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A new low-noise CMOS oscillator architecture is presented. The oscillator comprises of a loop formed by a switched capacitor integrator which sets the control voltage to a voltage controlled oscillator (VCO). The VCO output provides a clock for the integrator, thus closing the feedback loop. Phase noise reduction is obtained by suppressing the VCO noise by the feedback loop. Design considerations and simulation results supporting the architecture are presented. [ABSTRACT FROM AUTHOR]

Introduction: There are gender-specific differences in the epidemiology, pathophysiology, clinical presentation, treatment and outcome of atrial fibrillation. Their identification can have a major impact on the planning of screening campaigns and their treatment approaches. Objective: To identify the gender differences in the clinical and therapeutic profile of patients with atrial fibrillation. Method: A cross-sectional descriptive study was conducted in a sample of 146 patients at the Department of Cardiology of the Hospital Universitario General Calixto García in Havana, Cuba, from January 2014 to December 2017. Results: Female sex (65.1%), age group 70-79 years (43.1%), hypertension in both genders (women 76.8% and men 60.8%; p=0.814), obesity (64.2 vs. 33.3%; p=0.07) and diabetes mellitus (52.6 vs. 21.6%; p=0.02) predominated. Women were more symptomatic and had a faster ventricular rate. The main associated disese in them was heart failure with preserved left ventricular ejection fraction (11.6 vs. 7.8%; p= 0.05) as unstable angina and infarction were more frequent in men. Women received less oral anticoagulation (58.9 vs. 68.6%; p=0.013). Conclusions: Differences in the clinical profile between men and women with atrial fibrillation were observed, as well as suboptimal use of oral anticoagulation in general, with significant intersex difference. [ABSTRACT FROM AUTHOR]

Introduction: Cardiac resynchronization therapy (CRT) is an indication in heart failure with wide QRS and severely reduced left ventricular ejection fraction. Objectives: To define the response predictors favorable to CRT. Method: An observational, descriptive, retrospective study was conducted to evaluate the QRS index (difference between the QRS width before and after implantation, divided by its value before implantation, multiplied by 100) as a predictor of favorable response to CRT. Electrocardiograms were performed before the procedure, at 6 and 12 months after implantation. The measurements were made by two independent observers, the first digital on the operating room monitor and the rest manual. Results: A total of 91 patients (mean age 61.2 years, 76% men) were included, with QRS wider than 120 ms and ejection fraction less than 35%. A favorable response was obtained in 59%. There were no significant pre-implant differences in the QRS duration between responders and non-responders (151.3 ms vs. 151.34 ms, p=0.98), but there were differences post-implant (100 vs. 115 ms, p<0.0001), as well as in the QRS percentage of decrease (33.2% vs. 24.3%, p<0.0001). The ROC curve showed that a cut-off value of the QRS index of 30% was sensitive (62%) and specific (75%) in order to predict a favorable response. Conclusions: The decrease in the QRS width after the CRT implant is related to a favorable response to it. [ABSTRACT FROM AUTHOR]

Introduction: The implantable cardioverter-defibrillator (ICD) has proven useful in the primary and secondary prevention of sudden cardiac death. The increase of its use motivates interest on its effectiveness outside the clinical trials. The first registration of an ICD implantation in Cuba is performed. Objective: To know the current situation of an ICD implantation in Cuba, regarding clinical data, indication, type of implant, device and complications of the procedure. Method: The registration's data were obtained through the collection form, which was completed voluntarily by each implantation team during or after the implant. Results: The total number of implants was 121, and the rate of 10.76 per million inhabitants. The procedure was performed in 5 medical institutions in the country, and 69.4% of the devices were implanted at the «Instituto de Cardiología y Cirugía Cardiovascular». The mean age was 58.05 ± 14.83, with a predominance of men (71.1%). The 52.1% were primo-implantation, dual-chamber devices represented 43.8% and triple-chamber 16.5%. In the primoimplants predominated patients with ejection fraction =35% (42.9%), in sinus rhythm (92.1%), with functional class III-IV (49.2%) and ischemic heart disease (41.3%). The 79.4% of the first implants were secondary prevention, and sudden death (42.9%), the most common clinical presentation. Complications were infrequent (4.1%) and the hematoma predominated. Conclusions: The implantation rate of the ICD per million inhabitants is comparable with that of Latin American countries. The implants of triple-chamber systems and in primary prevention are still modest. [ABSTRACT FROM AUTHOR]