Beta-adrenergic antagonist tolerance in amyloid cardiomyopathy

Background: Beta-adrenergic antagonists or blockers (BB) are a cornerstone of cardiac therapy for multiple indications. However, BB are considered relatively contraindicated in amyloid cardiomyopathy due to poor tolerance. This intolerance is hypothesized to be due to concomitant neuropathy and significant restrictive cardiomyopathy. This study analyzes the incidence and characteristics of BB tolerance in patients with amyloid cardiomyopathy. Methods: Through a single-center retrospective chart review, patients with amyloid cardiomyopathy, confirmed by endomyocardial biopsy or technetium-99 pyrophosphate scan, were identified and clinical data was collected. Statistical methods included Chi-square test and two sample Results: Of 135 cardiac amyloidosis patients, 27 patients (20.0%) had no BB use, 56 patients (41.5%) were current BB users, and 52 patients (38.5%) were prior BB users. The most frequent indications for BB use were heart failure, hypertension, coronary artery disease, and arrhythmia. The most common reason for stopping BB therapy was hypotension (62.8%) followed by fatigue, bradycardia, and orthostasis. Neurologic symptoms at the initial BB prescription or most recent evaluation were not significantly different between current and prior BB users. Their cardiovascular profiles were similar by ejection fraction, wall thickness, troponin I, and brain natriuretic peptide. There was no association for BB discontinuation based on amyloid subtype, sex, or race. Conclusion: The majority of patients with amyloid cardiomyopathy were prescribed BB, and over half of these patients still tolerated BB therapy. Current and prior BB users had similar profiles from a cardiovascular and neurologic perspective, with no association identified to predict BB discontinuation

Modeling power VDMOSFET transistors: Device physics and equivalent circuit model with parameter extraction

775-782 A power VDMOSFET has been simulated using PISCES-II, a 2-D numerical device simulator. The doping densities and device dimensions are chosen so as to simulate a typical device structure with one micron channel length. These simulations are aimed at understanding the device physics through various internal electrical quantities like potential distribution, electric field distribution, and electron concentrations etc. in different regions of the device both in on/off states. Simulated results have been used to extract circuit model parameters like VT, KP and λ etc. for a VDMOSFET equivalent circuit model comprising of a lateral MOSFET in series with a JFET. It advances the earlier models in terms of number of parameters extracted for its SPICE implementation. The characteristics obtained from the dc circuit model show good agreement with the simulated data, thus validating the device operation, the circuit model and its parameter extraction procedures

Functional Impairments of Amyloidosis Patients: Physical Therapy Assessment

Amyloidosis is a rare, systemic disease that can result in significant functional impairment. Specific guidelines for the rehabilitation assessment of amyloidosis patients have yet to be established. The purpose of this study was to identify functional deficits and assess differences based on disease type, organ involvement, age, and gender of patients with amyloidosis. Materials and Methods: The multidisciplinary Comprehensive Amyloidosis Clinic (CAC) at Ohio State University (OSU) has developed structured assessment guidelines for amyloidosis patients. A retrospective, single-institution review of patients assessed in CAC between December 2017 and April 2020 was performed. Outcome measure data from the Timed Up and Go (TUG), 30 s sit-to-stand, and physical function portion of the SF 36 were gathered by chart review. Comparisons were made between CAC patient scores and normative data. Kruskal–Wallis tests were used to compare scores across the disease types (light chain, transthyretin wild-type, and hereditary variant transthyretin) and the Mann–Whitney U test was used for pairwise comparisons within disease types and cardiac involvement. Linear regression models were used to assess associations between patient characteristics (including age, gender, disease type, and cardiac involvement) and performance scores. Results: Data from sixty-four patients was evaluated. On the 30-s sit-to-stand test, patients with light chain amyloidosis performed 3.32 fewer repetitions than patients with transthyretin wild-type, p = 0.03. Patients with cardiac involvement had 2.55 fewer repetitions than patients without cardiac involvement, p = 0.03. Older patients were found to have slower TUG performance, and a 10-year increase in age was associated with an 11% increase in TUG scores. Conclusions: Findings indicate patients with light chain amyloidosis and patients with cardiac involvement, when compared to other amyloidosis patients, present with more physical impairments