Atrial fibrillation is common after ablation of isolated atrial flutter during long-term follow-up

BACKGROUND: Previous studies have shown that the incidence of atrial fibrillation after atrial flutter ablation is approximately 20% among patients presenting with typical atrial flutter and no history of fibrillation. However, studies involving this population have been small, with follow-up typically less than 2 years. OBJECTIVE: The purpose of this study was to provide a more accurate perspective on the long-term risk of atrial fibrillation in patients presenting with isolated typical flutter. METHODS: Clinical records of consecutive patients who had flutter ablations at Presbyterian Medical Center between 1999 and 2004 were assessed (n = 254). Patients with no apparent history of atrial fibrillation before their flutter ablation were identified. Retrospective follow-up data on these patients were obtained by review of medical records from our institution, from patients' cardiologists and primary care physicians, and by direct patient questionnaires. Postablation atrial fibrillation and other arrhythmias were identified by electrocardiography, Holter monitoring, and subsequent clinical records. RESULTS: Postablation atrial fibrillation was identified in 40 (50%) of 80 patients, and an additional three patients presented with atypical atrial flutter, after a mean follow-up of 29.6 +/- 21.7 months. The incidence of atrial fibrillation was progressive, with 49% occurring after 2 years. There was no difference in age, left atrial size, hypertension, structural heart disease, or left ventricular dysfunction in patients who developed atrial fibrillation compared with those who did not. CONCLUSION: Atrial fibrillation occurs in over half of patients who present with isolated typical flutter after cavotricuspid isthmus ablation. Asymptomatic patients should be screened for recurrent arrhythmias indefinitely after ablation. In certain patients, atrial fibrillation and flutter may be different expressions of the same electrical disease, and eradication of the flutter circuit will not prevent the eventual manifestation of atrial fibrillation.     

线粒体tRNAGlu A14693G突变与2型糖尿病的易感性研究

目的 研究湖北地区2型糖尿病(T2DM)中线粒体基因tRNAGlu A14693G和tRNALeu(UUR)A3243G突变的发生率及其与T2DM相关性.方法 采用聚合酶链反应-限制性片段长度多态性(PCR-RFLP)结合基因测序技术,对179例T2DM患者和208例糖耐量正常的健康对照进行检测.结果 首次在T2DM中发现4例tRNAGlu(A14693G)突变(2.23%),对照组末检出该突变,两组间A14693G突变率差异有统计学意义(χ2=4.697,P=0.030);未发现A3243G的点突变.结论 tRNAGlu A14693G突变可能与T2DM的易感性有关.     

线粒体tRNAGuluA14693G突变与2型糖尿病的易感性研究

目的 研究湖北地区2型糖尿病（T2DM）中线粒体基因tRNAGlu A14693G和tRNALeu（UCR）A3243G突变的发生率及其与T2DM相关性。方法 采用聚合酶链反应-限制性片段长度多态性（PCR—RFLP）结合基因测序技术，对179例T2DM患者和208例糖耐量正常的健康对照进行检测。结果首次在T2DM中发现4例tRNAGlu（A14693G）突变（2．23％），对照组未检出该突变，两组间A14693G突变率差异有统计学意义（X^2=4．697．P=0．030）；未发现A3243G的点突变。结论 tRNA^GluA14693G突变可能与T2DM的易感性有关。     

心房颤动患者心房组织醛固酮和心房基质重构研究

目的 探讨心房颤动患者心房组织醛固酮水平和心房基质重构的相关关系。方法 入选行人工瓣膜置换术的风湿性心脏病患者25例,其中窦性心律者12例,慢性心房颤动者（房颤时程≥6月）13例。术前进行经胸超声心动图检查并留取有关资料,于手术时取左右心房侧壁组织,用放射免疫法测定心房组织醛固酮水平;用VG染色法对总胶原容量分数（CVF）半定量分析;RT-PCR检测Ⅰ型和Ⅲ型胶原mRNA表达改变。结果 与窦性心律者比较心房颤动组左房内径显著扩大（均P<0.01）;心房肌组织醛固酮［右房:(310.3±69.6) vs (154.5±35.8)pg/g,左房:(334.2±76.6) vs (166.5±38.6)pg/g,均P<0.01］、Ⅰ型胶原mRNA表达［右房:(1.95±0.22) vs (0.71±0.11),左房:(2.05±0.28) vs (0.74±0.16),均P<0.01］和CVF［右房:(13.0±1.9)％ vs (6.5±1.1)％,左房:(14.1±1.7)％ vs (6.7±1.2)％,均P<0.01］均明显增加;Ⅲ型胶原mRNA表达在房颤组和窦性心律组间无差异;上述指标在左、右心房之间无差异。Ⅰ型胶原mRNA与左心房直径（r＝0.885,P<0.01）、CVF和左心房直径（r＝0.845,P<0.01）均显著正相关;心房组织醛固酮水平与左心房内径（r＝0.814,P<0.01）和CVF（r＝0.885,P<0.01）均呈明显正相关。结论 心房组织醛固酮水平可能在心房颤动心房基质重构中起重要作用,并可能参与了心房颤动的发生和维持。     

A common mitochondrial DNA variant is associated with insulin resistance in adult life

Summary Mitochondrial DNA is maternally inherited. Mitochondrial DNA mutations could contribute to the excess of maternal over paternal inheritance of non-insulin-dependent diabetes mellitus (NIDDM). We therefore investigated the relationship between this variant, insulin resistance and other risk factors in a cohort which had been well characterised with respect to diabetes. Blood DNA was screened from 251 men born in Hertfordshire 1920–1930 in whom an earlier cohort study had shown that glucose tolerance was inversely related to birthweight. The 16 189 variant (T- > C transition) in the first hypervariable region of mitochondrial DNA was detected using the polymerase chain reaction and restriction digestion. DNA analysis showed that 28 of the 251 men (11 %) had the 16 189 variant. The prevalence of the 16 189 variant increased progressively with fasting insulin concentration (p < 0.01). The association was independent of age and body mass index and was present after exclusion of the patients with NIDDM or impaired glucose tolerance. We found that insulin resistance in adult life was associated with the 16 189 variant. This study provides the first evidence that a frequent mitochondrial variant may contribute to the phenotype in patients with a common multifactorial disorder. [Diabetologia (1998) 41: 54–58] Received: 20 May 1997 and in revised form: 7 August 1997     

Atrial fibrillation is associated with increased mean platelet volume in patients with type 2 diabetes mellitus

Platelet abnormalities in diabetes mellitus (DM) and atrial fibrillation (AF) may underline the etiology of a prothrombotic state in these conditions. Increased mean platelet volume (MPV) is a marker of abnormal platelet function and activation. We aimed to investigate the possible association of chronic AF with MPV in patients who have type 2 DM. Patients who had type 2 DM with either chronic (≥6 months) AF or normal sinus rhythm (NSR) were included in the study. A total of 162 patients (aged 38–89 years) were divided into 2 groups according to the presence of either AF or NSR. Group 1 consisted of 81 diabetic patients with AF, and group 2 consisted of 81 diabetic patients with NSR. The two groups were not significantly different in terms of age, and gender, as well as in hypertension, smoking, history of coronary artery disease, previous cerebrovascular accidents, microalbuminuria, retinopathy, duration of DM, body mass index, hemoglobin A_1c, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triglyceride (p?>?0.05 for all variables). Although no significant difference was present between groups concerning platelet count; for patients with AF, MPV was higher compared with patients with NSR (9.0?±?0.2?fl vs. 8.4?±?0.2?fl; p?=?0.001). Furthermore, no significant difference was noted between groups regarding routine medications received by patients. In multivariate logistic regression analysis, MPV was the only variable independently related to AF (OR?=?2.659; 95% CI, 1.286–5.498; p?=?0.008). Consequently, it is concluded that AF is associated with increased MPV in patients with type 2 DM, suggesting the presence of tentatively related processes leading to reciprocal interaction.     

Fatal dilated cardiomyopathy associated with a mitochondrial DNA deletion

A 27-year-old man was admitted to hospital because of severe cardiac failure. Investigation revealed dilated cardiomyopathy with a left ventricular ejection fraction of 15-20%. During adolescence the patient had been investigated for growth retardation and he also had progressive external ophthalmoplegia. There had been no symptoms of cardiac disease until 2 weeks before admittance. An endomyocardial biopsy showed cardiomyocytes deficient in cytochrome c oxidase (COX) in a mosaic pattern. A skeletal muscle biopsy showed mitochondrial myopathy with COX-deficient ragged-red fibers. Molecular genetic analysis revealed a heteroplasmic, 3.8-kb, mitochondrial DNA (mtDNA) deletion in heart and muscle. PCR-based quantification of the proportion of mtDNA with deletion showed 47% mutated mtDNA in the myocardial biopsy and 68% in muscle. In spite of treatment, the condition deteriorated and the patient died 5 days after admittance. This case demonstrates that mtDNA deletions may occasionally be the cause of severe dilated cardiomyopathy, and that morphological and molecular genetic diagnosis may be obtained by endomyocardial biopsy.     

松花粉对衰老成纤维细胞线粒体DNA缺失突变的影响

目的 通过研究松花粉对衰老细胞线粒体(mt) DNA4977缺失突变的影响,探讨松花粉抗衰老的作用机制.方法 将细胞分为青年组、衰老细胞组、含240 mg/dl松花粉的衰老细胞处理组,三组细胞分别用不同培养基培养后,抽提线粒体DNA,进行PCR检测mtDNA4977缺失突变,以线粒体DNA中保守序列PCR扩增结果作为内参,比较各组mtDNA4977缺失突变在总线粒体DNA中的比例;同时对各组细胞进行β-半乳糖苷酶染色;并测定各组细胞超氧化物歧化酶(SOD)活性、丙二醛(MDA)含量.结果 松花粉能够改善衰老成纤维细胞的衰老变化,并能降低衰老细胞mtDNA4977的缺失突变,提高细胞SOD活性及降低其MDA含量(P＜0.05).结论 松花粉可能通过减轻成纤维细胞的氧化损伤,从而保护细胞mtDNA延缓成纤维细胞的衰老.     

Elevated levels of RDW is associated with non-valvular atrial fibrillation

Red cell distribution width (RDW) and neutrophil/lymphocyte ratio (NLR) have been found to be associated with cardiovascular diseases. Only a few trials have investigated the correlation of these parameters with postoperative atrial fibrillation (AF). However, the correlation of these parameters in non-valvular AF is still unclear. We retrospectively analyzed consecutive AF patients from medical records and included 117 non-valvular AF patients (103 paroxysmal and 14 chronic AF). All subjects underwent physical examination and echocardiographic imaging. Complete blood counts (CBCs) were analyzed for hemoglobin, RDW, neutrophil and lymphocyte counts as well as mean corpuscular volume. Results of CBC tests within the previous year were also included and the averages were used. The demographic and echocardiographic properties of non-valvular AF group were comparable to the control group except for left atrial volumes which were increased in AF (median 33.1, IQR 26.3–41.1 cm³ vs. median 26.4, IQR 24.2–28.9 cm³; p = 0.01). RDW levels were significantly higher in the AF group (median 13.4 %, IQR 12.9–14.1 %) compared to the control (median 12.6 %, IQR 12.0–13.1 %; p = 0.01). NLR was not statistically different in the AF group and the controls (2.04 ± 0.94 vs. 1.93 ± 0.64, respectively; p = 0.32). Hs-CRP levels were higher in the AF group compared to the controls (median 0.84, IQR 0.30–1.43 mg/L vs. median 0.29, IQR 0.18–0.50 mg/L, respectively; p = 0.01). Multivariate logistic regression analysis revealed RDW (OR 4.18, 95 % CI 2.15–8.15; p = 0.01), hs-CRP (OR 3.76, 95 % CI 1.43–9.89; p = 0.01) and left atrial volume (OR 1.31, 95 % CI 1.06–1.21; p = 0.01) as the independent markers of non-valvular AF. Multivariate linear regression analysis revealed that hemoglobin levels (standardized β coefficient = ?0.252; p = 0.01) and the presence of AF (standardized β coefficient = 0.336; p = 0.01) were the independent correlates of RDW levels. Elevated RDW levels, not NLR, may be an independent risk marker for non-valvular AF.     

特发性心房颤动相关TBX5基因新突变的识别

目的:识别特发性心房颤动(房颤)相关TBX5基因新突变。方法:入选特发性房颤患者116例及健康对照者200名,获取临床资料和外周静脉血标本,抽提全部研究对象的基因组DNA,扩增TBX5基因的全部编码外显子及其侧翼内含子,对扩增片段进行测序以寻找变异。检索PubMed和SNP数据库以明确所发现基因变异的新颖性。应用MUSCLE软件分析多物种TBX5蛋白,以显示被改变氨基酸在进化上的保守性,并应用在线程序MutationTaster和PolyPhen-2分析基因变异的致病性。结果:在1例家族史阴性的特发性房颤患者发现了1个TBX5基因变异,其TBX5基因编码核苷酸序列第314位的腺嘌呤变成了胸腺嘧啶(c.314AT),所编码蛋白的氨基酸序列第105位的天冬氨酸变成了缬氨酸(p.D105V)。该突变不存在于200名对照者,也不存在于PubMed和SNP数据库中。多序列比对分析显示第105位的天冬氨酸在进化上完全保守。在线程序分析表明所识别的基因变异具有致病性。结论:发现了1个特发性房颤相关TBX5基因新突变,提示TBX5基因突变可能是特发性房颤的少见遗传病因。     

线粒体DNA点突变有关的中国大家族母系遗传性高血压研究

目的 研究具有母系遗传性特点的原发性高血压中国大家系临床与遗传学特点。方法 对入选的1865例原发性高血压患者进行线粒体DNA测序分析,发现线粒体DNA点突变,对其进行家系随访,收集该家系成员临床资料进行分析,分析其遗传学特点。结果 该家系中母系成员高血压患病率高达55.6%,非母系成员高血压患病率15.6%（P＜0.01）;母系成员高血压发病年龄有提前的趋势[Ⅱ代（62.0±6.2）岁;Ⅲ代（46.3±5.8）岁;Ⅳ代（23.3±2.9）岁]母系成员血糖、总胆固醇、血钠明显高于非母系成员（P＜0.05）,而超声结果没有明显差异;遗传学分析发现母亲患病子代发病率明显高于父亲患病者（P＜0.05）,男女发病率没有差异（P＞0.05）;结论 该家系母系成员高血压发病率明显高于非母系成员,该家系符母系遗传特点,高血压发病与线粒体DNA突变有关,提示线粒体DNA突变可能与母系遗传性高血压发病有关,在高血压发病中发挥重要作用。