On account of the mechanical disturbance of external chest pressing to electrocardiogram (ECG) signal, the ECG rhythm cannot be identified reliably during the cardio-pulmonary resuscitation period. Whereas the possibility of successful resuscitation will be lowered due to interrupted external chest pressing, a new filtering algorithm, enhanced leastmean-square (eLMS) algorithm, was proposed and developed in our laboratory. The algorithm can filter the disturbance of external chest pressing without the support of hardware reference signal and correctly identify ventricular fibrillation (VF) rhythm and normal sinus rhythm in case of uninterrupted external chest pressing. Without other reference signals, this algorithm realizes filtering only through the interrupted electrocardiograma (cECG) signal. It was verified with ECG signal and disturbance signal under different signal to noise ratios and contrasted with other mature algorithms. The verification results showed that the identification effect of eLMS was superior to those of others under different signal to noise ratios. Furthermore, ECG rhythm can be correctly identified only through cECG signal. This algorithm not only reduces the research and development(R & D)costs of automated external defibrillator but also raises the identification accuracy of ECG rhythm and the possibility of successful resuscitation.
Objective Through analyzing BKCa channel expression in atrial fibroblasts in patients with sinus rhythm and atrial fibrillation (AF), to explore the mechanism of myocardial fibrosis and provide new therapeutic strategies for the treatment and reversal of AF structure reconstruction. Methods We selected 10 patients of rheumatic heart valvular disease who underwent valve replacement surgery. They were 5 patients with sinus rhythm (a sinus rhythm group, 2 males and 3 females with an average age of 49.1±8.3 years) and 5 with AF (an AF group, 3 males and 2 females with an average age of 50.3±5.8 years). About 100 mg tissue was obtained from the right auricula dextra, and the atrial fibroblasts were cultured by tissue block adherence method, and the expression of BKCa channel genes and proteins in cultured fibroblasts was detected by quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting methods. Results (1) The general data of 10 patients between the AF group and the sinus rhythm group were compared. There was no significant difference between the two groups in age (t=1.21, P=0.67) and sex (t=2.56, P=0.75). There was statistical difference in the left atrial diameter and the right atrium diameter between the two groups (t=19.45, P=0.01; t=23.52, P=0.06); (2) the mRNA expression of BKCa subunit was detected by qRT-PCR method, and there was no significant difference in the mRNA expression of BKCa α and BKCa β1 between the two groups (t=3.14, P=0.79; t=2.88, P=0.69); (3) the expression of BKCa protein was detected by western blotting method, and there was no significant difference in the protein expression of BKCa α and BKCa β1 between the two groups (t=0.55, P=0.31; t=0.73, P=0.46). Conclusion BKCa pathway may not be involved in the pathogenesis and maintenance of AF, but it may play an important role in the process of myocardial fibrosis.