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1.
Heart Rhythm ; 2024 Jul 03.
Article in English | MEDLINE | ID: mdl-38969049

ABSTRACT

BACKGROUND: After a cryptogenic stroke, patients will often require prolonged cardiac monitoring; however, the subset of patients who would benefit from long-term rhythm monitoring is not clearly defined. OBJECTIVE: Using significant predictors of AF using age, sex, comorbidities, baseline 12-lead electrocardiogram, short term rhythm monitoring and echocardiogram data, we created a risk score and compared it to previously published risk scores. METHODS: Patients admitted to Montefiore Medical Center between May 2017 and June 2022 with a primary diagnosis of cryptogenic stroke or TIA who underwent long-term rhythm monitoring with an implantable cardiac monitor were retrospectively analyzed. RESULTS: Variables positively associated with a diagnosis of clinically significant atrial fibrillation include age (p < 0.001), race (p = 0.022), diabetes status (p = 0.026), and COPD status (p = 0.012), the presence of atrial runs (p = 0.003), the number of atrial runs per 24 hours (p < 0.001), the total number of atrial run beats per 24 hours (p < 0.001) and the number of beats in the longest atrial run (p < 0.001), LA enlargement (p = 0.007) and at least mild mitral regurgitation (p = 0.009). We created a risk stratification score for our population, termed the "ACL score." The ACL score demonstrated superiority to the CHA2DS2-VASc score and comparability to the C2HEST score for predicting device-detected AF. CONCLUSION: The ACL score enables clinicians to better predict which patients are more likely to be diagnosed with device-detected AF after a cryptogenic stroke.

2.
J Cardiovasc Dev Dis ; 11(6)2024 May 30.
Article in English | MEDLINE | ID: mdl-38921670

ABSTRACT

Amidst an aging population and escalating obesity prevalence, elucidating the impact of obesity on transcatheter aortic valve replacement (TAVR) outcomes becomes paramount. The so-called "obesity paradox"-a term denoting the counterintuitive association of obesity, typically a risk factor for cardiovascular diseases, with improved survival outcomes in TAVR patients relative to their leaner or normal-weight counterparts-merits rigorous examination. This review comprehensively investigates the complex relationship between obesity and the clinical outcomes associated with TAVR, with a specific focus on mortality and periprocedural complications. This study aims to deepen our understanding of obesity's role in TAVR and the underlying mechanisms of the obesity paradox, thereby optimizing management strategies for this patient demographic, tailored to their unique physiological and metabolic profiles.

3.
Sci Rep ; 14(1): 13768, 2024 06 14.
Article in English | MEDLINE | ID: mdl-38877090

ABSTRACT

Sound transmission to the human inner ear by bone conduction pathway with an implant attached to the otic capsule is a specific case where the cochlear response depends on the direction of the stimulating force. A finite element model of the temporal bone with the inner ear, no middle and outer ear structures, and an immobilized stapes footplate was used to assess the directional sensitivity of the cochlea. A concentrated mass represented the bone conduction implant. The harmonic analysis included seventeen frequencies within the hearing range and a full range of excitation directions. Two assessment criteria included: (1) bone vibrations of the round window edge in the direction perpendicular to its surface and (2) the fluid volume displacement of the round window membrane. The direction of maximum bone vibration at the round window edge was perpendicular to the round window. The maximum fluid volume displacement direction was nearly perpendicular to the modiolus axis, almost tangent to the stapes footplate, and inclined slightly to the round window. The direction perpendicular to the stapes footplate resulted in small cochlear responses for both criteria. A key factor responsible for directional sensitivity was the small distance of the excitation point from the cochlea.


Subject(s)
Bone Conduction , Finite Element Analysis , Temporal Bone , Humans , Temporal Bone/physiology , Bone Conduction/physiology , Cochlea/physiology , Vibration , Round Window, Ear/physiology , Stapes/physiology , Models, Biological , Acoustic Stimulation
4.
Cureus ; 16(5): e59497, 2024 May.
Article in English | MEDLINE | ID: mdl-38826910

ABSTRACT

Cardiovascular diseases (CVDs) are the leading cause of death globally. Their prevalence and mortality rates continue to rise. This narrative review explores well-known risk factors for CVDs such as dyslipidemia, hypertension, diabetes, obesity, and smoking, and their prevalence among different racial and ethnic groups. In addition, we expand the discussion to include the impact of socioeconomic status (SES) on cardiovascular outcomes. The data demonstrate that non-Hispanic Black and Hispanic populations not only exhibit higher rates of hypertension, obesity, diabetes, and smoking but also face systemic barriers linked to lower SES, which worsen their cardiovascular outcomes. These barriers include a lack of education, lower income, higher rates of unemployment, and poor living conditions. Beyond these commonly studied factors, these groups also suffer from higher levels of food and housing insecurity and a lack of adequate insurance coverage, all of which contribute to poorer health. Additionally, there is a higher prevalence of mental health disorders, such as depression and anxiety, among these populations. This further compounds the risks and adverse outcomes associated with CVDs. It is essential to conduct further research into how SES and race influence cardiovascular health and to refine risk assessment methods. Concentrating on these aspects would make it possible to create interventions designed to meet the needs of diverse communities and strategies that could potentially reduce morbidity and mortality from CVD across populations. Moreover, this review advocates for integrating comprehensive socioeconomic data into cardiovascular health strategies, which is crucial for developing effective public health initiatives.

5.
Cureus ; 16(5): e60323, 2024 May.
Article in English | MEDLINE | ID: mdl-38756715

ABSTRACT

Acute coronary syndrome (ACS) presents significant diagnostic challenges, particularly in cases with atypical presentations and complex clinical scenarios. Here, we describe the case of a 59-year-old man who presented with presyncope, bradycardia, hypotension, and later syncope, attributed to the Bezold-Jarisch reflex. Electrocardiographic findings suggested both inferior and anterior wall infarction, with dynamic changes in T-wave morphology further complicating the diagnostic process. Despite a type A Wellens' pattern indicating critical stenosis in the proximal left anterior descending (LAD) artery, coronary angiography revealed a complete thrombotic lesion in the proximal right coronary artery (RCA), necessitating urgent intervention. Despite the Wellens pattern indicating LAD involvement, RCA revascularization took precedence due to immediate thrombotic risk. This case underscores the diagnostic challenges associated with conflicting clinical manifestations in ACS and highlights the importance of individualized management strategies integrating advanced diagnostic modalities to optimize outcomes. Understanding the interplay of complex clinical presentations and employing a nuanced approach to management are crucial in effectively navigating ACS scenarios.

6.
Biomolecules ; 14(4)2024 Apr 08.
Article in English | MEDLINE | ID: mdl-38672471

ABSTRACT

Numerous longitudinal studies suggest a strong association between cardiovascular risk factors and cognitive impairment. Individuals with atrial fibrillation are at higher risk of dementia and cognitive dysfunction, as atrial fibrillation increases the risk of cerebral hypoperfusion, inflammation, and stroke. The lack of comprehensive understanding of the observed association and the complex relationship between these two diseases makes it very hard to provide robust guidelines on therapeutic indications. With this review, we attempt to shed some light on how atrial fibrillation is related to dementia, what we know regarding preventive interventions, and how we could move forward in managing those very frequently overlapping conditions.


Subject(s)
Atrial Fibrillation , Dementia , Atrial Fibrillation/physiopathology , Atrial Fibrillation/complications , Humans , Dementia/etiology , Dementia/physiopathology , Risk Factors , Cognitive Dysfunction/physiopathology , Cognitive Dysfunction/etiology , Stroke/physiopathology , Stroke/complications
7.
Cureus ; 16(3): e55913, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38601377

ABSTRACT

This narrative review examines the complex interplay between social determinants of health (SDoH) and the outcomes for individuals living with human immunodeficiency virus (HIV) and heart failure (HF), two conditions that pose significant socioeconomic burdens globally. With millions affected by these conditions, the review delves into how socioeconomic status, education, geography, and immigration status influence health outcomes. It further explores the exacerbating roles of stigma and mental health issues, underscoring the need for comprehensive interventions and the importance of enhancing health literacy and community support. Key findings suggest that lower socioeconomic status, limited education, rural residency, and immigrant status are associated with poorer health outcomes in individuals with HIV and HF. These factors contribute to increased morbidity and mortality and decreased quality of life, highlighting the necessity of addressing SDoH to improve patient care and outcomes. There is a critical need for integrated care models that consider the medical, social, and psychological factors affecting those with HIV and HF. Strategies proposed include improving access to care, addressing socioeconomic disparities, enhancing educational efforts, and fostering community engagement. Moreover, the importance of mental healthcare integration into the management of HIV and HF is strongly advocated to improve patient outcomes. By taking a comprehensive look at the various social challenges, embracing integrated care models, and making sure everyone has fair access to healthcare services, we can make real progress in enhancing the lives of those affected by HIV and HF. This approach cannot only lower death rates but also significantly improve the quality of life for these individuals.

8.
Cureus ; 16(2): e54402, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38505437

ABSTRACT

There is a profound link between cardiovascular health and mental well-being. This narrative review shows that heart and mental health are not isolated domains but deeply interconnected, influencing each other. It describes how cardiovascular diseases (CVDs) can cause mental health issues such as stress, anxiety, and depression. It also explains how these mental conditions can, in turn, worsen or raise the risk of CVDs. In addition, it emphasizes the necessity of a holistic approach to healthcare that integrates the treatment of physical symptoms of CVDs with interventions aimed at addressing mental health issues. This approach advocates for comprehensive care strategies that include psychotherapy, pharmacological treatments, lifestyle modifications, and digital health technologies. It also highlights the significant role of family and social support in recovery and discusses barriers to integrating mental health care in cardiovascular treatment. The article argues for a paradigm shift in healthcare towards more inclusive and integrated care models. The authors hope to foster a healthcare environment that prioritizes holistic care by increasing awareness about the connection between heart and mind. The call to action includes policy changes and healthcare system reforms aimed at facilitating the integration of mental health services into cardiovascular care, ultimately leading to improved outcomes for patients with CVDs and associated mental health issues.

9.
Cureus ; 16(2): e54018, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38476807

ABSTRACT

Heart failure, particularly in its advanced stages, significantly impacts quality of life. Despite progress in Guideline-Directed Medical Therapy (GDMT) and invasive treatments, heart transplantation (HT) remains the primary option for severe cases. However, complications such as graft rejection present significant challenges that necessitate effective monitoring. Endomyocardial biopsy (EMB) is the gold standard for detecting rejection, but its invasive nature, associated risks, and healthcare costs have shifted interest in non-invasive techniques. Donor-derived cell-free DNA (dd-cfDNA) has gained attention as a promising non-invasive biomarker for monitoring graft rejection. Compared to EMB, dd-cfDNA detects graft rejection early and enables clinicians to adjust immunosuppression promptly. Despite its advantages, dd-cfDNA testing faces challenges, such as the need for specialized technology and potential inaccuracies due to other clinical conditions. Additionally, dd-cfDNA cannot yet differentiate between types of graft rejection, and its effectiveness in chronic rejection remains unclear. Research is ongoing to set precise standards for dd-cfDNA levels, which would enhance its diagnostic accuracy and help in clinical decisions. The article also points to the future of HT monitoring, which may involve combining dd-cfDNA with other biomarkers and integrating artificial intelligence to improve diagnostic capabilities and personalize patient care. Furthermore, it emphasizes both global and racial inequalities in dd-cfDNA testing and the ethical issues related to its use in transplant medicine.

10.
Cureus ; 16(2): e53505, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38440014

ABSTRACT

Pulmonary embolism (PE) represents a significant clinical challenge that substantially impacts healthcare systems. This case report focuses on the nuances of risk stratification in PE, highlighted through the presentation of a 64-year-old female patient. The uniqueness of this case lies in the patient's atypical presentation, where decreased exercise tolerance was the sole symptom leading to the diagnosis of PE. The patient was found to have new-onset atrial fibrillation, elevated levels of N-terminal pro-brain natriuretic peptide (NT-proBNP), and signs of right ventricular strain on imaging. This scenario underscores the necessity for a comprehensive assessment in PE cases, particularly when classic symptoms (e.g., tachycardia, shortness of breath, chest pain) are absent. We explore the incidence of PE in patients diagnosed with deep vein thrombosis, examining the critical role of cardiac biomarkers, including B-type natriuretic peptide, NT-proBNP, and troponins, in prognostication and their potential use in risk assessment tools for PE patients. Additionally, the significance of electrocardiogram evaluation in these patients and its role in risk stratification is thoroughly assessed.

11.
Cureus ; 16(1): e52677, 2024 Jan.
Article in English | MEDLINE | ID: mdl-38380205

ABSTRACT

Hemorrhagic pericardial effusion (HPE) is a subtype of pericardial effusion marked by the accumulation of serosanguineous or bloody fluid within the pericardial cavity. We present a case of a 65-year-old female who presented to the hospital with abdominal pain and was found to have pericardial effusion. The patient's condition evolved into cardiac tamponade, and employing diagnostic techniques such as imaging and pericardiocentesis, a substantial bloody effusion was uncovered, indicative of HPE. This report underscores the complexity of HPE diagnosis and examines the non-iatrogenic etiological factors contributing to HPE, focusing on three primary causes: malignancy, infection, and autoimmune disorders. It offers a detailed exploration of each etiology, backed by current medical literature and case studies. It outlines the diagnostic strategies pertinent to each cause, underscoring the need for a tailored approach to manage such cases. It emphasizes the importance of a meticulous and individualized diagnostic process, vital for accurate identification and effective management of this condition.

12.
Curr Probl Cardiol ; 49(1 Pt A): 102027, 2024 Jan.
Article in English | MEDLINE | ID: mdl-37557941

ABSTRACT

Nonbacterial thrombotic endocarditis (NBTE) is a distinctive condition marked by the presence of aseptic fibrin depositions on cardiac valves due to hypercoagulability and endocardial damage. There is a scarcity of large cohort studies clarifying factors associated with morbidity and mortality of this condition. A systematic literature review was performed utilizing the PubMed, Embase, Cochrane, and Web-of-Science databases to retrieve case reports and series documenting cases of NBTE from inception until September-2022. A descriptive analysis of basic characteristics was carried out, followed by multivariate regression analysis to identify risk factors associated with morbidity and mortality. A total of 416 case reports and series were identified, of which 450 patients were extracted. The female-to-male ratio was around 2:1 with an overall sample median age of 48 (interquartile range [IQR]:34-61). Stroke-like symptoms were the most common presentation and embolic phenomena occurred in 70% of cases, the majority of which were due to stroke. Cancer was associated with higher embolic complications (aOR:6.38, 95% CI = 3.75-10.83, p < 0.01) in comparison to other NBTE etiologies, while age, sex, and vegetation size were not (p > 0.05). All-cause in-hospital mortality was 36%, with cancer etiology being associated with higher mortality: 56% (aOR:3.64, 95% CI = 1.57-8.43, p < 0.01) in comparison to other NBTE etiologies:19%. A significant decrease in NBTE mortality was seen in recent years in comparison to admissions that occurred during the 20th century (aOR:0.07, 95% CI = 0.04-0.15, p < 0.01). While there has been an observed improvement in overall in-hospital mortality rates for patients admitted with NBTE in recent years, it is important to note that cases associated with a cancer etiology are still linked to high morbidity and mortality during hospitalization.


Subject(s)
Endocarditis, Non-Infective , Endocarditis , Neoplasms , Stroke , Humans , Male , Female , Endocarditis, Non-Infective/complications , Endocarditis/diagnosis , Endocarditis/epidemiology , Endocarditis/etiology , Neoplasms/complications , Stroke/etiology , Risk Factors
13.
BMJ Case Rep ; 16(9)2023 Sep 15.
Article in English | MEDLINE | ID: mdl-37714562

ABSTRACT

We present a case of a woman in her 70s, with a history of Mycobacterium avium complex (MAC) pulmonary disease, pectus excavatum, s-shaped thoracolumbar scoliosis, bronchiectasis of the right middle lobe, lingula of left upper lobe, and malnutrition with low body mass index of 14 kg/m2, who presented to the hospital due to worsening shortness of breath and small volume haemoptysis over 2 weeks. The patient was diagnosed with pulmonary MAC infection for the first time in 1999 without known history of pulmonary disease. Later on, it was complicated by massive haemoptysis requiring bronchial artery embolisation; however, she was unable to complete an oral antibiotic regimen due to gastrointestinal adverse reactions. Chest CT identified a newly found mass in the left upper lobe bulla, consistent with a radiological finding of aspergilloma. We present a rare symptoms constellation, described as 'Lady Windermere syndrome' and chronic untreated MAC infection progressing from reticulonodular changes to fibrocavitary lung disease and suspected aspergilloma formation.


Subject(s)
Bronchiectasis , Pneumonia , Pulmonary Aspergillosis , Tuberculosis , Female , Humans , Hemoptysis/etiology , Mycobacterium avium Complex , Pulmonary Aspergillosis/diagnosis , Pulmonary Aspergillosis/diagnostic imaging , Bronchiectasis/complications , Bronchiectasis/diagnostic imaging
14.
Cureus ; 15(7): e41424, 2023 Jul.
Article in English | MEDLINE | ID: mdl-37546045

ABSTRACT

Type V hyperlipoproteinemia or multifactorial chylomicronemia syndrome is a rare lipid disorder triggered mainly by uncontrolled diabetes, obesity, poor diet, or particular medications. It is associated with an increased risk of acute pancreatitis and accelerated coronary artery disease which may manifest in younger age groups. We present a case of a 42-year-old male who presented to the emergency department (ED) complaining of a non-healing hand injury. Upon laboratory workup, the patient was found to have an elevated total cholesterol (TC) of 1129 mg/dL, very low levels of high-density lipoprotein (HDL) and triglycerides (TG) > 4000 mg/dL with an inability to calculate low-density lipoprotein (LDL). Lipoprotein electrophoresis revealed an actual TG level of > 7000 mg/dL, increased chylomicrons, normal B and pre-B-lipoproteins, and increased L-lipoproteins with an elevated Apolipoprotein B. Despite these derangements, the patient did not exhibit any abdominal complaints, demonstrating a normal lipase level. The physical exam was indicative of bilateral arcus senilis and obesity. Insulin drip was initiated along with intravenous (IV) hydration and it required 12 days to bring triglycerides down to less than 1000 mg/dL. The total cholesterol was also seen to be down trending to around 500 mg/dL and the HDL improved to 22 mg/dL. We present this case as a unique presentation of asymptomatic chylomicronemia resistant to insulin treatment with an elevated ApoB but with no evidence of pancreatitis or coronary artery disease.

15.
Cureus ; 15(12): e50096, 2023 Dec.
Article in English | MEDLINE | ID: mdl-38186540

ABSTRACT

The prevalence of atrial flutter (AFL) is increasing among the elderly population, and managing this condition presents specific challenges within this demographic. As patients age, they often exhibit reduced responsiveness to conservative treatment, necessitating a more invasive approach. We present a case of a 93-year-old female who presented to the hospital with acute decompensated heart failure (ADHF) and AFL. A year prior, she was diagnosed with arrhythmia-induced cardiomyopathy. Despite recovering her ejection fraction (EF) through guideline-directed medical therapy (GDMT), her EF deteriorated again. The patient declined invasive management for her arrhythmia on multiple occasions. Managing such patients is challenging since the approach with pharmacotherapy alone often fails to maintain sinus rhythm or adequately control the ventricular rate. Growing evidence shows that invasive management, especially ablation, may be a safe and effective procedure for this patient population. Furthermore, the studies suggest that ablation may yield particular benefits for patients with simultaneous heart failure and atrial fibrillation/AFL (AF/AFL). Unfortunately, limited data exist regarding the invasive management of AFL in the elderly. Therefore, this case report aims to provide a comprehensive review of the current evidence regarding the safety and efficacy of ablation as a therapeutic option for AFL in elderly patients, with a particular focus on how patients with concomitant heart failure may benefit from ablation.

16.
Audiol Neurootol ; 25(3): 143-150, 2020.
Article in English | MEDLINE | ID: mdl-32007994

ABSTRACT

INTRODUCTION: The aims of this study included: (a) to develop a method of direct acoustic bone conduction (BC) stimulation applied directly to the otic capsule, (b) to investigate the effect of different stimulation sites on the promontory displacement amplitude, and (c) to find the best stimulation site (among 2 located directly on the otic capsule and 1 standard site approved for clinical use) that provides the greatest transmission of vibratory energy. METHODS: Measurements were performed on 9 cadaveric whole human heads. A commercial scanning laser Doppler vibrometer was used. The promontory displacement was recorded in response to BC stimulation delivered by an implant at 3 sites: BC1 on the squamous part of the temporal bone, BC2 on the ampulla of the lateral semicircular canal, and BC3 between the semicircular canals. The displacement of the promontory was analyzed in detail. RESULTS: The results show that BC1 caused an overall smaller promontory displacement than both sites BC2 and 3. BC3 stimulation is more efficient than that at BC2. CONCLUSIONS: BC is an effective method of acoustic stimulus delivery into the inner ear, with the effectiveness increasing when approaching closer to the cochlea. Placing the implant directly on the labyrinth and thus applying vibrations directly to the otic capsule is possible and very effective as proved in this study. The results are encouraging and represent the potential of new stimulation sites that could be introduced in the field of BC hearing rehabilitation as the possible future locations for implantable BC hearing devices.


Subject(s)
Bone Conduction/physiology , Cochlea/physiology , Temporal Bone/physiology , Vibration , Acoustic Stimulation/methods , Aged , Cadaver , Hearing Aids , Humans , Middle Aged
17.
Acta Bioeng Biomech ; 21(3): 75-86, 2019.
Article in English | MEDLINE | ID: mdl-31798024

ABSTRACT

PURPOSE: Bone conduction stimulation applied on the otic capsule may be used in a conductive hearing loss treatment as an alternative to the bone conduction implants in clinical practice. A finite element study was used to evaluate the force amplitude and direction needed for the stimulation. METHODS: A finite element model of a female temporal bone with a precisely reconstructed cochlea was subjected to a harmonic analysis assuming two types of stimulation. At first, the displacement amplitude in the form of air conduction stimulation was applied on the stapes footplate. Then the force amplitude was applied on the otic capsule in the form of bone conduction stimulation. The two force directions were considered: 1) the primary direction, when a typical opening is performed during mastoidectomy, and was coincident with the axis of an imaginary cone, inscribed in the opening, and 2) the direction perpendicular to the stapes footplate. The force amplitude was set so that the response from the cochlea corresponded to the result of air conduction stimulation applied on the stapes footplate. RESULTS: The amplitude and phase of vibration and the volume displacement on the round window membrane were considered as well as vibrations of the basilar membrane, spiral lamina, and promontory. CONCLUSIONS: The cochlear response was comparable for the two types of stimulation. The efficiency of bone conduction stimulation depended on the force direction. For the primary direction, the force was a few times smaller than for the direction perpendicular to the stapes footplate.


Subject(s)
Bone Conduction/physiology , Models, Theoretical , Stapes/physiology , Temporal Bone/physiology , Adult , Air , Basilar Membrane/physiology , Female , Finite Element Analysis , Humans , Temporal Bone/diagnostic imaging , Vibration
18.
Ear Hear ; 40(6): 1437-1444, 2019.
Article in English | MEDLINE | ID: mdl-31033633

ABSTRACT

OBJECTIVES: The aim of this study was to investigate the following: (1) the vibration pattern of the round window (RW) membrane in human cadavers during air (AC) and bone conduction (BC) stimulation at different excitation sites; (2) the effect of the stimulation on the fluid volume displacement (VD) at the RW and compare the VD between BC and AC stimulation procedures; (3) the effectiveness of cochlear stimulation by the bone implant at different excitation sites. DESIGN: The RW membrane vibrations were measured by using a commercial scanning laser Doppler vibrometer. The RW vibration amplitude was recorded at 69 measurement points evenly distributed in the measurement field covering the entire surface of the RW membrane and a part of the surrounding bony surface. RW vibration was induced first with AC and then with BC stimulation through an implant positioned at two sites. The first site was on the skull surface at the squamous part of the temporal bone (implant no. 1), a place typical for bone-anchored hearing aids. The second site was close to the cochlea at the bone forming the ampulla of the lateral semicircular canal (implant no. 2). The displacement amplitude (dP) of the point P on the promontory was determined and used to calculate the relative displacement (drRW) of points on the RW membrane, drRW = dRW - dP. VD parameter was used to analyze the effectiveness of cochlear stimulation by the bone implant screwed at different excitation sites. RESULTS: RW membrane displacement amplitude of the central part of the RW was similar for AC and BC implant no. 1 stimulation, and for BC implant no. 2 much larger for frequency range >1 kHz. BC implant no. 2 causes a larger displacement amplitude of peripheral parts of the RW and the promontory than AC and BC implant no. 1, and BC implant no. 1 causes larger than AC stimulation. The effect of BC stimulation exceeds that of AC with identical intensity, and that the closer BC stimulation to the otic capsule, the more effective this stimulation is. A significant decrease in the value of VD at the RW is observed for frequencies >2 kHz for both AC and BC stimulation with BC at both locations of the titanium implant placement. For frequencies >1 kHz, BC implant no. 2 leads to a significantly larger VD at the RW compared to BC implant no. 1. Thus, the closer to the otic capsule the BC stimulation is located, the more effective it is. CONCLUSIONS: Experimental conditions allow for an effective acoustic stimulation of the inner ear by an implant screwed to the osseous otic capsule. The mechanical effect of BC stimulation with a titanium implant placed in the bone of the ampulla of the lateral semicircular canal significantly exceeds the effect of an identical stimulation with an implant placed in the temporal squama at a conventional site for an implant anchored in the bone. The developed research method requires the implementation on a larger number of temporal bones in order to obtain data concerning interindividual variability of the observed mechanical phenomena.


Subject(s)
Acoustic Stimulation/methods , Bone Conduction/physiology , Round Window, Ear/physiology , Vibration , Cadaver , Humans , Male , Middle Aged , Physical Stimulation/methods
19.
Hear Res ; 310: 13-26, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24463104

ABSTRACT

The effect of different stapes prostheses on the basilar membrane (BM) motion was determined. To that end, a three dimensional finite element (FE) model of the passive human cochlea was developed. Passive responses of the BM were found based on coupled fluid-structure interactions between the cochlear solid structures and the scala fluids. The passive BM vibrations in normal (healthy) cochlea were compared with vibrations in the cochlea in which a 0.4-mm piston or a proposed new type of prosthesis was implanted. The proposed chamber prosthesis was not experimentally implanted, but only numerically simulated. Design of the new chamber stapes prosthesis is presented for the first time in this paper. The simulation results showed 10-20 dB decrease in BM displacement amplitude in the case of the piston. In contrast, the BM responses in the cochlea with the new prosthesis are higher with respect to the healthy ear. The results obtained in this study are promising for further research to optimize the design of the new chamber stapes prosthesis.


Subject(s)
Basilar Membrane/physiology , Cochlear Implants , Stapes Surgery/instrumentation , Finite Element Analysis , Humans , Models, Biological , Prosthesis Design , Stapes/anatomy & histology , Stapes/physiology , Stapes Surgery/methods , Vibration
20.
Biomech Model Mechanobiol ; 12(6): 1243-61, 2013 Nov.
Article in English | MEDLINE | ID: mdl-23462937

ABSTRACT

Piston stapes prostheses are implanted in patients with refractory conductive or mixed hearing loss due to stapes otosclerosis to stimulate the perilymph with varying degrees of success. The overclosure effect described by the majority of researchers affects mainly low and medium frequencies, and a large number of patients report a lack of satisfactory results for frequencies above 2 kHz. The mechanics of perilymph stimulation with the piston have not been studied in a systematic manner. The objective of this study was to assess the influence of stapedotomy surgery on round window membrane vibration and to estimate the postoperative outcomes using the finite element (FE) method. The study hypothesis is that the three-dimensional FE model developed of the human inner ear, which simulates the round window (RW) membrane vibration, can be used to assess the influence of stapedotomy on auditory outcomes achieved after the surgical procedure. An additional objective of the study was to enable the simulation of RW membrane vibration after stapedotomy using a new type of stapes prosthesis currently under investigation at Warsaw University of Technology. A three-dimensional finite element (FE) model of the human inner ear was developed and validated using experimental data. The model was then used to simulate the round window membrane vibration before and after stapedotomy surgery. Functional alterations of the RW membrane vibration were derived from the model and compared with the results of experimental measurements from temporal bones of a human cadaver. Piston stapes prosthesis implantation causes an approximately fivefold (14 dB) lower amplitude of the RW membrane vibrations compared with normal anatomical conditions. A satisfactory agreement between the FE model and the experimental data was found. The new prosthesis caused an increase of 20-30 dB in the RW displacement amplitude compared with the 0.4-mm piston prosthesis. In all frequencies, the FE model predicted a RW displacement curve that was above the experimental curves for the normal ear. The stapedotomy can be well simulated by the FE model to predict the auditory outcomes achieved following this otosurgery procedure. The 3D FE model developed in this study may be used to optimize the geometry of a new type of stapes prosthesis in order to achieve a similar sound transmission through the inner ear as for a normal middle ear. This should provide better auditory outcomes for patients with stapedial otosclerosis.


Subject(s)
Finite Element Analysis , Round Window, Ear/physiology , Round Window, Ear/surgery , Stapes Surgery , Vibration , Adolescent , Adult , Humans , Models, Biological , Ossicular Prosthesis , Reproducibility of Results , Temporal Bone/physiology , Temporal Bone/surgery
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