Diagnostic validation of smart wearable device embedded with single-lead electrocardiogram for arrhythmia detection.

Objective: To validate a single-lead electrocardiogram algorithm for identifying atrial fibrillation, atrial premature beats, ventricular premature beats, and sinus rhythm. Methods: A total of 656 subjects aged 19 to 94 years were enrolled. Participants were simultaneously tested with a wristwatch (Huawei Watch GT2 Pro, Huawei Technologies Co., Ltd, Shenzhen, China) and a 12-lead electrocardiogram for 3 minutes. A total of 1926 electrocardiogram signals from 628 subjects (282 men and 346 women) aged 19 to 94 years (median 64 years) were analyzed using an algorithm. Results: The numbers of subjects with atrial fibrillation, atrial premature beats, ventricular premature beats, and sinus rhythm were 129, 141, 107, and 251, respectively, and together they had a total of 1926 electrocardiogram signals. For the three-class classification system, the recall, precision, and F1 score were 97.6%, 96.5%, 97.0% for sinus rhythm; 96.7%, 96.9%, 96.8% for atrial fibrillation; and 92.8%, 94.2%, 93.5% for ectopic beats, respectively. The macro-F1 score of the three-class classification system was 95.8%. For the four-class classification system, the recall, precision, and F1 score were 97.6%, 96.5%, 97.0% for sinus rhythm; 96.7%, 96.9%, 96.8% for atrial fibrillation; 90.5%, 89.4%, 89.9% for atrial premature beats; and 86.1%, 89.6%, 87.8% for ventricular premature beats, respectively. The macro-F1 score of the four-class classification system was 92.9%. Conclusions: The single-lead electrocardiogram algorithm embedded into smart wearables demonstrated good performance in detecting atrial fibrillation, atrial/ventricular premature beats, and sinus rhythm, and thus would facilitate atrial fibrillation screening and management.

The value of right heart contrast echocardiography combined with migraine rating scale in evaluating the efficacy of patent foramen ovale closure.

OBJECTIVES: To investigate the clinical values of right heart contrast transthoracic echocardiography (cTTE) combined with migraine rating scale in evaluating the efficacy of patent foramen ovale (PFO) closure. METHODS: From January 2018 to December 2021, a total of 68 hospitalized patients, 21 males and 47 females, who were treated with transcatheter closure of PFO-induced migraine in the Heart Center of the First Affiliated Hospital of Tsinghua University were selected, with the age of 38.4 ± 11.9 years old. The changes of right heart contrast transthoracic echocardiography (cTTE), visual analogue pain score(VAS), headache impact test-6(HIT-6) and migraine disability assessment questionnaire(MIDAS) before and 6 months after PFO occlusion were compared. RESULTS: Pre-operative cTTE data show that 36 patients (52.9%) had moderate right-to-left shunt (RLS), and 32 patients (47.1%) had massive RLS. cTTE was reexamined 6 months after operation and 1 case in the moderate RLS group had minimal RLS, 2 cases in the large RLS group had minimal RLS, and no shunts were seen for the rest. The VAS, HIT-6 and MIDAS scores before and 6 months after the operation were 7.65 ± 1.39 vs. 1.28 ± 1.53, 70.78 ± 6.82 vs. 41.53 ± 6.07, and 30.60 ± 13.24 vs. 1.93 ± 3.87, respectively. All the indexes 6 months after the operation significantly improved compared with the preoperative baseline (P < 0.05). CONCLUSIONS: cTTE combined with migraine evaluation scale could be used as an objective index to evaluate the clinical effect of PFO occlusion.

Uric Acid Is Associated with Worsening of Diastolic Function and Adverse Outcomes in Patients with Coronary Slow Flow.

OBJECTIVE: The impact of uric acid on worsening of diastolic function and clinical outcomes in patients with coronary slow flow remains unclear. This study aims to investigate possible associations between serum uric acid, worsening of diastolic function, and major adverse cardiovascular events in coronary slow flow patients. METHODS: Blood samples were obtained prospectively from 537 patients who had been angiographically diagnosed with coronary slow flow. Of those, 425 patients underwent comprehensive cardiac function assessment both before and after maximal treadmill exertion by stress echocardiography. The association between serum uric acid and major adverse cardiovascular events was examined using Cox proportional hazards regression model. RESULTS: Among the 425 patients (mean age: 58 ± 11 years; 52.2% men), worsening of diastolic function occurred in 176 (41.4%) after exercise stress. Patients with worsening of diastolic function had elevated levels of serum uric acid compared to those without (5.7 [4.1, 6.7] vs 4.3 [3.6, 5.3] mg/dL, respectively; P <.001). Higher serum uric acid levels were also significantly associated with neutrophil counts and high-sensitive C-reactive protein in patients with worsening of diastolic function but not in those without. Multivariate regression analysis found serum uric acid to be an independent predictor of worsening of diastolic function (odds ratio = 1.87 [1.17-3.82], P =.023). Moreover, serum uric acid remained associated with major adverse cardiovascular events even after adjusting for echocardiographic and clinical variables (hazard ratio = 1.56 [1.03-2.89], P =.016). CONCLUSION: Serum uric acid is associated with worsening of diastolic function and may be mediated by inflammation. These findings indicate that uric acid is a risk factor for major adverse cardiovascular events in patients with coronary slow flow.

A naturally-occurring 'cold earth' spot in Northern China.

Permafrost is determined to a large extent by the Earth's surface temperature, therefore it distributes mainly in high altitude and latitude regions. However, stable, warm (about -1 °C) permafrost occurs within a scree slope in northern China that is more than 600 km south of the southernmost limit of latitudinal permafrost on the Eurasian Continent. It is at an elevation of only 900 m above sea level (ASL). The area has a mean annual air temperature (MAAT) of 6 to 8 °C. Thermal processes of the scree slope, investigated through field monitoring and numerical simulation, showed that the permafrost is caused by winter air convection within the porous rock deposits and is stable as air convection does not occur in summer time. The deposit is covered by a 30-cm-thick peaty soil layer dated (carbon C-14) to between 1,000 to 1,600 years ago. The layer also contributes to the permafrost's existence due to the peat's thermal conductivity offset when frozen and thawed. The existence of permafrost under such warm climatic conditions confirms the effectiveness of using crushed rock layer as basement or slope cover to protect the warm permafrost subgrade of the recently-constructed Qinghai-Tibet Railway (QTR), even under the predicted climate warming conditions.

[Association of beta-adrenoceptor gene polymorphism with resting heart rate].

This study was aimed to shed light on the association of beta-adrenoceptor (beta-AR, includeing three subgroups: beta1, beta2 and beta3)gene polymorphism with resting heart rate (RHR). The RHRs of 150 healthy subjects (male 80; female 70) in the supine were detected by computerized system for analyzing the electrocardiosignals. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and allele specific-PCR techniques were used to determine Ser49Gly and Arg389Gly polymorphism of beta1-adrenoceptor gene; Arg16Gly and Gln27Glu polymorphism of beta2-adrenoceptor gene and Trp64Arg polymorphism of beta3-adrenoceptor gene; in these subjects. The results were as follows: The Arg389Gly polymorphism of beta1-adrenoceptor gene is significantly associated with RHR (P<0. 05), and the difference among three RHRs in male group is significantly higher than in group female group (P=0.0030 vs 0.0045). Individuals with Gly/Gly genotype have the highest RHR (male: 80.98+/-3.09; female: 84.23+/-6.28). No significant association was found among Ser49Gly, Arg16Gly, Gln27Glu and Trp64Arg polymorphism with RHR respectively (P> 0.05). RHR is associated with genotype. Arg389Gly polymorphism of beta1-adrenoceptor gene is significantly associated with RHRs, and the higher significant difference among male's RHRs,when compared with that among female's, suggests that male's RHRs be more influenced by genotype. Thus the clinical phenomenon of "the correlation of heart rate and mortality in male is higher than that in female" could be explained at the gene level.

[The relationship between resting heart rate and single nucleotide polymorphism at 3 sites of nitric oxide synthase gene in the Chinese Han nationality population].

OBJECTIVE: To study the relationship between resting heart rate and single nucleotide polymorphisms (SNP) at 3 sites of nitric oxide synthase (NOS) gene including NOS3 -922A/G, NOS3 894G/T and NOS2 -1173C/T SNPs. METHODS: Genomic DNA was gained from 211 Chinese Han nationality population. The SNPs of NOS3 -922A/G, NOS3 894G/T and NOS2 -1173C/T were genotyped by allele-specific primer-polymerase chain reaction (ASP-PCR) technique. RESULTS: The distribution frequencies of GG, GT and TT genotypes of NOS3 894G/T and AA, AG and GG genotypes of NOS3 -922A/G and CC, CT and TT genotypes of NOS2 -1173C/T were consistent with Hardy-Weinberg equilibrium (P> 0.05). The resting heart rate of Chinese Han nationality population with AA genotypes was higher than that with GG genotype of NOS3 -922A/G (P< 0.01). The resting heart rate of the sub-population with GG genotype was higher than that with TT genotype of NOS3 894G/T (P< 0.05). There were no difference among the resting heart rates of the sub-populations with the allele genotypes of NOS2 -1173C/T. CONCLUSION: The resting heart rate of Chinese Han nationality population with mutated genotype GG of NOS3 -922A/G and with mutated genotype TT of NOS3 894G/T were lower than those with wild genotype of NOS3 -922A/G and NOS3 894G/T. The finding suggests that resting heart rate is associated with SNP of NOS3 -922A/G and NOS3 894G/T.

[Analysis on time-frequency feature of rabbit cortical somatosensory evoked potential].

This experiment was carried out to analyze the time-frequency feature of rabbit cortical somatosensory evoked potential (SEP). Rabbit was narcotized and subjected to craniotomy. SEP was from sensory and motor cortex. Stimulation was continuing many times and signal was sampled at 3 800 Hz. The peak latency of each waveform was measured. Power spectrum of SEP was analyzed. The time-frequency feature of single-trial was compared with that of average SEP. It was found that the variability of single-trial SEP latency enlarges with time in a stimulation period. The spectrum of SEP includes three main frequency spectrum packages. The technique of summation makes a lot of signal aberration such as waveform confluence, new waveform emerging and after-discharging components dismissing.

[Single nucleotide polymorphisms in NOS3 A-922G, T-786C and G894T: a correlation study of the distribution of their allelic combinations with hypertension in chinese Han population].

To study single nucleotide polymorphisms (SNP) in A-922G, T-786C and G894T of endothelial nitric oxide synthase (NOS3) and to correlate the distribution of their allelic combinations with hypertension in Chinese Han nationality population, genomic DNA was isolated from venous blood leukocytes from 192 unrelated patients with hypertension (95 females and 97 males) and 122 healthy unrelated individuals (46 females and 76 males) as controls. SNPs of NOS3 A-922G, T-786C and G894T were genotyped by allele-specific primer (ASP) PCR. The distribution of genotype combinations of three SNPs was determined by clustering analysis. There were no difference in allele genotype distribution frequency and haplotype frequency of NOS3 G894T, NOS3 A-922G and NOS3 T-786C between the essential hypertension group and the healthy population (P>0.05). According to sex stratification, no association between essential hypertension and SNP of NOS3 A-922G,NOS3 T-786C or NOS3 G894T has been found in either the male subgroup or the female subgroup. In respect of allele genotype combination frequency in the natural distribution of NOS3 A-922 G, NOS3 T-786C and NOS3 G894T SNP, there was significant difference only in the allele genotype combination frequency of NOS3 G894G+A-922G+T-786T between the hypertension group and the healthy group (P<0.05, Chi2=4.5944). According to sex stratification, there were no significant difference in all above allele genotype combination frequency in three sites of NOS3 SNP between the hypertension male subgroup and the healthy male subgroup (P>0.05). There was significant difference in the allele combination frequency of NOS3 G894G +A-922G+T-786C between the hypertension female subgroup and the healthy female subgroup(P<001, Chi2=8.502). There was no association of SNP in NOS3 A-922G, NOS3 T-786C or NOS3 G894T with hypertension in the Chinese Han nationality population, nor was there a sex difference. The combination frequency of allele NOS3 G894G + A-922G + T-786C in the hypertension female subgroup was much lower than that in the healthy female subgroup, suggesting that female population with this combination genotype may be less susceptible to hypertension.

[Genotype combination distribution of 5-site SNPs in 3 subtypes of beta adrenoceptor].

DNA was extracted from the peripheral venous blood of 338 subjects using BLOOD DNA MINI KIT. The 5 site SNP in 3 subtypes of Beta-AR were genotyped by PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism) and allele-specific primer PCR techniques. The genotypes combination distribution of SNP at 5 sites in the 3 subtypes of Beta-AR were determined by clustering analysis technique. The natural combination distribution characteristics for SNP at 5 sites in the 3 subtypes of Beta-AR in 338 subjects were obtained. Sixty-seven combinations types were found. The preceding 5 combinations in the natural combination distribution of the SNP were: (1) The genotype combination of forty subjects was B1-AR S/S49+B1-AR R/R389+B2-AR R/G16+B2-AR Q/E27+B3-AR W/W64, its probability was 11.83%. (2) The genotype combination of thirty-three subjects was B1-AR S/S49+B1-AR R/R389+B2-AR R/G16+B2-AR Q/Q27+B3-AR W/W64, its probability was 9.76%. (3) The genotype combination of nineteen subjects was B1-AR S/S49+B1-AR R/G389+B2-AR R/G16+B2-AR Q/Q27+B3-AR W/W64, its probability was 5.62%. (4) The genotype combination of sixteen subjects was B1-AR S/S49+B1-AR R/G389+B2-AR R/G16+B2-AR Q/E27+B3-AR W/W64, its probability was 4.74%. (5) The genotype combination of thirteen subjects was B1-AR S/G49+B1-AR R/R389+B2-AR R/G16+B2-AR Q/E27+B3-AR W/W64, its probability was 3.85%. The obvious correlations exist among full sample and female or male subgroup, and between female and male subgroups.

[Separating independent components in heart period signal].

To extract sub-signal of heart period signal (HPS), a new statistical signal processing approach, namely independent component analysis (ICA) was addressed. Electrocardiosignal (ECS) was acquired from ten volunteers. ECS was sampled 8 minutes when the volunteer was in supine position, and then when the same volunteer was in erect position. HPS was extracted from ECS. According to time-delay, HPS was divided into five groups as mixed signals. Five signals were reconstructed into two groups by ICA. The rebuilt signals were transformed by Fourier transformation. One centralized in low frequency (called IC1); the other did in high frequency (called IC2). The power of IC1 was significantly increased (P<0.01) while that of IC2 showed no significant change (P>0.05), and the ratio of IC1 to total power also significantly increased with the change from supine position to erect position. Comparsion between the two postural results reveals that IC1 may express sympathetic activity, and IC2 represents parasympathetic activity. Sympathetic and parasympathetic nervous functions can be evaluated respectively and quantitatively by use of data and graphs from the two decomposed components.

[Analyzing heart period signal for fetus and pregnant woman in perinatal period].

Analyzing the digital characteristics (chaotic and spectral features) of fetal and pregnant woman's heart period signal (HPS) can assess the autonomic nervous system function. Extracting and analyzing HPS of fetal and pregnant woman in perinatal period were realized by using the method of visual programming. The subjects were in supine position. Electrocardiography-signal (ECS) from the leads placed at symphysis pubic bone to inferior border of abdominal wall was acquired. ECS was preprocessed by wavelet filter. The sophisticated technique developed by our laboratory was used to analyze the digital characteristics of HPS. The system could be used to assess fetal and pregnant woman's autonomic nervous system function, furthermore, sympathetic and parasympathetic nervous function could be evaluated respectively and quantificationally. The system also could be used to prognosticate fetal distress. The digital characteristics of fetal and other age groups' HPS, which vary with age, suggest the physiological process of development, mature and senility of autonomic nervous system; based on it, we could find the way of anti-senility. Some digital parameters of fetal HPS stand between those of newborn and adult, which may imply that fetal autonomic nervous regulation is influenced by mother's nerve and endocrine system.