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1.
Artigo em Inglês | MEDLINE | ID: mdl-38606641

RESUMO

OBJECTIVE: Cochlear nerve deficiency (CND) is a common radiologic finding among unilateral sensorineural hearing loss (USNHL) patients. It is generally detected with magnetic resonance imaging (MRI), which is associated with higher cost, less availability, and possible need for sedation. Therefore, identifying computed tomography (CT) findings, such as cochlear aperture stenosis (CAS), that can reliably predict CND is valuable. Our study aimed to determine the prevalence of CND in pediatric patients with CT-diagnosed CAS. STUDY DESIGN: Retrospective study. SETTING: Tertiary care center. METHODS: We included pediatric patients diagnosed with CAS on temporal bone CT and with available temporal bone MRI. For each patient, an otolaryngologist and a pediatric neuroradiologist measured the cochlear aperture width on CT to confirm CAS (cochlear aperture < 1.4 mm) and assessed the status of the cochlear nerve on MRI. RESULTS: Fifty-five patients, representing 65 ears, had CAS on CT measurement. Median cochlear aperture width in CAS ears was 0.70 mm (interquartile range [IQR]: 0.40-1.05 mm) versus 2.00 mm in non-CAS ears (IQR: 1.80-2.30 mm, P < .001). CND was found in 98.5% (n = 64/65) of CAS ears, while a normal cochlear nerve was found in 1.5% (n = 1/65) of CAS ears. CONCLUSION: CND is highly prevalent among pediatric patients with CAS. This suggests that MRI may not be needed to assess for CND in USNHL patients with CAS, as initial CT may provide sufficient information to determine cochlear implant candidacy. We recommend thoughtful shared decision-making with parents of USNHL patients when determining whether to pursue MRI in the setting of a CAS diagnosis.

2.
Int J Med Robot ; 20(1): e2609, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38536718

RESUMO

BACKGROUND: Cochlear-implant electrode arrays (EAs) are currently inserted with limited feedback, and impedance sensing has recently shown promise for EA localisation. METHODS: We investigate the use of impedance sensing to infer the progression of an EA during insertion. RESULTS: We show that the access resistance component of bipolar impedance sensing can detect when a straight EA reaches key anatomical locations in a plastic cochlea and when each electrode contact enters/exits the cochlea. We also demonstrate that dual-sided electrode contacts can provide useful proximity information and show the real-time relationship between impedance and wall proximity in a cadaveric cochlea for the first time. CONCLUSION: The access resistance component of bipolar impedance sensing has high potential for estimating positioning information of EAs relative to anatomy during insertion. Main limitations of this work include using saline as a surrogate for human perilymph in ex vivo models and using only one type of EA.


Assuntos
Implante Coclear , Implantes Cocleares , Humanos , Impedância Elétrica , Cóclea/cirurgia , Eletrodos Implantados
3.
Health Sci Rep ; 6(11): e1704, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-38028705

RESUMO

Background and Aims: Modern health care faces a plethora of challenges including the delivery of quality and cost-efficient care. Physicians are first-hand observers of clinical problems but may lack the requisite training and education to develop innovations that improve patient care. Few medical education programs address innovation, leadership, and transdisciplinary collaboration despite being highlighted by national medical and education organizations including the American Medical Association. The University of Minnesota has implemented the Augustine program over the last 10-years to produce physicians that are leaders in medical innovation. Methods: As a novel joint engineering-medical school curriculum to educate medical students, residents, and fellows, the Augustine program incorporates engineering coursework, biomedical research, and a multidisciplinary design and business development experience to produce physicians capable of designing and marketing "disruptive technologies." The Augustine program takes 1-year to complete in addition to the 4-year medical education and provides a Master of Biomedical Engineering upon completion. Results: Augustine program graduates (n = 6) have reported significant contributions related to the joint engineering-medical education including peer-reviewed publications (Median: 13), deployable assets (Median: 2), and intellectual property (Median: 1). Most surveyed graduates (n = 5, 83%) continue to be active contributors to medical innovation and all (n = 6, 100%) utilize their transdisciplinary education to improve patient care. Conclusion: Augustine program graduates impact the entire spectrum of innovation and continue to improve patient care. The program will seek to emphasize the inclusion of physician residents and fellows with position expansion. The addition of a multi-week medical innovation clerkship will provide a more focused experience for students unable to dedicate an entire year to a transdisciplinary experience.

4.
Cochlear Implants Int ; 24(5): 273-281, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37489512

RESUMO

OBJECTIVE: To investigate whether revision surgery with the same device results in a change in three key indicators of electrode positioning: scalar location, mean modiolar distance (M¯), and angular insertion depth (AID). METHODS: Retrospective analysis of a cochlear implant database at a university-based tertiary medical center. Intra-operative CT scans were obtained after initial and revision implantation. Electrode array (EA) position was calculated using auto-segmentation techniques. Initial and revision scalar location, M¯, and AID were compared. RESULTS: Mean change in M¯ for all ears was -0.07 mm (SD 0.24 mm; P = 0.16). The mean change in AID for all ears was -5° (SD 67°; P = 0.72). Three initial implantations with pre-curved EAs resulted in a translocation from Scala Tympani (ST) to Scala Vestibuli (SV). Two remained translocated after revision, while one was corrected when revised with a straight EA. An additional five translocations occurred after revision. CONCLUSIONS: In this study examining revision cochlear implantation from a single manufacturer, we demonstrated no significant change in key indicators of EA positioning, even when revising with a different style of electrode. However, the revision EA is not necessarily confined by the initial trajectory and there may be an increased risk of translocation.


Assuntos
Implante Coclear , Implantes Cocleares , Humanos , Estudos Retrospectivos , Cóclea , Reimplante
5.
Cleft Palate Craniofac J ; : 10556656231178437, 2023 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-37222670

RESUMO

OBJECTIVE: To characterize the onset and prevalence of conductive hearing loss (CHL) in pediatric patients with cleft palate (CP) prior to palatoplasty with an enhanced audiologic protocol. DESIGN: Retrospective cohort study. SETTING: Multidisciplinary cleft and craniofacial clinic at a tertiary care center. PATIENTS: Patients with CP who received audiologic workup pre-operatively. Patients with bilateral permanent hearing loss, expiration prior to palatoplasty, or no pre-operative data were excluded. INTERVENTIONS: Patients with CP born February 2019 to November 2019 who passed newborn hearing screening (NBHS) received audiologic testing at 9 months of age (standard protocol). Patients born December 2019 to September 2020 underwent testing prior to 9 months of age (enhanced protocol). MAIN OUTCOME MEASURES: Age of identification of CHL in patients after implementation of the enhanced audiologic protocol. RESULTS: The number of patients who passed their NBHS in the standard protocol (n = 14, 54%) and the enhanced protocol (n = 25, 66%) did not differ. Infants who passed their NBHS, but demonstrated hearing loss on subsequent audiologic testing did not differ between enhanced (n = 25, 66%) and standard cohort (n = 14, 54%). Of patients who passed NBHS in the enhanced protocol, 48% (n = 12) had CHL identified by 3 months, and 20% (n = 5) by 6 months of age. With the enhanced protocol, patients who did not undergo additional testing post NBHS significantly dropped from 44.9% (n = 22) to 4.2% (n = 2) (P < .0001). CONCLUSION: Even with passed NBHS, CHL is still present for infants with CP pre-operatively. Earlier and more frequent testing for this population is recommended.

6.
Otol Neurotol ; 44(4): 353-359, 2023 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-36843071

RESUMO

OBJECTIVE: Compare incidence of sigmoid sinus wall abnormalities (SSWAs) and other radiographic abnormalities in patients with pulsatile tinnitus (PT) versus controls. STUDY DESIGN: Retrospective case-control. SETTING: Tertiary referral center. PATIENTS: Adults with PT and high-resolution computed tomography imaging were compared with adults undergoing cochlear implant workup including high-resolution computed tomography imaging. MAIN OUTCOME MEASURES: Incidence of SSWA in PT cohort (n = 141) compared with control (n = 149, n = 298 ears). Secondary outcome measures included differences in demographics and in other radiographic abnormalities between cohorts. RESULTS: Patients with PT had a higher incidence of SSWA (34% versus 9%, p < 0.001) and superior canal dehiscence (23% versus 12%, p = 0.017) than controls. Spearman product component correlations demonstrated that ipsilateral PT was weakly associated with SSWA ( r = 0.354, p < 0.001). When SSWA was present in the PT cohort (n = 48 patients, n = 59 ears), in 31 cases (64.6%), the SSWA correlated with PT laterality (e.g., left SSWA, left PT); in 12 (25.0%), SSWA partially correlated with PT laterality (e.g., bilateral SSWA, right PT); and in 5 (10.4%), the SSWA did not correlate with PT laterality (e.g., right SSWA, left PT). CONCLUSIONS: For our patients with both PT and SSWA, the SSWA is likely a contributing factor in approximately 65% of cases. For a third of patients with PT and concomitant SSWA, the association between the two is either not causative or not solely causative. Surgeons counseling patients with PT and SSWA may be optimistic overall regarding sigmoid resurfacing procedures but must appreciate the possibility of treatment failure, likely because of untreated comorbid conditions.


Assuntos
Zumbido , Adulto , Humanos , Zumbido/diagnóstico por imagem , Zumbido/etiologia , Zumbido/cirurgia , Estudos de Casos e Controles , Estudos Retrospectivos , Cavidades Cranianas/diagnóstico por imagem , Cavidades Cranianas/cirurgia , Tomografia Computadorizada por Raios X
7.
Otol Neurotol ; 44(4): 324-330, 2023 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-36728107

RESUMO

HYPOTHESIS: This study evaluated the utility of the pull-back technique in improving perimodiolar positioning of a precurved cochlear implant (CI) electrode array (EA) with simultaneous insertion force profile measurement and direct observation of dynamic EA behavior. BACKGROUND: Precurved EAs with perimodiolar positioning have improved outcomes compared with straight EAs because of lowered charge requirements for stimulation and decreased spread of excitation. The safety and efficacy of the pull-back technique in further improving perimodiolar positioning and its associated force profile have not been adequately demonstrated. METHODS: The bone overlying the scala vestibuli was removed in 15 fresh cadaveric temporal bones, leaving the scala tympani unviolated. Robotic insertions of EAs were performed with simultaneous force measurement and video recording. Force profiles were obtained during standard insertion, overinsertion, and pull-back. Postinsertion CT scans were obtained during each of the three conditions, enabling automatic segmentation and calculation of angular insertion depth, mean perimodiolar distance ( Mavg ), and cochlear duct length. RESULTS: Overinsertion did not result in significantly higher peak forces than standard insertion (mean [SD], 0.18 [0.06] and 0.14 [0.08] N; p = 0.18). Six temporal bones (40%) demonstrated visibly improved perimodiolar positioning after the protocol, whereas none worsened. Mavg significantly improved after the pull-back technique compared with standard insertion (mean [SD], 0.34 [0.07] and 0.41 [0.10] mm; p < 0.01). CONCLUSIONS: The pull-back technique was not associated with significantly higher insertional forces compared with standard insertion. This technique was associated with significant improvement in perimodiolar positioning, both visually and quantitatively, independent of cochlear size.


Assuntos
Implante Coclear , Implantes Cocleares , Humanos , Cóclea/diagnóstico por imagem , Cóclea/cirurgia , Implante Coclear/métodos , Rampa do Tímpano/cirurgia , Rampa do Vestíbulo , Eletrodos Implantados
9.
Ann Otol Rhinol Laryngol ; 132(9): 1085-1089, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36330593

RESUMO

BACKGROUND: Social media is an important tool for networking, recruitment, and promoting clinical practice. No study has specifically assessed which FPRS practitioners have professional social media accounts, how they utilize them, and what barriers or resources exist to their use. OBJECTIVES: This study aims to examine differences in social media use based on provider demographics and practice setting, and identify resources and barriers to professional social media use. METHODS: This cross-sectional analysis was an anonymous survey sent to AAFPRS members. Data collected included demographics, practice setting, resources, and barriers encountered to use of professional social media. RESULTS: Most facial plastic surgeons (80%) use professional social media, notably Instagram and Facebook, and mostly post patient photos and stories (67.9%). Social media is more commonly utilized in private practice (56% vs 23%, P = .0016), where there are less institutional barriers (10% vs 40%, P = .02) and more resources available (82.5% vs 12.5%, P = .01). CONCLUSIONS: Social media is widely used in FPRS. Working in private practice is associated with increased availability of resources for support, and a reduction in institutional barriers to maintaining a social media presence. With this understanding, facial plastic surgeons can be better equipped for networking, marketing, and promoting the field of FPRS.


Assuntos
Procedimentos de Cirurgia Plástica , Mídias Sociais , Cirurgiões , Cirurgia Plástica , Humanos , Estudos Transversais
11.
Otol Neurotol ; 43(10): 1149-1154, 2022 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-36201525

RESUMO

OBJECTIVE: Precurved cochlear implant (CI) electrode arrays have demonstrated superior audiometric outcomes compared with straight electrodes in a handful of studies. However, previous comparisons have often failed to account for preoperative hearing and age. This study compares hearing outcomes for precurved and straight electrodes by a single manufacturer while controlling for these and other factors in a large cohort. STUDY DESIGN: Retrospective cohort study. SETTING: Tertiary academic medical center. PATIENTS: Two hundred thirty-one adult CI recipients between 2015 and 2021 with cochlear (Sydney, Australia) 522/622 (straight) or 532/632 (precurved) electrode arrays. INTERVENTIONS: Postactivation speech recognition and audiometric testing. MAIN OUTCOME MEASURES: Speech recognition testing (consonant-nucleus-consonant word [CNCw] and AzBio) was collected at 6 and 12 months postactivation. Hearing preservation was characterized by a low-frequency pure-tone average shift, or the change between preoperative and postoperative low-frequency pure-tone average. RESULTS: Two hundred thirty-one patients (253 ears) with 6-month and/or 12-month CNCw or AzBio testing were included. One hundred forty-nine (59%) and 104 (41%) ears were implanted with straight and precurved electrode arrays, respectively. Average age at implantation was 70 years (interquartile range [IQR], 58-77 y). There was no significant difference in mean age between groups. CNCw scores were significantly different ( p = 0.001) between straight (51%; IQR, 36-67%) and precurved arrays (64%; IQR, 48-72%). AzBio scores were not significantly different ( p = 0.081) between straight (72%; IQR, 51-87%) and precurved arrays (81%; IQR, 57-90%). Controlling for age, race, sex, preoperative hearing, and follow-up time, precurved electrode arrays performed significantly better on CNCw (b = 10.0; 95% confidence interval, 4.2-16.0; p < 0.001) and AzBio (b = 8.9; 95% confidence interval, 1.8-16.0;, p = 0.014) testing. Hearing preservation was not different between electrodes on adjusted models. CONCLUSION: During the study period, patients undergoing placement of precurved electrode arrays had significantly higher CNC and AzBio scores than patients receiving straight electrodes, even after controlling for age, preoperative hearing, and follow-up time. PROFESSIONAL PRACTICE GAP AND EDUCATIONAL NEED: Understanding the difference in audiometric outcomes between precurved and straight electrode arrays will help to guide electrode selection. LEARNING OBJECTIVE: To understand differences in speech recognition scores postoperatively by electrode array type (precurved versus straight). DESIRED RESULT: To demonstrate a difference in hearing performance postoperatively by electrode type. LEVEL OF EVIDENCE: III. INDICATE IRB OR IACUC: Approved by the Institutional IRB (090155).


Assuntos
Implante Coclear , Implantes Cocleares , Percepção da Fala , Adulto , Humanos , Idoso , Percepção da Fala/fisiologia , Estudos Retrospectivos , Resultado do Tratamento
12.
Ear Nose Throat J ; : 1455613221129932, 2022 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-36148640

RESUMO

Opioid-induced hearing loss has been described as a form of sudden sensorineural hearing loss that can occur with chronic or acute opioid use. Here, we report a case of a 16-year-old patient with sudden onset hearing loss after opioid overdose requiring prolonged intubation with fentanyl sedation.

13.
Otol Neurotol ; 43(7): 835-839, 2022 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-35878641

RESUMO

OBJECTIVE: To investigate the prevalence of vestibular migraine (VM) in a cohort of patients with radiologic confirmation of superior canal dehiscence (SCD) and to compare management of superior canal dehiscence syndrome (SCDS) in patients with and without comorbid VM. STUDY DESIGN: Retrospective review of a SCD database. SETTING: University-based tertiary medical center. PATIENTS: Ninety-one patients identified with SCD from 2009 to 2017. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Coincidence of VM and SCD, and resolution of symptoms. RESULTS: Ninety-one patients with SCD met the inclusion and exclusion criteria. VM was diagnosed in 36 (39.6%) patients. Of those receiving medical therapy for VM alone, five (45.5%) reported symptom resolution, five (45.5%) reported partial improvement, one (9.1%) had no change, and none worsened. Fifteen patients (41.7%) were treated with both surgery (for SCD) and medical therapy (for VM). Seven (46.7%) reported symptom resolution, seven (46.7%) reported partial improvement, and one (6.7%) worsened. There was no statistically significant difference in symptom resolution between SCD + VM patients who were treated medically compared with those treated with medical therapy and surgery (p = 0.951). There was no significant difference in symptom resolution after surgery between SCD + VM and SCD-only cohorts (p = 0.286). CONCLUSIONS: This is the first study describing the incidence of VM in a cohort of patients with SCDS. The symptoms of VM confound those of SCDS and unrecognized or undertreated VM may contribute to surgical failure in SCDS. Therefore, we recommend a high index of suspicion for VM in patients with SCDS and a trial of medical therapy in the setting of suspected VM.


Assuntos
Transtornos de Enxaqueca , Deiscência do Canal Semicircular , Humanos , Transtornos de Enxaqueca/complicações , Transtornos de Enxaqueca/terapia , Estudos Retrospectivos , Canais Semicirculares/cirurgia , Vertigem/etiologia
16.
Ann Otol Rhinol Laryngol ; 131(7): 743-748, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34459286

RESUMO

OBJECTIVE: To compare outcomes of endoscope-assisted middle cranial fossa MCF) repair of superior semicircular canal dehiscence (SSCD) compared to microscopic MCF repair. STUDY DESIGN: Retrospective cohort. SETTING: Tertiary medical center neurotology practice. METHODS: Retrospective chart review and cohort study of patients who underwent surgical repair of SSCD via MCF approach from 2010 to 2019 at our institution. Patients were categorized according to use of endoscope intraoperatively. Pre- and post-operative symptom number was calculated from 8 patient-reported symptoms. Pre- and post-operative changes in symptom number were assessed using paired t-tests. Single-predictor binary logistic regression was used to compare final reported symptoms between cohorts. Linear regression was performed to assess air-bone gap (ABG) changes postoperatively between cohorts. RESULTS: Forty-six patients received surgical management for SSCD. Of these, 27 (59%) were male and 19 (41%) were female. Bilateral SSCD was present in 14 cases (29%), of which 3 underwent surgical management bilaterally, for a total of 49 surgical ears. Surgery was performed on the right ear in 19 cases (39%) and on the left in 30 cases (61%). Forty ears (82%) underwent microscopic repair while 9 (18%) underwent endoscope-assisted repair. Microscopic and endoscope-assisted MCF repair both demonstrated significantly improved symptom number postoperatively (P < .001 for each). There was no significant difference in change in ABG between the 2 cohorts. On average, patient-reported symptoms and audiometrically-tested hearing improved postoperatively in both groups. CONCLUSION: While endoscopic-assisted MCF repair has the potential to provide better visualization of medial and downslope defects, repair via this technique yields similar results and is equivalent to MCF repair utilizing the microscope alone.


Assuntos
Deiscência do Canal Semicircular , Canais Semicirculares , Estudos de Coortes , Endoscópios , Feminino , Humanos , Masculino , Estudos Retrospectivos , Canais Semicirculares/cirurgia
18.
Ear Nose Throat J ; : 1455613211037639, 2021 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-34338036

RESUMO

Chordomas are rare, malignant bone tumors that arise from embryological remnants of the notochord, typically affecting the skull base, mobile spine, and sacrum with uncommon metastasis to the larynx. Patients with metastasis to the larynx may present with slowly progressive dysphonia and dyspnea. Here, we report an organ-preservation treatment strategy for a patient with widely metastatic extra-axial chordoma presenting with airway compromise who was found to have a new metastasis to the cricoid cartilage.

19.
J Am Coll Cardiol ; 63(24): 2712-21, 2014 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-24794115

RESUMO

OBJECTIVES: This study mapped human ventricular fibrillation (VF) to define mechanistic differences between episodes requiring defibrillation versus those that spontaneously terminate. BACKGROUND: VF is a leading cause of mortality; yet, episodes may also self-terminate. We hypothesized that the initial maintenance of human VF is dependent upon the formation and stability of VF rotors. METHODS: We enrolled 26 consecutive patients (age 64 ± 10 years, n = 13 with left ventricular dysfunction) during ablation procedures for ventricular arrhythmias, using 64-electrode basket catheters in both ventricles to map VF prior to prompt defibrillation per the institutional review board-approved protocol. A total of 52 inductions were attempted, and 36 VF episodes were observed. Phase analysis was applied to identify biventricular rotors in the first 10 s or until VF terminated, whichever came first (11.4 ± 2.9 s to defibrillator charging). RESULTS: Rotors were present in 16 of 19 patients with VF and in all patients with sustained VF. Sustained, but not self-limiting VF, was characterized by greater rotor stability: 1) rotors were present in 68 ± 17% of cycles in sustained VF versus 11 ± 18% of cycles in self-limiting VF (p < 0.001); and 2) maximum continuous rotations were greater in sustained (17 ± 11, range 7 to 48) versus self-limiting VF (1.1 ± 1.4, range 0 to 4, p < 0.001). Additionally, biventricular rotor locations in sustained VF were conserved across multiple inductions (7 of 7 patients, p = 0.025). CONCLUSIONS: In patients with and without structural heart disease, the formation of stable rotors identifies individuals whose VF requires defibrillation from those in whom VF spontaneously self-terminates. Future work should define the mechanisms that stabilize rotors and evaluate whether rotor modulation may reduce subsequent VF risk.


Assuntos
Mapeamento Potencial de Superfície Corporal/normas , Cateterismo Cardíaco/normas , Técnicas Eletrofisiológicas Cardíacas/normas , Fibrilação Ventricular/diagnóstico , Fibrilação Ventricular/fisiopatologia , Idoso , Mapeamento Potencial de Superfície Corporal/métodos , Cateterismo Cardíaco/métodos , Técnicas Eletrofisiológicas Cardíacas/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Fatores de Tempo
20.
Circ Arrhythm Electrophysiol ; 5(6): 1149-59, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23027797

RESUMO

BACKGROUND: Mechanisms of atrial fibrillation (AF) initiation are incompletely understood. We hypothesized that rate-dependent changes (restitution) in action potential duration (APD) and activation latency are central targets for clinical interventions that induce AF. We tested this hypothesis using clinical experiments and computer models. METHODS AND RESULTS: In 50 patients (20 persistent, 23 paroxysmal AF, 7 controls), we used monophasic action potential catheters to define left atrial APD restitution, activation latency, and AF incidence from premature extrastimuli. Isoproterenol (n=14), adenosine (n=10), or rapid pacing (n=36) was then initiated to determine impact on these parameters. Compared with baseline in AF patients, isoproterenol and rapid pacing decreased activation latency (64±14 versus 31±13 versus 24±14 ms; P<0.05), steepened maximum APD restitution slope (0.8±0.7 versus 1.7±0.5 versus 1.1±0.5; P<0.05), and increased AF incidence (12% versus 64% versus 84%; P<0.05). Conversely, adenosine shortened APD (P<0.05), yet increased activation latency (86±27 ms; P=0.002) so that maximum APD restitution slope did not steepen (1.0±0.5; P=NS), and AF incidence was unchanged (10%; P=NS). In controls, no intervention steepened APD restitution or initiated AF. Computational modeling revealed that isoproterenol steepened APD restitution by increased L-type calcium current and decreased activation latency via enhanced rapid delayed potassium reactifier current inactivation, whereas rapid pacing steepened APD restitution via increased cardiac inward potassium rectifier current. CONCLUSIONS: Steep APD restitution is a common pathway for AF initiation by isoproterenol and tachycardia via reduced activation latency that enables engagement of steep APD restitution at rapid rates. Modeling suggests that AF initiation from each intervention uses distinct ionic mechanisms. This insight may help design interventions to prevent AF.


Assuntos
Potenciais de Ação/fisiologia , Fibrilação Atrial/fisiopatologia , Simulação por Computador , Sistema de Condução Cardíaco/fisiopatologia , Tempo de Reação/fisiologia , Adenosina/farmacologia , Agonistas Adrenérgicos beta/farmacologia , Adulto , Idoso , Antiarrítmicos/farmacologia , Canais de Cálcio Tipo L/fisiologia , Feminino , Humanos , Isoproterenol/farmacologia , Masculino , Pessoa de Meia-Idade , Canais de Potássio Corretores do Fluxo de Internalização/fisiologia , Fatores de Tempo
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