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1.
Front Cardiovasc Med ; 11: 1417029, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39119182

RESUMO

Background: Direct current cardioversion (DCCV) is used as elective and emergency rhythm control for atrial fibrillation (AF). We aimed to explore the role of P-wave parameters measured during sinus rhythm using body surface mapping (BSM) in predicting successful DCCV for persistent atrial fibrillation (persAF) at 12 months. Methods: This case-control study included 56 males >18 years old who underwent DCCV for persAF. P-wave parameter collection after DCCV for AF was done using 128 unipolar leads. A band-pass filter of 1-50 Hz was utilised. Corrected P-wave duration (PWDc), P-wave amplitude, and P-wave dispersion were measured to predict 12-month outcomes and time of recurrence. Results: The mean age was 64 ± 4 years, and 23 patients (44%) were on amiodarone. The 12-month success rate was 44% (n = 23), while the rest reverted to AF after 2.6 ± 0.4 months. The parameters were comparable between successful and failed DCCV in the entire cohort and patients not on amiodarone. In patients on amiodarone, patients with failed arms had higher PWDc than those with successful arms (188 vs. 150 ms, P = 0.04). Receiver operator characteristic curve analysis for PWDc in the amiodarone cohort showed an area under the curve (AUC) of 0.75 and P = 0.049. A recurrence cut-off >161 ms had a sensitivity of 69% and a specificity of 100%, with a hazard ratio of 10.7, P = 0.004. The parameters were not predictive of the time of recurrence. Conclusion: In patients on amiodarone, increased PWDc measured using BSM was associated with higher AF recurrence at 12 months following DCCV for persAF.

2.
Sensors (Basel) ; 24(15)2024 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-39123835

RESUMO

Deep learning (DL) models have shown promise for the accurate detection of atrial fibrillation (AF) from electrocardiogram/photoplethysmography (ECG/PPG) data, yet deploying these on resource-constrained wearable devices remains challenging. This study proposes integrating a customized channel attention mechanism to compress DL neural networks for AF detection, allowing the model to focus only on the most salient time-series features. The results demonstrate that applying compression through channel attention significantly reduces the total number of model parameters and file size while minimizing loss in detection accuracy. Notably, after compression, performance increases for certain model variants in key AF databases (ADB and C2017DB). Moreover, analyzing the learned channel attention distributions after training enhances the explainability of the AF detection models by highlighting the salient temporal ECG/PPG features most important for its diagnosis. Overall, this research establishes that integrating attention mechanisms is an effective strategy for compressing large DL models, making them deployable on low-power wearable devices. We show that this approach yields compressed, accurate, and explainable AF detectors ideal for wearables. Incorporating channel attention enables simpler yet more accurate algorithms that have the potential to provide clinicians with valuable insights into the salient temporal biomarkers of AF. Our findings highlight that the use of attention is an important direction for the future development of efficient, high-performing, and interpretable AF screening tools for wearable technology.


Assuntos
Algoritmos , Fibrilação Atrial , Aprendizado Profundo , Eletrocardiografia , Redes Neurais de Computação , Dispositivos Eletrônicos Vestíveis , Fibrilação Atrial/diagnóstico , Fibrilação Atrial/fisiopatologia , Humanos , Eletrocardiografia/métodos , Fotopletismografia/métodos , Processamento de Sinais Assistido por Computador
3.
Rev Cardiovasc Med ; 25(7): 250, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-39139441

RESUMO

Background: Pulmonary vein isolation (PVI) ablation is the established gold standard therapy for patients with symptomatic drug refractory atrial fibrillation (AF). Advancements in radiofrequency (RF) ablation, have led to the development of the novel contact force-sensing temperature-controlled very high-power short-duration (vHPSD) RF ablation. This setting delivers 90 W for up to 4 seconds with a constant irrigation flow rate of 8 mL/min. The aim of this study was to compare procedural outcomes and safety with conventional radiofrequency ablation. Methods: An observational study was conducted with patients who underwent first time PVI ablation between August 2020 and January 2022. The cohort was divided into: (1) vHPSD ablation; (2) High-power short duration (HPSD) ablation; (3) THERMOCOOL SMARTTOUCH™ SF (STSF). The vHPSD ablation group was prospectively recruited while the HPSD and STSF group were retrospectively collected. Primary outcomes were procedural success, PVI duration, ablation duration and incidence of perioperative adverse events. Secondary outcomes were intraprocedural morphine and midazolam requirement. Results: A total of 175 patients were included in the study with 100, 30 and 45 patients in the vHPSD, HPSD and STSF group, respectively. PVI was successfully attained in all vHPSD patients. vHPSD demonstrated significantly reduced time required for PVI and total energy application in comparison to the HPSD and STSF groups (67.7 ± 29.7 vs. 92.9 ± 25.7 vs. 93.6 ± 29.1 min, p < 0.0001; 9.87 ± 4.16 vs. 33.9 ± 7.49 vs. 36.0 ± 10.5 min, p < 0.0001, respectively). Intravenous morphine and midazolam requirement was lower in the vHPSD group compared to the HPSD and STSF groups (10.2 ± 3.43 vs. 16.1 ± 4.58 vs. 15.3 ± 3.94 mg, p < 0.0001; 4.04 ± 3.24 vs. 8.63 ± 5.22 vs. 8.58 ± 4.72 mg, p < 0.0001). One cardiac tamponade was observed in both the vHPSD and HPSD groups while the STSF group exhibited an embolic stoke and two pericardial effusions that did not require drainage. Conclusions: In this study, vHPSD demonstrated a comparable safety profile to the other treatment arms. Procedural duration and energy application time was substantially reduced along with sedation requirement notwithstanding the limitations of observational study design, these preliminary findings are promising with respect to periprocedural outcomes and safety of vHPSD however longitudinal outcomes will be essential to assessing the overall efficacy of this novel technology.

4.
Clin Infect Pract ; 23: 100362, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-39145146

RESUMO

Objectives: Little work has been done investigating the prevalence and impact of comorbidities on cholera outcomes within conflict settings. We describe the clinical outcomes of patients treated for cholera in Latakia, Syria, during the 2022-2023 cholera outbreak. Methods: We performed a single-centre retrospective observational cohort study of patients admitted to the hospital with suspected cholera between 15th December 2022 and 15th February 2023 at National Hospital, Latakia, Syria. Multivariable negative binomial regression analysis was used to investigate the variables' relationship to hospital length of stay. Results: The study involved 89 patients admitted to the hospital; none were vaccinated against cholera. Cholera rapid diagnostic test was positive in 91 % of patients. Half of the patients (51 %) were male; a third (35 %) had hypertension, and a fifth (19 %) had diabetes. One patient passed away during admission. Patients who were male, had diabetes and were hypertensive tended to have longer hospital stays in univariable analysis. When these factors were added to a multivariable negative binomial model (consisting of age, gender, hypertension and diabetes), male sex (IRR: 4.1, 95 % CI: 1.28-6.2, p = 0.001), the presence of hypertension (IRR: 2.1,95 % CI: 1.14 to 4.1, p = 0.004) and diabetes (IRR: 2, 95 % CI: 1.2 to 2.7, p = 0.001) were independent predictors of longer hospital stays. Conclusion: In conflict settings, hypertension and diabetes are common in patients admitted to hospital with cholera and are associated with longer hospital stays. Mortality from cholera, however, was low. Our findings highlight the importance of comorbidity control in mitigating excess morbidity during infectious disease outbreaks within conflict areas.

5.
Rev Cardiovasc Med ; 25(4): 143, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-39076563

RESUMO

Chronic kidney disease (CKD) and atrial fibrillation (AF) are associated with significant cardiovascular morbidity and mortality. Recent studies have highlighted an increased prevalence and incidence of AF in patients with CKD. This article aims to provide a comprehensive review of current management strategies and considerations of treating atrial fibrillation with concomitant CKD. Potential electrophysiological mechanisms between AF and CKD are explored. Current evidence and literature focusing on pharmacological rate and rhythm control along with procedural intervention is reviewed and presented. The management of AF and CKD together is complex, but particularly pertinent when considering the close cyclical relationship in the progression of both diseases.

6.
Artigo em Inglês | MEDLINE | ID: mdl-39028283

RESUMO

Chondroitin sulfate proteoglycans (CSPGs) inhibit sympathetic reinnervation in rodent hearts post myocardial infarction (MI), causing regional hypo-innervation that is associated with supersensitivity of ß-adrenergic receptors and increased arrhythmia susceptibility. To investigate the role of CSPGs and hypo-innervation in the heart of larger mammals, we used a rabbit model of reperfused MI and tested electrophysiological responses to sympathetic nerve stimulation (SNS). Innervated hearts from MI and sham rabbits were optically mapped using voltage and Ca2+-sensitive dyes. SNS was performed with electrical stimulation of the spinal cord and ß-adrenergic responsiveness was tested using isoproterenol. Sympathetic nerve density and CSPG expression were evaluated using immunohistochemistry. CSPGs were robustly expressed in the infarct region of all MI hearts, and the presence of CSPGs was associated with reduced sympathetic nerve density in the infarct vs. remote region. Action potential duration (APD) dispersion and susceptibility to ventricular tachycardia/fibrillation (VT/VF) were increased with SNS in MI hearts but not in sham. SNS decreased APD80 in MI but not sham hearts, while isoproterenol decreased APD80 in both groups. Isoproterenol also shortened Ca2+ transient duration (CaTD80) in both groups but to a greater extent in MI hearts. Our data suggest sympathetic remodeling post-MI is similar between rodents and rabbits, with CSPGs associated with sympathetic hypo-innervation. Despite a reduction in sympathetic nerve density, the infarct region of MI hearts remained responsive to both physiological SNS and isoproterenol, potentially through preserved or elevated ß-adrenergic responsiveness, which may underly increased APD dispersion and susceptibility for VT/VF.

7.
bioRxiv ; 2024 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-38895350

RESUMO

Chondroitin sulfate proteoglycans (CSPGs) inhibit sympathetic reinnervation in rodent hearts post myocardial infarction (MI), causing regional hypo-innervation that is associated with supersensitivity of ß-adrenergic receptors and increased arrhythmia susceptibility. To investigate the role of CSPGs and hypo-innervation in the heart of larger mammals, we used a rabbit model of reperfused MI and tested electrophysiological responses to sympathetic nerve stimulation (SNS). Innervated hearts from MI and sham rabbits were optically mapped using voltage and Ca 2+ -sensitive dyes. SNS was performed with electrical stimulation of the spinal cord and ß-adrenergic responsiveness was tested using isoproterenol. Sympathetic nerve density and CSPG expression were evaluated using immunohistochemistry. CSPGs were robustly expressed in the infarct and border zone of all MI hearts, and the presence of CSPGs was associated with reduced sympathetic nerve density in the infarct vs. remote region. Action potential duration (APD) dispersion and susceptibility to ventricular tachycardia/fibrillation (VT/VF) were increased with SNS in MI hearts but not in sham. SNS decreased APD 80 in MI but not sham hearts, while isoproterenol decreased APD 80 in both groups. Isoproterenol also shortened Ca 2+ transient duration (CaTD 80 ) in both groups but to a greater extent in MI hearts. Our data suggest sympathetic remodeling post-MI is similar between species, with CSPGs associated with sympathetic hypo-innervation. Despite a reduction in sympathetic nerve density, the infarct region of MI hearts remained responsive to both physiological SNS and isoproterenol, potentially through preserved or elevated ß-adrenergic responsiveness, which may underly increased APD dispersion and susceptibility for VT/VF. NEW & NOTEWORTHY: Here we show that CSPGs are present in the infarcts of rabbit hearts with reperfused MI, where they are associated with reduced sympathetic nerve density. Despite hypo-innervation, sympathetic responsiveness is maintained or enhanced in MI rabbit hearts, which also demonstrate increased APD dispersion and tendency for arrhythmias following sympathetic modulation. Together, this study indicates that the mechanisms of sympathetic remodeling post-MI are similar between species, with hypo-innervation likely associated with enhanced ß-adrenergic sensitivity.

8.
Perfusion ; : 2676591241259140, 2024 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-38830625

RESUMO

BACKGROUND: Atrial fibrillation (AF) is the most common sustained arrhythmia worldwide. However, there is no data on AF inpatient management strategies and clinical outcomes in Syria. OBJECTIVES: The study aims were to review the inpatient management of patients with AF and assess cardiovascular (CV) mortality in a tertiary cardiology centre in Latakia, Syria. METHODS: A single-centre retrospective observational cohort study was conducted at Tishreen's University Hospital, Latakia, Syria, from June 2021 to June 2023. Patients ≥16 years of age presenting and being treated for AF as the primary diagnosis with or without a thromboembolic event were included. Medical records were examined for patients' demographics, laboratory results, treatment plans and inpatient details. Studied outcomes include inpatient all-cause and CV mortality, ischemic and bleeding events, and conversion to sinus rhythm (SR). RESULTS: The study included 596 patients. The median age was 58, and 61% were males. 121 patients (20.3%) were known to have AF. A rhythm control strategy was pursued in 39% of patients. Ischemic and bleeding events occurred in 62 (11%) and 12 (2%), respectively. CV and all-cause mortality occurred in 28 (4.7%) and 31 patients (5%), respectively. The presence of valvular heart disease (VHD) (adjusted odds ratio (aOR) = 9.1, 95% confidence interval (CI): 1.7 to 55.1, p < .001), thyroid disease (aOR: 9.7, 95% CI = 1.2 to 91.6, p < .001) and chronic obstructive pulmonary disease (COPD) (aOR: 82, 95% CI: 12.7 to 71, p < .001) were independent risk factors of increased CV inpatient mortality. CONCLUSION: Syrian inpatients admitted with AF in Latakia are relatively younger than those in other countries. Active thyroid disease, COPD and VHD were independent risk factors of inpatient CV mortality with AF.

10.
Eur Heart J Digit Health ; 5(3): 384-388, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38774363

RESUMO

Aims: European and American clinical guidelines for implantable cardioverter defibrillators are insufficiently accurate for ventricular arrhythmia (VA) risk stratification, leading to significant morbidity and mortality. Artificial intelligence offers a novel risk stratification lens through which VA capability can be determined from the electrocardiogram (ECG) in normal cardiac rhythm. The aim of this study was to develop and test a deep neural network for VA risk stratification using routinely collected ambulatory ECGs. Methods and results: A multicentre case-control study was undertaken to assess VA-ResNet-50, our open source ResNet-50-based deep neural network. VA-ResNet-50 was designed to read pyramid samples of three-lead 24 h ambulatory ECGs to decide whether a heart is capable of VA based on the ECG alone. Consecutive adults with VA from East Midlands, UK, who had ambulatory ECGs as part of their NHS care between 2014 and 2022 were recruited and compared with all comer ambulatory electrograms without VA. Of 270 patients, 159 heterogeneous patients had a composite VA outcome. The mean time difference between the ECG and VA was 1.6 years (⅓ ambulatory ECG before VA). The deep neural network was able to classify ECGs for VA capability with an accuracy of 0.76 (95% confidence interval 0.66-0.87), F1 score of 0.79 (0.67-0.90), area under the receiver operator curve of 0.8 (0.67-0.91), and relative risk of 2.87 (1.41-5.81). Conclusion: Ambulatory ECGs confer risk signals for VA risk stratification when analysed using VA-ResNet-50. Pyramid sampling from the ambulatory ECGs is hypothesized to capture autonomic activity. We encourage groups to build on this open-source model. Question: Can artificial intelligence (AI) be used to predict whether a person is at risk of a lethal heart rhythm, based solely on an electrocardiogram (an electrical heart tracing)? Findings: In a study of 270 adults (of which 159 had lethal arrhythmias), the AI was correct in 4 out of every 5 cases. If the AI said a person was at risk, the risk of lethal event was three times higher than normal adults. Meaning: In this study, the AI performed better than current medical guidelines. The AI was able to accurately determine the risk of lethal arrhythmia from standard heart tracings for 80% of cases over a year away-a conceptual shift in what an AI model can see and predict. This method shows promise in better allocating implantable shock box pacemakers (implantable cardioverter defibrillators) that save lives.

11.
Indian Heart J ; 76(3): 147-153, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38609052

RESUMO

Heart failure (HF) is emerging as a major public health problem both in high- and low - income countries. The mortality and morbidity due to HF is substantially higher in low-middle income countries (LMICs). Accessibility, availability and affordability issues affect the guideline directed therapy implementation in HF care in those countries. This call to action urges all those concerned to initiate preventive strategies as early as possible, so that we can reduce HF-related morbidity and mortality. The most important step is to have better prevention and treatment strategies for diseases such as hypertension, ischemic heart disease (IHD), type-2 diabetes, and rheumatic heart disease (RHD) which predispose to the development of HF. Setting up dedicated HF-clinics manned by HF Nurses, can help in streamlining HF care. Subsidized in-patient care, financial assistance for device therapy, use of generic medicines (including polypill strategy) will be helpful, along with the use of digital technologies.


Assuntos
Cardiologia , Insuficiência Cardíaca , Sociedades Médicas , Humanos , Insuficiência Cardíaca/terapia , Insuficiência Cardíaca/tratamento farmacológico , Índia/epidemiologia , Pandemias , Consenso , Congressos como Assunto , Morbidade/tendências , Saúde Global
12.
Am J Physiol Heart Circ Physiol ; 326(6): H1337-H1349, 2024 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-38551482

RESUMO

Nicotine is the primary addictive component of tobacco products. Through its actions on the heart and autonomic nervous system, nicotine exposure is associated with electrophysiological changes and increased arrhythmia susceptibility. To assess the underlying mechanisms, we treated rabbits with transdermal nicotine (NIC, 21 mg/day) or control (CT) patches for 28 days before performing dual optical mapping of transmembrane potential (RH237) and intracellular Ca2+ (Rhod-2 AM) in isolated hearts with intact sympathetic innervation. Sympathetic nerve stimulation (SNS) was performed at the first to third thoracic vertebrae, and ß-adrenergic responsiveness was additionally evaluated following norepinephrine (NE) perfusion. Baseline ex vivo heart rate (HR) and SNS stimulation threshold were higher in NIC versus CT (P = 0.004 and P = 0.003, respectively). Action potential duration alternans emerged at longer pacing cycle lengths (PCL) in NIC versus CT at baseline (P = 0.002) and during SNS (P = 0.0003), with similar results obtained for Ca2+ transient alternans. SNS shortened the PCL at which alternans emerged in CT but not in NIC hearts. NIC-exposed hearts tended to have slower and reduced HR responses to NE perfusion, but ventricular responses to NE were comparable between groups. Although fibrosis was unaltered, NIC hearts had lower sympathetic nerve density (P = 0.03) but no difference in NE content versus CT. These results suggest both sympathetic hypoinnervation of the myocardium and regional differences in ß-adrenergic responsiveness with NIC. This autonomic remodeling may contribute to the increased risk of arrhythmias associated with nicotine exposure, which may be further exacerbated with long-term use.NEW & NOTEWORTHY Here, we show that chronic nicotine exposure was associated with increased heart rate, increased susceptibility to alternans, and reduced sympathetic electrophysiological responses in the intact rabbit heart. We suggest that this was due to sympathetic hypoinnervation of the myocardium and diminished ß-adrenergic responsiveness of the sinoatrial node following nicotine treatment. Though these differences did not result in increased arrhythmia propensity in our study, we hypothesize that prolonged nicotine exposure may exacerbate this proarrhythmic remodeling.


Assuntos
Potenciais de Ação , Frequência Cardíaca , Coração , Nicotina , Sistema Nervoso Simpático , Animais , Nicotina/toxicidade , Nicotina/efeitos adversos , Coelhos , Frequência Cardíaca/efeitos dos fármacos , Potenciais de Ação/efeitos dos fármacos , Coração/inervação , Coração/efeitos dos fármacos , Sistema Nervoso Simpático/efeitos dos fármacos , Sistema Nervoso Simpático/fisiopatologia , Masculino , Agonistas Nicotínicos/toxicidade , Agonistas Nicotínicos/administração & dosagem , Sinalização do Cálcio/efeitos dos fármacos , Arritmias Cardíacas/induzido quimicamente , Arritmias Cardíacas/fisiopatologia , Arritmias Cardíacas/metabolismo , Adesivo Transdérmico , Preparação de Coração Isolado , Administração Cutânea , Norepinefrina/metabolismo
14.
IEEE Trans Biomed Eng ; 71(7): 2143-2153, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38319768

RESUMO

Electrocardiogram (ECG) delineation to identify the fiducial points of ECG segments, plays an important role in cardiovascular diagnosis and care. Whilst deep delineation frameworks have been deployed within the literature, several factors still hinder their development: (a) data availability: the capacity of deep learning models to generalise is limited by the amount of available data; (b) morphology variations: ECG complexes vary, even within the same person, which degrades the performance of conventional deep learning models. To address these concerns, we present a large-scale 12-leads ECG dataset, ICDIRS, to train and evaluate a novel deep delineation model-ECGVEDNET. ICDIRS is a large-scale ECG dataset with 156,145 QRS onset annotations and 156,145 T peak annotations. ECGVEDNET is a novel variational encoder-decoder network designed to address morphology variations. In ECGVEDNET, we construct a well-regularized latent space, in which the latent features of ECG follow a regular distribution and present smaller morphology variations than in the raw data space. Finally, a transfer learning framework is proposed to transfer the knowledge learned on ICDIRS to smaller datasets. On ICDIRS, ECGVEDNET achieves accuracy of 86.28%/88.31% within 5/10 ms tolerance for QRS onset and accuracy of 89.94%/91.16% within 5/10 ms tolerance for T peak. On QTDB, the average time errors computed for QRS onset and T peak are -1.86 ± 8.02 ms and -0.50 ± 12.96 ms, respectively, achieving state-of-the-art performances on both large and small-scale datasets. We will release the source code and the pre-trained model on ICDIRS once accepted.


Assuntos
Aprendizado Profundo , Eletrocardiografia , Processamento de Sinais Assistido por Computador , Humanos , Eletrocardiografia/métodos , Bases de Dados Factuais , Algoritmos
15.
Radiography (Lond) ; 30(1): 178-184, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38035431

RESUMO

INTRODUCTION: Newly qualified radiographers often find working in the operating theatre (OT) challenging and intimidating. These perceptions, which inhibit confidence, may hinder their effectiveness in interprofessional teamwork, which may in turn adversely affect patient outcomes. A collaborative education programme was designed, building upon the foundations of competency-based education (CBE) and simulation-based mastery learning (SBML) to examine its potential in mitigating these perceptions. The objective of this research was to assess participants' experience and level of competency after attending the curated collaborative educational programme. METHODS: The programme was developed based on the Analysis, Design, Development, Implementation, and Evaluation (ADDIE) model and comprises two teaching and learning phases: educational session and simulation. A collaborative approach was undertaken to develop an assessment checklist for the interprofessional simulation. Requirements for the simulation, such as scenario design, information and storyboard, task trainer, logistics, and learners' briefing, debrief, and feedback, were identified and assembled. The radiographers' performance was recorded using a practical skills assessment checklist and a theory assessment. RESULTS: Twelve radiographers participated and showed improvement in their self-rating of learning objectives before and after the programme. The median (interquartile range) score achieved in the theory assessment, out of a possible of 11, was 9.00 (7.75-9.50). The median (interquartile range) score achieved in the simulation component, out of a possible of 16, was 15.00 (14.00-15.00). There was statistically significant difference in self-perceived performance in all learning objective domains. CONCLUSION: The findings from the programme were promising. The use of simulation and an assessment checklist proved to be useful learning tools in preparing newly qualified radiographers for work in the OT. IMPLICATIONS FOR PRACTICE: Assessment checklists are valuable tools that should be considered to facilitate teaching and learning. The use of interprofessional simulation activities can support radiographers in developing knowledge, professional skills, and clinical competency. It should be conducted in a timely manner to facilitate the introduction to role understanding and effective communication.


Assuntos
Nefrolitotomia Percutânea , Humanos , Currículo , Aprendizagem
16.
bioRxiv ; 2023 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-38045290

RESUMO

Nicotine is the primary addictive component in tobacco products. Through its actions on the heart and autonomic nervous system, nicotine exposure is associated with electrophysiological changes and increased arrhythmia susceptibility. However, the underlying mechanisms are unclear. To address this, we treated rabbits with transdermal nicotine (NIC, 21 mg/day) or control (CT) patches for 28 days prior to performing dual optical mapping of transmembrane potential (RH237) and intracellular Ca 2+ (Rhod-2 AM) in isolated hearts with intact sympathetic innervation. Sympathetic nerve stimulation (SNS) was performed at the 1 st - 3 rd thoracic vertebrae, and ß-adrenergic responsiveness was additionally evaluated as changes in heart rate (HR) following norepinephrine (NE) perfusion. Baseline ex vivo HR and SNS stimulation threshold were increased in NIC vs. CT ( P = 0.004 and P = 0.003 respectively). Action potential duration alternans emerged at longer pacing cycle lengths (PCL) in NIC vs. CT at baseline ( P = 0.002) and during SNS ( P = 0.0003), with similar results obtained for Ca 2+ transient alternans. SNS reduced the PCL at which alternans emerged in CT but not NIC hearts. NIC exposed hearts also tended to have slower and reduced HR responses to NE perfusion. While fibrosis was unaltered, NIC hearts had lower sympathetic nerve density ( P = 0.03) but no difference in NE content vs. CT. These results suggest both sympathetic hypo-innervation of the myocardium and diminished ß-adrenergic responsiveness with NIC. This autonomic remodeling may underlie the increased risk of arrhythmias associated with nicotine exposure, which may be further exacerbated with continued long-term usage. NEW & NOTEWORTHY: Here we show that chronic nicotine exposure was associated with increased heart rate, lower threshold for alternans and reduced sympathetic electrophysiological responses in the intact rabbit heart. We suggest that this was due to the sympathetic hypo-innervation of the myocardium and diminished ß- adrenergic responsiveness observed following nicotine treatment. Though these differences did not result in increased arrhythmia propensity in our study, we hypothesize that prolonged nicotine exposure may exacerbate this pro-arrhythmic remodeling.

17.
Eur Heart J Case Rep ; 7(12): ytad531, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38046645

RESUMO

Background: Ebstein's anomaly occurs when there is an apical displacement of the tricuspid valve with septal and posterior valve leaflets tethering. This condition often occurs in association with other congenital, structural, or conduction system diseases, including intracardiac shunts, valvular lesions, arrhythmias, accessory conduction pathways, and first-degree atrioventricular (AV) block. We present for the first time a case of a patient with Ebstein's anomaly who presented with second-degree Mobitz II AV block and was successfully treated with conduction system pacing (CSP) due to her young age and the likelihood of a long-term high percentage of pacing. Case summary: We present a case of a 42-year-old lady with a background of complex congenital heart disease, including severe pulmonary stenosis, Ebstein anomaly, and atrial septal defect (ASD). She required complex surgical intervention, including tricuspid valve (TV) repair and subsequently replacement, ASD closure, and pulmonary balloon valvuloplasty. She presented to our hospital with symptomatic second-degree Mobitz II AV block (dizziness, shortness of breath, and exercise intolerance) and right bundle branch block (RBBB) on her baseline ECG. Her echocardiogram showed dilated right ventricle (RV) and left ventricle (LV) with low normal LV systolic function. Due to her young age and the likelihood of a long-term high percentage of RV pacing, we opted for CSP after a detailed discussion and patient consent. The distal HIS position is the preferred pacing strategy at our centre. We could not cross the TV with the standard Medtronic C315 HIS catheter, so we had to use the deflectable C304 HIS catheter. Mapping and pacing of the distal HIS bundle were achieved by Medtronic Selectsecure 3830, 69 cm lead. HIS bundle pacing led to the correction of both second-degree Mobitz II AV block and pre-existing RBBB. The implantation was uneventful, and the patient was discharged home the next day without any acute complications. Discussion: Distal HIS pacing is feasible in patients with surgically treated complex Ebstein anomaly and heart block. This approach can normalize the QRS complex with a high probability of preserving or improving LV function.

18.
Eur Rev Med Pharmacol Sci ; 27(20): 9648-9659, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37916330

RESUMO

OBJECTIVE: This study aimed to conduct a meta-analysis to compare the effectiveness and safety between titanium mesh cage (TMC) and nano-hydroxyapatite/polyamide 66 cage (n-HA/PA66) in the surgical treatment of cervical spondylotic myelopathy (CSM) through anterior cervical corpectomy and fusion (ACCF). MATERIALS AND METHODS: We implemented a comprehensive search strategy across multiple databases, including Wanfang, China Knowledge Network, China Biomedical Literature Database, Wipu, PubMed, Cochran, Embase, and Web of Science. To ensure a thorough examination of available literature, the databases were searched from their inception to January 2023. Two independent researchers evaluated the quality of the included studies by using established criteria. We used RevMan 5.4 (Review Manager Web, The Cochrane Collaboration, Copenhagen, Denmark) to facilitate data extraction and analysis. RESULTS: This analysis included seven controlled clinical studies. The meta-analysis results showed no statistically significant differences between the two groups in terms of operating time, intraoperative bleeding, preoperative Japanese Orthopedic Association (JOA) score, preoperative visual analog scale (VAS) score, preoperative and final follow-up C2-7 Cobb angles, and intervertebral fusion rate (p > 0.05). However, a significant difference was observed between the two groups in terms of the final follow-up JOA [MD = 0.77, 95% CI (0.58, 0.97), p < 0.00001], VAS [MD = -0.50, 95% CI (-0.71, -0.30), p < 0.00001], and sedimentation rate [RR = 0.30, 95% CI (0.18, 0.48), p < 0.00001]. CONCLUSIONS: The use of n-HA/PA66 in ACCF for treating CSM is safe and effective treatment with positive clinical efficacy. In addition, n-HA/PA66 has both effective clinical efficacy and significantly lower fusion settling rates compared to TMC.


Assuntos
Doenças da Medula Espinal , Fusão Vertebral , Espondilose , Humanos , Nylons , Durapatita , Fusão Vertebral/métodos , Espondilose/cirurgia , Resultado do Tratamento , Doenças da Medula Espinal/cirurgia , Vértebras Cervicais/cirurgia , Estudos Retrospectivos
20.
J Mol Cell Cardiol Plus ; 5: 100044, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37745157

RESUMO

Aims: Heart failure is a clinical syndrome typified by abnormal autonomic tone, impaired ventricular function, and increased arrhythmic vulnerability. This study aims to examine electrophysiological, structural and neuronal remodeling following myocardial infarction in a rabbit heart failure model to establish its neuro-cardiac profile. Methods and results: Weight-matched adult male New Zealand White rabbits (3.2 ± 0.1 kg, n = 25) were randomized to have coronary ligation surgeries (HF group, n = 13) or sham procedures (SHM group, n = 12). Transthoracic echocardiography was performed six weeks post-operatively. On week 8, dual-innervated Langendorff-perfused heart preparations were set up for terminal experiments. Seventeen hearts (HF group, n = 10) underwent ex-vivo cardiac MRI. Twenty-two hearts (HF group, n = 7) were examined histologically. Electrical remodeling and abnormal autonomic profile were evident in HF rabbits with exaggerated sympathetic and attenuated vagal effect on ventricular fibrillation threshold, ventricular refractoriness and restitution curves, in addition to increased spatial restitution dispersion. Histologically, there was significant neuronal enlargement at the heart hila and conus arteriosus in HF. Structural remodeling was characterized by quantifiable myocardial scarring, enlarged left ventricles, altered ventricular geometry and impaired contractility. Conclusion: In an infarct-induced rabbit heart failure model, extensive structural, neuronal and electrophysiological remodeling in conjunction with abnormal autonomic profile provide substrates for ventricular arrhythmias.

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