Реферат
Objective: To investigate the level of nucleic acid oxidation in myocardial tissue of patients aged over 85 with heart failure with preserved ejection fraction (HFpEF) and the correlation with myocardial amyloid deposition. Methods: This was a retrospective case-control study. Data of patients≥85 years old who underwent systematic pathological autopsy in Beijing Hospital from 2003 to 2017 were retrospectively collected. Twenty-six patients were included in the HFpEF group and 13 age-and sex-matched patients who had not been diagnosed with heart failure and died of non-cardiovascular diseases served as the control group. The left ventricular myocardium slices of both groups were semi-quantitatively analyzed using immunohistochemical staining of 8-oxidized guanine riboside (8-oxo-G) and 8-oxidized guanine deoxyriboside (8-oxo-dG) to evaluate the oxidation of RNA and DNA in cardiomyocytes. Using the median of the mean absorbance value of 8-oxo-G immunohistochemical staining as the cut-off value, patients were divided into high-absorbance group and low-absorbance group. Congo red staining was used to compare myocardial amyloid deposition between the two groups. Results: The mean age of patients in HFpEF group was (91.8±3.7) years, 24 (92.3%) were males. The mean age of patients in control group was (91.7±3.7) years old, 11 (84.6%) were males. The median mean optical absorbance value of 8-oxo-G immunohistochemical staining of myocardium was significantly higher in HFpEF patients than in control group (0.313 8 (0.302 2, 0.340 6) vs. 0.289 2 (0.276 7, 0.299 4), Z=-3.245, P=0.001). The median mean absorbance value of 8-oxo-dG immunohistochemical staining of myocardial tissue was similar between the two groups (0.300 0 (0.290 0, 0.322 5) vs. 0.300 0 (0.290 0, 0.320 0), Z=-0.454, P=0.661). Proportion of patients with moderate and severe cardiac amyloid deposition was significantly higher in the high-absorbance group than in the low-absorbance group ((85.0%, 17/20) vs. (31.6%, 6/19), P=0.001). Conclusion: The RNA oxidation degree of myocardium in HFpEF patients is higher than that in elderly people without heart failure. Degree of myocardial amyloid deposits is higher in patients with high levels of RNA oxidation.
Тема - темы
Aged , Male , Humans , Aged, 80 and over , Female , Heart Failure/pathology , Retrospective Studies , Stroke Volume , Case-Control Studies , Nucleic Acids , 8-Hydroxy-2'-Deoxyguanosine , Myocytes, Cardiac/pathology , RNA , Oxidative Stress , Guanine , Ventricular Function, LeftРеферат
Objective: To investigate the level of nucleic acid oxidation in myocardial tissue of patients aged over 85 with heart failure with preserved ejection fraction (HFpEF) and the correlation with myocardial amyloid deposition. Methods: This was a retrospective case-control study. Data of patients≥85 years old who underwent systematic pathological autopsy in Beijing Hospital from 2003 to 2017 were retrospectively collected. Twenty-six patients were included in the HFpEF group and 13 age-and sex-matched patients who had not been diagnosed with heart failure and died of non-cardiovascular diseases served as the control group. The left ventricular myocardium slices of both groups were semi-quantitatively analyzed using immunohistochemical staining of 8-oxidized guanine riboside (8-oxo-G) and 8-oxidized guanine deoxyriboside (8-oxo-dG) to evaluate the oxidation of RNA and DNA in cardiomyocytes. Using the median of the mean absorbance value of 8-oxo-G immunohistochemical staining as the cut-off value, patients were divided into high-absorbance group and low-absorbance group. Congo red staining was used to compare myocardial amyloid deposition between the two groups. Results: The mean age of patients in HFpEF group was (91.8±3.7) years, 24 (92.3%) were males. The mean age of patients in control group was (91.7±3.7) years old, 11 (84.6%) were males. The median mean optical absorbance value of 8-oxo-G immunohistochemical staining of myocardium was significantly higher in HFpEF patients than in control group (0.313 8 (0.302 2, 0.340 6) vs. 0.289 2 (0.276 7, 0.299 4), Z=-3.245, P=0.001). The median mean absorbance value of 8-oxo-dG immunohistochemical staining of myocardial tissue was similar between the two groups (0.300 0 (0.290 0, 0.322 5) vs. 0.300 0 (0.290 0, 0.320 0), Z=-0.454, P=0.661). Proportion of patients with moderate and severe cardiac amyloid deposition was significantly higher in the high-absorbance group than in the low-absorbance group ((85.0%, 17/20) vs. (31.6%, 6/19), P=0.001). Conclusion: The RNA oxidation degree of myocardium in HFpEF patients is higher than that in elderly people without heart failure. Degree of myocardial amyloid deposits is higher in patients with high levels of RNA oxidation.
Тема - темы
Aged , Male , Humans , Aged, 80 and over , Female , Heart Failure/pathology , Retrospective Studies , Stroke Volume , Case-Control Studies , Nucleic Acids , 8-Hydroxy-2'-Deoxyguanosine , Myocytes, Cardiac/pathology , RNA , Oxidative Stress , Guanine , Ventricular Function, LeftРеферат
Objective: To summarize the clinical characteristics of heart failure patients with recovered ejection fraction (HFrecEF) and identify variables capable of predicting left ventricular ejection fraction (LVEF) recovery. Methods: This case control study included patients with heart failure, who admitted to Department of Cardiology of Beijing Hospital from January 1, 2009 to December 31, 2017. The patients were divided into 3 groups based on the baseline LVEF and changes of LVEF: heart failure with reduced ejection fraction (HFrEF, baseline LVEF≤40%, follow-up LVEF≤40% or follow-up LVEF>40% but LVEF increase<10% from baseline), HFrecEF(baseline LVEF≤40%, follow-up LVEF>40% and increase≥10% from baseline), and heart failure with preserved ejection fraction (HFpEF, baseline LVEF>40%). Clinical data were collected and endpoint events (all-cause death, cardiovascular death and sudden death) were recorded. The Log-rank test was used to evaluate the differences of terminal events in different groups, and Kaplan-Meier survival analysis was performed. Logistic regression equation was used to identify prognostic factors of HFrecEF. Results: A total of 310 patients with heart failure were included. There were 91(29.4%) HFrEF patients, 38(12.3%) HFrecEF patients and 181(58.4%) HFpEF patients. Compared with HFrEF patients and HFpEF patients, HFrecEF patients were featured by younger age, more likely to be female, higher systolic blood pressure, diastolic blood pressure and resting heart rate (all P<0.05). Dilated cardiomyopathies were more common, while old myocardial infarctions were less common in HFrecEF (both P<0.05). During a median follow-up of 36.7(18.0, 63.9) months, Kaplan-Meier survival analysis found that HFrecEF patients had the lowest all-cause mortality (Log-rank P=0.047, HFrecEF vs. HFpEF P=0.017, HFrecEF vs. HFrEF P=0.016, and HFpEF vs. HFrEF P=0.782).The cardiovascular mortality ranged from low to high was in HFrecEF patients, HFpEF patients, and HFrEF patients (Log-rank P<0.001, HFrecEF vs. HFpEF P=0.029, HFrecEF vs. HFrEF P<0.001, HFrEF vs. HFpEF P=0.005). Sudden death rate was similar among the three groups (Log-rank P=0.520). Logistic regression analysis showed that left ventricular end-diastolic diameter (LVEDD)≤55 mm (OR=5.922, 95%CI 1.685-20.812, P=0.006), higher diastolic blood pressure (OR=1.058, 95%CI 1.017-1.100, P=0.005), faster resting heart rate (OR=1.042, 95%CI 1.006-1.080, P=0.024), absence of old myocardial infarction (OR=5.343, 95%CI 1.731-16.488, P=0.004) were independent prognostic factors of LVEF recovery after clinical treatment. Conclusions: Patients with HFrecEF are associated with a better prognosis as compared to patients with HFrEF and HFpEF. LVEDD≤55 mm, higher diastolic blood pressure, faster heart rate,and absence of old myocardial infarction are independent prognostic factors of LVEF recovery after clinical treatment.
Тема - темы
Female , Humans , Male , Case-Control Studies , Heart Failure , Prognosis , Stroke Volume , Ventricular Dysfunction, Left , Ventricular Function, LeftРеферат
Objective: To investigate the predictive value of N-terminal type B natriuretic peptide(NT-proBNP) on the prognosis of elderly hospitalized patients without heart failure(non-heart failure). Method: Elderly patients aged 65 years or older, who were admitted to Beijing Hospital from September 2018 to February 2019, were enrolled in this study. Patients with clinical diagnosis of heart failure or left ventricular ejection fraction(LVEF)<50% were excluded. The patients were divided into 2 groups based on the serum NT-proBNP level: low NT-proBNP group (<125 ng/L) and high NT-proBNP group(≥125 ng/L). Patients were followed up at 3, 6, and 12 months after enrollment, and the major adverse events were recorded. The composite endpoint events included all-cause mortality, readmission or Emergency Department visits. Cardiovascular events include death, readmission or emergency room treatment due to cardiogenic shock, myocardial infarction, angina pectoris, arrhythmia, heart failure or stroke/transient ischemic attack. Results: A total of 600 elderly patients with non-heart failure were included in the analysis. The average age was (74.9±6.5) years, including 304(50.7%) males. The median follow-up time was 344(265, 359) days. One hundred and seventy-eight(29.7%) composite endpoint events were recorded during the follow-up, 19(3.2%) patients died, and 12(2.0%) patients were lost to follow-up. There were 286(47.7%) cases in low NT-proBNP group and 314 cases(52.3%) in high NT-proBNP group. Patients were older, prevalence of atrial fibrillation and myocardial infarction was higher; MMSE scores and ADL scores, albumin and creatinine clearance rate were lower in high NT-proBNP group than in low NT-proBNP group(all P<0.05). At 1-year follow-up, the incidence of composite endpoint events was significantly higher in high NT-proBNP group than in low NT-proBNP group(33.4%(105/314) vs. 24.8%(71/286), P = 0.02). Cardiovascular events were more common in high NT-proBNP group than in low NT-proBNP group(17.5%(55/314) vs. 8.4%(24/286), P = 0.001). Kaplan-Meier survival analysis showed both composite endpoint events(Log-rank P=0.016) and cardiovascular events(Log-rank P=0.001) were higher in high NT-proBNP group than in low NT-proBNP group. All-cause mortality was also significantly higher in highNT-proBNP group than in lowNT-proBNP group(4.8%(15/314) vs. 1.4%(4/286), P = 0.020), and Kaplan-Meier survival analysis demonstrated borderline statistical significance(Log-rank P = 0.052). Cox proportional hazard regression analysis showed that after adjusting for age, sex, creatinine clearance rate, myocardial infarction, and atrial fibrillation, NT-proBNP remained as an independent risk factor for composite endpoint events(HR=1.376,95%CI 1.049-1.806, P=0.021), and cardiovascular events(HR=1.777, 95%CI 1.185-2.664, P=0.005), but not for all-cause mortality(P=0.206). Conclusions: NT-proBNP level at admission has important predictive value on rehospitalization and cardiovascular events for hospitalized elderly non-heart failure patients. NT-proBNP examination is helpful for risk stratification in this patient cohort.
Тема - темы
Aged , Aged, 80 and over , Humans , Male , Biomarkers , Heart Failure , Natriuretic Peptide, Brain , Peptide Fragments , Prognosis , Stroke Volume , Ventricular Function, LeftРеферат
<p><b>BACKGROUND</b>Many recipients of implantable cardiac electronic devices have atrial fibrillation (AF) occurrences after device implantation, even if there is no previous history of AF, and some of the episodes are asymptomatic. The purpose of this study was to evaluate trends in AF burden following early AF detection in patients treated with pacemakers equipped with automatic, daily Home Monitoring function.</p><p><b>METHODS</b>Between February 2009 and December 2010, the registry recruited 701 pacemaker patients (628 dual-chamber, 73 biventricular devices) at 97 clinical centers in China. Daily Home Monitoring data transmissions were analyzed to screen for the AF burden. In-office follow-ups were scheduled for 3 and 6 months after implantation. Upon first AF (i.e., mode-switch) detection in a patient, screening of AF burden by Home Monitoring was extended for the next 180 days.</p><p><b>RESULTS</b>At least one episode of AF was observed in 22.9% of patients with dual-chamber pacemakers and in 28.8% of patients with biventricular pacemakers. The first AF detection in a patient occurred, on average, about 2 months before scheduled follow-up visits. In both pacemaker groups, mean AF burden decreased significantly (P < 0.05) over 180 days following first AF detection: from 12.0% to 2.5% in dual-chamber and from 12.2% to 0.5% in biventricular pacemaker recipients. The number of patients with an AF burden >10% per month was significantly reduced over 6 months of implantation in both dual chamber (38 patients in the first month vs. 21 patients in month 6, P < 0.05) and biventricular (7 patients in the first month vs. 0 patient in months 4-6, P < 0.05) pacemaker recipients.</p><p><b>CONCLUSIONS</b>Automatic, daily Home Monitoring of patients treated with cardiac pacemakers allows early detection of AF, and there is a gradual and significant decrease in AF burden.</p>
Тема - темы
Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Atrial Fibrillation , Pacemaker, ArtificialРеферат
<p><b>OBJECTIVE</b>To explore the status of glucometabolic abnormalities in cardiological outpatients without previous diabetes diagnosis and with coronary artery disease (CAD) and hypertension.</p><p><b>METHODS</b>Patients without previous diagnosis of diabetes but with hypertension and CAD aged 18 years or above were recruited from cardiology departments of 11 general hospitals in China. Demographic data, disease diagnosis and medical history were collected. Physical examination and questionnaire survey were performed after the random blood glucose test. Oral glucose tolerance test (OGTT) examination was made for patients with fasting blood glucose ≥ 6.1 mmol/L or postprandial random glucose ≥ 7.8 mmol/L. Adjusted prevalence rates were used in the study.</p><p><b>RESULTS</b>A total of 7778 patients were included in 11 centers. After preliminary screening by fasting blood glucose and random blood glucose tests, 3861 patients were required to take OGTT, and 3019 (78.2%) patients actually took the test. 1287 out of 3019 patients screened with OGTT were diagnosed with diabetes, and the adjusted diabetes prevalence rate was 18.64% (1287/6904). The prevalence rate of diabetes was 19.87% (95/478), 9.22% (352/3819) and 14.81% (153/1033) in patients with CAD, hypertension, and CAD combined with hypertension, respectively. A total of 996 patients were diagnosed with impaired glucose tolerance (IGT) and its prevalence was 14.43% (996/6904). Of the enrolled population, 153 patients with random blood glucose lower than 7.8 mmol/L were also screened with OGTT test, 26.14% (40/153) patients met the diagnostic criteria of diabetes.</p><p><b>CONCLUSION</b>A high prevalence of diabetes is found in patients without previous diagnosis of diabetes and with hypertension and CAD consulting at cardiology departments. We thus suggest to perform OGTT in this patient cohort to improve the early diagnosis of IGT and diabetes, and prevent missed detection of type 2 diabetes mellitus or IGT in cardiovascular patients with normal fasting blood glucose. Our results indicate that it was feasible to use OGTT as a screening tool for detecting diabetes in these patients and the patient compliance is satisfactory.</p>
Тема - темы
Female , Humans , Male , Blood Glucose , Metabolism , Coronary Disease , Diabetes Mellitus, Type 2 , Diagnosis , Glucose Tolerance Test , Hypertension , Mass Screening , OutpatientsРеферат
<p><b>OBJECTIVE</b>To determine the relationship between estimated glomerular filtration rate (eGFR) and proteinuria with cardiovascular events in subjects aged 80 years or older.</p><p><b>METHODS</b>Data for this retrospective prognostic study were drawn from the patient database for routine checkup in Beijing hospital between January 2001 to December 2001. Baseline eGFR and proteinuria were evaluated in 340 subjects [mean age: (85.6 ± 4.0) years]. eGFR was calculated using the modified abbreviated MDRD equations based on the Chinese chronic kidney disease patients. The subjects were divided into normal renal function group and reduced renal function group (eGFR <60 ml·min(-1)·1.73 m(-2)). The subjects were divided into subjects without proteinuria and subjects with proteinuria group. Cardiovascular events included cardiovascular death, nonfatal myocardial infarction, nonfatal stroke.</p><p><b>RESULTS</b>The proportion of reduced renal function was 36.8% (125/340). The proportion of proteinuria was 10.3% (35/340). The proportion of reduced renal function or proteinuria was 41.8% (142/340). Follow-up time was 79 months (40-114 months). Cardiovascular events rate was significantly higher in reduced renal function group than in normal renal function group [37.6% (47/125) vs. 26.2% (55/210), P < 0.05 ] and in proteinuria group than in without proteinuria group [50.0% (17/34) vs. 28.2% (85/301), P < 0.01 ]. Cox multivariate analysis revealed that both eGFR (HR = 0.978, 95%CI:0.961-0.994, P < 0.05 ) and proteinuria (HR = 2.049, 95%CI:1.132-3.709, P < 0.05) were independent risk factors for cardiovascular events after adjusting for age, gender, triglyceride, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, uric acid, hypertension, coronary heart disease, diabetes mellitus.</p><p><b>CONCLUSIONS</b>Reduced eGFR and presence of proteinuria are independent risk factors for cardiovascular event in subjects aged 80 years or older. eGFR and proteinuria can thus be used for cardiovascular event risk stratification in subjects aged 80 years or older.</p>
Тема - темы
Aged, 80 and over , Female , Humans , Male , Cardiovascular Diseases , Glomerular Filtration Rate , Multivariate Analysis , Proteinuria , Retrospective Studies , Risk FactorsРеферат
<p><b>BACKGROUND</b>A study of prenatal genetic diagnosis for 22q11.2 microdeletion, which has a wide phenotypic spectrum that involves almost all organs, is rarely reported in China. This study aimed to explore the prevalence of 22q11.2 microdeletion in congenitally malformed fetuses via the fluorescent in situ hybridization (FISH) technique and to investigate the feasibility of use of amniocytes to diagnose 22q11.2 microdeletion syndrome prenatally.</p><p><b>METHODS</b>The study enrolled 23 cases of fetal cardiac malformation, as indicated by ultrasound in Beijing Anzhen Hospital and 14 cases of non-cardiac malformation, as determined by type-B ultrasound in Beijing Anzhen Hospital and other hospitals. Amniotic fluid was obtained by amniocentesis before odinopoeia, and the stillborn fetuses of the induced labor were preceded to autopsy. The amniotic fluid of 20 cesarean deliveries during the same period of time was used as a control. The TUPLE1 gene in the amniotic fluid of malformed and normal fetuses was assessed by the FISH method.</p><p><b>RESULTS</b>The prevalence rates of the TUPLE1 gene deletion in the amniotic fluid cells from fetuses with cardiac deformations and fetuses without such malformations were 43.5% and 57.1%, respectively. The deletion of TUPLE1 was significantly associated with fetal malformation.</p><p><b>CONCLUSION</b>Chromosome 22q11.2 microdeletion is one of the major factors leading to fetal congenital malformations, and prenatal FISH screening for 22q11.2 microdeletion syndrome is technically feasible using amniocytes.</p>
Тема - темы
Adult , Female , Humans , Pregnancy , Amniocentesis , Cell Cycle Proteins , Genetics , Chromosome Deletion , Chromosomes, Human, Pair 22 , Genetics , Feasibility Studies , Fetal Diseases , Genetics , Gestational Age , Histone Chaperones , Genetics , In Situ Hybridization, Fluorescence , Pregnancy Outcome , Prenatal Diagnosis , Transcription Factors , GeneticsРеферат
<p><b>BACKGROUND</b>Atrial fibrillation is a common arrhythmia and a major risk factor for ischaemic stroke. We investigated the prevalence of atrial fibrillation and its relation to age, gender and underlying heart disease in patients aged 60 years and over who died during hospitalization.</p><p><b>METHODS</b>Between 1955 and 2005, 1519 autopsies of in-hospital deaths in Beijing Hospital were performed. Among them, 540 cases met criteria of age > or = 60 years and full clinical history including electrocardiogram, echocardiogram, myocardial perfusion images and detailed cardiac pathology records from autopsy.</p><p><b>RESULTS</b>Atrial fibrillation occurred in 193 of 540 patients and prevalence increased with age (10.5% in patients younger than 60 years, 39.6% (80-89 years) and 54.8% (> or = 90 years)) being higher in patients with underlying heart disease than without heart disease (P < 0.0001). Coronary artery disease (CAD), congestive heart failure, cardiac valve dysfunction and chronic renal failure were associated with a higher prevalence of atrial fibrillation (P < 0.001). CAD with anterior myocardial infarction or left anterior descending artery disease was also associated with an increased prevalence of atrial fibrillation (P < 0.05). Following autopsy, clinical misdiagnosis of CAD increased with age and missed clinical diagnosis of CAD decreased with age. Multivariate Logistic regression analysis revealed independent predictors of atrial fibrillation: age (OR = 1.335, 95% CI: 1.114 - 1.600, P < 0.0001), underlying heart disease (OR = 2.019, 95% CI: 1.244-3.278, P < 0.005), chronic heart failure (OR = 1.873, 95% CI: 1.272-2.757, P < 0.005), mitral regurgitation (OR = 2.163, 95% CI: 1.093-4.278, P < 0.05) and mitral stenosis (OR = 33.575, 95% CI: 2.852-395.357, P < 0.05).</p><p><b>CONCLUSIONS</b>A high prevalence of atrial fibrillation was found in Chinese patients > or = 60 years who died in hospital, especially when associated with underlying heart disease. The independent risk factors of atrial fibrillation were age, underlying heart disease, congestive heart failure and mitral valve dysfunction. High clinical misdiagnosis and missed diagnosis of CAD were associated with age.</p>
Тема - темы
Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Atrial Fibrillation , Epidemiology , China , Epidemiology , Electrocardiography , Inpatients , Multivariate Analysis , Prevalence , Retrospective Studies , Risk FactorsРеферат
<p><b>OBJECTIVE</b>To investigate the relation between atrial fibrillation (AF) and coronary heart disease according to the pathological data.</p><p><b>METHOD</b>Total 540 out of 1012 anatomic older cases were admitted to our study, according to the clinical and pathological data in our hospital.</p><p><b>RESULTS</b>(1) The incidence of AF increased significantly with aging (Cochran-Armitage trend test, P<0.01). (2) The AF patients were more likely to accompany coronary heart disease (P=0.0028) based on the anatomical documentation; the incidence of myocardial infarction in the AF group was statistically significant higher than that in the sinus rhythm group (P=0.0144). The level of coronary artery lesion in AF group was statistically significant severe than that in the sinus rhythm group. (3) Age (OR=1.34, 95% CI 1.11 - 1.60), male (OR=5.71, 95% CI 1.87 - 17.39) and chronic heart failure (OR=1.87, 95% CI 1.27 - 2.76) were independent risk factors of AF based on multivariant logistic analysis, while coronary heart disease (OR=1.47, 95% CI 0.91 - 2.39) was not an independent risk factor.</p><p><b>CONCLUSIONS</b>The incidence of AF increases significantly with aging in the elderly. The AF patients seem more likely to accompany coronary heart disease but coronary heart disease may be not the independent risk factor of AF in the elderly.</p>
Тема - темы
Aged , Aged, 80 and over , Humans , Middle Aged , Age Factors , Atrial Fibrillation , Epidemiology , Coronary Disease , Epidemiology , Incidence , Pathology, Clinical , Risk FactorsРеферат
<p><b>OBJECTIVE</b>To investigate the effect of anti-atrial fibrillation of Philos DDDR pacemaker on atrial tachyarrhythmia.</p><p><b>METHODS</b>Thirty-eight patients with sick sinus syndrome and paroxysmal atrial fibrillation (AF) were implanted with Philos DDDR pacemaker. After implantation, auto-Mode-Switch (AMS) function was switched "on" and AF preventive algorithms were "off" in all cases. The number of AMS, atrial premature beats, heart rate and the percentage of atrial and ventricular pacing were recorded by pacemaker diagnostic function for one-month after procedure. AF preventive algorithms function with "middle" (approx 8 bpm) was then switched on and the same parameters as above from the database of pacemaker diagnostic function were collected for additional one month.</p><p><b>RESULTS</b>The symptoms of dizziness, dyspnoea, and palpitation in the majority of patients were dramatically improved regardless of whether the AF preventive algorithms function was switched "on" or "off" after pacemaker implantation. There were no significant clinical changes in most patients when AF preventive algorithms were "on". However, 5 cases (13.2%) had palpitations and short of breath. These symptoms were relieved by changing the algorithms from "middle to slight (approx 4 bpm)". When AF preventive algorithms were switched on, atrial premature beats were reduced significantly (P < 0.05) with a dramatic increase in atrial pacing percentage and heart rate (P < 0.05). However, there was no significant difference in AMS (P > 0.05) between the two groups of AF preventive algorithms function switching "on" and "of", indicating that atrial tachyarrhythmias were not inhibited by anti-atrial fibrillation pacemaker.</p><p><b>CONCLUSION</b>This study suggested that atrial fibrillation and atrial tachycardia were not reduced by implantation of an anti-atrial fibrillation Philos DDDR pacemaker, although atrial premature beats decreased significantly with increasing atrial pacing percentage when AF preventive algorithms were in "middle" and "slight".</p>