Prospective echocardiographic evaluation of atrioventricular conduction in fetuses with maternal Sjögren's antibodies

Outcome of Antibody-Mediated Fetal Heart Disease With Standardized Anti-Inflammatory Transplacental Treatment

Background Transplacental fetal treatment of immune-mediated fetal heart disease, including third-degree atrioventricular block (AVB III) and endocardial fibroelastosis, is controversial. Methods and Results To study the impact of routine transplacental fetal treatment, we reviewed 130 consecutive cases, including 108 with AVB III and 22 with other diagnoses (first-degree/second-degree atrioventricular block [n=10]; isolated endocardial fibroelastosis [n=9]; atrial bradycardia [n=3]). Dexamethasone was started at a median of 22.4 gestational weeks. Additional treatment for AVB III included the use of a β-agonist (n=47) and intravenous immune globulin (n=34). Fetal, neonatal, and 1-year survival rates with AVB III were 95%, 93%, and 89%, respectively. Variables present at diagnosis that were associated with perinatal death included an atrial rate <90 beats per minute (odds ratio [OR], 258.4; 95% CI, 11.5-5798.9; P<0.001), endocardial fibroelastosis (OR, 28.9; 95% CI, 1.6-521.7; P<0.001), fetal hydrops (OR, 25.5; 95% CI, 4.4-145.3; P<0.001), ventricular dysfunction (OR, 7.6; 95% CI, 1.5-39.4; P=0.03), and a ventricular rate <45 beats per minute (OR, 12.9; 95% CI, 1.75-95.8; P=0.034). At a median follow-up of 5.9 years, 85 of 100 neonatal survivors were paced, and 1 required a heart transplant for dilated cardiomyopathy. Cotreatment with intravenous immune globulin was used in 16 of 22 fetuses with diagnoses other than AVB III. Neonatal and 1-year survival rates of this cohort were 100% and 95%, respectively. At a median age of 3.1 years, 5 of 21 children were paced, and all had normal ventricular function. Conclusions Our findings reveal a low risk of perinatal mortality and postnatal cardiomyopathy in fetuses that received transplacental dexamethasone±other treatment from the time of a new diagnosis of immune-mediated heart disease.

Reference ranges and Z-scores of atrioventricular and ventriculoatrial time intervals in normal fetuses

OBJECTIVE

To establish a reference range and compare differences among three methods, and then to construct Z-score reference ranges in normal fetuses from the three methods to provide an extra tool for fetal conduction time assessment.

METHODS

A total of 227 echocardiographic examinations were finally included. Fetal atrioventricular (AV) time and ventriculoatrial (VA) time intervals were measured by three methods: superior vena cava/ascending aorta (SVC/AAO), pulmonary artery/pulmonary vein (PA/PV) and tissue Doppler imaging (TDI). Regression analysis of the mean and standard deviation was performed to establish Z-scores.

RESULTS

With the three methods, positive correlations of intervals with gestational age (GA) and fetal heart rate (FHA) were observed, while intervals were negatively correlated with fetal heart rate (FHR). Correlations between VA/AV and GA, FHA and FHR were weak. The general trend of all intervals was towards an increase. In AV intervals, PA/PV revealed the longest mean AV time interval and SVC/AAO showed the shortest interval. In addition, PA/PV revealed the shortest VA interval.

CONCLUSION

This study presents not only the reference range of AV and VA intervals with the three methods but also the Z-score reference ranges for these indices against GA and FHA in normal fetuses. Each method has a different reference range, and appropriate application can facilitate diagnosis and treatment.

Autoimmune Congenital Heart Block: A Review of Biomarkers and Management of Pregnancy

Autoimmune Congenital Heart Block (CHB) is an immune-mediated disease due to transplacental passage of circulating anti-Ro/SSA and anti-La/SSB autoantibodies. It occurs in 2% of anti-Ro/SSA-exposed pregnancies, and recurrence rate is nine times higher in subsequent pregnancies. Aim of this review is to identify biomarkers of CHB and treatment strategies. The Ro-system is constituted by two polypeptides targeted by the anti-Ro52 and anti-Ro60 autoantibodies. The central portion of Ro52 (p200), more than the full amino-acid sequence of Ro-52, is recognized to be the fine specificity of anti-Ro associated to the highest risk of cardiac damage. If anti-p200 antibody should be tested, as biomarker of CHB, over standard commercial ELISAs is still debated. Recent studies indicate that type I-Interferon (IFN) can activate fibroblasts in fetal heart. In the mother the anti-Ro/La antibodies activate the type I IFN-signature, and maternal IFN-regulated genes correlate with a similar neonatal IFN-gene expression. Evaluation of maternal IFN-signature could be used as novel biomarker of CHB. The measurement of "mechanical" PR interval with weekly fetal echocardiogram (ECHO) from 16 to at least 24 weeks of gestation is strongly recommended for CHB prenatal diagnosis. However, ECHO screening presents some limitations due to difficult identification of first-degree block and possible occurrence of a complete block from a normal rhythm in few days. Maternal administration of Hydroxychloroquine from the tenth week of gestation, modulating toll-like receptor and autoantibody-dependent type I IFN activation on the fetus, has an important role in preventing CHB in pregnant women with high risk for recurrent CHB.

Keeping upbeat to prevent the heartbreak of anti-Ro/SSA pregnancy

Linked Comment: Ultrasound Obstet Gynecol 2019; 54: 87-95.

Fetal cardiac arrhythmias: Current evidence

This article reviews important features for improving the diagnosis of fetal arrhythmias by ultrasound in prenatal cardiac screening and echocardiography. Transient fetal arrhythmias are more common than persistent fetal arrhythmias. However, persistent severe bradycardia and sustained tachycardia may cause fetal hydrops, preterm delivery, and higher perinatal morbidity and mortality. Hence, the diagnosis of these arrhythmias during the routine obstetric ultrasound, before the progression to hydrops, is crucial and represents a challenge that involves a team of specialists and subspecialists on fetal ultrasonography. The images in this review highlight normal cardiac rhythms as well as pathologic cases consistent with premature atrial and ventricular contractions, heart block, supraventricular tachycardia (VT), atrial flutter, and VT. In this review, the details of a variety of arrhythmias in fetuses were provided by M-mode and Doppler ultrasound/echocardiography with high-quality imaging, enhancing diagnostic accuracy. Moreover, an update on the intrauterine management and treatment of many arrhythmias is provided, focusing on improving outcomes to enable planned delivery and perinatal management.

Measurement of fetal atrioventricular time intervals: A comparison of 3 spectral Doppler techniques

OBJECTIVE

To establish nomograms for fetal atrioventricular (AV) time intervals assessed by 3 different pulsed-wave Doppler techniques: left ventricular inflow and outflow tracts (LV in/out), superior vena cava and ascending aorta (SVC/AA), and pulmonary artery and pulmonary vein (PA/PV).

METHODS

A cross-sectional study was performed in 311 normal fetuses divided into 5 groups between 16 and 38 weeks. Pulsed-wave Doppler-derived AV intervals were measured by interrogation of flow in LV in/out, SVC/AA, and PA/PV. Linear regression analyses were performed to examine correlations with gestational age (GA) and fetal heart rate (FHR). Intraclass correlation coefficients for reproducibility of each method were compared.

RESULTS

Pulmonary artery and pulmonary vein revealed the longest mean AV time intervals (P < .001). The AV intervals in all methods were positively correlated with GA (R²  = 0.20-0.36; P < .001) and negatively correlated with FHR (R²  = 0.09-0.19; P < .001). The SCV/AA time intervals demonstrated the weakest influence of FHR. For LV in/out, SVC/AA, and PA/PV, intraobserver and interobserver reliability coefficients showed excellent agreements (all intraclass correlation coefficients ≥ 0.80).

CONCLUSION

All pulsed-wave Doppler-derived AV time intervals increased with advancing GA and decreased with increasing FHR. Fetal AV interval measurements can be obtained in a clinically viable fashion with excellent reproducibility.

Clinical practice guideline for Sjögren's syndrome 2017

OBJECTIVES

The objective of this study is to develop clinical practice guideline (CPG) for Sjögren's syndrome (SS) based on recently available clinical and therapeutic evidences.

METHODS

The CPG committee for SS was organized by the Research Team for Autoimmune Diseases, Research Program for Intractable Disease of the Ministry of Health, Labor and Welfare (MHLW), Japan. The committee completed a systematic review of evidences for several clinical questions and developed CPG for SS 2017 according to the procedure proposed by the Medical Information Network Distribution Service (Minds). The recommendations and their strength were checked by the modified Delphi method. The CPG for SS 2017 has been officially approved by both Japan College of Rheumatology and the Japanese Society for SS.

RESULTS

The CPG committee set 38 clinical questions for clinical symptoms, signs, treatment, and management of SS in pediatric, adult and pregnant patients, using the PICO (P: patients, problem, population, I: interventions, C: comparisons, controls, comparators, O: outcomes) format. A summary of evidence, development of recommendation, recommendation, and strength for these 38 clinical questions are presented in the CPG.

CONCLUSION

The CPG for SS 2017 should contribute to improvement and standardization of diagnosis and treatment of SS.

Finding the "PR-fect" solution: what is the best tool to measure fetal cardiac PR intervals for the detection and possible treatment of early conduction disease?

In the absence of structural heart disease, the great majority of cases with complete congenital heart block will be associated with the maternal autoantibodies directed to components of the SSA/Ro-SSB/La ribonucleoprotein complex. Usually presenting in fetal life before 26 weeks' gestation, once third-degree (complete) heart block develops, it is irreversible. Therefore, investigators over the past several years have attempted to predict which fetuses will be at risk for advanced conduction abnormalities by identifying a biomarker for less severe or incomplete disease, in this case, PR interval prolongation or first-degree atrioventricular block. In this state-of-the-art review, we critically analyze the various approaches to defining PR interval prolongation in the fetus, and then analyze several clinical trials that have attempted to address the question of whether complete heart block can be predicted and/or prevented. We find that, first and foremost, definitions of first-degree atrioventricular block vary but that the techniques themselves are all similarly valid and reliable. Nevertheless, the task of predicting those fetuses at risk, and who are therefore candidates for treatment, remains challenging. Of concern, despite anecdotal evidence, there is currently no conclusive proof that a prolonged PR interval predicts complete heart block.

Atrioventricular conduction time in fetuses assessed by Doppler echocardiography

We performed measurement of mechanical atrioventricular conduction time intervals in human fetuses assessed by Doppler echocardiography and provided reference values. We found that atrioventricular conduction time interval was prolonged with gestational age and decreased with increasing fetal heart rate. No correlation between gestational age and heart rate was found. Using normal limits established by this study, mechanical atrioventricular interval >135 ms in the 20(th) week and/or >145 ms in the 26(th) week of gestation could be suspected of having the first-degree AV block. We compared reference values with fetuses of mothers with anti-SSA Ro/SSB La autoantibodies, being in risk of isolated congenital heart block development. One of 21 fetuses of mothers with positive autoantibodies was affected by prolonged atrioventricular interval according to the established limits, with sinus rhythm after the birth.

Examination of the fetal cardiovascular system

Doppler evaluation of the placenta and fetal cardiovascular system is one of the primary surveillance tools in prenatal medicine. By assessing uterine and umbilical arteries, placental development can be documented. This is useful for the prediction of hypertensive maternal disorders and placental dysfunction and fetal growth failure. The umbilical artery flow velocity waveform provides an estimate of villous vascular occlusion in the fetal compartment of the placenta. Middle cerebral artery Doppler is important in studying fetal responses to abnormal oxygenation and fetal anemia. Precordial venous Doppler gives insight into the cardiac effects of many conditions such as fetal growth restriction, twin-twin transfusion syndrome and fetal arrhythmia. Further quantification of these effects requires cardiac Doppler to quantify diastolic and systolic function as well as global myocardial performance. This article reviews important characteristics of arterial and venous Doppler waveform analysis, individual vascular beds and their clinical application in fetal evaluation.

Diagnosing foetal atrioventricular heart blocks

Foetal echocardiographic ultrasound techniques still remain the dominating modality for diagnosing foetal atrioventricular block (AVB). Foetal electrocardiography might become a valuable tool to measure time intervals, but magnetocardiography is unlikely to get a place in clinical practice. Assuming that AVB is a gradually progressing and preventable disease, starting during a critical period in mid-gestation with a less abnormal atrioventricular conduction before progressing to a complete irreversible AVB (CAVB), echocardiographic methods to detect first-degree AVB have been developed. The time intervals obtained with these techniques are all based on the identification of mechanical or hemodynamic events as markers of atrial (A) and ventricular (V) depolarizations and will accordingly include both electrical and mechanical components. Prospective observational studies have demonstrated a transient prolongation of AV time intervals in anti-Ro/SSA antibody-exposed foetuses, but it has not succeeded to identify a degree of AV time prolongation predicting irreversible cardiac damage and progression to CAVB. Causes of sustained bradycardia include CAVB, 2:1 AVB, sinus bradycardia and blocked atrial bigeminy (BAB). Using foetal echocardiographic techniques and a systematic approach, a correct diagnosis can be made in almost every case. Sinus bradycardia and CAVB are usually easy to diagnose, but BAB has a tendency to be sustained and shows a high degree of resemblance with 2:1 AVB when diagnosed during mid-gestational. As BAB resolves without treatment and 2:1 AVB may respond to treatment with fluorinated steroids, a correct diagnosis becomes an issue of major importance to avoid unnecessary treatment of harmless and spontaneously reversing conditions.

The benefits of transplacental treatment of isolated congenital complete heart block associated with maternal anti-Ro/SSA antibodies: a review

Isolated congenital complete atrio-ventricular block (CAVB) is associated with the transplacental passage of maternal autoantibodies directed to foetal Ro/SSA ribonucleoproteins. Their interactions most likely trigger the inflammation of the atrio-ventricular node and the myocardium in susceptible foetuses. The inflamed tissues may then heal with fibrosis that may cause heart block, endocardial fibroelastosis, and dilated cardiomyopathy. CAVB, the most common cardiac complication, typically develops between 18 and 24 gestational weeks. Untreated, the condition carries a significant mortality risk as the foetus needs to overcome the sudden drop in ventricular rate, the loss of normal atrial systolic contribution to ventricular filling, and perhaps concomitant myocardial inflammation and fibrosis. The rationale to treat a foetus at the stage of CAVB is primarily to mitigate myocardial inflammation and to augment foetal cardiac output. Maternal dexamethasone administration has been shown to improve incomplete foetal AV block, myocardial dysfunction, and cavity effusions. Beta-sympathomimetics may be useful to increase the foetal heart rate and myocardial contractility. Published data from our institution suggest an improved survival >90% if maternal high-dose dexamethasone was initiated at the time of CAVB detection and maintained during the pregnancy and if a beta-adrenergic drug was added at foetal heart rates below 55 beats/min. Despite the improvement in outcome, there is an ongoing debate about treatment-related risks. In this review, we will appraise the natural history of untreated CAVB, discuss currently available management options, and examine the results and risks of in-utero treatment of antibody-mediated CAVB.

Ultrasonographic diagnosis of delayed atrioventricular conduction during fetal life: a reliability study

OBJECTIVE

The objective of the study was to evaluate the reliability of the 2 most commonly used ultrasonographic approaches for monitoring fetal atrioventricular conduction time (AVCT): (1) superior vena cava/ascending aorta (SVC/AA), and (2) left ventricular inflow/outflow tract (LVI/O) Doppler recordings.

STUDY DESIGN

Echographic studies from fetuses followed up for first-degree atrioventricular block (AVB-1) between 1998 and 2008 were reviewed. The ability to identify atrial contractions in the same fetuses by the SVC/AA and LVI/O approaches was analyzed.

RESULTS

Sixty-six studies of 13 fetuses with AVB-1 were available. Atrial contractions were visible in all SVC/AA studies. With the LVI/O approach, atrial contractions could not be identified in 26 studies (39%). AVCT delay was significantly greater in the nonidentifiable compared with the identifiable atrial contraction group (P < .001). Differences in heart rate and gestational age were not significant.

CONCLUSION

The LVI/O is unsuitable for prenatal screening of conduction system anomalies.

Fetal Doppler mechanical PR interval: correlation with fetal heart rate, gestational age and fetal sex

OBJECTIVES

To establish normal fetal values for the mechanical PR interval by pulsed-wave Doppler at 16-36 weeks of gestation, and to evaluate the influence of fetal heart rate (FHR), gestational age (GA) and fetal sex.

METHODS

Fetal mechanical PR intervals were evaluated prospectively by obstetric ultrasound examination. Healthy mothers with sonographically normal fetuses from singleton pregnancies were included. Mechanical PR intervals were measured from simultaneous mitral and aortic Doppler waveforms, from the onset of left atrial contraction (mitral A-wave) to the onset of left ventricular ejection (aortic pulse wave). Simple and multiple linear regression analyses were performed to examine the correlation between PR interval and GA, FHR and fetal sex.

RESULTS

We evaluated 336 fetuses at 16-36 weeks. The mean +/- SD FHR was 143.4 +/- 8.3 beats per min (bpm). The PR intervals had a typical Gaussian distribution with a mean +/- SD of 122.4 +/- 10.3 ms. Robust linear regression showed that the PR increased by about 0.40 ms (95% CI, 0.22-0.58) per gestational week (P < 0.001), and this relationship remained after adjustment for FHR and fetal sex. PR intervals diminished by 1.4 (95% CI, 0.75 to 2.0) ms for each 5 bpm increase in FHR (P < 0.001), independently of GA and fetal sex. No fetal sex differences were observed.

CONCLUSIONS

We provide normal fetal values for the mechanical PR interval at 16-36 weeks of gestation. Mechanical PR intervals in normal fetuses are influenced by GA and FHR independently, and both variables should be taken into account when evaluating fetuses at risk for congenital heart block.

[Fetal ultrasonography and Doppler in isolated congenital heart block]

Isolated congenital heart block is linked to transplacental passage of maternal anti-SSA/Ro and/or anti-SSB/La antibodies that may be related to a connective tissue disease. Ultrasonography and Doppler are essential to screen fetus at risk. They allow the diagnosis of first- and second-degree blocks which are probably preliminary stages in conducting tissue's injury. In these situations, a maternal treatment by fluorinated steroids can be proposed because of its possible effect on partial blocks. However, these early signs of nodal injury can be lacking: some fetus present a complete heart block without previously detected less advanced block. Moreover, the significance of first-degree block is unclear since it could reverse spontaneously. Other markers of nodal injury would be valuable. In case of complete congenital heart block, ultrasonography is useful to detect congestive heart failure and help the obstetrical management when unfavorable prognostic signs occur.

The challenge of fetal dysrhythmias: echocardiographic diagnosis and clinical management

OBJECTIVE

The present study aimed to evaluate the management of fetal cardiac dysrhythmias based on prior identification of the underlying electrophysiological mechanism.

METHODS

We studied 36 consecutive fetuses with cardiac dysrhythmia. Rhythm diagnosis was based on M-mode, pulsed wave Doppler and tissue Doppler imaging (TDI). Only fetuses with: (i) incessant tachycardia (> 12 h) and mean ventricular rate > 200 beats/min, (ii) signs of left ventricular dysfunction, or (iii) hydrops, were treated using oral maternal drug therapy.

RESULTS

The mean gestational age at diagnosis was 24.3 +/- 4.5 weeks. Twenty-one fetuses had tachycardia with a 1: 1 atrial-ventricular (AV) conduction. Based on ventricular-atrial interval, prenatal diagnosis was: permanent junctional reciprocating (n = 6), atrial ectopic (n = 6) or atrial-ventricular re-entry tachycardia (n = 9). One had atrial flutter, one ventricular tachycardia and four congenital AV block. Nine showed premature atrial or ventricular beats. Fifteen fetuses with incessant tachycardia, left ventricular dysfunction or hydrops were prenatally treated with maternal administration of digoxin, sotalol or flecainide. The total success rate (sinus rhythm or rate control) was 14/15 (93%). Seven fetuses were hydropics. Three of these died (one at 28 weeks of gestation, two in the first week of life). The prenatal diagnosis of dysrhythmia was confirmed at the birth in 31 of 35 live-born. No misdiagnosis was made using TDI. At 3 +/- 1.1-year follow-up, 33/35 children were alive and well.

CONCLUSIONS

Fetal echocardiography could clarify the electrophysiological mechanism of fetal cardiac dysrhythmias and guide the therapy.

FETAL BRADYCARDIA. A PRACTICAL APPROACH

Fetal bradycardia may herald fetal demise. This article highlights arrhythmic fetal bradycardia rather than bradycardia caused by perinatal distress. We briefly examine the embryonic conduction system's development and physiology and we review the classification, aetiology, evaluation, and approach to fetal bradycardia. Our aim is to provide the clinician with practical information about fetal bradycardia that enlightens causative conditions and aids management.

Specificity and effector mechanisms of autoantibodies in congenital heart block

Complete congenital atrio-ventricular (AV) heart block develops in 2-5% of fetuses of Ro/SSA and La/SSB autoantibody-positive pregnant women. During pregnancy, the Ro/SSA and La/SSB antibodies are transported across the placenta and affect the fetus. Emerging data suggest that this happens by a two-stage process. In the first step, maternal autoantibodies bind fetal cardiomyocytes, dysregulate calcium homestasis and induce apoptosis in affected cells. This step might clinically correspond to a first-degree heart block, and be reversible. La/SSB antibodies can bind apoptotic cardiomyocytes and thus increase Ig deposition in the heart. The tissue damage could, as a second step, lead to spread of inflammation in genetically pre-disposed fetuses, progressing to fibrosis and calcification of the AV-node and subsequent complete congenital heart block. Early intrauterine treatment of an incomplete AV-block with fluorinated steroids has been shown to prevent progression of the heart block, making it clinically important to find specific markers to identify the high-risk pregnancies.

Doppler echocardiographic and electrocardiographic atrioventricular time intervals in newborn infants: evaluation of techniques for surveillance of fetuses at risk for congenital heart block

OBJECTIVE

To evaluate one novel and two previously reported Doppler flow velocimetric techniques to estimate atrioventricular (AV) time intervals, suggested to be useful for early identification of fetuses at risk for congenital heart block.

METHODS

In 22 newborn infants, Doppler tracings were obtained from the mitral valve/aortic outflow and the superior vena cava/ascending aorta, as an ECG was recorded simultaneously. AV time intervals were measured using the onsets of the mitral A-wave/aortic outflow (MV-Ao), superior vena cava a-wave/aortic flow (SVC-Ao), and mitral A-wave/mitral valve closure (MV) as indirect markers of electrical atrial/ventricular activation.

RESULTS

Close positive linear relationships to the electrocardiographic PR interval were demonstrated for the MV-Ao (r = 0.82, S(y/x) = 7.4 ms), SVC-Ao (r = 0.85, S(y/x) = 6.8 ms), and MV (r = 0.92, S(y/x) = 3.8 ms) approaches. Both techniques using the aortic flow to indicate ventricular activation overestimated the PR interval: the MV-Ao by + 32 +/- 7.7 ms (mean +/- SD) and the SVC-Ao approach by + 22 +/- 7.0 ms. The new MV approach using mitral closure for the same purpose did not overestimate the PR interval, but there was a trend towards underestimation of the PR intervals as time intervals increased.

CONCLUSIONS

When systematic differences between echocardiographic and electrocardiographic AV time intervals are compensated for, all three techniques are useful to get indirect estimates of the PR interval. As MV recordings only need insonation of a single valve, and are thus easier to obtain, this technique may be of value as a first screening method to identify fetuses in need for further surveillance. In cases with AV time prolongation the SVC-Ao method seems superior.

Assessment of fetal atrioventricular time intervals by tissue Doppler and pulse Doppler echocardiography: normal values and correlation with fetal electrocardiography

OBJECTIVE

To establish gestational age-specific reference values of normal fetal atrioventricular (AV) time interval by spectral tissue Doppler imaging (TDI) and pulse-wave Doppler (PD) methods, and to assess their correlation with signal-averaged fetal PR intervals (ECG).

DESIGN

Cohort study.

SETTING

Tertiary centre for fetal cardiology. PATIENTS AND MEASURES: 131 pregnant women between 14 and 42 weeks' gestation underwent 196 fetal echocardiograms and 158 fetal ECG studies. TDI-derived AV intervals were measured as the intervals from atrial contraction (Aa) to isovolumic contraction (IV) and from Aa to ventricular systole (Sa) at the right ventricular free wall. PD-derived AV intervals were measured from simultaneous left ventricular inflow/outflow (in/out) and superior vena cava/aorta (V/AO) recordings.

RESULTS

Measurements were possible by ECG in 61%, by TDI in 100%, by in/out in 100% and by V/AO in 97% of examinations. Aa-IV correlated significantly better with PR intervals (y = 0.67x + 38.29, R(2) = 0.15, p < 0.0001, mean bias 8.0 ms) than did in/out (R(2) = 0.10, p = 0.002, bias 18.7 ms) and V/AO (R(2) = 0.06, p = 0.02, bias 12.4 ms). Gestational age and AV intervals were positively correlated with all imaging modalities (R(2) = 0.19-0.31, p < 0.0001).

CONCLUSION

This study showed the feasibility of fetal AV interval measurements by TDI, and established gestational age-specific reference data. TDI-derived Aa-IV intervals track ECG PR intervals more closely than PD-derived AV intervals and thus should be used as the ultrasound method of choice in assessing fetal AV conduction.

Doppler tissue imaging in the assessment of atrioventricular conduction time: validation of a novel technique and comparison with electrophysiologic and pulsed wave Doppler-derived equivalents in an animal model

Accurate assessment of atrioventricular conduction time (AVCT) is crucial for early detection of evolving fetal heart block. Simultaneous pulsed wave Doppler (PD) interrogation of left ventricular inflow and outflow is mainly used to study fetal AVCT. Limitations of this modality include its dependency on loading conditions and merging early and late diastolic inflow waves at faster heart rate (HR). Sequential analysis of atrioventricular myocardial motion by Doppler tissue imaging (DTI) might be more useful in this regard. In 15 open-chest pigs, AVCT was measured by PD, DTI, and electrocardiogram at baseline HR and during incremental atrial pacing up to 200 beats/min. Electromechanical delay and pre-ejection period were assessed at baseline and maximal HR. DTI-derived AVCT correlated better with PR intervals and allowed measurements at faster HRs than did PD (P < .05). Pre-ejection period prolonged with faster HR (P < .001), unlike electromechanical delay. In conclusion, DTI allows more accurate measurement of AVCT over a wider HR range than does PD.

Syndrome de Gougerot-Sjögren en gynécologie obstétrique

Sjogren syndrome (SS) is an immune disease characterized by a progressive degeneration of exocrine glands. It leads to dryness of mucosa and conjunctivitis. Gynecologists and obstetricians may encounter this disease in women at any age, including during pregnancy. Knowledge of the main characteristics is required for early diagnosis and multidisciplinary program. In the event of secondary Sjögren syndrome occurring during pregnancy, treatment focuses on the associated disease, mainly systemic lupus erythematosus. In primary Sjögren syndrome, pregnancy does not appear to influence disease course. However, patients with both primary and secondary Sjögren syndrome must be monitored carefully. There is a risk of neonatal lupus and congenital atrioventricular bloc associated with high morbidity and mortality. These patients should benefit from multidisciplinary care in a hospital with a neonatal intensive care unit.

Conduction system disease in fetuses evaluated for irregular cardiac rhythm

OBJECTIVES

To determine the prevalence of 1st and 2nd degree AV block in fetuses with an irregular cardiac rhythm, and to summarize outcome of these pregnancies.

BACKGROUND

The diagnosis of irregular cardiac rhythm or 'skipped beats' includes isolated ectopy that resolves spontaneously. Recently, Doppler measurements of the 'mechanical' PR interval have been shown to identify AV conduction disease prenatally. Prenatal therapy of these conduction abnormalities may limit the progression to more advanced disease either in utero or after birth.

METHODS

A retrospective review was performed of fetuses evaluated between 1996 and 2004 with the findings of irregular cardiac rhythm. 1st or 2nd degree AV block was diagnosed on Doppler and M-mode recordings, and confirmed using either fetal magnetocardiography (fMCG) or postnatal 12-lead ECG. Dexamethasone was administered to 4 mothers with abnormal fetal AV conduction in the setting of anti-Ro/anti-La antibodies.

RESULTS

Of 702 fetuses initially referred for arrhythmia, 306 had an irregular rhythm. Eight (2.6%) had intermittent 1st or 2nd degree AV block confirmed by fMCG and/or postnatal 12-lead ECG. AV block was presumed idiopathic in 2, associated with congenital long QT syndrome in 2 or with clinically unsuspected maternal anti-Ro or anti-La antibodies in 4. During the intrauterine period there was no progression to complete AV block and all were born alive at 34-40 weeks of gestation.

CONCLUSION

A small but clinically significant population of fetuses with irregular rhythm will have 1st or 2nd degree AV block. Transplacental therapy may limit the intrauterine progression to more advanced disease.

Assessing fetal cardiac ventricular function

Fetal echocardiography has been used primarily to identify fetuses with structural malformations of the heart. Evaluation of fetal ventricular function, however, has received minimal attention since the inception of fetal echocardiography in the early 1980s. This communication reviews the use of M-mode, B-mode and pulsed Doppler ultrasound to examine cardiac function. M-mode ultrasound is used to determine the size of the fetal heart, the end-diastolic and end-systolic dimensions of the ventricular chambers, and the thickness of the ventricular walls and the interventricular septum, and to measure the diameter of the mitral and tricuspid valves as well as the diameter of the aorta and pulmonary artery. B-mode evaluation of the fetal heart includes measurement of atrial and ventricular dimensions as well as dimensions of the outflow tracts. This modality is useful when M-mode measurements cannot be made due to fetal position. Once measurements of cardiac structures are obtained using either M-mode or B-mode ultrasound, pulsed Doppler recording of mitral valve, tricuspid valve, aortic valve and pulmonary artery waveforms can be used to compute cardiac output as well as stroke volume. In addition, pulsed Doppler can be used to evaluate diastolic and systolic cardiac functions by examining the components of each waveform.

Three-dimensional and four-dimensional fetal echocardiography: a new frontier

PURPOSE OF REVIEW

One of the difficulties of conventional two-dimensional cardiac imaging is the inability to examine fetal cardiac anatomy from multiple angle planes. Three-dimensional and four-dimensional ultrasound allows the fetal examiner to more accurately accomplish this task. Currently, multiple disciplines may be involved in the examination of the fetal heart (pediatric cardiologists, obstetricians, maternal-fetal medicine specialists, and radiologists). The three-dimensional and four-dimensional imaging equipment used by these specialty physicians varies greatly. The purpose of this communication is to review techniques using three-dimensional and four-dimensional imaging that the pediatric cardiologist may not be exposed to in the clinical environment, however, in consulting with colleagues needs to have an understanding of these imaging modalities.

RECENT FINDINGS

The reconstruction of cardiac structures using this technology allows the examiner to view cardiac anatomy in a manner that was limited by previous two-dimensional imaging. Volume datasets are obtained in the three-dimensional static mode (no cardiac motion) or using four-dimensional - the three-dimensional heart is observed contracting during one or multiple cardiac cycles. Therefore, the fourth dimension is time. Using either three-dimensional or four-dimensional technology datasets are acquired, followed by image reconstruction. The image reconstruction enables the examiner to evaluate a two-dimensional image using multiple views, evaluate intracardiac anatomy at different depth planes, and recreate casts of blood flow of the chambers and great vessels.

SUMMARY

This new technology has enhanced the ability of the examiner to identify normal and complex fetal heart anatomy during the early second to the late third trimesters of pregnancy.