Publications by authors named "Bradley P Knight"

Article Synopsis
  • The study investigates how cardiac implantable electronic devices (CIEDs) affect the accuracy and precision of phase-contrast MRI measurements of aortic velocity in both adult and pediatric patients.
  • A total of 29 subjects (21 adults and 8 children) were scanned using various MRI techniques while simulating the presence of CIEDs to analyze image artifacts.
  • Results showed that the proximity of the CIED to the aortic valve worsens measurement accuracy, with biases and variations increasing as the distance decreases, highlighting the need to consider CIED impact during MRI readings.
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  • The study investigates the rates and reasons for the removal of subcutaneous implantable cardioverter defibrillators (S-ICDs) among patients who've had them implanted.
  • Out of 372 patients studied over a median follow-up of 4.4 years, 5.9% required extraction, mainly due to bradycardia pacing needs, infections, and inappropriate shocks.
  • Factors such as a history of smoking and a higher body mass index were linked to an increased likelihood of S-ICD extraction, indicating the importance of careful patient selection for the device.
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Article Synopsis
  • The study evaluates the long-term performance and safety of the extravascular implantable cardioverter-defibrillator (EV ICD) after initial findings showed its effectiveness for 6 months.
  • A total of 316 patients were enrolled, with a successful implant in 299 cases, experiencing various arrhythmic events that were effectively treated using antitachycardia pacing (ATP) and shocks.
  • The results indicated high success rates for both ATP (77.1%) and shock therapy (100%), with low rates of complications and inappropriate shocks over the three-year study period.
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Aims: The extravascular implantable cardioverter-defibrillator (EV ICD) has been shown to be safe and effective for patients at risk of sudden cardiac death, but little is known about EV ICD lead removal in humans. This analysis aimed to characterize the EV ICD lead removal experience thus far.

Methods And Results: This was a retrospective analysis of lead removals from the EV ICD Pilot, Pivotal, and Continued Access Studies.

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Limited comparative data exist regarding the risk of cardiogenic emboli in patients with isolated atrial flutter (AFL). Some studies suggest a lower complication risk in AFL compared to atrial fibrillation (AFib), but methodological limitations and conflicting reports necessitate a comprehensive investigation. Our analysis proposes that isolated AFL carries a lower risk of ischemic events and left atrial thrombus formation than AFib.

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Article Synopsis
  • The study compared high-density (HD) mapping to non-HD mapping in atrial flutter ablation to assess outcomes and healthcare utilization.
  • Results showed that HD mapping led to a higher rate of successful circuit identification and a greater overall procedure success rate.
  • Additionally, patients who had HD mapping experienced fewer emergency department visits and hospitalizations related to atrial flutter within a year post-procedure.
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Background: Catheter ablation for atrial fibrillation (AFCA) has been shown to reduce AF burden and improve quality of life. Earlier studies demonstrated that women are less likely to undergo AFCA despite having more AF symptoms. We investigated whether an association exists between referral patterns and this sex disparity.

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Background: The use of intravenous (IV) sotalol loading following recent U.S. Food and Drug Administration (FDA) approval of a 1-day loading protocol has reduced the obligatory 3-day hospital stay for sotalol initiation when given orally.

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Introduction: The extravascular implantable cardioverter defibrillator (EV ICD) has extended projected battery longevity compared to the subcutaneous implantable cardioverter defibrillator (S-ICD). This study used modeling to characterize the need for generator changes, long-term complications, and overall costs for both the EV ICD and S-ICD in healthcare systems of various countries.

Methods: Battery longevity data were modeled using a Markov model from averages reported in device labeling for the S-ICD and with engineering estimates based on real life usage from EV ICD Pivotal Study patient data to introduce variability.

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Introduction: The pivotal study of the extravascular implantable cardioverter-defibrillator (EV ICD) recently demonstrated primary efficacy and safety endpoints comparable to previous ICD systems. Patient experience with this novel device has not been reported. The current study examined the standardized patient-reported outcome (PRO) metrics of quality of life (QOL) and patient acceptance of the device.

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  • This study investigates device-related thrombus (DRT) occurrences after left atrial appendage closure (LAAC), focusing on how often it persists or recurs.
  • It found that about 29% of DRT cases persist, with being female and having a larger initial thrombus size being significant predictors.
  • Unfavorable DRT evolution is linked to a higher rate of thromboembolic events, emphasizing the importance of monitoring thrombus size post-LAAC.
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Background: The temporal progression states of the molecular and structural substrate in atrial fibrillation (AF) are not well understood. We hypothesized that these can be detected by AF electrograms and magnetic resonance imaging parametric mapping.

Methods And Results: AF was induced in 43 dogs (25-35 kg, ≥1 year) by rapid atrial pacing (RAP) (3-33 weeks, 600 beats/min), and 4 controls were used.

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We present a case of a quadriplegic male who developed ventricular fibrillation associated with an anomalous aortic origin of the right coronary artery. Successful revascularization was achieved with percutaneous coronary intervention. This case highlights the application of an unconventional approach to resolve ischemia in a patient with prohibitive surgical risk.

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Introduction: Mechanical force to achieve transseptal puncture (TSP) using a standard needle may lead to overshooting and injury, and can potentially be avoided using a radiofrequency (RF)-powered needle or wire. Applying electrocautery to needles and guidewires as an alternative to purpose-built RF systems has been associated with safety risks, such as tissue coring and thermal damage. The commercially available AcQCross needle-dilator system (Medtronic) features a sharp open-ended needle for mechanical puncture, as well as a built-in connector to enable energy delivery for RF puncture.

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Background: The subcutaneous implantable cardioverter-defibrillator (S-ICD) is an accepted alternative to transvenous (TV) ICD to provide defibrillation therapy to treat life-threatening ventricular tachyarrhythmias in high-risk patients. S-ICD outcomes by age group have not been reported.

Objectives: In this study, the authors sought to report S-ICD outcomes in different age groups in a multicenter S-ICD post-approval study (PAS) involving the largest cohort of patients ever reported.

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Background: The subcutaneous implantable cardioverter-defibrillator (S-ICD) was developed to avoid complications related to transvenous implantable cardioverter-defibrillator (TV-ICD) leads. Device safety and efficacy were demonstrated previously with atypical clinical patients or limited follow-up.

Objectives: The S-ICD PAS (Subcutaneous Implantable Cardioverter-Defibrillator System Post Approval Study) is a real-world, multicenter, registry of U.

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Traditional anatomically guided ablation and attempts to perform electrogram-guided atrial fibrillation (AF) ablation (CFAE, DF, and FIRM) have not been shown to be sufficient treatment for persistent AF. Using biatrial high-density electrophysiologic mapping in a canine rapid atrial pacing model of AF, we systematically investigated the relationship of electrogram morphology recurrence (EMR) (Rec% and CL) with established AF electrogram parameters and tissue characteristics. Rec% correlates with stability of rotational activity and with the spatial distribution of parasympathetic nerve fibers.

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Background: To date, few risk models have been validated to predict recurrent atrial fibrillation (AF) >1 year after ablation. The SCALE-CryoAF score was previously derived to predict very late return of AF (VLRAF) >1 year following cryoballoon ablation (CBA), with strong predictive ability. In this study, we aim to validate the SCALE-CryoAF score for VLRAF after CBA in a novel patient cohort.

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Introduction: Oral sotalol initiation requires a multiple-day, inpatient admission to monitor for QT prolongation during loading. A 1-day intravenous (IV) sotalol loading protocol was approved by the United States Food and Drug Administration in March 2020, but limited data on clinical use and administration currently exists. This study describes implementation of an IV sotalol protocol within an integrated health system, provides initial efficacy and safety outcomes, and examines length of stay (LOS) compared with oral sotalol initiation.

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Background: Subcutaneous implantable cardioverter-defibrillators (S-ICD) are an alternative to transvenous ICDs for patients without a need for cardiac pacing. Obese patients have been proposed to be at higher risk for conversion failure with S-ICDs due to subcutaneous fat underneath the device. Optimal device positioning may promote equivalent outcomes between obese and non-obese patients by minimizing the effects of excess adipose tissue.

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