Electrocardiogram (ECG) serves as a crucial tool for diagnosing cardiovascular diseases. With the rapid advancement of artificial intelligence (AI) technology, the application of AI in ECG analysis has gradually become a research hotspot. AI technology not only enables automated and accurate ECG interpretation, but also significantly improves the efficiency and accuracy of largescale cardiovascular disease screening in populations. This review summarizes the latest progress in AIassisted ECG analysis for cardiovascular system diseases, with a focus on its applications in arrhythmias, structural heart diseases, and acute cardiovascular events. Furthermore, it discusses development directions. As explainable AI technology evolves in the future, AIECG models are expected to be more widely adopted in clinical practice.

Objective  To study the diagnostic value of echocardiography and phonocardiography for coronary heart disease (CHD). Methods  A total of 102 patients suspected with CHD were selected, including 7 negative patients and 95 positive patients. Among the positive cases, there were 3 cases with the stenosis degree of arterial vessel's diameter less than 50% (group A), 36 cases with the stenosis degree of arterial vessel's diameter greater than or equal to 50% and less than 75% (group B), and 56 cases with the stenosis degree of arterial vessel's diameter greater than or equal to 75% (group C). Based on coronary angiography results as the gold standard, the positive rates of CHD and the detection rates of different degrees of coronary artery stenosis were compared between the two examination methods. Results  Coronary stenosis was detected in 7 patients (7.37%) by echocardiography; no coronary stenosis was detected in group A, one case (2.78%) was detected in group B, and 6 cases (10.71%) were detected in group C. Coronary stenosis was detected in 78 patients (82.11%) by phonocardiography including 2 patients (66.67%) in group A, 28 patients (77.78%) in group B, and 48 patients (85.71%) in group C. The difference in the positive rate of CHD was statistically significant between the two examination methods (P<0.05). In the diagnosis of CHD, the specificity, sensitivity and accuracy rate of echocardiography were 100%, 7.37% and 13.73%, respectively; the specificity, sensitivity and accuracy rate of phonocardiography were 14.23%, 82.11% and 77.45%, respectively. Conclusion  The diagnostic results of phonocardiogram based on the fourth heart sound are more in line with the diagnostic results of the gold standard. Therefore, phonocardiogram has a relatively high diagnostic value for CHD. Meanwhile, its overall diagnostic coincidence rate is also higher than that of echocardiography.

Objective  To explore interleukin-6 (IL-6) and neutrophils to lymphocytes ratio (NLR) combined with native T1 value in the prognosis evaluation of patients with viral myocarditis (VMC). Methods  A total of 156 patients with confirmed VMC were selected as research objects. After 12 months of follow-up, they were grouped into a poor prognosis group (40 cases) and a good prognosis group (116 cases) according to the follow-up results. The clinical data of the patients were collected, and Logistic regression analysis was used to investigate the influence of IL-6, NLR and native T1 value on the prognosis of VMC patients. ROC curve was utilized to evaluate the predictive efficiency of the above parameters for the prognosis of VMC patients. ResultsThe levels of IL-6, hs-cTn I and NT-proBNP, NLR, and native T1 value in the poor prognosis group were all significantly higher than those in the good prognosis group, and the differences were all statistically significant (all P<0.05). Binary Logistic regression analysis showed that IL-6, NLR and native T1 value were all independent influencing factors for the prognosis of VMC. ROC analysis demonstrated that the effect of the combination of IL-6 (regarding 12.895 pg/mL as the optimal cut-off value), NLR (regarding 3.495 as the optimal cut-off value) and native T1 value (regarding 1 122.0 ms as the optimal cut-off value) in predicting the prognosis of VMC patients was better than that of any single test, with a sensitivity of 87.5% and a specificity of 96.6%. Conclusion  The level of IL-6, NLR and native T1 value were significantly elevated in VMC patients with poor prognosis, and they could be served as auxiliary predictive indicators for the prognosis. The combined detection of the three indicators shows good predictive efficiency for poor prognosis of VMC.

Objective To analyze the therapeutic effect of low-flow oxygen inhalation in elderly patients with hypertension complicated by obstructive sleep apnea syndrome (OSAS). Methods A total of 175 elderly patients with hypertension and OSAS were selected as study subjects. All patients received conventional antihypertensive medication as recommended by guidelines. Those receiving continuous positive airway pressure (CPAP) therapy, low-flow oxygen inhalation therapy, and no corresponding intervention were assigned to a CPAP group (55 cases), a low-flow oxygen group (60 cases), and a control group (60 cases), respectively. Clinical data were collected, including body mass index, waist circumference, underlying diseases, laboratory test results and color Doppler echocardiography parameters, as well as systolic/diastolic blood pressure, Epworth sleepiness scale (ESS) scores, nocturnal minimum saturation of peripheral oxygen (SpO2), and apnea hypopnea index (AHI) before and after intervention (3 months of treatment). ResultsBlood pressure control and respiratory parameters in the low-flow oxygen group both improved significantly after oxygen inhalation (both P<0.05). After 3 months of follow-up, the nocturnal minimum SpO2 in both the low-flow oxygen and CPAP groups increased significantly compared with pre-intervention levels (both P<0.01). There was statistically significant difference in nocturnal minimum SpO2 after intervention among the three groups (P<0.01). After pharmacotherapy or intervention, systolic and diastolic blood pressures both decreased significantly in all the three groups compared with pre-intervention levels (all P<0.05), and post-intervention differences in systolic and diastolic blood pressures among the three groups were statistically significant (all P<0.05). Compared with baseline, both the low-flow oxygen group and the CPAP group demonstrated significant reduction in ESS score and AHI after the intervention (both P<0.05). Conclusion Low-flow oxygen inhalation therapy in elderly patients with hypertension and OSAS could partially improve sleep respiratory parameters, increase nocturnal SpO2, and help to increase the compliance rate of blood pressure control, reduce the use of antihypertensive medication and alleviate economic burden.

Objective  By comparing the characteristics of chest lead electrocardiogram (ECG) indicators related to premature ventricular contraction (PVC), to explore the ECG indicators that can identify the origin point of outflow tract PVC more accurately. Methods  Seventy-eight patients with outflow tract PVC who had received successful radiofrequency catheter ablation were retrospectively analyzed. Among them, 52 cases of PVC were originated from the right ventricular outflow tract (RVOT), while 26 cases were originated from the left ventricular outflow tract (LVOT). The V2 transition index, SV2/RV3 index, RV1 wave duration index (RdV1/QRSdV1) and RV1/SV1 amplitude index were measured respectively. Each parameter and its diagnostic efficacy in differentiating outflow tract PVC were compared, and analyzed between the two groups. Results  There were no statistically significant differences in clinical features including age, sex, body mass index, smoking history, drinking history, complicated hypertension, complicated diabetes, cardiac structural and functional parameters, preoperative ventricular arrhythmia burden by 24-hour ambulatory electrocardiography (AECG), and preoperative anti-arrhythmic drug types between the two groups (all P>0.05). V2 transition index, SV2/RV3 index, RdV1/QRSdV1 and RV1/SV1 amplitude index were all significantly different between the two groups (all P<0.01). ROC analysis and decision curve analysis (DCA) were used to explore the diagnostic performance of each parameter in distinguishing the origin of outflow tract PVC. The AUC value of V2 transition index was 0.837, its optimal cut-off value was 0.76, and the sensitivity, specificity and accuracy rate were separately 0.718, 1.000 and 0.780. The AUC value of SV2/RV3 index was 0.859, its optimal cut-off value was 3.48, and the sensitivity, specificity and optimal accuracy rate were separately 0.718, 1.000 and 0.780. The AUC value of RdV1/QRSdV1 was 0.741, its optimal cut-off value was 0.35, and the sensitivity, specificity and accuracy rate were separately 0.487, 1.000 and 0.600. The AUC value of RV1/SV1 amplitude index was 0.836, its optimal cut-off value was 0.34, and the sensitivity, specificity and accuracy rate were separately 0.692, 0.909 and 0.740. V2 transitional index and SV2/RV3 index had higher diagnostic predictive value. DCA results showed that SV2/RV3 index demonstrated the highest net benefit. Based on age, sex, body mass index, smoking and drinking history, hypertension, diabetes, cardiac structural and functional parameters, preoperative ventricular arrhythmia burden, and the use of preoperative anti-arrhythmic drugs, we constructed a basic model. After adding V2 transition index to it, the differentiation performance of the model was significantly improved (C-index was 0.924, 95% confidence interval: 0.851-0.996, P=0.003); after adding SV2/RV3 index, its differentiation performance was further improved (C-index was 0.953, 95% confidence interval: 0.905-1.000, P<0.001). Conclusion  V2 transition index and SV2/RV3 index have relatively high differentiation value in locating the origin of outflow tract PVC, especially SV2/RV3 index demonstrating very high clinical utility value for PVC migrating in lead V2-V3.

Objective To explore the clinical performance of non-invasive prenatal testing (NIPT) in screening for fetal chromosomal copy number variations (CNVs). Methods In this retrospective cohort study, 196 high-risk NIPT samples were analyzed. The results of chromosomal karyotyping analysis or chromosomal microarray analysis (CMA) were compared. The positive rate and positive predictive value (PPV) of fetal CNVs, and other clinical data were screened by NIPT, so as to assess the detection value of NIPT for fetal CNVs. Results A total of 20 378 NIPT samples were tested. Among the 196 high-risk samples, 54 were CNVs, with a screening positive rate of 0.265%. Forty-six pregnant women underwent interventional prenatal diagnosis, among whom there were 21 cases confirmed with CNVs including 13 cases with pathogenic variations, 3 cases with likely pathogenic variations, and 5 cases with variations of unknown significance. The PPV of NIPT for screening CNVs was 45.65%. Seventeen cases of microdeletion CNVs and 36 cases of microduplication CNVs were screened out by NIPT, and 1 case was microdeletion combined with microduplication CNVs, accounting for 31.48% (17/54), 66.67% (36/54), and 1.85% (1/54), respectively. The corresponding PPVs were 64.29%, 35.48% and 100.00%, respectively. Statistical analysis showed that there were no statistically significant differences in the positive rate and PPV of NIPT for screening microdeletion CNVs and microduplication CNVs (all P>0.05). Conclusion NIPT demonstrates relatively high positive rate and PPV for screening fetal CNVs. Interventional prenatal diagnosis should be recommended for those with high-risk of CNVs by NIPT. NIPT combined with chromosomal karyotyping analysis and CMA could provide precise genetic counseling and guidance for clinical practice.

Objective  To study the clinical efficacy and safety of radiofrequency catheter ablation for atrial fibrillation (AF) by domestic minimally invasive Columbus  system. Methods  A total of 26 patients with AF who had undergone radiofrequency catheter ablation with Columbus  system and its supporting catheter were successively selected. The immediate success rate of surgery, intraoperative related parameters and surgery-related complications were recorded, while the recurrence of AF and the occurrence of adverse events were observed during follow-up. Results  The enrolled 26 patients were all paroxysmal AF. Pulmonary vein isolation was successfully achieved during operation, and there were no complications related to radiofrequency catheter ablation during perioperative period. During a mean follow-up of (5.92±1.94) months, AF recurred in 5 of 26 patients (19.23%). No serious adverse events such as embolism, bleeding, atrial esophageal fistula, or death occurred during the follow-up. Conclusion  Radiofrequency catheter ablation for AF by using domestic minimally invasive Columbus system is clinically feasible, with satisfactory short-term efficacy and safety.

Resting heart rate is an index reflecting the balance of cardiac autonomic nervous system, and it is also a risk factor leading to the occurrence of cardiovascular diseases and the increase of all-cause mortality. Resting heart rate as a simple and easy-to-measure physiological index has attracted more and more attention in the field of cardiovascular diseases in recent years. This paper reviews the research progress of the correlation between resting heart rate and cardiovascular diseases from different angles, including its influence on common cardiovascular diseases such as coronary heart disease, hypertension, heart failure and atrial fibrillation, as well as the control of resting heart rate.

Objective  To investigate the effect of intra-aortic balloon pumping (IABP) combined with percutaneous coronary intervention (PCI) in the treatment of cardiogenic shock after acute myocardial infarction. Methods  Sixty patients with cardiogenic shock after acute myocardial infarction were selected. They were divided into two groups by the random number table method. Patients undergoing PCI treatment were enrolled in the PCI group, while patients receiving a combined therapy of PCI and IABP were assigned to the combination treatment group, with 30 cases in each group. We compared the changes in vital signs, cardiac function, and levels of inflammatory factors and myocardial injury markers before and after treatment, as well as the incidence of adverse cardiovascular events after surgery between the two groups. Results  After treatment, the mean arterial pressure in the combination treatment group was significantly higher than that in the PCI group ［（104.06±9.79） mmHg vs. （91.27±8.84） mmHg, P<0.01］; the heart rate was significantly lower than that of the PCI group ［（85.37±8.13） times/min vs. （94.72±8.94） times/min，P<0.01］. The peak IL-6 level of patients in the combination treatment group was advanced to 24 hours after surgery, while the combination treatment group exhibited a significantly smaller magnitude of TNF-α elevation compared with the PCI group (P<0.05). In the combination treatment group, the LVEF ［ (45.27±4.35)%］, cardiac output ［ (5.52±0.77) L/min］, and stroke volume ［(78.89±7.75) mL］ were all significantly higher than those in the PCI group ［values of the above indexes were (40.84±3.81)%, (5.01±0.64) L/min, and (71.28±7.03) mL, respectively］, while the left ventricular end-diastolic diameter was significantly smaller than that in the PCI group ［（50.09±4.87） mm vs. （55.27±5.36） mm, P<0.01］. After treatment, the levels of N-terminal B-type natriuretic peptide (NT-proBNP), cardiac troponin and creatine kinase isoenzymes, and the incidence of adverse cardiovascular events in the combination treatment group were all significantly lower than those in the PCI group (all P<0.05). Conclusion  The combination of IABP and PCI for treating cardiogenic shock after acute myocardial infarction could significantly improve cardiac function compared with PCI therapy alone, which may be associated with alleviating the inflammatory response in the acute phase of myocardial infarction.

Objective  To observe the efficacy of breviscapine combined with levocarnitine in the treatment of patients with acute viral myocarditis (AVM), and analyze its impact on cardiac function and myocardial injury. Methods  Clinical data of 96 patients with AVM were retrospectively analyzed. These patients were divided into a levocarnitine group and a combination group according to the treatment plan, with 48 cases in each group. In addition to conventional therapy received by patients in both groups, the levocarnitine group received levocarnitine treatment, while the combination group received intravenous infusion therapy with breviscapine combined with levocarnitine. Both groups received continuous medication administration for 14 days. The efficacy and adverse reactions between the two groups were compared, as well as cardiac function indexes ［LVEF, stroke volume (SV) and cardiac output (CO)］, myocardial injury markers ［cTn I, creatine kinase MB(CK-MB), lactate dehydrogenase (LDH), aspartate aminotransferase (AST) and creatine kinase］, inflammatory factors, and oxidative stress indicator levels before and after treatment. ResultsThe total effective rate of the combination group was higher than that of the levocarnitine group (91.67% vs. 70.83%, P<0.05). Compared with the levocarnitine group, the LVEF, SV and CO in the combination group were increased after treatment; serum cTn I, CK-MB, LDH, AST, creatine kinase, interleukin-6 and tumor necrosis factor-α (TNF-α) levels in the combination group after treatment were reduced, while the level of interleukin-4 was increased (all P<0.05). Compared with the levocarnitine group, serum superoxide dismutase (SOD) level in the combination group increased, while the advanced oxidation protein products (AOPP) and malondialdehyde levels reduced after treatment (all P<0.05). There was no statistically significant difference in the incidence of adverse reactions between the two groups (P>0.05). Conclusion  Breviscapine combined with levocarnitine could significantly improve the therapeutic effect on AVM patients, significantly ameliorate cardiac function, which may be related to the inhibition of inflammation-oxidative stress response, and has good safety.