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Nowadays the interoperability of web applications is carried out by the use of data exchange formats such as XML and JavaScript Object Notation (JSON). Due to its simplicity, JSON objects are the most common way for sending information over the HTTP protocol. With the aim of adding a security mechanism to JSON objects, in this work we propose an encryption approach for cipher JSON objects through the use of chaotic synchronization. Synchronization ability between two chaotic systems offers the possibility of securing information between two points. Our approach includes mechanisms for diffusing and confusing JSON objects (plaintext), which yields a proper ciphertext. Our approach can be applied as an alternative to the existing securing JSON approaches such as JSON Web Encryption (JWE).

Background: Experimental data suggest ryanodine receptor-mediated intracellular calcium leak is a mechanism for atrial fibrillation (AF), but evidence in humans is still needed. Propafenone is composed of two enantiomers that are equally potent sodium-channel blockers; however, (R )-propafenone is an ryanodine receptor inhibitor whereas (S )-propafenone is not. This study tested the hypothesis that ryanodine receptor inhibition with (R )-propafenone prevents induction of AF compared to (S )-propafenone or placebo in patients referred for AF ablation. Methods: Participants were randomized 4:4:1 to a one-time intravenous dose of (R )-propafenone, (S )-propafenone, or placebo. The study drug was given at the start of the procedure and an AF induction protocol using rapid atrial pacing was performed before ablation. The primary endpoint was 30 s of AF or atrial flutter. Results: A total of 193 participants were enrolled and 165 (85%) completed the study protocol (median age: 63 years, 58% male, 95% paroxysmal AF). Sustained AF and/or atrial flutter was induced in 60 participants (84.5%) receiving (R )-propafenone, 60 (80.0%) receiving (S )-propafenone group, and 12 (63.2%) receiving placebo. Atrial flutter occurred significantly more often in the (R )-propafenone (N=23, 32.4%) and (S )-propafenone (N=26, 34.7%) groups compared to placebo (N=1, 5.3%, P =0.029). There was no significant difference between (R )-propafenone and (S )-propafenone for the primary outcome of AF and/or atrial flutter induction in univariable ( P =0.522) or multivariable analysis ( P =0.199, adjusted for age and serum drug level). Conclusions: There is no difference in AF inducibility between (R )-propafenone and (S )-propafenone at clinically relevant concentrations. These results are confounded by a high rate of inducible atrial flutter due to sodium-channel blockade. Registration: https://clinicaltrials.gov ; Unique Identifier: NCT02710669.

Efficacy of Bio-Absorbable Antibacterial Envelope Introduction Cardiac implantable electronic device (CIED) infections are potentially preventable complications associated with high morbidity, mortality, and cost. A recently developed bio-absorbable antibacterial envelope (TYRX™-A) might prevent CIED infections in high-risk subjects. However, data regarding safety and efficacy have not been published. Methods and Results In a single-center retrospective cohort study, we compared the prevalence of CIED infections among subjects with ≥2 risk factors treated with the TYRX™-A envelope (N = 135), the nonabsorbable TYRX™ envelope (N = 353), and controls who did not receive an envelope (N = 636). Infection was ascertained by individual chart review. The mean (95% confidence interval) number of risk factors was 3.08 (2.84–3.32) for TYRX™-A, 3.20 (3.07–3.34) for TYRX™, and 3.09 (2.99–3.20) for controls, P = 0.3. After a minimum 300 days follow-up, the prevalence of CIED infection was 0 (0%) for TYRX™-A, 1 (0.3%) for TYRX™, and 20 (3.1%) for controls (P = 1 for TYRX™-A vs. TYRX™, P = 0.03 for TYRX™-A vs. controls, and P = 0.002 for TYRX™ vs. controls). In a propensity score-matched cohort of 316 recipients of either envelope and 316 controls, the prevalence of infection was 0 (0%) and 9 (2.8%), respectively, P = 0.004. When limited to 122 TYRX™-A recipients and 122 propensity-matched controls, the prevalence of CIED infections was 0 (0%) and 5 (4.1%), respectively, P = 0.024. Conclusions Among high-risk subjects, the TYRX™-A bio-absorbable envelope was associated with a very low prevalence of CIED related infections that was comparable to that seen with the nonabsorbable envelope.

Background: It has been established that areas of slow conduction within a myocardial scar identified by isochronal mapping during sinus rhythm harbor the functional substrate that is involved in sustaining ventricular tachycardia (VT). We sought to test the hypothesis that targeting the region of slowest conduction during sinus rhythm would reduce VT recurrence following ablation. Methods and Results: 32 subjects underwent ablation for sustained monomorphic VT associated with structural heart disease from 2013 to 2014. Sustained VT recurred in 12 patients (37.5%). Isochronal late activation maps were created to display activation during sinus rhythm in the region of bipolar scar. The scar was divided into three zones of equal activation time. The zone with the densest isochrones was designated as having the slowest conduction . We retrospectively analyzed isochronal maps and measured the proportion of the slowest zone that was ablated (median 14%, IQR 0-50). During a mean follow-up of 6 months, recurrence of ventricular arrhythmia was significantly associated with ablation of the slowest zone (OR 0.126, CI 0.024-0.68, p 0.016). Furthermore, univariate logistic regression demonstrated reduction of 30% in the 6-month VT recurrence rate for every 10% increase in percent of the slowest zone ablated (OR 0.7, 95% CI 0.5-1.0, p=0.05). Conclusions: Patients who had ablation in the region of slowest conduction were significantly less likely to have recurrence of ventricular tachycardia. Our data suggests a strategy to target the slowest region of conduction for substrate modification may hold promise for improving outcomes of scar-mediated VT ablation.

Objectives To determine if arterial properties and wave reflection characteristics are favorably altered after enhanced external counterpulsation (EECP) treatment in patients with refractory angina. Background Early return of reflected waves from the lower body, resulting from increased arterial stiffness, augments central aortic pressure and increases left ventricular (LV) afterload and myocardial oxygen demand. EECP acutely enhances coronary perfusion (supply) and reduces LV afterload (demand). However, the mechanisms responsible for the sustained beneficial effects of EECP treatment are unclear. Methods Radial artery pressure waveforms were recorded by applanation tonometry and central aortic pressure waveforms generated using a mathematical transfer function in 20 patients with stable refractory angina. Data were collected before and after 34 1-h EECP sessions. Augmentation index (AIa) and timing of the reflected pressure wave were calculated from the aortic waveform. Results EECP treatment caused a decline in AIaand an increase in reflected wave travel time. These modifications in wave reflection characteristics caused a decrease in aortic systolic pressure and wasted LV pressure energy. The average number of angina episodes and Canadian Cardiovascular Society (CCS) class, both decreased in concordance with the physiologic changes due to EECP treatment. Conclusions EECP treatment reduces arterial stiffness and improves wave reflection characteristics in patients with refractory angina. These changes decrease LV afterload and myocardial oxygen demand and reduce the number of angina episodes, therefore enabling patients to participate in continuous exercise programs which in turn may provide long-term benefits and sustained improved quality of life.

Background Sildenafil is commonly used in the treatment of erectile dysfunction in hypertensive male cardiac transplant recipients (CTR); however, little is known about the vascular effects of sildenafil in these patients. Methods Central and peripheral arterial blood pressure (BP), heart rate, and brachial artery reactivity were determined in 15 hypertensive male CTR before and after oral sildenafil (50 mg) administration. Results Sildenafil improved brachial and aortic systolic BP, pulse pressure, aortic augmentation index, left ventricular tension time index, travel time of the reflected aortic pressure wave, and brachial artery reactivity (P < .01 for each comparison). No patient became hypotensive with sildenafil despite continuation of usual antihypertensive medications. Conclusions Sildenafil (50 mg) is well tolerated in hypertensive CTR and improves BP, aortic augmentation index, and endothelial function. By decreasing the amplitude of the reflected pressure wave and delaying its return to the heart, sildenafil reduces left ventricular afterload and systolic stress.