1
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Congenital atrioventricular heart block: From diagnosis to treatment. Rev Port Cardiol 2022; 41:231-240. [DOI: 10.1016/j.repc.2019.09.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 09/23/2019] [Indexed: 11/22/2022] Open
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2
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Perley A, Roustaei M, Aguilar-Rivera M, Kunkel DC, Hsiai TK, Coleman TP, Abiri P. Miniaturized wireless gastric pacing via inductive power transfer with non-invasive monitoring using cutaneous Electrogastrography. Bioelectron Med 2021; 7:12. [PMID: 34425917 PMCID: PMC8383397 DOI: 10.1186/s42234-021-00074-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 07/12/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Gastroparesis is a debilitating disease that is often refractory to pharmacotherapy. While gastric electrical stimulation has been studied as a potential treatment, current devices are limited by surgical complications and an incomplete understanding of the mechanism by which electrical stimulation affects physiology. METHODS A leadless inductively-powered pacemaker was implanted on the gastric serosa in an anesthetized pig. Wireless pacing was performed at transmitter-to-receiver distances up to 20 mm, frequency of 0.05 Hz, and pulse width of 400 ms. Electrogastrogram (EGG) recordings using cutaneous and serosal electrode arrays were analyzed to compute spectral and spatial statistical parameters associated with the slow wave. RESULTS Our data demonstrated evident change in EGG signal patterns upon initiation of pacing. A buffer period was noted before a pattern of entrainment appeared with consistent and low variability in slow wave direction. A spectral power increase in the EGG frequency band during entrainment also suggested that pacing increased strength of the slow wave. CONCLUSION Our preliminary in vivo study using wireless pacing and concurrent EGG recording established the foundations for a minimally invasive approach to understand and optimize the effect of pacing on gastric motor activity as a means to treat conditions of gastric dysmotility.
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Affiliation(s)
- Andrew Perley
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Mehrdad Roustaei
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Marcelo Aguilar-Rivera
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, 92093, USA
| | - David C Kunkel
- Division of Gastroenterology, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Tzung K Hsiai
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA, 90095, USA.,Department of Medicine, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Todd P Coleman
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Parinaz Abiri
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA, 90095, USA. .,Department of Medicine, University of California, Los Angeles, Los Angeles, CA, 90095, USA.
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3
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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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4
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Liao H, Tang C, Qiao L, Zhou K, Hua Y, Wang C, Li Y. Prenatal Management Strategy for Immune-Associated Congenital Heart Block in Fetuses. Front Cardiovasc Med 2021; 8:644122. [PMID: 33996939 PMCID: PMC8113399 DOI: 10.3389/fcvm.2021.644122] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Accepted: 03/30/2021] [Indexed: 12/13/2022] Open
Abstract
Fetal congenital heart block (CHB) is the most commonly observed type of fetal bradycardia, and is potentially life-threatening. More than 50% of cases of bradycardia are associated with maternal autoimmunity, and these are collectively termed immune-associated bradycardia. Several methods have been used to achieve reliable prenatal diagnoses of CHB. Emerging data and opinions on pathogenesis, prenatal diagnosis, fetal intervention, and the prognosis of fetal immune-associated CHB provide clues for generating a practical protocol for clinical management. The prognosis of fetal immune-associated bradycardia is based on the severity of heart blocks. Morbidity and mortality can occur in severe cases, thus hieratical management is essential in such cases. In this review, we mainly focus on optimal strategies pertaining to autoimmune antibodies related to CHB, although the approaches for managing autoimmune-mediated CHB are still controversial, particularly with regard to whether fetuses benefit from transplacental medication administration. To date there is still no accessible clinical strategy for autoimmune-mediated CHB. This review first discusses integrated prenatal management strategies for the condition. It then provides some advice for clinicians involved in management of fetal cardiovascular disorder.
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Affiliation(s)
- Hongyu Liao
- Key Laboratory of Birth Defects and Related Diseases of Women and Children of Ministry of Education (MOE), Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, China
| | - Changqing Tang
- Key Laboratory of Birth Defects and Related Diseases of Women and Children of Ministry of Education (MOE), Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, China
| | - Lina Qiao
- Key Laboratory of Birth Defects and Related Diseases of Women and Children of Ministry of Education (MOE), Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, China
| | - Kaiyu Zhou
- Key Laboratory of Birth Defects and Related Diseases of Women and Children of Ministry of Education (MOE), Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, China
| | - Yimin Hua
- Key Laboratory of Birth Defects and Related Diseases of Women and Children of Ministry of Education (MOE), Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, China
| | - Chuan Wang
- Key Laboratory of Birth Defects and Related Diseases of Women and Children of Ministry of Education (MOE), Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, China
| | - Yifei Li
- Key Laboratory of Birth Defects and Related Diseases of Women and Children of Ministry of Education (MOE), Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, China
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5
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Abiri P, Duarte-Vogel S, Chou TC, Abiri A, Gudapati V, Yousefi A, Roustaei M, Chang CC, Cui Q, Hsu JJ, Bersohn M, Markovic D, Chen J, Tai YC, Hsiai TK. In Vivo Intravascular Pacing Using a Wireless Microscale Stimulator. Ann Biomed Eng 2021; 49:2094-2102. [PMID: 33537925 DOI: 10.1007/s10439-021-02729-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 01/07/2021] [Indexed: 11/26/2022]
Abstract
Millions of patients worldwide are implanted with permanent pacemakers for the treatment of cardiac arrhythmias and conduction disorders. The increased use of these devices has established a growing clinical need to mitigate associated complications. Pacemaker leads, in particular, present the primary risks in most implants. While wireless power transfer holds great promise in eliminating implantable device leads, anatomical constraints limit efficient wireless transmission over the necessary operational range. We thereby developed a transmitter-centered control system for wireless power transfer with sufficient power for continuous cardiac pacing. Device safety was validated using a computational model of the system within an MRI-based anatomical model. The pacer was then fabricated to meet the acute constraints of the anterior cardiac vein (ACV) to enable intravascular deployment while maintaining power efficiency. Our computational model revealed the wireless system to operate at > 50 times below the tissue energy absorption safety criteria. We further demonstrated the capacity for ex vivo pacing of pig hearts at 60 beats per minute (BPM) and in vivo pacing at 120 BPM following pacer deployment in the ACV. This work thus established the capacity for wireless intravascular pacing with the potential to eliminate complications associated with current lead-based deep tissue implants.
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Affiliation(s)
- Parinaz Abiri
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA, 90095, USA
- Department of Cardiology, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Sandra Duarte-Vogel
- Division of Laboratory Animal Medicine, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Tzu-Chieh Chou
- Department of Medical Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Arash Abiri
- School of Medicine, University of California, Irvine, Irvine, CA, 92697, USA
| | - Varun Gudapati
- Department of Cardiology, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Alireza Yousefi
- Department of Electrical Engineering, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Mehrdad Roustaei
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Chih-Chiang Chang
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Qingyu Cui
- Department of Cardiology, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Jeffrey J Hsu
- Department of Cardiology, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Malcolm Bersohn
- Department of Cardiology, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Dejan Markovic
- Department of Electrical Engineering, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Jun Chen
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Yu-Chong Tai
- Department of Medical Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Tzung K Hsiai
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA, 90095, USA.
- Department of Cardiology, University of California, Los Angeles, Los Angeles, CA, 90095, USA.
- Department of Medical Engineering, California Institute of Technology, Pasadena, CA, 91125, USA.
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6
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Abiri P, Yousefi A, Abiri A, Gudapati V, Ding Y, Nguyen KL, Abiri A, Markovic D, Tai YC, Hsiai TK. A Multi-Dimensional Analysis of a Novel Approach for Wireless Stimulation. IEEE Trans Biomed Eng 2020; 67:3307-3316. [PMID: 32248088 DOI: 10.1109/tbme.2020.2983443] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The elimination of integrated batteries in biomedical implants holds great promise for improving health outcomes in patients with implantable devices. However, despite extensive research in wireless power transfer, achieving efficient power transfer and effective operational range have remained a hindering challenge within anatomical constraints. OBJECTIVE We hereby demonstrate an intravascular wireless and batteryless microscale stimulator, designed for (1) low power dissipation via intermittent transmission and (2) reduced fixation mechanical burden via deployment to the anterior cardiac vein (ACV, ∼3.8 mm in diameter). METHODS We introduced a unique coil design circumferentially confined to a 3 mm diameter hollow-cylinder that was driven by a novel transmitter-based control architecture with improved power efficiency. RESULTS We examined wireless capacity using heterogenous bovine tissue, demonstrating >5 V stimulation threshold with up to 20 mm transmitter-receiver displacement and 20° of misalignment. Feasibility for human use was validated using Finite Element Method (FEM) simulation of the cardiac cycle, guided by pacer phantom-integrated Magnetic Resonance Images (MRI). CONCLUSION This system design thus enabled sufficient wireless power transfer in the face of extensive stimulator miniaturization. SIGNIFICANCE Our successful feasibility studies demonstrated the capacity for minimally invasive deployment and low-risk fixation.
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7
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Abiri P, Abiri A, Gudapati V, Chang CC, Roustaei M, Bourenane H, Anwar U, Markovic D, Hsiai TK. Wireless Pacing Using an Asynchronous Three-Tiered Inductive Power Transfer System. Ann Biomed Eng 2020; 48:1368-1381. [PMID: 31974869 DOI: 10.1007/s10439-020-02450-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Accepted: 01/06/2020] [Indexed: 11/29/2022]
Abstract
Despite numerous advancements in pacemaker technology for the treatment of cardiac arrhythmias and conduction disorders, lead-related complications associated with these devices continue to compromise patient safety and survival. In this work, we present a system architecture that has the capacity to deliver power to a wireless, batteryless intravascular pacer. This was made possible through a three-tiered, dual-sub-system, four-coil design, which operates on two different frequencies through intermittent remote-controlled inductive power transfer. System efficiency was enhanced using coil design optimization, and validated using numerical simulations and experimental analysis. Our pacemaker design was concepted to achieve inductive power transfer over a 55 mm range to a microscale pacer with a 3 mm diameter. Thus, the proposed system design enabled long-range wireless power transfer to a small implanted pacer with the capacity for intravascular deployment to the anterior cardiac vein. This proposed stent-like fixation mechanism can bypass the multitude of complications associated with pacemaker wires while wireless power can eliminate the need for repeated procedures for battery replacement.
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Affiliation(s)
- Parinaz Abiri
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA, 90095, USA.,Department of Medicine, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Arash Abiri
- Department of Medicine, University of California, Irvine, Irvine, CA, 92697, USA
| | - Varun Gudapati
- Department of Medicine, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Chih-Chiang Chang
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Mehrdad Roustaei
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Hamed Bourenane
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Usama Anwar
- Department of Electrical Engineering, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Dejan Markovic
- Department of Electrical Engineering, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Tzung K Hsiai
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA, 90095, USA. .,Department of Medicine, University of California, Los Angeles, Los Angeles, CA, 90095, USA.
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8
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Bar-Cohen Y, Silka MJ, Hill AC, Pruetz JD, Chmait RH, Zhou L, Rabin SM, Norekyan V, Loeb GE. Minimally Invasive Implantation of a Micropacemaker Into the Pericardial Space. Circ Arrhythm Electrophysiol 2019; 11:e006307. [PMID: 29945929 DOI: 10.1161/circep.118.006307] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 05/08/2018] [Indexed: 11/16/2022]
Abstract
BACKGROUND Permanent cardiac pacemakers require invasive procedures with complications often related to long pacemaker leads. We are developing a percutaneous pacemaker for implantation of an entire pacing system into the pericardial space. METHODS Percutaneous micropacemaker implantations were performed in 6 pigs (27.4-34.1 kg) using subxyphoid access to the pericardial space. Modifications in the implantation methods and hardware were made after each experiment as the insertion method was optimized. In the first 5 animals, nonfunctional pacemaker devices were studied. In the final animal, a functional pacemaker was implanted. RESULTS Successful placement of the entire nonfunctional pacing system into the pericardial space was demonstrated in 2 of the first 5 animals, and successful implantation and capture was achieved using a functional system in the last animal. A sheath was developed that allows retractable features to secure positioning within the pericardial space. In addition, a miniaturized camera with fiberoptic illumination allowed visualization of the implantation site before electrode insertion into myocardium. All animals studied during follow-up survived without symptoms after the initial postoperative period. CONCLUSIONS A novel micropacemaker system allows cardiac pacing without entering the vascular space or surgical exposure of the heart. This pericardial pacemaker system may be an option for a large number of patients currently requiring transvenous pacemakers but is particularly relevant for patients with restricted vascular access, young children, or those with congenital heart disease who require epicardial access.
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Affiliation(s)
- Yaniv Bar-Cohen
- Division of Cardiology, Children's Hospital Los Angeles, CA (Y.B.-C., M.J.S., A.C.H., J.D.P.). .,Keck School of Medicine, Los Angeles, CA (Y.B.-C., M.J.S., A.C.H., J.D.P.)
| | - Michael J Silka
- Division of Cardiology, Children's Hospital Los Angeles, CA (Y.B.-C., M.J.S., A.C.H., J.D.P.).,Keck School of Medicine, Los Angeles, CA (Y.B.-C., M.J.S., A.C.H., J.D.P.)
| | - Allison C Hill
- Division of Cardiology, Children's Hospital Los Angeles, CA (Y.B.-C., M.J.S., A.C.H., J.D.P.).,Keck School of Medicine, Los Angeles, CA (Y.B.-C., M.J.S., A.C.H., J.D.P.)
| | - Jay D Pruetz
- Division of Cardiology, Children's Hospital Los Angeles, CA (Y.B.-C., M.J.S., A.C.H., J.D.P.).,Keck School of Medicine, Los Angeles, CA (Y.B.-C., M.J.S., A.C.H., J.D.P.)
| | - Ramen H Chmait
- Department of Obstetrics and Gynecology, Keck School of Medicine, Los Angeles, CA (R.H.C.)
| | - Li Zhou
- Department of Biomedical Engineering, University of Southern California, Los Angeles (L.Z., S.M.R., V.N., G.E.L.)
| | - Sara M Rabin
- Department of Biomedical Engineering, University of Southern California, Los Angeles (L.Z., S.M.R., V.N., G.E.L.)
| | - Viktoria Norekyan
- Department of Biomedical Engineering, University of Southern California, Los Angeles (L.Z., S.M.R., V.N., G.E.L.)
| | - Gerald E Loeb
- Department of Biomedical Engineering, University of Southern California, Los Angeles (L.Z., S.M.R., V.N., G.E.L.)
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9
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Batra AS, Balaji S. Fetal arrhythmias: Diagnosis and management. Indian Pacing Electrophysiol J 2019; 19:104-109. [PMID: 30817991 PMCID: PMC6531664 DOI: 10.1016/j.ipej.2019.02.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 02/20/2019] [Accepted: 02/22/2019] [Indexed: 11/23/2022] Open
Abstract
This article reviews important features for improving the diagnosis and management of fetal arrhythmias. The normal fetal heart rate ranges between 110 and 160 beats per minute. A fetal heart rate is considered abnormal if the heart rate is beyond the normal ranges or the rhythm is irregular. The rate, duration, and origin of the rhythm and degree of irregularity usually determine the potential for hemodynamic consequences. Most of the fetal rhythm disturbances are the result of premature atrial contractions (PACs) and are of little clinical significance. Other arrhythmias include tachyarrhythmias (heart rate in excess of 160 beats/min) such as atrioventricular (AV) reentry tachycardia, atrial flutter, and ventricular tachycardia, and bradyarrhythmias (heart rate <110 beats/min) such as sinus node dysfunction, complete heart block (CHB) and long QT syndrome (which is associated with sinus bradycardia and pseudo-heart block).
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Affiliation(s)
- Anjan S Batra
- Department of Pediatrics, University of California, Irvine, CA, USA.
| | - Seshadri Balaji
- Department of Pediatrics, Oregon Health & Science University, Portland, OR, USA
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10
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Carvalho JS. Fetal dysrhythmias. Best Pract Res Clin Obstet Gynaecol 2019; 58:28-41. [PMID: 30738635 DOI: 10.1016/j.bpobgyn.2019.01.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 12/31/2018] [Accepted: 01/07/2019] [Indexed: 11/18/2022]
Abstract
Fetal dysrhythmias are common abnormalities, usually manifesting as irregular rhythms. Although most irregularities are benign and caused by isolated atrial ectopics, in a few cases, rhythm irregularity may indicate partial atrioventricular block, which has different etiological and prognostic implications. We provide a flowchart for the initial management of irregular rhythm to help select cases requiring urgent specialist referral. Tachycardias and bradycardias are less frequent, can lead to hemodynamic compromise, and may require in utero therapy. Pharmacological treatment of tachycardia depends on the type (supraventricular tachycardia or atrial flutter) and presence of hydrops, with digoxin, flecainide, and sotalol being commonly used. An ongoing randomized trial may best inform about their efficacy. Bradycardia due to blocked bigeminy normally resolves spontaneously, but if it is due to established complete heart block, there is no effective treatment. Ongoing research suggests hydroxychloroquine may reduce the risk of autoimmune atrioventricular block. Sinus bradycardia (rate <3rd centile) may be a prenatal marker for long-QT syndrome.
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Affiliation(s)
- Julene S Carvalho
- Royal Brompton and Harefield NHS Foundation Trust, Sydney Street, London, SW3 6NP, UK; Fetal Medicine Unit, St George's University Hospital, Blackshaw Road, London, SW17 0QT, UK; Molecular and Clinical Sciences Research Institute, St George's, University of London, Cranmer Terrace, London, SW17 0RE, UK.
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11
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Huang X, Denprasert PM, Zhou L, Vest AN, Kohan S, Loeb GE. Accelerated life-test methods and results for implantable electronic devices with adhesive encapsulation. Biomed Microdevices 2018; 19:46. [PMID: 28536859 DOI: 10.1007/s10544-017-0189-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have developed and applied new methods to estimate the functional life of miniature, implantable, wireless electronic devices that rely on non-hermetic, adhesive encapsulants such as epoxy. A comb pattern board with a high density of interdigitated electrodes (IDE) could be used to detect incipient failure from water vapor condensation. Inductive coupling of an RF magnetic field was used to provide DC bias and to detect deterioration of an encapsulated comb pattern. Diodes in the implant converted part of the received energy into DC bias on the comb pattern. The capacitance of the comb pattern forms a resonant circuit with the inductor by which the implant receives power. Any moisture affects both the resonant frequency and the Q-factor of the resonance of the circuitry, which was detected wirelessly by its effects on the coupling between two orthogonal RF coils placed around the device. Various defects were introduced into the comb pattern devices to demonstrate sensitivity to failures and to correlate these signals with visual inspection of failures. Optimized encapsulation procedures were validated in accelerated life tests of both comb patterns and a functional neuromuscular stimulator under development. Strong adhesive bonding between epoxy and electronic circuitry proved to be necessary and sufficient to predict 1 year packaging reliability of 99.97% for the neuromuscular stimulator.
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Affiliation(s)
- Xuechen Huang
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA. .,General Stim Inc., Los Angeles, CA, USA.
| | | | - Li Zhou
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA
| | - Adriana Nicholson Vest
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA
| | - Sam Kohan
- General Stim Inc., Los Angeles, CA, USA
| | - Gerald E Loeb
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA.,General Stim Inc., Los Angeles, CA, USA
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12
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Abstract
INTRODUCTION Congenital complete heart block affects 1/15,000 live-born infants, predominantly due to atrioventricular nodal injury from maternal antibodies of mothers with systemic lupus erythermatosus or Sjogren's syndrome. The majority of these children will need a pacemaker implanted prior to becoming young adults. This article will review the various patient and technical factors that influence the type of pacemaker implanted, and the current literature on optimal pacing practices. Areas covered: A literature search was performed using PubMed, Embase and Web of Science. Data regarding epicardial versus transvenous implants, pacing-induced ventricular dysfunction, alternative pacing strategies (including biventricular pacing, left ventricular pacing, and His bundle pacing), and complications with pacemakers in the pediatric population were reviewed. Expert commentary: There are numerous pacing strategies available to children with congenital complete heart block. The risks and benefits of the initial implant should be weighed against the long-term issues inherent with a life-time of pacing.
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Affiliation(s)
- Stephanie F Chandler
- a Department of Cardiology , Boston Children's Hospital , Boston , MA , USA.,b Department of Pediatrics , Harvard Medical School , Boston , MA , USA
| | - Francis Fynn-Thompson
- c Department of Cardiovascular Surgery , Boston Children's Hospital , Boston , MA , USA.,d Department of Surgery , Harvard Medical School , Boston , MA , USA
| | - Douglas Y Mah
- a Department of Cardiology , Boston Children's Hospital , Boston , MA , USA.,b Department of Pediatrics , Harvard Medical School , Boston , MA , USA
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13
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Huang X, Zheng K, Kohan S, Denprasert PM, Liao L, Loeb GE. Neurostimulation Strategy for Stress Urinary Incontinence. IEEE Trans Neural Syst Rehabil Eng 2017; 25:1068-1078. [DOI: 10.1109/tnsre.2017.2679077] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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