The automatic detection of arrhythmia is of great significance for the early prevention and diagnosis of cardiovascular diseases. Traditional arrhythmia diagnosis is limited by expert knowledge and complex algorithms, and lacks multi-dimensional feature representation capabilities, which is not suitable for wearable electrocardiogram (ECG) monitoring equipment. This study proposed a feature extraction method based on autoregressive moving average (ARMA) model fitting. Different types of heartbeats were used as model inputs, and the characteristic of fast and smooth signal was used to select the appropriate order for the arrhythmia signal to perform coefficient fitting, and complete the ECG feature extraction. The feature vectors were input to the support vector machine (SVM) classifier and K-nearest neighbor classifier (KNN) for automatic ECG classification. MIT-BIH arrhythmia database and MIT-BIH atrial fibrillation database were used to verify in the experiment. The experimental results showed that the feature engineering composed of the fitting coefficients of the ARMA model combined with the SVM classifier obtained a recall rate of 98.2% and a precision rate of 98.4%, and the F1 index was 98.3%. The algorithm has high performance, meets the needs of clinical diagnosis, and has low algorithm complexity. It can use low-power embedded processors for real-time calculations, and it’s suitable for real-time warning of wearable ECG monitoring equipment.
ObjectiveTo observe the ocular manifestations of presumed ocular tuberculosis in patients with pulmonary tuberculosis. MethodsOne hundred and fifty nine patients with pulmonary tuberculosis received examinations of visual acuity, slit lamp microscopy and indirect ophthalmoscopy. Those patients with retinochoroidal inflammatory lesions, retinal hemorrhages or detachments underwent fundus fluorescein angiography (FFA) and optical coherence tomography (OCT) to determine whether the presumed ocular tuberculosis was involved. There were 9 patients (16 eyes, 5.67%) of presumed ocular tuberculosis, including 5 males and 4 females. The age was ranged from 19 to 64 years old, with an average of 35.12 years. Seven patients were affected bilaterally and 2 patients affected unilaterally. There were 8 patients (15 eyes, 93.75%) with uveitis and 1 patient (1 eye, 6.25%) with central retinal vein occlusion (CRVO). The blood laboratory tests were negative in all cases. ResultsThe corrected vision was from light sensation to 0.15 in 6 uveitis eyes, 0.8 to 1.0 in 10 eyes. The anterior segment change was found in 10 eyes, which including granulomatous uveitis (8 eyes) and non-granulomatous uveitis (2 eyes). Granulomatous uveitis eyes had iris nodules, posterior synechia of the iris and mutton-fat keratic precipitates (KP). Non-granulomatous uveitis eyes had KP only. Choroidal tubercles were found in 7 eyes in which 3-7 off-white lesions of varying sizes were found with local retinal detachment. FFA revealed hypo-fluorescence with obscure boundary in arterial phase and arterial and venous phase, and hyper-fluorescence with obscure boundary in later phase. OCT showed retinal pigment epithelium uplift. There was 1 eye with CRVO, which had punctate, splinter and linear hemorrhage, white lesions in some hemorrhagic focus. ConclusionThe presumed ocular tuberculosis eyes showed mainly granulomatous inflammation and multiple choroid tubercles, and CRVO sometime.