Atrial Fibrillation (AFib) is the most common cardiac arrhythmia, increasing in prevalence with age. AFib is often associated with structural heart disease and a substantial proportion of AFib patients lead to the significant morbidity, mortality, and cost. Thus, AFib is the most prevalent and costly health problems in the world and a major global healthcare challenge. This study presents a beat-to-beat AFib detection system to provide a healthcare system for AFib patients. For real-time Electrocardiogram (ECG) signals, the beat-to-beat AFib detection system consists of two methods in this study: an improved ECG R peak detection method and a beat-to-beat Gaussian voting AFib method. The improved R peak detection method proposes two different optimization algorithms to replace the knowledge-based theory in previous R peak detection method that consists of three stages: band-pass filter, interesting blocks and threshold. The beat-to-beat Gaussian voting AFib method extracts features based on the R-R intervals to identify the possibility of AFib. Based the R-R intervals, the heart rate can be estimated, and the system can detect the tachycardia and bradycardia in addition. The results using the MIT-BIH database show that the proposed R peak detection method can detect beats with 99.9984% accuracy in testing data. Clinical testing reveals that the proposed beat-to-beat Gaussian voting AFib method is about 94.72% accurate and 98.11% sensitivity for 6 normal subjects and 6 AFib patients.

Aim: Atrial Fibrillation (AF) is the most common cardiac arrhythmia. The numerous researches about the causes, the mechanism of its development and its links with other diseases have not given definite answers to these many questions. I propose a hypothesis which can explain the reason for the development of AF, its correlation with various diseases and the interpretations of the well- known facts and phenomena associated with this arrhythmia.
Methods and results: The hypothesis results from the comparison of the hydrodynamics of the sinus rhythm and atrial fibrillation. According to this hypothesis AF is not a disease, but the protective physiological mechanism. In the conditions of left ventricle dysfunction/heart failure, the termination of the atrial mechanical systole reduces hydrostatic pressure in the pulmonary veins and alveolar capillaries which then reduces danger of pulmonary congestion. The hypothesis allows to build the algorithms of the relations between AF and various diseases.
Conclusion: The hypothesis suggested that AF is a physiological protective mechanism that is activated in the conditions of LV dysfunction.

The optimal medical treatment can fail in the intention to improve symptoms and quality of life of heart failure (HF) patients with severe left ventricular dysfunction and atrial fibrillation (AF) with uncontrolled ventricular rate. In these refractory cases to medical management, the necessity to utilize cardiac resynchronization therapy (CRT), or the need to use catheter ablation, or both, emerges in order to achieve hemodynamic improvement. Several clinical studies with CRT demonstrated structural and functional ventricular improvement. Moreover, there are additional beneficial effects in left ventricular remodeling. It was demonstrated that there is a significant improvement in left ventricular ejection fraction, and a significant decrease in end systolic and end diastolic volumes. However, CRT may be interrupted in over 30% of patients after successful implantation of a device and the most common reason for CRT interruption is the development of AF in 18% of the cases. Those patients whom do not respond to drug therapy will require atrioventricular nodal (AVN) catheter ablation in order to restore 100% CRT functionality and improvements in clinical outcomes. There are interesting published data documenting significant acute and longterm improvement in left ventricular function, cardiac performance, symptoms, exercise tolerance, clinical outcomes, and quality of life in selected HF patients with paroxysmal and persistent drug-refractory AF who have undergone AVN ablation and permanent pacemaker implantation.

HF preserved EF (HFpEF) is not common in children but have been reported in patients with congenital heart disease and open heart surgery. In adult group, acute myocarditis can be presented as HFpEF. We report the HFpEF in children without underlying congenital heart disease, probably associated with acute myocarditis.