Deconvoluting kernel density estimation and regression for locally differentially private data.

Local differential privacy has become the gold-standard of privacy literature for gathering or releasing sensitive individual data points in a privacy-preserving manner. However, locally differential data can twist the probability density of the data because of the additive noise used to ensure privacy. In fact, the density of privacy-preserving data (no matter how many samples we gather) is always flatter in comparison with the density function of the original data points due to convolution with privacy-preserving noise density function. The effect is especially more pronounced when using slow-decaying privacy-preserving noises, such as the Laplace noise. This can result in under/over-estimation of the heavy-hitters. This is an important challenge facing social scientists due to the use of differential privacy in the 2020 Census in the United States. In this paper, we develop density estimation methods using smoothing kernels. We use the framework of deconvoluting kernel density estimators to remove the effect of privacy-preserving noise. This approach also allows us to adapt the results from non-parametric regression with errors-in-variables to develop regression models based on locally differentially private data. We demonstrate the performance of the developed methods on financial and demographic datasets.

Drug-induced thrombocytopenia after anticoagulation with rivaroxaban.

A 66-year-old man presented to the emergency department with complaints of dark-colored stool and rash developing over the last couple of days. The patient was started on rivaroxaban and flecainide for months prior for atrial fibrillation. Upon arrival, he was awake, alert, and oriented with a blood pressure of 111/63mmHg, heart rate of 68 beats per minute, and oxygen saturation of 96% on room air. A review of systems was unremarkable with the exception of skin rash and light-headedness. The patient's initial laboratory results were significant for red blood cell (RBC) count of 4.05×106/mcL, hemoglobin of 12.1g/dL, hematocrit of 35.6%, and platelet count of 1×103/mcL. Aggressive hydration was started in the ED, initially with two 1-L boluses of normal saline followed by an infusion of 10mL/h. One unit of platelets was transfused. Rivaroxaban and flecainide were held on admission. Twenty-four hours after admission, the patient was initiated on immune globulin (IVIG) Gammagard (Baxter, West Lake, CA), 75g on 3 consecutive days and steroids for possible immune thrombocytopenia. His platelet count steadily improved over the 6-day period to 119×103/mcL on the day of hospital discharge. This is the second reported case of possible rivaroxaban-induced thrombocytopenia.

Comparison of the Efficancy and Complication Rates of the Hybrid Maze, Complete Cox-Maze and Catheter Ablation in the Treatment of Atrial Fibrillation.

INTRODUCTION: Atrial fibrillation is the most common cardiac arrhythmia in the United States. It has been associated with a reduction in patient quality of life and more serious complications such as stroke and heart failure. The aim of this study was to compare the efficacy of commonly performed invasive procedures in keeping patients in normal sinus rhythm. METHODS AND RESULTS: A retrospective chart review was performed on all patients who underwent primary radiofrequency catheter ablation, the complete Cox-maze, or the hybrid maze at OSF Saint Anthony Medical Center between January 2010 and December 2013 (n=140). Immediately post-procedure, arrhythmia recurrence rates did not differ between the groups (p = 0.28). At all follow-up points thereafter, however, differences in procedural efficacy between surgical and catheter therapy remained highly significant (p < 0.001). At 2 years, 20.3% of the catheter ablation patients were in normal sinus rhythm, when compared to 57.9% of hybrid maze and 72.7% the complete Cox-maze groups. A difference in major complication rates was noted (p = 0.04), with the complete Cox-maze having a 17.4%, the hybrid having 22.7%, and the catheter ablation group having 5.6%. CONCLUSIONS: This study was unable to detect differences in the efficacy rates of the surgical procedures, however they were both superior to catheter ablation. Although the hybrid approach is considered minimally invasive, complication rates were similar to those of the complete Cox-maze. Catheter ablation was the safest procedure, and since evidence of reduced mortality after the use of aggressive rhythm therapy is currently lacking, the results suggest that hybrid surgery for atrial fibrillation should be used after the failure of more conservative measures.

When the heart remembers.

We present a 61-year-old patient who showed deep T wave inversion on her electrocardiogram (ECG) after cardioversion of her atrial flutter to sinus rhythm. A cardiac catheterization showed normal coronary arteries. The T wave inversion on her ECG is thought to be due to a cardiac memory phenomenon. Cardiac memory is a phenomenon that appears with T wave inversion on ECG after a change in the activation sequence of the heart. It may mimic cardiac ischemia and may mask any condition that appears with T wave abnormality on the ECG.

Cardiovascular manifestations of myotonic dystrophy-1.

Myotonic dystrophy (DM) is an inherited disorder transmitted in an autosomal dominant fashion and characterized by myotonia with dystrophic involvement of muscles and other multisystemic manifestations. It is the most common muscular dystrophy in whites. DM1, the most common type of DM, is associated with conduction defects, tachyarrhythmia, cardiomyopathy, and other cardiac disorders such as valvular diseases. The conduction defects in patients with DM1 are progressive; therefore, these patients should undergo careful work-up and follow-up, even if presenting with a benign conduction defect such as first-degree atrioventricular block. Atrial tachyarrhythmias are the most common arrhythmias in DM1, although ventricular tachycardia (VT) with a bundle branch re-entry mechanism can also occur. Interestingly, such VT can be cured by right bundle branch ablation with no need for an implantable cardioverter defibrillator. A significant portion of DM1 patients have heart failure, which is not clinically apparent, in part, because of the limited ability for exertion. Therefore, a low threshold should be used regarding when evaluating the heart by echocardiogram. Cardiovascular manifestations of DM1 have several important aspects that require careful attention and knowledge of the current evidence to make the best treatment decision. This article reviews the relevant DM1 literature and provides suggestions for diagnosis and treatment of patients with DM1.