated with complete heart block (n = 14) in 2 (14%) fetuses with hydrops and heart rate of less than 55 per minute, and with supraventricular tachycardia (n = 21) in three (14%) neonates delivered prematurely at a mean gestational age of 33 weeks. Furthermore, nine of 12 fetuses (75%) with structural heart defects and arrhythmia died. Among fetuses with non-structural cardiac abnormalities, survival was 73%. Poor outcome was evident in fetuses with dilated cardiomyopathy in eight of 13 (62%) and with hypertrophic cardiomyopathy in one of eight (13%) of cases.

CONCLUSIONS

Factors associated with a poor prognosis were: structural heart defect associated with chromosomal abnormality or arrhythmia, congestive heart failure associated with supraventricular tachycardia or complete heart block, especially if delivery occurs preterm; and fetal hydrops with congestive heart failure and atrioventricular valve regurgitation.

Atrial flutter in the human fetus: diagnosis, hemodynamic consequences, and therapy

In the context of a large program of prenatal echocardiographic detection of fetal heart disease, special attention was paid to the in utero detection and identification of fetal heart rate disorders. This article focuses on 18 cases of tachycardiac fetuses. It provides information on how to identify the nature of the detected tachycardia, the hemodynamic consequences of tachycardia, the particular characteristics of fetal atrial flutter, and the efficacy of the transmaternal treatment of fetal tachycardia. It also describes an original way to grade and score the degree of fetal heart failure that proved useful for the assessment and monitoring of in utero therapeutic procedures. The results presented stress the efficacy of digoxin for fetal atrial flutter as well as the usefulness of prenatal echocardiography in the assessment of anatomical, functional, and rhythmic conditions of the fetal heart.

Medical fetal therapy

Medical fetal therapy describes any therapy in which a pharmacological agent is administered to a woman or her fetus in order to avoid or alleviate fetal disease. Treatment of the fetus with blood products or injection of other agents can also be considered to be medical fetal therapy. This chapter reviewed the application of medical fetal therapy to the prevention of NTDs, treatment of endocrinological and metabolic disorders, such as CAH, thyroid disease and others, and the medical management of cardiac arrhythmias. Several haematological disorders and reviews of recent advances in genetic manipulation involving the use of stem-cell implantation were discussed. The field of medical fetal therapy has been extremely exciting and continues to evolve at a rapid pace. No doubt, future advances involving genetic manipulation or the use of molecular genetic techniques for diagnosis will continue to keep this field at the forefront of treatment and prevention of fetal disorders.

Induced cardioversion of fetal flutter by artificial rupture of membranes at term

A term fetus with atrial flutter and no signs of cardiac decompensation is described. A trial of pharmacologic cardioversion was unsuccessful, and induction of labor was initiated. Immediately after artificial rupture of the membranes, spontaneous conversion to normal sinus rhythm occurred. The possible mechanism of the cardioverion and the optional treatments for the term fetus with atrial flutter are discussed.

Management outcome and follow-up of fetal tachycardia

OBJECTIVES

The aim of this study was to evaluate fetal tachycardia and the efficacy of maternally administered antiarrhythmic agents and the effect of this therapy on delivery and postpartum management.

BACKGROUND

Sustained fetal tachycardia is a potentially life-threatening condition in which pharmacologic therapy is reported to be effective. There is ongoing discussion about optimal management.

METHODS

A group of 51 patients with M-mode echocardiographically documented fetal tachycardia was studied retrospectively.

RESULTS

Thirty-three fetuses had supraventricular tachycardia; 15 had atrial flutter; 1 had two episodes of both; and 2 had ventricular tachycardia. Fetal hydrops was seen in 22 patients. Thirty-four fetuses received maternal therapy with either digoxin or flecainide as the first administered drug (additional drugs were given in 12). Drug treatment was successful in establishing acceptable rhythm control in 82% (84% without, 80% with hydrops). In the latter group the median number of drugs and number of days to conversion were higher. Three patients with fetal hydrops died. In 50% of cases, tachycardia reappeared at delivery: 9 neonates presented with atrial flutter, 14 with supraventricular tachycardia and 1 with ventricular tachycardia. Seventy-eight percent of the group had pharmacologic therapy by 1 month of age and 14% by 3 years.

CONCLUSIONS

Fetal tachycardia can be treated adequately in the majority of patients, even in the presence of hydrops, and therefore emergency delivery might not be indicated. Digoxin and flecainide were drugs of first choice and produced no serious adverse effects in this series of patients. The majority of patients do not require prolonged therapy.

Drug therapy of the fetus

The fetus has become an intended object of drug therapy administered through the mother with the successful prevention of hyaline membrane disease with glucocorticoids. Maternal drug treatment has now been undertaken for a variety of fetal problems, including arrhythmias, congestive heart failure, infections, and inborn errors of adrenal metabolism. Interestingly, this planned maternal drug exposure during pregnancy coincided with increasing concerns during the last two decades about inadvertent transplacental exposure of the fetus to licit and illicit drugs. Efforts to direct drug therapy to the fetus have pointed out important gaps in knowledge of the pharmacology of the maternal-placental-fetal-unit (MPFU), whereas other observations illustrated recognized principles of the pharmacology of the MPFU. Many of these principles fit the basic framework of pharmacokinetics: absorption, distribution, metabolism and excretion. Rapid changes in maternal-placental physiology and fetal development during gestation, however, lead to dramatic variations in these processes throughout pregnancy.

Current concepts of fetal therapy

The development of fetal diagnostic techniques has facilitated the analysis of pathological conditions in abnormal fetuses. This has led to systematic fetal therapy for such diseases as fetal hydronephrosis and fetal struma. In this report, general characteristics and problems of fetal therapy are discussed and several representative diseases that have been treated by surgical and pharmaceutical methods are outlined.

Anesthesia, cardiopulmonary bypass, and the pregnant patient

For the perioperative management of pregnant patients with severe cardiac or aortic disease who require a cardiac surgical procedure and cardiopulmonary bypass, a close, cohesive, working relationship must exist among several medical and surgical specialties. For appropriate management, the well-being of both the mother and the fetus must be considered. The best interests of the mother and the fetus may not coincide, and optimal therapy for one may be inappropriate for the other. We present 10 cases of severe cardiac or aortic disease in pregnant women who required surgical intervention. Eight patients underwent cardiopulmonary bypass during pregnancy, and two patients had cesarean section performed immediately before cardiopulmonary bypass. We also discuss the pertinent pharmacologic aspects related to the perioperative period and the management of cardiopulmonary bypass for the pregnant patient.

Hydrops revisited: literature review of 1,414 cases published in the 1980s

This paper reviews 47 series of hydrops fetalis (804 cases) and 610 individual cases published since 1980. From this large number of cases, guidelines are derived for prenatal diagnosis and management.

Clinical and electrophysiologic features of fetal and neonatal paroxysmal atrial tachycardia resulting in congestive heart failure

Those clinical and electrophysiologic features of paroxysmal atrial tachycardia (PAT) that appeared to be the cause of prenatal congestive heart failure (CHF) (hydrops fetalis) were evaluated in 12 neonates, ages 1 to 14 days, and compared with those occurring in 12 neonates, ages 2 to 34 days, who developed CHF from PAT diagnosed postnatally. Transesophageal electrophysiologic evaluation was performed after birth or at the time of PAT occurrence in the prenatal CHF group and at the time of CHF diagnosis in the postnatal CHF group. Before the electrophysiologic study, spontaneous PAT onset and termination were observed in all prenatal CHF neonates. In the postnatal CHF neonates, however, a single, prolonged episode of PAT was observed. During PAT, all neonates were observed to have a regular heart rate, normal QRS morphology and ventriculoatrial interval exceeding 80 ms. These findings suggested an orthodromic reciprocating tachycardia using an accessory atrioventricular connection as the tachycardia mechanism. In the 12 neonates with prenatal CHF, the PAT cycle length measured 243 +/- 30 ms, whereas in the 12 neonates with postnatal CHF it measured 208 +/- 19 ms (p less than 0.003). Neonates with prenatal CHF secondary to PAT appear to develop CHF from multiple PATs recurring at relatively long cycle lengths (slow heart rates), whereas postnatal CHF neonates develop heart failure symptoms during a sustained tachycardia episode with relatively short cycle lengths (fast heart rates).

Obstetric importance, diagnosis, and management of fetal tachycardias

During 1980-7, 23 pregnancies of 22-38 weeks' duration were investigated for fetal tachycardia. Twelve were cases of supraventricular tachycardia, eight of atrial flutter, and three cases in which the rhythm varied between supraventricular tachycardia and atrial flutter. In 11 cases the fetus had developed non-immune fetal hydrops before referral; 12 cases were non-hydropic at referral but one of this group of fetuses became hydropic during treatment. No relation was found between the rate or type of arrhythmia and the presence or absence of intrauterine heart failure. One non-hydropic infant was delivered electively prematurely. Maternal antiarrhythmic treatment was instituted in the remaining 22 cases. Conversion of the arrhythmia was achieved with digoxin alone in five cases and with a combination of digoxin and verapamil in nine. Control of the arrhythmia was achieved in seven of the 10 non-hydropic fetuses, and all were delivered at term with no deaths. Of the 12 hydropic fetuses, control was achieved in seven. Only three of the hydropic fetuses were delivered close to term. There were two deaths, both in the hydropic group. Of the whole group, five neonates suffered severe complications of prematurity. In this series the main benefit of treatment appeared to be in prolonging gestation of those hydropic fetuses in which conversion was achieved.

Diagnosis of fetal arrhythmias using echocardiographic and Doppler techniques

Fetal echocardiography is the most practical method for diagnosing prenatal arrhythmias. Because some prenatal tachyarrhythmias have been shown to respond to antiarrhythmic drugs, correctly diagnosing fetal arrhythmias has assumed new importance. With the aid of two-dimensional echocardiographic imaging, an M-mode cursor can be aligned to record atrial and ventricular wall motion--either independently or simultaneously. A consistent feature in the fetus is prominent atrial wall contractions that can be readily recorded on the M-mode tracing. By matching atrial and ventricular wall contractions with assumed P waves and QRS complexes, the fetal electrocardiogram can be reconstructed. In 57 fetuses studied, recurrent atrial and ventricular ectopic beats were the most common prenatal arrhythmias. However, atrial flutter, ventricular tachycardia, atrial and ventricular bigeminy and atrial and ventricular bradyarrhythmias have been correctly identified and in some instances appropriately treated. Marked fetal bradycardia in the midtrimester of pregnancy is shown for the first time to be caused by transducer pressure on the maternal abdominal wall.

Intrauterine treatment of fetal tachycardia

The presence of sustained tachycardia in a fetus can result in congestive heart failure, hydrops, and eventual fetal death. With the increased use of advanced technology in routine obstetric practice, fetal tachycardias are being diagnosed with greater frequency. Recently, administration of antiarrhythmic medications to the mother has been successful in slowing the fetal heart rate and preventing or reversing potentially lethal complications in the fetus. The medications that have been used to treat fetal tachycardia and their potential effects on the mother are discussed. A case study and nursing protocol are presented.

New concepts and drugs in the treatment of congestive heart failure

This article seeks to make clear the basic differences in the treatment of heart failure between therapeutic maneuvers that are aimed at improving the mechanical loading conditions of the heart and those that are aimed at augmenting the fundamental contractile or inotropic state of the myocardium. Emphasis is placed on recognizing that treatment expectations must be viewed within an age- or maturity-dependent framework, since a diminished margin of cardiocirculatory reserve exists in the smallest and youngest patients that limits the extent of benefit that may be derived from diverse treatment approaches.

Investigation of nonimmune hydrops fetalis

Fifty pregnancies complicated by fetal ascites and generalized edema are reviewed and their prenatal findings, obstetric management, and fetal outcome are discussed. From the myriad of maternal, fetal, and placental problems which are known to cause nonimmune hydrops fetalis, many different causes of the disorder could be identified in 84% of all patients studied by extensive prenatal and postnatal workup. Therefore, in only 16% of the cases was the nonimmune hydrops fetalis labeled "idiopathic." The most common demonstrable causes of the disorder in this series were cardiac anomalies, followed by chromosomal disorders, congenital malformations, alpha-thalassemia, and the twin-twin transfusion syndrome. A systematic approach to the prenatal diagnostic workup of nonimmune hydrops fetalis is outlined, starting with the least invasive techniques (ultrasound, echocardiography, complete blood count, Kleihauer-Betke analysis, TORCH testing, and so forth) followed by more invasive techniques (amniocentesis and fetoscopy). Although the detection and prognostic evaluation of nonimmune hydrops fetalis are greatly improved by applying these techniques, the overall prognosis for most fetuses with nonimmune hydrops fetalis is still very poor, and only a few conditions causing the disorder, such as prenatally detected cardiac arrhythmias or selected cases of urinary tract obstruction, are amenable to treatment in utero.

Evaluation and treatment of fetal arrhythmias

In a series of 31 cases referred for the evaluation of fetal arrhythmia, it was possible to identify the rhythm disturbance correctly using M-mode echocardiography. Cross-sectional echocardiography delineated structural abnormality where it occurred in association with an arrhythmia. Fifteen cases had premature atrial or ventricular contractions occurring in structurally normal hearts. These were not associated with perinatal mortality or morbidity in our series. Nine cases had complete heart block, three of which had structural cardiac anomalies. Seven cases were of atrial tachycardia, six were treated prenatally, one was delivered prematurely. Correct identification of an arrhythmia and appropriate prenatal therapy where indicated, was found to prevent unnecessary operative or premature deliveries.

Fetal blood flow measurements during fetal cardiac arrhythmia

3 cases of fetal complete heart block, 1 case of fetal bradycardia and 2 cases of fetal supraventricular tachycardia were studied. Using an ultrasonic technique combining real-time ultrasound with a pulsed Doppler system, blood flow measurements at the lower thoracic level of the fetal descending aorta were taken. Despite alterations in rhythm, the blood flow in the aorta descendens was maintained within normal range. With a reduced heart rate, there was an increase in stroke volume, blood flow velocity, acceleration of blood flow velocity and maximum diameter change; conversely, with an increased heart rate the same four parameters were lowered. These alterations reflect changes in cardiac contraction force, and illustrate the ability of the fetal myocardium in maintaining blood flow in the growing fetus.

Fetal cardiac structure and function as studied by ultrasound

Present combined two-dimensional real-time and M-mode echocardiograph systems allow detailed analysis of fetal cardiac structure and function. Standard scanning planes for systematic investigation of various cardiac structures are described. There is a curvilinear increase in left ventricular volume (Qlv), stroke volume (Qlvs), and output Q'lv) during the last trimester of pregnancy with a mean Q'lv value at term of 126 +/- 11 ml/kg/min. Scanning for cardiac defects should preferably be done between 18 and 24 weeks of gestation. In a total of 444 patients referred to our ultrasound unit for ultrasonic analysis of fetal cardiac structure, a total of 13 cardiac defects were diagnosed. The incidence of structural cardiac defects present among those with fetal dysrhythmia was 15%.

Fetal echocardiography; basic and clinical considerations

Present 2-D real-time and M-mode systems allow detailed studies of fetal left and right ventricular cardiac geometry and function. Antenatally, both ventricles are geometrically uniform. There is a curvilinear increase in left ventricular volume (Q1v), stroke volume (Q1v,s) and output (Q'1v) during the last trimester of pregnancy. At term a mean Q'1v of 126 +/- 11 ml kg-1 min-1 was found. Structural analysis of the fetal heart has resulted in the diagnosis of fetal congenital heart disease and cardiac dysrhythmias. Possibilities of antenatal medical treatment of fetal cardiac dysfunction are currently under investigation.

Arrhythmia and structural abnormalities of the fetal heart

Thirty fetuses with cardiac arrhythmias were referred for ultrasonography. This included cross sectional and M mode echocardiography and pulsed Doppler analysis of the fetal heart. Three types of arrhythmias were observed: ectopic beats, tachyarrhythmias, and bradycardia. Ectopic beats were associated with cardiac structural abnormalities in two cases, resulting in fetal death in one. Tachycardia was not associated with structural defect, but death from cardiac failure occurred in one patient. Transplacental treatment for tachyarrhythmia was not successful in our experience. In the group with bradycardia four cases had congenital cardiac abnormalities and the mortality rate was 50%. When a fetal cardiac arrhythmia has been established careful structural and rhythm analysis is of vital importance in facilitating prognosis, planning of time and mode of delivery, and monitoring of transplacental treatment where indicated.

Evaluation of fetal arrhythmias by echocardiography

The normal fetal heart shows variation in rate and rhythm. Twenty three cases that fell outside the normal patterns of variation of heart rate and rhythm were evaluated by echocardiography. Ten showed atrial or ventricular extrasystoles and these were not associated with perinatal morbidity or mortality. Seven cases showed complete heart block, two in association with structural cardiac abnormality. Six cases were of supraventricular tachycardia, five of which were successfully treated and one was delivered prematurely. It was possible to diagnose accurately the type of arrhythmia using the M-mode echocardiogram to compare the relation between atrial and ventricular contraction. Cross-sectional echocardiography allowed identification of associated structural abnormalities. Recognition that an arrhythmia is present and appropriate prenatal treatment if this is indicated will avoid unnecessary operative or premature deliveries.