Hollandvilladsen2387

Detection of Atrial fibrillation (AF) from premature atrial contraction (PAC) and premature ventricular contraction (PVC) is challenging as frequent occurrences of these ectopic beats can mimic the typical irregular patterns of AF. In this paper, we present a preliminary study of using density Poincare plot based machine learning method to detect AF from PAC/PVCs using electrocardiogram (ECG) recordings. First, we propose creation of this new density Poincare plot which is derived from the difference of the heart rate. Next, from this density Poincare plot, template correlation and discrete wavelet transform are used to extract suitable image-based features, which is followed by infinite latent feature selection algorithm to rank the features. Finally, classification of AF vs PAC/PVC is performed using K-Nearest Neighbor, discriminant analysis and support vector machine (SVM) classifiers. Our method is developed and validated using a subset of Medical Information Mart for Intensive Care (MIMIC) III database containing 8 AF and 8 PAC/PVC subjects. Both 10-fold and leave-one-subject-out cross validations are performed to show the robustness of our proposed method. During the 10-fold cross-validation, SVM achieved the best performance with 99.49% sensitivity, 94.51% specificity and 97.29% accuracy with the extracted features while for the leave-one-subject-out, the highest overall accuracy is 90.91%. Moreover, when compared with two state-of-the-art methods, the proposed algorithm achieves superior AF vs. PAC/PVC discrimination performance.Clinical Relevance-This preliminary study shows that with the help of density Poincare plot, AF can be separated from PAC/PVC with better accuracy.Left ventricular assist devices (LVADs) are used to treat patients with severe (New York Heart Association class IV) heart failure. Thrombosis and bleeding are severe LVAD-related complications; thus, an effective anticoagulation regimen is crucial for successful postoperative management. The CH-VAD™ (CH Biomedical, Inc.) is a small, implantable, full-support (>5 L/min) LVAD with a centrifugal flow pump that has a fully magnetically levitated rotor, which confers superior hemocompatibility. In this study, the CH-VAD™ was implanted in two calves to evaluate its hemocompatibility and to establish an anticoagulation regimen for future GLP (good laboratory practice) studies. Heparin infusion was used during the surgery, and during postoperative management, the proper dosage of warfarin was given orally to maintain an international normalized ratio (INR) between 2.0 and 3.0. Pump performance, animal condition, and hematology results were recorded throughout the study (approximately 60 days). 4EGI-1 nmr The results show that under the established anticoagulation regimen, the CH-VAD™ was well tolerated in the bovine model, with no significant thrombus or thromboembolic lesion formation in distal end organs. Low plasma free hemoglobin levels suggest that the device did not cause hemolysis. These results and the experience gained pave the way for future GLP studies.Increase in transmural dispersion of repolarisation along with a diminished QT interval have been known to aid in the development of arrhythmia during KCNQ1-linked short QT syndrome type 2 (SQTS2). However, the percentage by which action potential duration (APD) shortens in the different cell types that make up the ventricular wall are not fully understood. In this study, the percentage of APD shortening of M-cells was varied to determine the conditions under which re-entry occurs during SQTS2. A 2D transmural section of the heart with anisotropic properties is considered. Slight modifications to the TP06 equations are used to simulate the electrophysiology of the endocardial (endo), midmyocardial (M) and epicardial (epi) cells. A discrete network of 250×100 cells are interconnected using gap junction conductances and from this, a pseudo ECG is generated. On pacing the tissue with premature beats in the midst of normal pacing pulses and on including SQTS, it is observed that re-entry is sustained for a longer duration when the APD shortening in M-cells is more compared to the epi or endo cells while the percentage reduction in APD of M-cells is about 5% to 7% lesser than that in epi and endo cells. Further, when the percentage reduction in APD of M-cells is similar to epi or endo cells, no re-entry is generated. This analysis highlights the key role of percentage reduction in APD of M-cells compared to epi and endo cells in maintaining the re-entrant waves.The objective of this study was to determine potential effects of Respiratory-gated Auricular Vagal Afferent Nerve Stimulation (RAVANS) on cardiac autonomic activity in hypertensive patients.20 hypertensive subjects (57.3±6.2 years; 11 females, 9 males) were randomized to receive either active RAVANS at 25 Hz or sham stimulation for 5 consecutive days and were assessed 5 and 10 days later. Continuous electrocardiogram, pulse rate, and blood pressure signals were collected during 10-minute baseline, 30-minute stimulation, and 10-minute recovery periods for each session. LabChart was used to acquire and process heart rate variability and blood pressure indices. Percent changes of mean values during the recovery period were calculated comparing the final stimulation session and follow-up sessions to the first stimulation session. General linear models were applied to assess the effects of RAVANS on the variables evaluated, considering baseline values and sex as covariates in the models.We found that RAVANS increased high frequency (HF-HRV) power during recovery of the final stimulation session and both follow-up sessions in comparison to sham. RAVANS also lowered heart rate and increased average RR and root mean square of successive RR interval differences (RMSSD) during recovery on the final day of stimulation. No significant effects on blood pressure values were observed during these periods.These results suggest that RAVANS effectively stimulates cardiovagal activity in hypertension, with effects lasting up to 10 days. Future research incorporating larger sample sizes is needed to replicate the effects of RAVANS.Clinical Relevance- This research has implications for potential therapeutic effects of respiratory-gated tVNS on cardiovagal modulation in hypertensive patients.