The prevalence rate of cardiovascular diseases in China has been increasing, therefore the precise diagnosis and treatment of arrhythmias is particularly critical. ECG examination is the main basis for the diagnosis of arrhythmias. At present, artificial intelligence ECG analysis technology has brought new possibilities to improve the efficiency and accuracy of clinical diagnosis and treatment of arrhythmias. This paper reviews the latest progress in the application of artificial intelligence ECG analysis technology at home and abroad, and summarizes the prospects and challenges of the technology in the diagnosis of arrhythmias.

Atrial fibrillation (AF) is one of the most common arrhythmias. It is characterized by concealment, paroxysmal nature, complexity, and high mortality and disability rate; the prevalence rate of AF is on the rise. The new emergence of artificial intelligence technology breaks through the limitations of traditional methods of AF screening, showing unique advantages and broad application prospects in the screening, diagnosis and prediction of AF. Intelligent wearable devices have higher feasibility, specificity and sensitivity in the screening  of AF, with high cost-effectiveness in clinical application.

Objective  To investigate the importance of standard operation of ECG examination for quality control of remote ECG network. Methods  We analyzed ECGs transmitted through the network from January 1,2022 to June 30,2023 at the ECG Network Center of the First People’s Hospital of Xianyang. During the time period, we took every six months as a stage, and performed targeted operation training of ECG examination at each stage. We compared the graphic quality problems and the number of ECGs with quality problems among different stages. Results  After regular ECG operation training for clinical medical staff and instrument maintenance, the quality of ECG graphics has been greatly improved. Conclusion  Standard operation of remote ECG network directly affects the diagnostic accuracy of ECGs. Regular standardized training of ECG operation for clinical medical staff could improve the accuracy of ECG examination results, and avoid the occurrence of medical adverse events.

Atrial fibrillation (AF) has become an important disease that endangers the health of middle-aged and elderly people in China, and it is related to the risk of stroke and death. At present, pathophysiological mechanisms such as atrial structural remodeling, electrical remodeling, inflammation, autonomic nervous system disorders, and non-coding RNA may explain the occurrence and development of AF. The treatment of AF mainly includes anticoagulation, conversion of sinus rhythm, and control of ventricular rate. In addition, antiinflammatory, autonomic nerve intervention and genomics intervention therapy may become  new types of therapies for AF. This article reviews the research progress in the   pathogenesis and treatment of AF.

Atrial fibrillation (AF) is the most common arrhythmia and may easily lead to various complications. Therefore, precision medical methods are needed to identify and enhance AF detection to achieve early diagnosis and treatment. Artificial intelligencebased wearable devices are of great value for the screening and management of AF patients. This article reviews the relevant literature on recent applications of such devices for AF screening.

In recent years, the combination of remote ECG monitoring and artificial intelligence (AI) technology has greatly assisted the diagnosis and treatment of cardiovascular diseases, and shows extremely broad development prospect. This paper summarizes the progress in the application of AIbased remote ECG monitoring technology in the intelligent diagnosis, hierarchical diagnosis and treatment, prognosis evaluation, and individualized management of acute coronary syndrome. It also introduces the active health intelligent management system of the heart which has been constructed and gradually improved in China on this basis.

Objective To analyze initial and reexaminations of ECGs among enlisted male youths excluding functional changes due to various adverse influencing factors so as to prevent adverse cardiac events after enlistment and ensure the selection of physically and psychologically qualified candidates for the military. Methods Retrospective analysis was performed in the ECG examination results of 2 065 enlisted male youths. The age range of the examines was 18 to 22 years with a mean of (20.0±1.5) years. According to ECG diagnostic criteria, ECG changes of initial and reexaminations were analyzed. ResultsAmong the 2 065 enlisted male youths, abnormal ECGs were detected in 330 cases: sinus tachycardia in 30 cases (including 13 cases with concurrent ST-T changes), sinus bradycardia in 11 cases, premature beats in 19 cases, STT changes in 60 cases, early repolarization with elevated J point in 80 cases, right ventricular dominance in 12 cases, short PR interval in 56 cases, significant axis deviation in 10 cases, firstdegree atrioventricular block in 25 cases, seconddegree atrioventricular block in 1 case, left anterior fascicular block in 6 cases, atrial rhythm and atrial escape rhythm in 2 cases each, complete right bundle branch block in 12 cases, atrial fibrillation in 1 case, and ventricular preexcitation in 3 cases. A week later, reexamination was performed in the 330 cases with abnormal ECGs out of whom 277 cases turned to be normal, including sinus tachycardia (including 11 cases with concurrent ST-T changes) in 28 cases (93.33%), sinus bradycardia in 11 cases (100%), premature beats in 17 cases (89.47%), ST-T changes in 56 cases (93.33%), early repolarization with elevated J point in 68 cases (85.00%), right ventricular dominance in 11 cases (91.67%), short PR interval in 50 cases (89.29%), significant axis deviation in 8 cases (80.00%), firstdegree atrioventricular block in 22 cases(88.00%), left anterior fascicular block in 2 cases (33.33%), and atrial rhythm and atrial escape rhythm in 2 cases each (100%); the remaining cases were all unqualified in the reexamination. Except for seconddegree atrioventricular block, left anterior fascicular block, complete right bundle branch block, atrial fibrillation and ventricular preexcitation, there were statistically significant differences in the incidences of other ECG abnormalities between initial and reexaminations (all P<0.05). ConclusionBefore physical examinations of enlisted male youths, they should correct unhealthy living habits and keep a positive attitude in advance. ECG physicians should patiently recheck unqualified ECGs to exclude functional changes before confirming unqualified ECG results.

Based on a brief introduction to fetal electrocardiogram (FECG), this paper illustrates the clinical application of FECG technology in recent years in aspects such as detecting fetal arrhythmias and monitoring fetal intrauterine hypoxia in patients with pregnancyinduced hypertension syndrome. It sorts out the limitations of FECG itself. This paper also summarizes the progress of FECG signal processing techniques, and looks forward to the development prospect of FECG in the future.

More and more patients with renal artery stenosis (RAS) have been found in the clinical practice of cardiovascular disease. RAS is an important cause of hypertension and(or) renal insufficiency, and its main cause is atherosclerosis. In China, with aging of population, among the patients with coronary artery disease and peripheral vascular disease, those with atherosclerotic renal artery stenosis (ARAS) have been  constantly increasing. ARAS is one of the important causes of secondary hypertension. If ARAS patients can be found in an early phase, and made correction, diagnosis, treatment and effective intervention, it will be of positive significance for them to control blood pressure and improve the quality of life. This review focuses on the epidemiology for ARAS, the relationship between ARAS and hypertension, the diagnostic clues for ARAS, and its examination methods and treatment.

Objective  To investigate the changes of serum creatine kinase isoenzyme (CK-MB), homocysteine (Hcy) and B-type natriuretic peptide (BNP) levels in patients with acute myocardial infarction (AMI), and to analyze their correlation with the severity of the disease and their predictive value on major adverse cardiovascular events (MACEs). Methods   A total of 102 patients with AMI were selected as the research group while another 102 healthy physical examinees during the same period were selected as the control group. The changes of serum CK-MB, Hcy and BNP levels were compared separately between different groups and among the enrolled patients with different numbers of coronary lesions. Spearman and Pearson correlation analysis was utilized to explore the correlation between serum indicators and the number of coronary lesions or Gensini score. Patients in the research group were treated by percutaneous coronary intervention (PCI). They were divided into subgroups with or without MACEs according to the presence or absence of MACEs 6 months after the surgery. The serum CK-MB, Hcy and BNP levels were analyzed in each group before PCI and one month after the surgery. The predictive value of each serum indicator level one month after operation on MACEs was analyzed by using ROC curve. ResultsThe serum levels of CK-MB, Hcy and BNP in the research group were higher than those in the control group (P<0.01); serum CK-MB, Hcy and BNP levels were positively correlated with the number of coronary lesions and Gensini score (P<0.05). One month after surgery, the serum CK-MB, Hcy and BNP levels of the patients with MACEs were higher than those of the patients without MACEs (P<0.05). The AUC value of the combination of serum CK-MB, Hcy and BNP levels one month after surgery for MACEs was 0.943, which was higher than the AUC value of single indicator (0.769, 0.847 and 0.794, respectively;P<0.05). Conclusion  The serum levels of CK-MB, Hcy and BNP in AMI patients are elevated, which are closely related to the severity of the disease. The combined detection of the above serum indicators has certain predictive value for the occurrence of MACEs.

At present, many studies have shown that QRS complex duration is not completely linear with ventricular mechanical asynchrony, however, synchronous ventricular electrical activation is an important prerequisite for normal systole and diastolic functions of the ventricle. Patients with chronic heart failure (HF) often have ventricular systolic dysfunction. Although in the early stages of HF, the heart makes adaptive changes, once the compensatory limit is exceeded, it can lead to heart remodeling and serious damage to heart functions. Electrocardiography and mechanical remodeling is influenced by multiple factors such as cardiac structure, and cellular and molecular levels, which is manifested by prolonged QRS complex duration in the ECG. In the treatment of HF, in addition to traditional pacemakers, the emerged conduction system pacing in recent years is more suitable to the characteristics of physiological conduction, not only significantly shortening the QRS complex duration but also significantly improving ventricular mechanical synchronization. This review summarizes the possible mechanisms of electricalmechanical asynchrony in patients with chronic HF, and its relationship with QRS complex duration. It also covers the influence of the two factors on cardiac function.

Handheld ECG collector is a simple bipolar singlelead ECG recording device. A standard Ⅰlead ECG can be conveniently recorded just by pressing the positive and negative electrodes with both thumbs. It is mainly utilized in the monitoring of arrhythmias. As a household medical equipment, it is quite popular with the majority of middleaged and elderly friends. Based on the nature of unipolar  and bipolar leads, and their intrinsic connection, this paper derives a recording method of standard leads and augmented unipolar leads. Meanwhile, on the basis of further exploring the internal connection between CR lead and Wilson lead, the method of directly recording CR chest lead ECGs by handheld ECG collector is creatively proposed. Both theory and practice show that the equivalent recording method of augmented unipolar limb lead and the bipolar recording method of CR chest lead can not only meet the clinical needs, but also prove to be unique. This method can fully develop the medical value of household medical devices, which is worthy of be promoted and popularized.

Unlike other types of heart failure (HF), the efficacy of traditional medication and therapies are usually not reliable in  patients with HF with preserved ejection fraction (HFpEF). It may be attributed to obviously heterogeneous etiologies and inconsistent pathophysiological pathways among such patients. GE's phenotyping is a novel etiology oriented classification method. It not only facilitates grouping HFpEF patients with similar pathophysiological mechanisms, but also contributes to making appropriate diagnosis and treatment plans, and taking prognosis assessment and management measures for different types of HF patients. In the future, GE's phenotyping is expected to be an important reference for clinical study design for these patients.

Objective To assess the accuracy of wearable electrocardiogram ( ECG) monitoring device for detecting arrhythmias ( sinus rhythm, premature ventricular contraction premature atrial contraction, and atrial fibrillation), and heart rate in a clinical. Methods A total of 321 volunteers (875 ECG records) participated in this study, including 146 males ( 531 ECG records) and 175 females ( 344 ECG records). A wearable ECG monitoring device was employed to record ECGs for detecting arrhythmias and heart rate. The detection results were compared with physicians clinical diagnostic results based on 12-lead ECG machine (regraded as the gold standard for diagnosing arrhythmias and detecting heart rate). Accuracy and consistency evaluation of the two detection methods was conducted in all the subjects, including accuracy, sensitivity, specificity, F1 score, area under curve (AUC) of the receiver operating characteristic curve, Bland-Altman consistency analysis, mean absolute error, and correlogram. Results Regarding arrhythmia identification, wearable ECG monitoring device exhibits impressive performance metrics, with an AUC of 0. 98, accuracy of 0. 98, sensitivity of 0. 96, specificity of 0. 99, and an F1 score of 0. 96. In terms of heart rate monitoring, a robust correlation between the wearable ECG monitoring equipment and the ECG machine is evident, with a substantial total correlation coefficient of 0. 84 (P< 0. 01). Bland-Altman consistency analysis reveals that the two methods display a mean difference of - 0. 97 times per minute, a mean standard deviation of 8. 02 times per minute, and a 95% confidence interval ranging from -16. 69 to 14. 75 within an acceptable level. Conclusion Wearable ECG monitoring device can accurately detect arrhythmias and heart rate.

Objective  To compare the effectiveness and safety of secondgeneration cryoballoon ablation and conventional drug therapy separately as the initial treatment for patients with paroxysmal atrial fibrillation (AF). Methods  We selected 44 patients with paroxysmal AF who had been initially treated by secondgeneration cryoballoon ablation as the ablation group. The operation time, ablation time, X-ray fluoroscopy time, pulmonary vein isolation rate, and surgical complications were observed. We selected another 44 inpatients with paroxysmal AF who had been initially treated by drug therapy during the same period as the medication group. The two groups were followed up separately one month, and 3, 6 and 12 months after discharge to observe the recurrence rate and complications of AF. The efficacy and safety of treatment were further compared between the two groups. Results  The operation time, ablation time and X-ray fluoroscopy time of the ablation group were (108.0±39.0) minutes, (35.0±11.7) minutes and (10.0±6.9) minutes, respectively; the immediate isolation rate of pulmonary vein was 100%; there were 3 cases (6.8%) of operationrelated complications, including one case of vagus reflex and 2 cases of transient phrenic nerve injury. In the medication group, drug-induced sinus bradycardia occurred in 2 cases, QTc was prolonged in one case, and thyroid function was decreased in one case. After a mean follow-up of (12.0±5.) months, the recurrence rate of AF was 11.4% in the ablation group while the rate was 20.5% in the medication group. The recurrence rate in the ablation group was significantly lower than that in the medication group (P=0.033). The incidence of complications or adverse reactions did not vary significantly from the ablation group to the medication group (6.8% vs 9.1%, P=0.108). Conclusion  Compared with drug therapy, the secondgeneration cryoballoon ablation has a higher success rate for paroxysmal AF without increased risk of complications. The secondgeneration cryoballoon ablation can be considered as one of the initial treatment strategies for paroxysmal AF.

Atrial fibrillation (AF) is one of the most common arrhythmias with high disability rate and mortality, which seriously affects the quality of patients  life. Thromboembolism is one of the most serious complications of AF, however, the mechanism of thromboembolism caused by AF has not been fully clarified at present. Some biomarkers and risk scores could be applied in predicting the occurrence and development of AF related thromboembolism. This paper reviews the research progress in risk factors of thromboembolism among patients with AF in terms of  patients  basic data, laboratory examinations, echocardiography, etc.

患者女，63岁，因心前区不适，行24 h动态心电图检查。24 h时间散点图呈多层分布；Lorenz-RR散点图呈四分布，还可见与夺获相关的两个点集，逆向心电图显示为窦房阻滞,交界性逸搏及自主节律合并逸搏窦性夺获。本病例二度窦房阻滞的散点图特征明显，Lorenz-RR散点图与差值散点图相结合，是快速、准确地分析这类复杂心律失常的重要手段，夺获点集在鉴别二度窦房或房室阻滞中有重要作用。

Deceleration capacity of rate (DC) is one of the indicators reflecting the function of autonomic nervous regulation. Due to its noninvasiveness, and high sensitivity and specificity, it had been widely used in the prognosis and sudden death risk assessment of cardiovascular diseases at present. In recent years, domestic and foreign researchers have applied DC detection to research related to diseases other than heart diseases, and have made great progress. This article reviews the clinical research progress related to DC at home and abroad, aiming to further comprehensively and systematically sort out the clinical application value and potential  of DC.

Objective  To study the changes and significance of serum Hcy and NT-proBNP levels in patients with chronic heart failure. Methods  We selected 102 patients with chronic heart failure as the observation group while another 102 healthy physical examinees  during the same period were enrolled as the control group. The serum Hcy and NT-proBNP levels were separately tested in the two groups, and made comparison. Meanwhile, left ventricular ejection fraction (LVEF) was measured. The correlation between serum Hcy, NT-proBNP and LVEF was analyzed. Results  The serum Hcy and NT-proBNP levels of the observation group before and after treatment were higher than those of the control group while LVEF  was  lower than that of the control group with statistically significant differences (P<0.05). Before treatment, the levels of serum Hcy and NT-proBNP in the observation group increased with the upgraded NYHA grading while  LVEF decreased; there was a statistically significant difference of each index among the patients with different NYHA grades in pairwise comparison (P<0.05). The levels of serum Hcy and NT-proBNP were negatively correlated with LVEF (P<0.05) before treatment. Conclusion  The changes of serum Hcy and NT-proBNP levels could reflect the cardiac function grading and severity of patients with chronic heart failure.

Objective  To investigate the application value of 24hour ambulatory electrocardiography (AECG) in the diagnosis of silent myocardial ischemia (SMI). Methods  A total of 135 patients with suspected SMI were selected as the research subjects, and they underwent both routine ECG and 24-hour AECG. The detection rate of SMI was compared between the two examination methods. The diagnostic efficiency of SMI was analyzed by using coronary angiography (CAG) as the gold standard. Results  Among the 135 patients suspected with SMI, 107 cases were confirmed by CAG. Ninety-two cases were detected by routine ECG with a positive detection rate of 85.98% (92/107) while 24-hour AECG detected 102 cases with a positive rate of 95.33% (102/107). The positive rate of 24-hour AECG proves to be significantly higher than that of routine ECG (χ2=5.515, P=0.019). The diagnostic sensitivity, accuracy rate and negative predictive value of 24-ccuracy in the diagnosis of SMI.

Many commonly used medications have the potential to induce QT interval or QTc prolongation, subsequently leading to torsade de pointes (TdP) and other arhythmias, which may further deteriorate into ventricular fibrillation and even sudden cardiac death. Therefore, it is crucial to  make identification, early warning and correction of risk factors in order to prevent and reduce the risk of druginduced QT interval prolongation and TdP. In recent years, clinical decision support systems and other early warning strategies have been widely employed for predicting QT interval or QTc prolongation by identifying various risk factors, and  warning to the highrisk population susceptible to TdP. This article summarizes drugs and related risk factors that contribute to prolonged QT interval and TdP risk, as well as concludes the existing warning measures, aiming to offer guidance for managing patients exposed to the related risks.

Objective  To evaluate the efficacy and safety of the domestic Columbus 2.0 three-dimension (3D) cardiac electrophysiological mapping system and its supporting catheter in the treatment of tachyarrhythmias through a prospective, multicenter and singlearm study. Methods  We selected 50 consecutive patients with tachyarrhythmias from 4 electrophysiological centers of Shanghai;  20 patients (40.0%) are males, the mean age of patients is (55.38±18.14) years old. Radiofrequency ablation was performed on these patients guided by Columbus 2.0 system and its supporting catheter. The immediate success rate, operation time, X-ray exposure time and dose, and adverse events were recorded. All the patients were followed up for 6 months. Results  There are 34 patients with atrioventricular nodal reentry tachycardia, 11 cases with atrioventricular reentry tachycardia, one with atrial tachycardia, one with typical  atrial flutter, and 3 patients with premature ventricular ntraction.  The immediate success rate of the procedure is 100%; no catheter ablation related adverse event occurs during the perioperative period. The average operation time is 114.00 (89.75, 166.25) min, the  average X-ray exposure time is 5.90 (3.78, 8.07) min, and the  average X-ray exposure dose is 23.96 (8.00, 50.00) mGy. There is no recurrence during 6 months of follow-up.  Conclusion  The efficacy and safety of Columbus  2.0 3D cardiac electrophysiological mapping system and its supporting catheter is satisfying in treating tachyarrhythmias, especially supraventricular arrhythmias.

Besides conventional chemotherapy, cancer therapy also includes biotargeted therapy, endocrine therapy and immune checkpoint inhibitor therapy and so on at present. Cardiovascular adverse events associated with cancer therapy arouse much attention, among which QT interval prolongation as an abnormal ventricular repolarization phenomenon related to many cancer therapeutic drugs may induce torsades de pointes. Currently known factors that affect QT interval include medications, heart rate, electrolyte disturbances, etc. Based on the latest research progress at home and abroad, this paper reviews the measurement and influencing factors of QT interval, grading of QTc related adverse events, antitumor drugs leading to QT interval prolongation and adjuvant  medications, and monitoring and management strategies of QT interval in patients with cancer therapy.

Objective  To evaluate the impact of pulmonary vein anatomical variations on the efficacy of cryoablation in patients with persistent atrial fibrillation. Method  A retrospective analysis was conducted on the clinical data of 98 patients with persistent atrial fibrillation who had undergone cryoballoon ablation. According to the presence or absence of pulmonary vein variations, they were divided into pulmonary vein variation group (variants group, 21 cases) and non-pulmonary vein variation group (normal group, 77 cases). The procedure time, duration and dose of X-ray exposure, intraoperative complications, procedure success rate of isolation, and each follow-up index were compared between the two groups. Results  Compared with the normal group, the ablation procedure time\[(35.1±13.4) min vs. (64.3±17.7) min] and X-ray exposure time [(22.3±5.8) min vs. (33.6±6.0) min] of the variants group were both longer (P<0.01) while the CD value of radiation exposure [(607.1±212.9) mGy vs. (1 018.5±280.8) mGy] significantly increased (P<0.01). In the normal group, the success rate of primary isolation was significantly higher than that in the variants group (75/77 vs. 16/21, P=0.01). However, both groups completed pulmonary vein isolation 100% at the end of procedure. The recurrence rate of the two groups did not vary significantly during one-year follow-up (19/77 vs. 6/21, P=0.726). Conclusion  For patients with persistent atrial fibrillation and pulmonary vein variations, the acute-stage and long-term success rates of cryoablation are similar to the rates in the patients without pulmonary vein variation. However, patients with pulmonary vein variations have prolonged procedure time and increased radiation exposure.

Objective  To investigate the clinical significance of 24hour ambulatory electrocardiography (AECG) in patients with pacemaker implantation. Methods  A total of 65 patients with pacemaker implantation were selected as research subjects, and all of them both underwent routine 12 lead electrocardiogram(ECG) and 24hour AECG. The detection rates of pacemaker dysfunction \[abnormal pacing, and abnormal perception (absence of atrial perception, atrial over perception, absence of ventricular perception and ventricular over perception)\], special functions of pacemaker (pacing mode switching, frequency response, frequency lag, dynamic threshold monitoring and ventricular pacing management), self arrhythmias (atrial tachycardia, paroxysmal atrial fibrillation, atrial premature beats and premature ventricular beats), and pacemaker mediated arrhythmias (atrioventricular block, pacemaker mediated tachycardia, rapid rate and ventricular escape) separately by the two examination methods were compared. Results  By using 24hour AECG, the detection rates of pacemaker dysfunction and abnormal perception, and special functions of pacemaker such as pacing mode switching and frequency response were all significantly higher than those of routine ECG (P<0.05). The detection rates of self arrhythmias and pacemaker mediated arrhythmias were also significantly higher than those of routine ECG (P<0.05). Conclusion  The 24-hour AECG examination could effectively detect the working state of pacemaker in patients implanted with pacemaker, and sensitively make judgment of pacemaker dysfunction and cardiovascular events such as arrhythmias.

在非ST段抬高型急性冠脉综合征（non-ST segment elevation acute coronary syndrome，NSTE-ACS）患者中，当梗死相关动脉为旋支时，心电图表现多不典型，没有明显特异性，所以易导致临床延误诊断。本文报道1例NSTE-ACS患者心电图出现类似鱼钩样改变，其可用于临床辅助诊断旋支病变，有助于对犯罪靶血管的识别和诊断，从而为患者争取最佳的治疗时机。