Evolution of the fetal atrioventricular interval from 6 to 40 weeks of gestation

Doppler-based methods of estimating the atrioventricular interval are commonly used as a surrogate for the electrical PR in fetuses at risk of conduction abnormalities; however, to date, normal values for the fetal atrioventricular interval and an understanding of the evolution of its components in the late first trimester are lacking. We sought to investigate changes in the fetal atrioventricular interval from the first trimester to 40 weeks gestational age, and to explore functional and electrophysiological events that potentially impact its evolution. We prospectively examined healthy pregnancies by fetal echocardiography from 6 to 40 weeks' gestational age. The atrioventricular interval, heart rate, isovolumic contraction time, and A-wave duration were measured from simultaneous ventricular inflow-outflow Doppler tracings. Regression analysis was used to examine relations with gestational age, and linear relations with heart rate were assessed by Pearson's correlation coefficient. Data were collected in 305 fetuses from 279 pregnancies. Atrioventricular interval demonstrated an inverse relation with heart rate (r = -0.45, p <0.0001), dramatically decreasing before 10 weeks and slowly increasing thereafter. Between 6 and 9 weeks, isovolumic contraction time acutely decreasedapproaching 0, thereafter minimally increasing to term. In contrast, from 6 weeks, the A-wave duration linearly increased through gestation, and negatively correlated with heart rate (r = -0.62, p <0.0001). In conclusion, we have established normal measures of the atrioventricular interval from 6 to 40 weeks' gestational age. Before 10 weeks, a prolonged atrioventricular interval in healthy fetuses largely reflects the lengthened isovolumic contraction time which is likely influenced by the evolution of ventricular function and afterload. (AU)

The incremental benefit of color tissue doppler in fetal arrhythmia assessment

BACKGROUND: Accurate fetal arrhythmia (FA) diagnosis is key for effective management. Currently, FA assessment relies on standard echocardiography-based techniques (M mode and spectral Doppler), which require adequate fetal position and cursor alignment to define temporal relationships of mechanical events. Few data exist on the application of color Doppler tissue imaging (c-DTI) in FA assessment. The aim of this study was to examine the feasibility and clinical applicability of c-DTI in FA assessment in comparison with standard techniques. METHODS: Pregnancies with diagnosed FA were prospectively recruited to undergo c-DTI following fetal echocardiography. Multiple-cycle four-chamber clips in any orientation were recorded (mean frame rate, 180 ± 16 frames/sec). With offline analysis, sample volumes were placed on atrial (A) and ventricular (V) free walls for simultaneous recordings. Atrial and ventricular rates, intervals (for atrial-ventricular conduction and tachyarrhythmia mechanism), and relationships were assessed to decipher FA mechanism. FA diagnosis by c-DTI, conventional echocardiographic techniques, and postnatal electrocardiography and/or Holter monitoring were compared. RESULTS: FA was assessed by c-DTI in 45 pregnancies at 15 to 39 weeks, including 16 with atrial and/or ventricular ectopic beats; 18 with supraventricular tachyarrhythmias, including ectopic atrial tachycardia in 11, atrioventricular reentrant tachycardia in four, atrial flutter in two, and intermittent atrial flutter and junctional ectopic rhythm in one; three with ventricular tachycardias; and eight with bradycardias or atrioventricular conduction pathology, including five with complete atrioventricular block (AVB), one with first-degree AVB evolving into complete AVB, one with second-degree AVB, and one with sinus bradycardia. After training, FA diagnosis by c-DTI could be made irrespective of fetal orientation within 10 to 15 min. FA diagnosis by c-DTI concurred with standard techniques in 41 cases (91%), with additional findings identified by c-DTI in 10. c-DTI led to new FA diagnoses in four cases (9%) not definable by standard techniques. FA diagnosis by c-DTI was confirmed in all 20 with persistent arrhythmias after birth, including three with new diagnoses defined by c-DTI. c-DTI was particularly helpful in deciphering SVT mechanism (long vs short ventricular-atrial interval) in all 18 cases, whereas standard techniques permitted definition in only half. CONCLUSIONS: c-DTI with offline analysis permits rapid and accurate definition of FA mechanism, providing new information in nearly one-third of affected pregnancies. AU

The Incremental Benefit of Color Tissue Doppler in Fetal Arrhythmia Assessment.

BACKGROUND: Accurate fetal arrhythmia (FA) diagnosis is key for effective management. Currently, FA assessment relies on standard echocardiography-based techniques (M mode and spectral Doppler), which require adequate fetal position and cursor alignment to define temporal relationships of mechanical events. Few data exist on the application of color Doppler tissue imaging (c-DTI) in FA assessment. The aim of this study was to examine the feasibility and clinical applicability of c-DTI in FA assessment in comparison with standard techniques. METHODS: Pregnancies with diagnosed FA were prospectively recruited to undergo c-DTI following fetal echocardiography. Multiple-cycle four-chamber clips in any orientation were recorded (mean frame rate, 180 ± 16 frames/sec). With offline analysis, sample volumes were placed on atrial (A) and ventricular (V) free walls for simultaneous recordings. Atrial and ventricular rates, intervals (for atrial-ventricular conduction and tachyarrhythmia mechanism), and relationships were assessed to decipher FA mechanism. FA diagnosis by c-DTI, conventional echocardiographic techniques, and postnatal electrocardiography and/or Holter monitoring were compared. RESULTS: FA was assessed by c-DTI in 45 pregnancies at 15 to 39 weeks, including 16 with atrial and/or ventricular ectopic beats; 18 with supraventricular tachyarrhythmias, including ectopic atrial tachycardia in 11, atrioventricular reentrant tachycardia in four, atrial flutter in two, and intermittent atrial flutter and junctional ectopic rhythm in one; three with ventricular tachycardias; and eight with bradycardias or atrioventricular conduction pathology, including five with complete atrioventricular block (AVB), one with first-degree AVB evolving into complete AVB, one with second-degree AVB, and one with sinus bradycardia. After training, FA diagnosis by c-DTI could be made irrespective of fetal orientation within 10 to 15 min. FA diagnosis by c-DTI concurred with standard techniques in 41 cases (91%), with additional findings identified by c-DTI in 10. c-DTI led to new FA diagnoses in four cases (9%) not definable by standard techniques. FA diagnosis by c-DTI was confirmed in all 20 with persistent arrhythmias after birth, including three with new diagnoses defined by c-DTI. c-DTI was particularly helpful in deciphering SVT mechanism (long vs short ventricular-atrial interval) in all 18 cases, whereas standard techniques permitted definition in only half. CONCLUSIONS: c-DTI with offline analysis permits rapid and accurate definition of FA mechanism, providing new information in nearly one-third of affected pregnancies.

The incremental benefit of color tissue doppler in fetal arrhythmia assessment

BACKGROUND: Accurate fetal arrhythmia diagnosis is key for effective management. Standard echo-based techniques (M-mode and spectral Doppler) require adequate fetal position and cursor alignment to define temporal relationships of mechanical events. Little data exists on the application of cTDI in fetal rhythm assessment. OBJECTIVE: We sought to determine the benefit of color tissue Doppler imaging (cTDI) in fetal arrhythmia assessment over conventional fetal echo techniques. METHODS: Pregnancies with a diagnosis of fetal arrhythmia were prospectively recruited to undergo cTDI following fetal echocardiography. Multiple cycle 4-chamber clips in any orientation were recorded (frame rates >180 fps). With offline analysis, sample-volumes were placed on atrial (A) and ventricular (V) free walls with simultaneous recordings. A and V rates, intervals and relationships were evaluated. RESULTS: Arrhythmias were assessed in 45 fetuses by cTDI at 15-39 weeks and included: 11 atrial and 5 ventricular ectopic beats; 18 supraventricular tachyarrhythmias (SVT) including ectopic atrial tachycardia in 11, AV re-entry SVT in 4, atrial flutter (AF) in 2, intermittent AF and junctional ectopic rhythm in 1; ventricular tachycardias in 3; 8 bradycardias or AV conduction pathology including complete AV block (AVB) in 5, 1 AVB evolving into complete AVB in 1, 2 AVB in 1, sinus bradycardia in 1. Arrhythmia diagnosis by cTDI could be made irrespective of orientation of the fetus, after training, within 10-15 minutes. cTDI findings concurred with the diagnosis by standard techniques in 95% of cases and added new findings in 29%. In 5%, cTDI provided a new diagnosis, confirmed postnatally. In cases with SVT, cTDI permitted assessment of A-V and V-A intervals elucidating arrhythmia mechanism in all, whereas standard techniques had failed to define mechanism in 45%. CONCLUSION: cTDI with offline analysis permits rapid and accurate definition of fetal arrhythmia mechanism, providing new information in a significant proportion of affected pregnancies. (AU)

Prenatal detection of congenital heart disease.

OBJECTIVES: To define current frequency of prenatal detection of congenital heart disease (CHD), factors affecting prenatal detection, and its influence on postnatal course. STUDY DESIGN: We prospectively identified all fetuses and infants < or =6 months of age with major CHD at 3 referral centers in Northern California over 1 year; we obtained prenatal and demographic data, reviewed prenatal ultrasound (US) and postnatal records, and used logistic regression to analyze maternal, fetal, and prenatal-care provider risk factors for prenatal diagnosis. RESULTS: Ninety-eight of 309 infants with major CHD had prenatal diagnosis (36% accounting for 27 pregnancy terminations); 185 infant-families participated in the postnatal survey, and although 99% had prenatal US, only 28% were prenatally diagnosed. Anomalous pulmonary venous return (0%), transposition of the great arteries (19%), and left obstructive lesions (23%) had the lowest prenatal detection. Heterotaxy (82%), single ventricle (64%), and HLHS (61%) had the highest. Prenatal diagnosis was higher at university versus community practices (P = .001). Sociodemographics were not associated with prenatal diagnosis. Infants diagnosed prenatally were less frequently ventilated (P < .01) or treated with prostaglandin (P < .05). CONCLUSIONS: Prenatal detection of major CHD significantly alters postnatal course but remains low despite nearly universal US. CHD type and US practice type are important determinants of prenatal detection.

Fetal rhabdomyoma: prenatal diagnosis, clinical outcome, and incidence of associated tuberous sclerosis complex.

OBJECTIVES: We reviewed our institution's experience with fetal cardiac rhabdomyoma to document the clinical outcome and incidence of associated tuberous sclerosis complex (TSC) and compared our findings with those of patients diagnosed with cardiac rhabdomyoma after birth. STUDY DESIGN: We reviewed the medical records of all cases diagnosed prenatally and postnatally with cardiac rhabdomyoma between January 1990 and June 2002. RESULTS: Twenty fetuses with cardiac rhabdomyoma were diagnosed at 28.4+/-6.0 weeks' gestational age. Of 19 continued pregnancies, there was one spontaneous intrauterine death, and 18 were delivered at term. Although none had prenatal hemodynamic complications, after birth seven had cardiac symptoms requiring medical (n=4) or surgical intervention (n=3). On follow-up, 15 of 19 with available outcome had TSC (79%), including six with neurodevelopmental disease. Over the same period, 26 patients were diagnosed with cardiac rhabdomyoma postnatally. Most (77%) were referred for cardiac assessment after findings suggesting TSC. On follow-up, TSC was confirmed in 25 (96%), including 22 with neurodevelopmental disease. The incidence of cardiac symptoms and TSC was not statistically different between the prenatal and postnatal diagnosis groups. CONCLUSIONS: Cardiac rhabdomyomas are benign from the cardiovascular standpoint in most affected fetuses. As observed in postnatally diagnosed cardiac rhabdomyoma, TSC is diagnosed in most cases of fetal cardiac rhabdomyoma.

Incidence and spectrum of neonatal lupus erythematosus: a prospective study of infants born to mothers with anti-Ro autoantibodies.

OBJECTIVE: Neonatal lupus erythematosus (NLE) is characterized by complete congenital heart block (CCHB), cutaneous rash, and laboratory abnormalities in infants born to mothers with autoantibodies directed against SSA/Ro, SSB/La, or both. We carried out a prospective study to determine the incidence of individual NLE features. STUDY DESIGN: The study was performed in two centers: Toronto, Canada, and Milano, Italy. Mothers had been referred for the presence of anti-SSA/Ro autoantibodies, regardless of their diagnosis. All the children were seen at least once within the first 6 months of life for clinical evaluation and laboratory testing. The study group consisted of 128 infants born from 124 pregnancies in 112 women with anti-Ro antibodies with or without anti-La antibodies. RESULTS: There were two cases of CCHB for an overall percentage of 1.6%. Twenty-one children (16%) developed cutaneous NLE. Laboratory testing showed hematologic abnormalities in 27% of the babies and elevation of liver enzymes in 26%. CONCLUSIONS: Mothers with autoimmune diseases and anti-Ro antibodies are at risk of delivering a child with NLE but at a low risk of delivering a child with CCHB. Infants born to mothers with anti-Ro or anti-La antibodies should be monitored for other features of NLE in addition to CCHB.

Fetal cardiomyopathies pathogenic mechanisms, hemodynamic findings, and clinical outcome

Background—Although the prenatal diagnosis of most fetal structural heart defects and dysrhythmias has been described,there is a paucity of information about cardiomyopathies (CMs) in prenatal life.Methods and Results—-To determine the pathogenic mechanisms, hemodynamic findings, and outcome of fetal CM, wereviewed the fetal echocardiograms and perinatal histories of 55 affected fetuses. Dilated CM was diagnosed in 22 cases,including 2 with congenital infections, 5 familial cases, 6 with endocardial fibroelastosis related to maternal anti-Ro/Laantibodies, and 9 idiopathic cases. Thirty-three had hypertrophic CM, 7 associated with maternal diabetes, 2 withNoonan’s syndrome, 2 with -thalassemia, 18 with twin-twin transfusion syndrome, 1 with familial hypertrophy, and3 with idiopathic hypertrophy. Systolic dysfunction was present in all cases of dilated CM and 15 cases of hypertrophicCM. Diastolic dysfunction was present in 19 of 30 fetuses with assessment of diastolic function parameters. Significantmitral or tricuspid valve regurgitation was seen in 32 cases. Eight fetuses were hydropic and 23 had signs of earlyhydrops. Seven pregnancies were terminated. Of 46 continued pregnancies with follow-up, 29 (63%) died perinatally.The presence of systolic dysfunction, diastolic dysfunction, and significant atrioventricular valve regurgitation wereidentified as risk factors for mortality. By multiple logistic regression, diastolic dysfunction was associated with an8-fold increased risk relative to the other parameters.Conclusions—Fetal CM has a broad spectrum of intrinsic and extrinsic causes. A poor outcome is observed in manyaffected fetuses. Diastolic dysfunction in fetal CM is associated with the highest risk of mortality.