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Treatment of Fetal Arrhythmias. J Clin Med 2021; 10:jcm10112510. [PMID: 34204066 PMCID: PMC8201238 DOI: 10.3390/jcm10112510] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Revised: 06/01/2021] [Accepted: 06/01/2021] [Indexed: 11/16/2022] Open
Abstract
Fetal arrhythmias are mostly benign and transient. However, some of them are associated with structural defects or can cause heart failure, fetal hydrops, and can lead to intrauterine death. The analysis of fetal heart rhythm is based on ultrasound (M-mode and Doppler echocardiography). Irregular rhythm due to atrial ectopic beats is the most common type of fetal arrhythmia and is generally benign. Tachyarrhythmias are diagnosed when the fetal heart rate is persistently above 180 beats per minute (bpm). The most common fetal tachyarrhythmias are paroxysmal supraventricular tachycardia and atrial flutter. Most fetal tachycardias can be terminated or controlled by transplacental or direct administration of anti-arrhythmic drugs. Fetal bradycardia is diagnosed when the fetal heart rate is slower than 110 bpm. Persistent bradycardia outside labor or in the absence of placental pathology is mostly due to atrioventricular (AV) block. Approximately half of fetal heart blocks are in cases with structural heart defects, and AV block in cases with structurally normal heart is often caused by maternal anti-Ro/SSA antibodies. The efficacy of prenatal treatment for fetal AV block is limited. Our review aims to provide a practical guide for the diagnosis and management of common fetal arrythmias, from the joint perspective of the fetal medicine specialist and the cardiologist.
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Strand S, Strasburger JF, Cuneo BF, Wakai RT. Complex and Novel Arrhythmias Precede Stillbirth in Fetuses With De Novo Long QT Syndrome. Circ Arrhythm Electrophysiol 2020; 13:e008082. [PMID: 32421437 DOI: 10.1161/circep.119.008082] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
BACKGROUND Long QT syndrome (LQTS) is a leading cause of sudden cardiac death in early life and has been implicated in ≈10% of sudden infant deaths and unexplained stillbirths. The purpose of our study was to use fetal magnetocardiography to characterize the electrophysiology and rhythm phenotypes of fetuses with de novo and inherited LQTS variants and identify risk factors for sudden death before birth. METHODS We reviewed the fetal magnetocardiography database from the University of Wisconsin Biomagnetism Laboratory for fetuses with confirmed LQTS. We assessed waveform intervals, heart rate, and rhythm, including the signature LQTS rhythms: functional 2° atrioventricular block, T-wave alternans, and torsade de pointes (TdP). RESULTS Thirty-nine fetuses had pathogenic variants in LQTS genes: 27 carried the family variant, 11 had de novo variants, and 1 was indeterminate. De novo variants, especially de novo SCN5A variants, were strongly associated with a severe rhythm phenotype and perinatal death: 9 (82%) showed signature LQTS rhythms, 6 (55%) showed TdP, 5 (45%) were stillborn, and 1 (9%) died in infancy. Those that died exhibited novel fetal rhythms, including atrioventricular block with 3:1 conduction ratio, QRS alternans in 2:1 atrioventricular block, long-cycle length TdP, and slow monomorphic ventricular tachycardia. Premature ventricular contractions were also strongly associated with TdP and perinatal death. Fetuses with familial variants showed a lower incidence of signature LQTS rhythm (6/27=22%), including TdP (3/27=11%). All were live born. CONCLUSIONS The malignancy of de novo LQTS variants was remarkably high and demonstrate that these mutations are a significant cause of stillbirth. Their ability to manifest rhythms not known to be associated with LQTS increases the difficulty of echocardiographic diagnosis and decreases the likelihood that a resultant fetal loss is attributed to LQTS. Registration: URL: http://www.clinicaltrials.gov. Unique identifier: NCT03047161.
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Affiliation(s)
- Sarah Strand
- Department of Medical Physics, University of Wisconsin-Madison (S.S. R.T.W.)
| | - Janette F Strasburger
- Division of Cardiology, Department of Pediatrics, Children's Hospital of Wisconsin, Medical College of Wisconsin, Milwaukee (J.F.S.)
| | - Bettina F Cuneo
- Division of Cardiology, Department of Pediatrics (B.F.C.), Children's Hospital Colorado & University of Colorado School of Medicine, Aurora.,The Colorado Fetal Care Center (B.F.C), Children's Hospital Colorado & University of Colorado School of Medicine, Aurora
| | - Ronald T Wakai
- Department of Medical Physics, University of Wisconsin-Madison (S.S. R.T.W.)
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Su PC, Miller S, Idriss S, Barker P, Wu HT. Recovery of the fetal electrocardiogram for morphological analysis from two trans-abdominal channels via optimal shrinkage. Physiol Meas 2019; 40:115005. [PMID: 31585453 DOI: 10.1088/1361-6579/ab4b13] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVE We propose a novel algorithm to recover fetal electrocardiogram (ECG) for both the fetal heart rate analysis and morphological analysis of its waveform from two or three trans-abdominal maternal ECG channels. APPROACH We design an algorithm based on the optimal-shrinkage under the wave-shape manifold model. For the fetal heart rate analysis, the algorithm is evaluated on publicly available database, 2013 PhyioNet/Computing in Cardiology Challenge, set A (CinC2013). For the morphological analysis, we analyze CinC2013 and another publicly available database, non-invasive fetal ECG arrhythmia database (nifeadb), and propose to simulate semi-real databases by mixing the MIT-BIH normal sinus rhythm database and MITDB arrhythmia database. MAIN RESULTS For the fetal R peak detection, the proposed algorithm outperforms all algorithms under comparison. For the morphological analysis, the algorithm provides an encouraging result in recovery of the fetal ECG waveform, including PR, QT and ST intervals, even when the fetus has arrhythmia, both in real and simulated databases. SIGNIFICANCE To the best of our knowledge, this is the first work focusing on recovering the fetal ECG for morphological analysis from two or three channels with an algorithm potentially applicable for continuous fetal electrocardiographic monitoring, which creates the potential for long term monitoring purpose.
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Affiliation(s)
- Pei-Chun Su
- Department of Mathematics, Duke University, Durham, NC, United States of America
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Sulai IA, DeLand ZJ, Bulatowicz MD, Wahl CP, Wakai RT, Walker TG. Characterizing atomic magnetic gradiometers for fetal magnetocardiography. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:085003. [PMID: 31472627 PMCID: PMC6690843 DOI: 10.1063/1.5091007] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 07/19/2019] [Indexed: 05/25/2023]
Abstract
Atomic magnetometers (AMs) offer many advantages over superconducting quantum interference devices due to, among other things, having comparable sensitivity while not requiring cryogenics. One of the major limitations of AMs is the challenge of configuring them as gradiometers. We report the development of a spin-exchange relaxation free vector atomic magnetic gradiometer with a sensitivity of 3 fT cm-1 Hz-1/2 and common mode rejection ratio >150 in the band from DC to 100 Hz. We introduce a background suppression figure of merit for characterizing the performance of gradiometers. It allows for optimally setting the measurement baseline and for quickly assessing the advantage, if any, of performing a measurement in a gradiometric mode. As an application, we consider the problem of fetal magnetocardiography (fMCG) detection in the presence of a large background maternal MCG signal.
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Affiliation(s)
- I A Sulai
- Department of Physics & Astronomy, Bucknell University, Lewisburg, Pennsylvania 17837, USA
| | - Z J DeLand
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - M D Bulatowicz
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - C P Wahl
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - R T Wakai
- Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - T G Walker
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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Pruetz JD, Miller JC, Loeb GE, Silka MJ, Bar-Cohen Y, Chmait RH. Prenatal diagnosis and management of congenital complete heart block. Birth Defects Res 2019; 111:380-388. [PMID: 30821931 DOI: 10.1002/bdr2.1459] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 01/04/2019] [Indexed: 01/03/2023]
Abstract
Congenital complete heart block (CCHB) is a life-threatening medical condition in the unborn fetus with insufficiently validated prenatal interventions. Maternal administration of medications aimed at decreasing the immune response in the fetus and beta-agonists intended to increase fetal cardiac output have shown only marginal benefits. Anti-inflammatory therapies cannot reverse CCHB, but may decrease myocarditis and improve heart function. Advances in prenatal diagnosis and use of strict surveillance protocols for delivery timing have demonstrated small improvements in morbidity and mortality. Ambulatory surveillance programs and wearable fetal heart rate monitors may afford early identification of evolving fetal heart block allowing for emergent treatment. There is also preliminary data suggesting a roll for prevention of CCHB with hydroxychloroquine, but the efficacy and safety is still being studied. To date, intrauterine fetal pacing has not been successful due to the high-risk invasive placement techniques and potential problems with lead dislodgement. The development of a fully implantable micropacemaker via a minimally invasive approach has the potential to pace fetal patients with CCHB and thus delay delivery and allow fetal hydrops to resolve. The challenge remains to establish accepted prenatal interventions capable of successfully managing CCHB in utero until postnatal pacemaker placement is successfully achieved.
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Affiliation(s)
- Jay D Pruetz
- Department of Pediatrics/Division of Pediatric Cardiology, Children's Hospital Los Angeles, Los Angeles, California.,Keck School of Medicine of USC, Los Angeles, California
| | - Jennifer C Miller
- Department of Pediatrics/Division of Pediatric Cardiology, Children's Hospital Los Angeles, Los Angeles, California.,Keck School of Medicine of USC, Los Angeles, California
| | - Gerald E Loeb
- Department of Biomedical Engineering, University of Southern California (USC), Los Angeles, California
| | - Michael J Silka
- Department of Pediatrics/Division of Pediatric Cardiology, Children's Hospital Los Angeles, Los Angeles, California.,Keck School of Medicine of USC, Los Angeles, California
| | - Yaniv Bar-Cohen
- Department of Pediatrics/Division of Pediatric Cardiology, Children's Hospital Los Angeles, Los Angeles, California.,Keck School of Medicine of USC, Los Angeles, California
| | - Ramen H Chmait
- Department of Obstetrics and Gynecology/Division of Maternal Fetal Medicine, Keck School of Medicine of USC, Los Angeles, California
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Kuleva M, Le Bidois J, Decaudin A, Villain E, Costedoat-Chalumeau N, Lemercier D, Dumez Y, Ville Y, Bonnet D, Salomon LJ. Clinical course and outcome of antenatally detected atrioventricular block: experience of a single tertiary centre and review of the literature. Prenat Diagn 2015; 35:354-61. [PMID: 25487821 DOI: 10.1002/pd.4547] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 12/03/2014] [Accepted: 12/03/2014] [Indexed: 01/20/2023]
Abstract
OBJECTIVE The objective is to study the course and outcome of fetuses with congenital atrioventricular block (AVB) in a single centre. METHODS Retrospective analysis of cases diagnosed prenatally with second and third degree AVB. The clinical characteristics and outcome of fetal AVB were evaluated including in utero treatment. RESULTS Sixty-two cases were studied. AVB was associated with a congenital heart defect (CHD-AVB) in 17 cases (27%), whereas it was isolated (i-AVB) in 45 (73%), 42 of which were associated with maternal antibodies. There were nine (52.9%) live births in the CHD-AVB group, five of which (55%) resulted in infant deaths. In the i-AVB group, there were 40/45 (88.9%) live births and 1/40 (2.5%) infant death; 36 (90%) babies required a permanent pacemaker. The only factor predictive of postnatal death was the presence of CHD (5/9 vs 1/39 or 48.7 [3.6; 1457.7], p < 0.001). Nineteen fetuses (40.5%) with i-AVB received steroids in utero. No difference in outcome was found between the AVB treated in utero versus the no-treatment group in terms of permanent pacemaker placement, postnatal death or development of dilated cardiomyopathy. CONCLUSION The most important prognostic factor for congenital AVB is the association with CHD. In utero treatment remains questionable.
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Affiliation(s)
- M Kuleva
- Department of Obstetrics and Gynecology, M3C-Necker, Hôpital Necker Enfants malades, 75015, Paris, France
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Wyllie R, Kauer M, Wakai RT, Walker TG. Optical magnetometer array for fetal magnetocardiography. OPTICS LETTERS 2012; 37:2247-9. [PMID: 22739870 PMCID: PMC3386557 DOI: 10.1364/ol.37.002247] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
We describe an array of spin-exchange-relaxation-free optical magnetometers designed for detection of fetal magnetocardiography (fMCG). The individual magnetometers are configured with a small volume with intense optical pumping, surrounded by a large pump-free region. Spin-polarized atoms that diffuse out of the optical pumping region precess in the ambient magnetic field and are detected by a probe laser. Four such magnetometers, at the corners of a 7 cm square, are configured for gradiometry by feeding back the output of one magnetometer to a field coil to null uniform magnetic field noise at frequencies up to 200 Hz. We present the first measurements of fMCG signals using an atomic magnetometer.
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Affiliation(s)
- Robert Wyllie
- Department of Physics, University of Wisconsin–Madison, 1150 University Avenue, Madison, Wisconsin 53706, USA
| | - Matthew Kauer
- Department of Physics, University of Wisconsin–Madison, 1150 University Avenue, Madison, Wisconsin 53706, USA
| | - Ronald T. Wakai
- Department of Medical Physics, University of Wisconsin–Madison, 1111 Highland Avenue, Madison, Wisconsin 53705, USA
| | - Thad G. Walker
- Department of Physics, University of Wisconsin–Madison, 1150 University Avenue, Madison, Wisconsin 53706, USA
- Corresponding author:
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Tutschek B, Schmidt KG. Pulsed-wave tissue Doppler echocardiography for the analysis of fetal cardiac arrhythmias. ULTRASOUND IN OBSTETRICS & GYNECOLOGY : THE OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY OF ULTRASOUND IN OBSTETRICS AND GYNECOLOGY 2011; 38:406-412. [PMID: 21656866 DOI: 10.1002/uog.9070] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
OBJECTIVES Rhythm analysis of the fetal heart is hampered by the inability to routinely obtain electrocardiographic recordings of the fetus. Doppler studies of fetal cardiac tissue movements, assessing cardiac movements both qualitatively and quantitatively, have recently been described. We used a conventional high-resolution ultrasound system to obtain rhythm data from pulsed-wave tissue Doppler signals of the fetal heart in normal cardiac rhythm and in a variety of fetal cardiac arrhythmias. METHODS Fifty-five fetuses with normal (sinus) rhythm, 45 fetuses with rhythm disturbances and two neonates (one with arrhythmia and one with normal sinus rhythm) were studied. Using a conventional high-resolution ultrasound system equipped for fetal studies, but without specific tissue Doppler hardware or software, we performed pulsed-wave tissue Doppler echocardiography (PW-TDE) of atrioventricular valve ring excursions to study the atrial and ventricular mechanical actions. In the neonates, electrocardiograms were also recorded. RESULTS PW-TDE in normal fetuses shows a typical pattern of tissue motion parallel to the long axis of the heart and in the opposite direction to the blood flow, both in systole and diastole. This pattern is easily obtained from the tricuspid valve annulus in normal sinus rhythm and shows characteristic changes in various fetal arrhythmias. CONCLUSION PW-TDE of atrioventricular valve annulus movement patterns may prove to be a valuable additional tool for assessing fetal cardiac arrhythmias.
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Affiliation(s)
- B Tutschek
- Department of Obstetrics and Gynecology, Bern University Hospital, Bern, Switzerland; Medical Faculty, Heinrich Heine University, Düsseldorf, Germany.
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Yu S, Wakai RT. Maternal MCG interference cancellation using splined independent component subtraction. IEEE Trans Biomed Eng 2011; 58:2835-43. [PMID: 21712157 DOI: 10.1109/tbme.2011.2160635] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Signal distortion is commonly observed when using independent component analysis (ICA) to remove maternal cardiac interference from the fetal magnetocardiogram. This can be seen even in the most conservative case where only the independent components dominated by maternal interference are subtracted from the raw signal, a procedure we refer to as independent component subtraction (ICS). Distortion occurs when the subspaces of the fetal and maternal signals have appreciable overlap. To overcome this problem, we employed splining to remove the fetal signal from the maternal source component. The maternal source components were downsampled and then interpolated to their original sampling rate using a cubic spline. A key aspect of the splining procedure is that the maternal QRS complexes are downsampled much less than the rest of the maternal signal so that they are not distorted, despite their higher bandwidth. The splined maternal source components were projected back onto the magnetic field measurement space and then subtracted from the raw signal. The method was evaluated using data from 24 subjects. We compared the results of conventional, i.e., unsplined, ICS with our method, splined ICS, using matched filtering as a reference. Correlation and subjective assessment of the P-wave and QRS complex were used to assess the performance. Using ICS, we found that the P-wave was adversely affected in 7 of 24 (29%) subjects, all having correlations less than 0.8. Splined ICS showed negligible distortion and improved the signal fidelity to some extent in all subjects. We also demonstrated that maternal T-wave interference could be problematic when the fetal and maternal heartbeats were synchronous. In these instances, splined ICS was more effective than matched filtering.
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Affiliation(s)
- Suhong Yu
- Department of Medical Physics, University of Wisconsin, Madison, WI 53706, USA.
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Abstract
'Neonatal' lupus erythematosus (NLE) describes a clinical spectrum of cardiac and non-cardiac abnormalities observed in neonates and foetuses whose mothers have the auto-antibodies anti-SSA/Ro (anti-Ro) and anti-SSB/La (anti-La). Of the cardiac abnormalities, congenital AVB is the most common cardiovascular abnormality found in affected foetuses and infants. Many other cardiovascular manifestations of NLE have been more recently recognized including atrial and ventricular arrhythmias and other conduction abnormalities, myocarditis, cardiomyopathy often with endocardiofibroelastosis and structural heart disease, particularly valvar lesions. In this report, the spectrum of cardiovascular manifestations observed in foetuses and infants with NLE are reviewed and the pathogenesis, diagnosis and clinical outcomes are briefly discussed.
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Affiliation(s)
- L K Hornberger
- Fetal & Neonatal Cardiology Program, Division of Cardiology, Department of Pediatrics, Stollery Children's Hospital, Women's & Children's Health Research Institute, Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, AB, Canada.
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Sekar P, Hornberger LK. The role of fetal echocardiography in fetal intervention: a symbiotic relationship. Clin Perinatol 2009; 36:301-27, ix. [PMID: 19559322 DOI: 10.1016/j.clp.2009.03.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
In this review, the authors explore the role of noninvasive and invasive fetal interventions in fetal cardiovascular disease guided by observations at fetal echocardiography. They first review fetal cardiac lesions that may be ameliorated by fetal intervention and then review noncardiac fetal pathologic findings for which fetal echocardiography can provide important insight into the pathophysiology and aid in patient selection for and timing of intervention and postintervention surveillance.
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Affiliation(s)
- Priya Sekar
- Department of Pediatrics, Division of Cardiology, Fetal and Neonatal Cardiology Program, WCMC 4C2 Stollery Children's Hospital, Alberta, Canada
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Comani S, Van Leeuwen P, Lange S, Geue D, Grönemeyer D. Influence of gestational age on the effectiveness of spatial and temporal methods for the reconstruction of the fetal magnetocardiogram. ACTA ACUST UNITED AC 2009; 54:29-37. [PMID: 19182871 DOI: 10.1515/bmt.2009.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Fetal magnetocardiography (fMCG) has been shown to augment fetal ultrasound evaluation for high-risk conditions, but the clinical utility of fMCG depends on the reliability of the cardiac traces reconstructed. We performed a methodological study to examine the influence of gestational age on the properties of the fetal magnetocardiograms extracted with two methods of signal reconstruction: the template matching technique (TMT), which extracts the maternal components from the signal using only temporal information, and independent component analysis (ICA), which separates the fetal signals by using information on the spatial distribution of the mixed source signals in addition to higher order temporal statistics. Efficiency and accuracy were evaluated in terms of fetal beat detection, signal characteristics, and duration of cardiac time intervals (CTIs) on the averaged traces. ICA outperformed TMT with regard to beat detection and signal-to-noise ratio. The timing of the heartbeats and the duration of the CTIs were essentially the same, whereas some alterations in signal morphology were observed in the ICA traces. We conclude that ICA may be useful in early gestation when the signals are noisy, while TMT may be preferred when accurate beat morphology is required for diagnostic purposes.
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Affiliation(s)
- Silvia Comani
- Behavioral Imaging and Neural Dynamics (BIND) Center, University of Chieti-Pescara, Chieti, Italy.
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Kyoon Lim H, Kim K, Lee YH, Chung N. Detection of non-ST-elevation myocardial infarction using magnetocardiogram: new information from spatiotemporal electrical activation map. Ann Med 2009; 41:533-46. [PMID: 19626486 DOI: 10.1080/07853890903107883] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
BACKGROUND AND AIM Non-ST-segment elevation myocardial infarction (NSTEMI) cannot be easily detected in the emergency room. We evaluate a method to detect NSTEMI using 64-channel magnetocardiography (MCG). METHODS MCG recordings were made in 20 NSTEMI patients (aged 59.7+/-12.4 years), 15 young (aged 26.8+/-3.4 years), and 13 age-matched control subjects (aged 57.3+/-3.6). We evaluated three approaches to analysis, including 1) determination when individual subjects' MCG results fell outside normal ranges for ten MCG parameters, 2) the magnetic field map at the T-wave peak (T-MFM), and 3) a pair of spatiotemporal activation graphs (STAGs) showing two projections of electrical excitation during repolarization. RESULTS Significant differences were found between normal controls and patients for all MCG parameters. None of the healthy controls had more than four MCG abnormal parameters, whereas 19 NSTEMI patients (95%) were abnormal in more than four parameters. STAGs and T-MFM also showed clear differences between healthy controls and NSTEMI patients. CONCLUSIONS These results suggest that the MCG is sensitive to changes in the cardiac electrical pathway after myocardial infarction as described by these graphs and parameters, and therefore MCG may be a useful tool to detect severe ischemic patients.
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Affiliation(s)
- Hyun Kyoon Lim
- Korea Research Institute of Standards and Science, Daejeon, Korea
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Abstract
PURPOSE OF REVIEW Though fetal arrhythmias account for a small proportion of referrals to a fetal cardiologist, they may be associated with significant morbidity and mortality. The present review outlines the current literature with regard to the diagnosis and, in brief, some management strategies in fetal arrhythmias. RECENT FINDINGS Advances in echocardiography have resulted in significant improvements in our ability to elucidate the mechanism of arrhythmia at the bedside. At the same time, magnetocardiography is broadening our understanding of mechanisms of arrhythmia especially as it pertains to ventricular arrhythmias and congenital heart block. It provides a unique window to study electrical properties of the fetal heart, unlike what has been available to date. Recent reports of bedside use of fetal ECG make it a promising new technology. Fetal magnetocardiography is also developing. The underlying mechanisms resulting in immune-mediated complete heart block in a small subset of 'at-risk' fetuses is under investigation. SUMMARY There have been great strides in noninvasive diagnosis of fetal arrhythmias. However, we still need to improve our knowledge of the electromechanical properties of the fetal heart as well as the mechanisms of arrhythmia to further improve outcomes. Multiinstitutional collaborative studies are needed to help answer some of the questions regarding patient, drug selection and management algorithms.
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