Outflow-tract ventricular tachycardia: Can 12 lead ECG during sinus rhythm identify underlying cardiac sarcoidosis?

BackgroundPatients with outflow tract ventricular tachycardia (OTVT) with normal echocardiogram are labeled as idiopathic VT (IVT). However, a subset of these patients is subsequently diagnosed with underlying cardiac sarcoidosis (CS). Objective:Whether electrocardiogram (ECG) abnormalities in sinus rhythm (SR) can differentiate underlying CS from IVT.MethodsWe retrospectively analyzed the SR-ECGs of 42 patients with OTVT/premature ventricular complexes (PVC) and normal echocardiography. All underwent advanced imaging with cardiac magnetic resonance (CMR)/¹⁸FDG PET-CT for screening of CS. Twenty-two patients had significant abnormalities in cardiac imaging and subsequently had biopsy-proven CS (Cases). Twenty patients had normal imaging and were categorized as IVT (Controls). SR-ECGs of all patients were analyzed by 2 independent, blinded observers.ResultsBaseline characteristics were comparable. Among the ECG features analyzed – fascicular (FB) or bundle branch block (BBB) was seen in 9/22 Cases vs. 1/20 controls (p = 0.01). Among patients without FB or BBB, fragmented QRS (fQRS) was present in 9/13 cases but in none of the controls (p < 0.001). Low voltage QRS was more often seen among cases as compared to controls (10/22 vs. 3/20 p = 0.03). A stepwise algorithm based on these 3 sets of ECG findings helped to diagnose CS among patients presenting with OTVT/PVC with sensitivity of 91%, specificity of 75%, a PPV of 80%, and a NPV of 88%.ConclusionsIn patients presenting with OTVT/PVC: FB/BBB, fQRS, and low QRS voltage on the baseline ECG were more often observed among patients with underlying CS as compared to true IVT. These findings may help to distinguish underlying CS among Cases presenting with OTVT/PVC.     

消痰化瘀利窍中药组方对改善慢性间歇性低氧大鼠心肌纤维化的作用及其机制*

目的: 探讨转化生长因子-β(TGF-β)信号通路在消痰化瘀利窍中药组方(XC)对改善慢性间歇性低氧(CIH)大鼠心肌纤维化中的作用。方法: 40只SD 大鼠,随机分为常氧组(Normoxia)、常氧+中药干预组(TCMC)、慢性间歇性低氧模型组(CIH)、CIH +中药干预组(TCMC+CIH),每组10只。通过向舱内充入氮气,使舱内氧体积分数在90 s内从21%下降到9%,随后90 s再充氧气使舱内氧体积分数逐渐上升到21%为一循环建立CIH模型。CIH 与 TCMC+CIH 组大鼠置于CIH装置, Normoxia 和TCMC组大鼠置于正常氧舱。此外TCMC+CIH 与 TCMC 组大鼠于每日XC生药(24 g/kg)煎制灌胃,而 CIH 组与 Normoxia 组大鼠给予等体积生理盐水。造模结束后,天狼星红染色观察大鼠心肌间质内胶原沉积情况;Western blot 法检测大鼠心肌间质中 CollagenⅠ、Collagen Ⅲ、Fibronectin、TGF-β、p-Smad2、p-Smad3的蛋白表达水平。采用Q-PCR法检测基质金属蛋白酶2(MMP-2)和基质金属蛋白酶抑制因子 2 (TIMP-2) 的 mRNA表达水平。结果: 与正常组比较,CIH大鼠心肌组织出现明显胶原的沉积,CollagenⅠ、Collagen Ⅲ和Fibronectin蛋白表达明显增多(P均＜0.01),TGF-β、p-Smad2、p-Smad3蛋白表达水平也明显增高(P均＜0.01);CIH大鼠心肌组织TIMP-2 mRNA上调导致MMP-2 mRNA明显减少(P均＜0.01)。给予XC干预后,CIH大鼠心肌组织胶原沉积明显减少,CollagenⅠ、Collagen Ⅲ和Fibronectin蛋白表达明显降低(P＜0.05,P＜ 0.01,P＜0.05);CIH大鼠心肌组织中TGF-β、p-Smad2、p-Smad3蛋白表达水平明显降低(P＜0.01,P＜0.05,P＜ 0.01)。心肌组织中TIMP-2明显基因减少致MMP-2增多(P均＜0.05)。 结论: 消痰化瘀利窍中药组方可抑制CIH大鼠心肌纤维化的形成,进而改善CIH大鼠心肌功能。其机制与该中药组方下调TGF-β/ Smad2/3信号通路及下调TIMP-2mRNA有关。     

α-荼异硫氰酸酯诱导小鼠胆汁淤积性肝纤维化及其炎症通路*

目的: 探讨α-荼异硫氰酸酯(ANIT)诱导的胆汁淤积性肝纤维化的发展及其炎症通路。方法: 将15只体重为(23±2) g的129/Sv小鼠随机分为对照组(n=5)和实验组(n=10)。对照组常规饲料喂养,实验组小鼠给予0.05% ANIT饲料食饲。实验组分别在14 d和28 d各处死5只小鼠,收集胆囊、血清、肝脏等标本。按试剂盒程序检测胆汁淤积生化指标,组织病理学评估肝细胞损伤程度,Q-PCR和WB分析肝纤维化、炎症反应等水平。结果: 与对照组相比,造模第2周ANIT -14 d组(A-D14)中的主要胆汁淤积指标总胆汁酸(TBA)从(3.2±0.9) μmol/L显著增加至(31.6±4.3) μmol/L,肝损伤指标谷草转氨酶(AST)和谷丙转氨酶(ALT)也显著升高(P＜0.05);纤维化因子金属蛋白酶组织抑制因子1(TIMP-1)、单核细胞趋化因子(MCP-1)、I型胶原蛋白(Collagen I)表达高于对照组(P＜0.05);Collagen I和α-SMA纤维化蛋白表达均上调;肝脏胶原纤维大量沉积,纤维化已产生(P＜0.05)。炎症因子表达高于对照组,JNK、c-Jun、STAT3等均被激活(P＜0.05)。ANIT-28 d组(A-D28)中除AST、基质金属蛋白酶2(MMP-2),Collagen I指标稍有降低外,其余胆汁淤积、肝损伤、肝纤维化、炎症等指标继续上调或保持稳定(P＜ 0.05)。结论: 0.05%的ANIT饲料干预14 d,小鼠即发生明显的胆汁淤积性肝纤维化;28 d后,胆汁淤积性肝纤维化趋于稳定;JNK炎症通路在肝纤维化的发生发展中起着至关重要的作用。     

外源性H2S对糖尿病小鼠肝纤维化的作用及其机制*

目的: 探讨外源性硫化氢(H₂S)对糖尿病小鼠肝纤维化作用及其相关机制。方法: 将 C57 雄性体重为(22±2)g 24只小鼠随机分为3组(n=8):①正常对照组(Control):小鼠腹腔注射生理盐水,注射时间同实验组;②糖尿病模型组(HG):按体重(150 mg/kg)一次性腹腔注射链脲佐菌素(STZ)诱导小鼠建立糖尿病模型;③NaHS 处理组(HG + NaHS):方法同组别②,只是糖尿病模型建立后,腹腔注射NaHS(100 μmol/L·kg·d),每天一次,连续12周。HE染色检测肝细胞损伤;Masson染色检测肝纤维化;Western blot检测相关蛋白胱硫醚-β-合成酶(CBS,内源性H₂S产生的关键酶)、胶原I (Col-I)、胶原III (Col-III)和基质金属蛋白酶-9(MMP-9)的表达。结果: 与对照组比较,糖尿病模型组肝细胞损伤及肝纤维化均显著加重,CBS 蛋白表达显著减少(P＜0.01),Col-I、Col-III和MMP-9蛋白表达均显著增加(P＜0.01)。与糖尿病模型组比较,NaHS处理组肝细胞损伤及肝纤维化均显著减轻、CBS 蛋白表达显著增加、Col-I、Col-III和MMP-9蛋白表达均减少(P＜0.01)。结论: 外源性H₂S可抑制糖尿病小鼠肝纤维化,其机制与降低胶原含量和基质金属蛋白酶-9的表达相关。     

外泌体在肝纤维化中的作用

外泌体(exosomes)是一种能被大多数细胞分泌的微小膜泡,是具有脂质双层膜结构的细胞外囊泡。现认为外泌体是细胞外囊泡(extracellular vesicles, EVs)的一种亚群。研究表明,外泌体是细胞间信息传递的一种载体。肝脏既可以分泌外泌体,同时也是其他组织细胞产生的外泌体的作用靶点,且肝内与肝外来源的外泌体与肝纤维化的形成、发生、发展均有密切联系。本文主要就外泌体在肝纤维化相关疾病中的作用及外泌体与肝纤维化指标之间的关系进行综述。     

蚓激酶在慢性乙型肝炎治疗中的潜在作用

纤连蛋白(FN)是参与乙型肝炎病毒感染和肝脏纤维化的重要分子。 蚓激酶(LK)是从赤子爱胜蚓(Eisenia foetide)中提取的一组蛋白水解同工酶,能水解纤维蛋白治疗凝血相关疾病。 从这组同工酶中分离纯化出单一活性成分,在体外可降解纤连蛋白,被命名为蚯蚓纤连蛋白水解酶(EFNase)。 然而,LK 能否预防乙型肝炎病毒感染以及缓解因乙型肝炎导致的肝脏损伤等问题还不清楚。本研究以人肝癌细胞系HepG2.2.15为细胞模型,观察LK 对乙型肝炎表面抗原(HBsAg)或 FN 水平的影响;以 C57BL / 6J-HBV 转基因小鼠为动物模型,探讨 LK 对小鼠血清中 HBsAg、FN、丙氨酸氨基转移酶(ALT)、天门冬氨酸氨基转移酶(AST)水平及肝脏病理改变的影响。结果表明,LK 在体内外均能抑制HBsAg 的生成,降低血清和肝脏FN。与生理盐水处理组相比,LK 改善了肝脏的状态。这些数据为理解LK 作为治疗乙型肝炎的潜在有效药物的治疗作用提供了有价值的信息。     

Machine Learning Approach to Detect Cardiac Arrhythmias in ECG Signals: A Survey

Cardiac arrhythmia is a condition when the heart rate is irregular either the beat is too slow or too fast. It occurs due to improper electrical impulses that coordinates the heart beats. Sudden cardiac death may occurs due to some dangerous arrhythmias conditions. Hence the main objective of the electrocardiogram (ECG) analysis is to detect the life-threatening arrhythmias accurately for appropriate treatment in order to save life. Since the last decades, several methods were reported for automatic ECG beat classifications. In this work, we present a systematic review of the current state-of-the-art methods used to detect cardiac arrhythmia using on ECG signals. It includes the signal decomposition, feature extraction and machine learning approaches used for automatic detection and decision making process. The articles covers the pre-processing, detection of QRS complex, feature extraction and classification of ECG beats. Based on the past studies, it is understood that the automated approach using computer-aided decision making process is highly required for real-time detection of cardiac arrhythmias. The advantages and limitations of different methods are discussed and also the future scopes is highlighted in the process of effective detection of cardiac arrhythmias. This study could be beneficial for researchers to analyze the existing state-of-art techniques used in detection of arrhythmia conditions.