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1.
Am J Emerg Med ; 82: 21-25, 2024 May 08.
Article in English | MEDLINE | ID: mdl-38759250

ABSTRACT

BACKGROUND: In the context of polysubstance use and fentanyl detection in non-opioid drugs supplies (e.g., cocaine, methamphetamine), it is important to re-evaluate and expand our understanding of which populations are at high risk for fatal drug overdoses. The primary objective of this pilot study was to gather data from the ED to characterize the population presenting with drug overdose, including demographics, drug use patterns and comorbidities, to inform upstream overdose prevention efforts. METHODS: A consecutive sample of ED patients undergoing treatment for non-fatal overdose were prospectively recruited for study participation at the time of ED visit. Participants reported history of substance use over the past six months, recent and lifetime overdose, and naloxone receipt and administration history. RESULTS: A total of 76 eligible participants were enrolled over the course of seven months. Participants reported high rates of opioid (56%), stimulant (56%), and cannabis use (59%). Self-reported polysubstance use, defined as self-reported use of more than one substance, was 83%. Of enrolled participants, 64% reported at least one overdose and 39% reported three or more lifetime overdoses prior to their index overdose ED visit. Participants with no self-reported intentional opioid use (n = 32) in the past six months had fentanyl positive urine drug screen 84% of the time versus 89% in the overall study population (n = 74). Participants who did not report opioid use in the past six months were less likely to possess (34% vs. 55%) or to know how to acquire (50% vs. 74%) naloxone compared to participants with self-reported history of opioid use. CONCLUSION: This study demonstrated high rates of fentanyl exposure on toxicology testing at time of overdose across all participants including study participants without self-reported intentional opioid use. Data gathered in the ED at time of overdose can be used to inform upstream naloxone distribution and public health initiatives.

2.
Clin Breast Cancer ; 24(4): e289-e296, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38458842

ABSTRACT

INTRODUCTION: Premenopausal women with high-risk hormone receptor (HR)-positive breast cancer often receive ovarian function suppression (OFS) and anti-estrogen therapy which induces near complete estrogen deprivation (NCED). This treatment improves recurrence-free survival but may increase cardiovascular risk. We sought to identify patterns of cardiovascular care and outcomes in premenopausal women with operable breast cancer. METHODS: Premenopausal women ≤ 50 years of age with stage I-III HR-positive or triple negative breast cancer (TNBC) were identified by retrospective review. We categorized women into 3 groups based on anti-estrogen therapy approach: NCED (HR + OFS), anti-estrogen therapy without OFS (HRnoOFS), and no anti-estrogen therapy (TNBC). Baseline characteristics, post-diagnosis cardiovascular events and cardiovascular actions (tests, referrals and medications) were recorded. Categorical variables were compared among the groups using chi-square and Fisher's exact tests; continuous outcomes were compared using ANOVA. RESULTS: 82, 83, and 52 women were identified in the HR + OFS, HRnoOFS, and TNBC groups respectively; mean follow-up was 5.0 years. Mean number of cardiovascular actions per year were highest in the HR + OFS group compared with HRnoOFS and TNBC groups (0.35 vs. 0.20 and 0.27, respectively; P = .036). The HR + OFS group had significantly more referrals and tests per year than the other groups. Cardiovascular medication initiation did not differ among groups. CONCLUSIONS: In this early follow-up period, there were meaningful numbers of cardiovascular actions, with women on NCED experiencing the most per year. Future work should seek to further understand the impact of anti-estrogen therapy on the cardiovascular health of premenopausal women and test strategies to mitigate cardiotoxicity.


Subject(s)
Breast Neoplasms , Cardiovascular Diseases , Premenopause , Referral and Consultation , Humans , Female , Adult , Middle Aged , Retrospective Studies , Breast Neoplasms/drug therapy , Breast Neoplasms/pathology , Referral and Consultation/statistics & numerical data , Estrogen Antagonists/therapeutic use , Follow-Up Studies , Receptors, Estrogen/metabolism , Triple Negative Breast Neoplasms/drug therapy , Triple Negative Breast Neoplasms/pathology
3.
Harm Reduct J ; 21(1): 54, 2024 Feb 29.
Article in English | MEDLINE | ID: mdl-38424553

ABSTRACT

BACKGROUND: Overdose prevention centers (OPCs) are being implemented in the United States as a strategy to reduce drug-related mortality and morbidity. Previous studies have suggested that people who use drugs (PWUD) with a history of criminal legal system (CLS) involvement (e.g. current probation/parole) are at greater risk of overdose but may also encounter significant barriers to OPC use. The objective of this study was to explore the association between willingness to use an OPC and probation/parole status in a sample of PWUD in Rhode Island. METHODS: This study utilized data from the Rhode Island Prescription and Illicit Drug Study, which enrolled adult PWUD from August 2020 to February 2023. We used Pearson's chi-square and Wilcoxon rank-sum tests to assess bivariate associations between willingness to use an OPC and probation/parole status (current/previous/never), as well as other sociodemographic and behavioral characteristics. In multivariable Poisson analyses, we examined the association between willingness to use an OPC and probation/parole status, adjusting for key sociodemographic and behavioral characteristics. RESULTS: Among 482 study participants, 67% were male, 56% identified as white, 20% identified as Hispanic/Latine, and the median age was 43 (IQR 35-53). Nearly a quarter (24%) had never been on probation/parole, 44% were not currently on probation/parole but had a lifetime history of probation and parole, and 32% were currently on probation/parole. Most participants (71%) reported willingness to use an OPC, and in both bivariate and multivariable analyses, willingness to use an OPC did not vary by probation/parole status. Crack cocaine use and lifetime non-fatal overdose were associated with greater willingness to use an OPC (all p < 0.05). CONCLUSIONS: These data demonstrate high willingness to use OPC among PWUD in Rhode Island regardless of CLS-involvement. As OPCs begin to be implemented in Rhode Island, it will be imperative to engage people with CLS-involvement and to ensure access to the OPC and protection against re-incarceration due to potential barriers, such as police surveillance of OPCs.


Subject(s)
Cocaine-Related Disorders , Criminals , Drug Overdose , Illicit Drugs , Adult , Humans , Male , United States , Female , Rhode Island/epidemiology , Drug Overdose/epidemiology , Drug Overdose/prevention & control
4.
Am Heart J ; 267: 33-43, 2024 Jan.
Article in English | MEDLINE | ID: mdl-37890547

ABSTRACT

Survival with operable breast cancer has improved markedly in recent decades, however, treatment-related cardiovascular toxicities threaten to offset these gains. Ovarian function suppression paired with aromatase inhibition, for premenopausal women with hormone receptor (HR)-positive breast cancer, is a newer widely adopted therapy with the potential for significant long-term cardiovascular toxicity. Abrupt estrogen deprivation for non-cancer reasons is associated with accelerated coronary artery disease. Women with breast cancer treated with aromatase inhibition in addition to ovarian function suppression experience a dual hit with regards to estrogen exposure. The CaRdiac Outcomes With Near-complete estrogen deprivation (CROWN) study seeks to understand the early, subclinical natural history of cardiovascular compromise in young women undergoing near-complete estrogen deprivation (NCED) therapy. It is critical to understand the early subclinical development of cardiovascular disease to identify a window for therapeutic intervention before overt cardiovascular events occur. This three-site regional study (Atrium Health Wake Forest, Duke, and Virginia Commonwealth University) uses serial stress cardiac magnetic resonance (CMR) imaging and cardiac computed tomography angiography (CCTA) obtained during the initial two years of NCED therapy to study myocardial prefusion reserve (MPR), large cardiovascular vessel changes, left ventricular function, and other cardiovascular parameters. The CROWN cohort will consist of 90 premenopausal women with breast cancer, 67 with HR-positive disease receiving NCED and 23 comparators with HR-negative disease. Participants will undergo three annual CMR scans and 2 CCTA scans during the 2-year study period. After initial activation hurdles, accrual has been brisk, and the study is expected to complete accrual in December 2024. Efforts are in place to encourage participant retention with the study primary outcome, change in MPR between the two groups, to be reported in 2026 to 2027. The results of this study will enable premenopausal women with breast cancer to balance the health burdens of cancer at a young age and treatment-related cardiovascular morbidity. Finally, the tools developed here can be utilized to study cardiovascular risk across a range of cancer types and cancer therapies with the ultimate goals of both developing generalizable risk stratification tools as well as validating interventions which prevent overt cardiovascular compromise.


Subject(s)
Breast Neoplasms , Cardiovascular System , Humans , Female , Breast Neoplasms/drug therapy , Breast Neoplasms/pathology , Aromatase/therapeutic use , Estrogens/therapeutic use , Heart
5.
Circ Cardiovasc Imaging ; 16(6): e015063, 2023 06.
Article in English | MEDLINE | ID: mdl-37339173

ABSTRACT

BACKGROUND: The optimal diagnostic strategy for patients with chest pain and detectable to mildly elevated serum troponin is not known. The objective was to compare clinical outcomes among an early decision for a noninvasive versus an invasive-based care pathway. METHODS: The CMR-IMPACT trial (Cardiac Magnetic Resonance Imaging Strategy for the Management of Patients with Acute Chest Pain and Detectable to Elevated Troponin) was conducted at 4 United States tertiary care hospitals from September 2013 to July 2018. A convenience sample of 312 participants with acute chest pain symptoms and a contemporary troponin between detectable and 1.0 ng/mL were randomized early in their care to 1 of 2 care pathways: invasive-based (n=156) or cardiac magnetic resonance (CMR)-based (n=156) with modification allowed as the patient condition evolved. The primary outcome was a composite including death, myocardial infarction, and cardiac-related hospital readmission or emergency visits. RESULTS: Participants (N=312, mean age, 60.6 years, SD 11.3; 125 women [59.9%]), were followed over a median of 2.6 years (95% CI, 2.4-2.9). Early assigned testing was initiated in 102 out of 156 (65.3%) CMR-based and 110 out of 156 (70.5%) invasive-based participants. The primary outcome (CMR-based versus invasive-based) occurred in 59% versus 52% (hazard ratio, 1.17 [95% CI, 0.86-1.57]), acute coronary syndrome after discharge 23% versus 22% (hazard ratio, 1.07 [95% CI, 0.67-1.71]), and invasive angiography at any time 52% versus 74% (hazard ratio, 0.66 [95% CI, 0.49-0.87]). Among patients completing CMR imaging, 55 out of 95 (58%) were safely identified for discharge based on a negative CMR and did not have angiography or revascularization within 90 days. Therapeutic yield of angiography was higher in the CMR-based arm (52 interventions in 81 angiographies [64.2%] versus 46 interventions in 115 angiographies [40.0%] in the invasive-based arm [P=0.001]). CONCLUSIONS: Initial management with CMR or invasive-based care pathways resulted in no detectable difference in clinical and safety event rates. The CMR-based pathway facilitated safe discharge, enriched the therapeutic yield of angiography, and reduced invasive angiography utilization over long-term follow-up. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT01931852.


Subject(s)
Myocardial Infarction , Troponin , Humans , Female , Middle Aged , Heart , Chest Pain/diagnosis , Chest Pain/etiology , Myocardial Infarction/diagnosis , Magnetic Resonance Imaging/methods , Coronary Angiography/methods
6.
Epidemiol Infect ; 150: e192, 2022 10 28.
Article in English | MEDLINE | ID: mdl-36305040

ABSTRACT

We developed an agent-based model using a trial emulation approach to quantify effect measure modification of spillover effects of pre-exposure prophylaxis (PrEP) for HIV among men who have sex with men (MSM) in the Atlanta-Sandy Springs-Roswell metropolitan area, Georgia. PrEP may impact not only the individual prescribed, but also their partners and beyond, known as spillover. We simulated a two-stage randomised trial with eligible components (≥3 agents with ≥1 HIV+ agent) first randomised to intervention or control (no PrEP). Within intervention components, agents were randomised to PrEP with coverage of 70%, providing insight into a high PrEP coverage strategy. We evaluated effect modification by component-level characteristics and estimated spillover effects on HIV incidence using an extension of randomisation-based estimators. We observed an attenuation of the spillover effect when agents were in components with a higher prevalence of either drug use or bridging potential (if an agent acts as a mediator between ≥2 connected groups of agents). The estimated spillover effects were larger in magnitude among components with either higher HIV prevalence or greater density (number of existing partnerships compared to all possible partnerships). Consideration of effect modification is important when evaluating the spillover of PrEP among MSM.


Subject(s)
HIV Infections , Pre-Exposure Prophylaxis , Sexual and Gender Minorities , Male , Humans , Homosexuality, Male , HIV Infections/epidemiology , HIV Infections/prevention & control , HIV Infections/drug therapy , Georgia/epidemiology
7.
JACC Case Rep ; 4(20): 1363-1365, 2022 Oct 19.
Article in English | MEDLINE | ID: mdl-36299648

ABSTRACT

We describe a first suspected case of fibrosing mediastinitis following anti-programmed death (PD)-1 therapy, pembrolizumab. Multimodality imaging, including cardiac magnetic resonance imaging, and a multidisciplinary team approach were integral to the diagnosis. If further substantiated, systematic surveillance after anti-PD-1 therapy for fibrosing mediastinitis may be warranted. (Level of Difficulty: Intermediate.).

8.
Open Forum Infect Dis ; 9(7): ofac274, 2022 Jul.
Article in English | MEDLINE | ID: mdl-35855962

ABSTRACT

Background: Disruptions in access to in-person human immunodeficiency virus (HIV) preventive care during the coronavirus disease 2019 (COVID-19) pandemic may have a negative impact on our progress towards the Ending the HIV Epidemic goals in the United States. Methods: We used an agent-based model to simulate HIV transmission among Black/African American men who have sex with men in Mississippi over 5 years to estimate how different reductions in access affected the number of undiagnosed HIV cases, new pre-exposure prophylaxis (PrEP) starts, and HIV incidence. Results: We found that each additional 25% decrease in HIV testing and PrEP initiation was associated with decrease of 20% in the number of cases diagnosed and 23% in the number of new PrEP starts, leading to a 15% increase in HIV incidence from 2020 to 2022. Conclusions: Unmet need for HIV testing and PrEP prescriptions during the COVID-19 pandemic may temporarily increase HIV incidence in the years immediately after the disruption period.

9.
PLoS One ; 16(5): e0250669, 2021.
Article in English | MEDLINE | ID: mdl-33951080

ABSTRACT

Mature mRNA molecules are expected to be comprised of a 5'UTR, a 3'UTR and a coding region (CDS). Unexpectedly, however, there have been multiple recent reports of widespread differential expression of mRNA 3'UTRs and their cognate coding regions (CDS), reflecting the expression of isolated 3'UTRs (i3'UTRs); these i3'UTRs can be highly expressed, often in reciprocal patterns to their cognate CDS. As with other long non-coding (lncRNAs), isolated 3'UTRs are likely to play an important role in gene regulation, but little is known about the contexts in which they are deployed. To illuminate the functions of i3'UTRs, here we carry out in vitro, in vivo and in silico analyses of differential 3'UTR/CDS mRNA ratio usage across tissues, development and cell state changes both for a select list of developmentally important genes as well as by unbiased transcriptome-wide analyses. Across two developmental paradigms we find a distinct switch from high i3'UTR expression for stem cell related genes in proliferating cells to high CDS for these genes in newly differentiated cells. Unbiased transcriptome analysis across multiple gene sets shows that regardless of tissue, genes with high 3'UTR to CDS ratios belong predominantly to gene ontology categories related to cell-type specific functions. In contrast, the gene ontology categories of genes with low 3'UTR to CDS ratios are similar across tissues and relate to common cellular functions. We further show that, at least for some genes, traditional transcriptional start site genomic elements correspond to identified RNAseq 3'UTR peak regions, suggesting that some i3'UTRs may be generated by de novo transcription. Our results provide critical information from which detailed hypotheses for individual i3'UTRs can be tested, with a common theme that i3'UTRs appear poised to regulate cell-specific gene expression and state.


Subject(s)
3' Untranslated Regions/genetics , Gene Expression Profiling , Humans , Polyadenylation
10.
JACC Clin Electrophysiol ; 7(1): 36-46, 2021 01.
Article in English | MEDLINE | ID: mdl-33478710

ABSTRACT

OBJECTIVES: This study aimed to determine the long-term outcomes and predictors of left ventricular (LV) ejection fraction (LVEF) improvement in patients with severe cardiomyopathies undergoing cardiac resynchronization therapy (CRT). BACKGROUND: Whether patients with severe LV dysfunction benefit from CRT or have reached a point in disease severity past the point at which CRT is beneficial is unknown. METHODS: We collected clinical and echocardiographic data on 420 patients with an LVEF of ≤15% and a QRS duration of ≥120 ms undergoing CRT at the Cleveland Clinic and 2 hospitals in the Johns Hopkins Health System between April 2003 and May 2014. Multivariate models were created to determine factors associated with response to CRT, defined as an absolute improvement in LVEF of >5% and survival free of LVAD and heart transplant. Procedure-related deaths were also collected. RESULTS: A total of 298 patients had pre- and appropriately timed post-CRT echocardiograms, of whom 145 (48.7%) met the criteria for response. In multivariate analysis, LV size and left bundle branch block (LBBB) were associated with response. Among the most dilated quintile (LV end-diastolic diameter [LVEDD] of >7.8 cm), 30.4% met the criteria for response. In multivariate analysis, smaller LV end-diastolic dysfunction and presence of LBBB were associated with improved survival free of heart failure and LVAD over a mean follow-up period of 5.2 years. There were no procedure-related deaths. CONCLUSIONS: Patients with severe LV dysfunction respond to CRT, although at a lower rate compared to traditional CRT candidates. Smaller LV size and LBBB are important predictors of positive outcomes in this population. Even among the most dilated patients, 30.4% realized a meaningful improvement in LVEF with CRT. The CRT implant procedure itself appears well tolerated.


Subject(s)
Cardiac Resynchronization Therapy , Bundle-Branch Block/therapy , Humans , Stroke Volume , Treatment Outcome , Ventricular Function, Left
12.
J Cardiovasc Transl Res ; 13(3): 367-376, 2020 06.
Article in English | MEDLINE | ID: mdl-32248349

ABSTRACT

Animal models of chemotherapy-induced cardiotoxicity have been instrumental in understanding the underlying mechanisms of the disease. The use of cardiac magnetic resonance (CMR) imaging and nuclear magnetic resonance (NMR) imaging in preclinical models allows the non-invasive study of subclinical pathophysiological processes that influence cardiac function and establish imaging parameters that can be adopted into clinical practice to predict cardiovascular outcomes. Given the rising population of cancer survivors and the current lack of effective therapies for the management of cardiotoxicity, research combining clinically relevant animal models and non-invasive cardiac imaging remains essential to improve methods to monitor, predict, and treat cardiovascular adverse events. This comprehensive review summarizes the lessons learned from animal models of cardiotoxicity employing CMR and tissue characterization techniques and discusses the ongoing challenges and hopes for the future.


Subject(s)
Antineoplastic Agents , Heart Diseases/diagnostic imaging , Magnetic Resonance Imaging , Animals , Cardiotoxicity , Disease Models, Animal , Heart Diseases/chemically induced , Heart Diseases/physiopathology , Humans , Predictive Value of Tests
13.
Circ Arrhythm Electrophysiol ; 12(7): e007316, 2019 07.
Article in English | MEDLINE | ID: mdl-31216884

ABSTRACT

BACKGROUND: Cardiac resynchronization therapy (CRT) has significant nonresponse rates. We assessed whether machine learning (ML) could predict CRT response beyond current guidelines. METHODS: We analyzed CRT patients from Cleveland Clinic and Johns Hopkins. A training cohort was created from all Johns Hopkins patients and an equal number of randomly sampled Cleveland Clinic patients. All remaining patients comprised the testing cohort. Response was defined as ≥10% increase in left ventricular ejection fraction. ML models were developed to predict CRT response using different combinations of classification algorithms and clinical variable sets on the training cohort. The model with the highest area under the curve was evaluated on the testing cohort. Probability of response was used to predict survival free from a composite end point of death, heart transplant, or placement of left ventricular assist device. Predictions were compared with current guidelines. RESULTS: Nine hundred twenty-five patients were included. On the training cohort (n=470: 235, Johns Hopkins; 235, Cleveland Clinic), the best ML model was a naive Bayes classifier including 9 variables (QRS morphology, QRS duration, New York Heart Association classification, left ventricular ejection fraction and end-diastolic diameter, sex, ischemic cardiomyopathy, atrial fibrillation, and epicardial left ventricular lead). On the testing cohort (n=455, Cleveland Clinic), ML demonstrated better response prediction than guidelines (area under the curve, 0.70 versus 0.65; P=0.012) and greater discrimination of event-free survival (concordance index, 0.61 versus 0.56; P<0.001). The fourth quartile of the ML model had the greatest risk of reaching the composite end point, whereas the first quartile had the least (hazard ratio, 0.34; P<0.001). CONCLUSIONS: ML with 9 variables incrementally improved prediction of echocardiographic CRT response and survival beyond guidelines. Performance was not improved by incorporating more variables. The model offers potential for improved shared decision-making in CRT (online calculator: http://riskcalc.org:3838/CRTResponseScore ). Significant remaining limitations confirm the need to identify better variables to predict CRT response.


Subject(s)
Cardiac Resynchronization Therapy/standards , Decision Support Techniques , Heart Failure/therapy , Machine Learning , Practice Guidelines as Topic/standards , Stroke Volume , Ventricular Function, Left , Aged , Baltimore , Cardiac Resynchronization Therapy/adverse effects , Cardiac Resynchronization Therapy/mortality , Clinical Decision-Making , Disease Progression , Echocardiography/standards , Female , Heart Failure/diagnosis , Heart Failure/mortality , Heart Failure/physiopathology , Heart Transplantation , Heart-Assist Devices , Humans , Male , Middle Aged , Ohio , Patient Selection , Predictive Value of Tests , Progression-Free Survival , Recovery of Function , Retrospective Studies , Risk Assessment , Risk Factors , Time Factors
14.
Nat Biomed Eng ; 2(10): 732-740, 2018 Oct.
Article in English | MEDLINE | ID: mdl-30847259

ABSTRACT

Ventricular tachycardia (VT), which can lead to sudden cardiac death, occurs frequently in patients with myocardial infarction. Catheter-based radiofrequency ablation of cardiac tissue has achieved only modest efficacy, owing to the inaccurate identification of ablation targets by current electrical mapping techniques, which can lead to extensive lesions and to a prolonged, poorly tolerated procedure. Here we show that personalized virtual-heart technology based on cardiac imaging and computational modelling can identify optimal infarct-related VT ablation targets in retrospective animal (5 swine) and human studies (21 patients) and in a prospective feasibility study (5 patients). We first assessed in retrospective studies (one of which included a proportion of clinical images with artifacts) the capability of the technology to determine the minimum-size ablation targets for eradicating all VTs. In the prospective study, VT sites predicted by the technology were targeted directly, without relying on prior electrical mapping. The approach could improve infarct-related VT ablation guidance, where accurate identification of patient-specific optimal targets could be achieved on a personalized virtual heart prior to the clinical procedure.

15.
Article in English | MEDLINE | ID: mdl-26874704

ABSTRACT

OPINION STATEMENT: Cardiac sarcoidosis is a protean disease, capable of causing nearly any cardiac abnormality. Electrical abnormalities including heart block and ventricular tachyarrhythmias are some of the most feared manifestations of cardiac sarcoidosis. Despite increasing awareness, cardiac sarcoidosis remains underdiagnosed in clinical practice, and as a result, many patients do not receive potentially disease-altering immunosuppressant therapy. In this review, we discuss cardiac sarcoidosis and its management, focusing diagnostic and therapeutic approaches to arrhythmias in cardiac sarcoidosis.

16.
PLoS One ; 9(1): e86947, 2014.
Article in English | MEDLINE | ID: mdl-24489810

ABSTRACT

BACKGROUND: Organ-scale arrhythmogenic consequences of source-sink mismatch caused by impaired excitability remain unknown, hindering the understanding of pathophysiology in disease states like Brugada syndrome and ischemia. OBJECTIVE: We sought to determine whether sodium current (INa) reduction in the structurally normal heart unmasks a regionally heterogeneous substrate for the induction of sustained arrhythmia by premature ventricular contractions (PVCs). METHODS: We conducted simulations in rabbit ventricular computer models with 930 unique combinations of PVC location (10 sites) and coupling interval (250-400 ms), INa reduction (30 or 40% of normal levels), and post-PVC sinus rhythm (arrested or persistent). Geometric characteristics and source-sink mismatch were quantitatively analyzed by calculating ventricular wall thickness and a newly formulated 3D safety factor (SF), respectively. RESULTS: Reducing INa to 30% of its normal level created a substrate for sustained arrhythmia induction by establishing large regions of critical source-sink mismatch (SF<1) for ectopic wavefronts propagating from thin to thick tissue. In the same simulations but with 40% of normal INa, PVCs did not induce reentry because the volume of tissue with SF<1 was >95% smaller. Likewise, when post-PVC sinus activations were persistent instead of arrested, no ectopic excitations initiated sustained reentry because sinus activation breakthroughs engulfed the excitable gap. CONCLUSION: Our new SF formulation can quantify ectopic wavefront propagation robustness in geometrically complex 3D tissue with impaired excitability. This novel methodology was applied to show that INa reduction precipitates source-sink mismatch, creating a potent substrate for sustained arrhythmia induction by PVCs originating near regions of ventricular wall expansion, such as the RV outflow tract.


Subject(s)
Arrhythmias, Cardiac/pathology , Arrhythmias, Cardiac/physiopathology , Heart Ventricles/pathology , Heart Ventricles/physiopathology , Sodium Channels/metabolism , Action Potentials , Animals , Rabbits , Ventricular Premature Complexes/pathology , Ventricular Premature Complexes/physiopathology
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