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SUDDEN CARDIAC DEATH

SUDDEN CARDIAC DEATH

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SUDDEN CARDIAC DEATH

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  1. SUDDEN CARDIAC DEATH Yuanxiu Chen, MD, Ph.D DEPT. OF CARDIOLOGY RENMIN HOSPITAL WUHAN UNIVERSITY

  2. DEFINITION • Sudden cardiac death:unexpected natural death due to a cardiac cause within a short time period from the onset of symptoms in a person without any prior condition that would appear fatal

  3. Key points • Time ≤1 hour (24hours) from the onset • Cardiac arrest Discontinuation of blood supply to brain • Die or survive • History of heart disease: with or without

  4.  Pathophysiological Mechanism病理生理机制 • Life threaten arrhythmias arising from several pathological condition • Tachyarrhythmias • Bradyarrhythmias or asystolic arrest • Pulseless electrical activity,PEA

  5. Tachyarrhythmias 快速性心律失常 Ventricular fibrillation 70%心室颤动

  6. Sustained ventricular tachycardia <2% 持续性室速

  7. Bradyarrhythmias or asystolic arrest 缓慢性心律失常 心搏停顿 Sinus asystole

  8. Pulseless electrical activity,PEA (无脉搏性电活动) Electromechanical dissociation (电机械分离)

  9. EPIDEMIOLOGY(流行病学) • Incidence 发生率300,000-400,000 yearly in USA • Account for >50% cardiac death • In China no accurate figure huge population victims must might be numerous

  10. Influence of Age, Race, and Gender • AGE 年龄The incidence of sudden cardiac death increases with age, in both men and women as well as whites and nonwhites because of the higher prevalence of ischemic heart disease at older age

  11. RACIAL DIFFERENCES 种族差异rate of sudden coronary death is higher in blacks than in whites • GENDER 性别Higher in men than in women

  12. ETIOLOGY( 病因学) • The relationship between structure and function of the heart in sudden cardiac death:Cardiac death is related to a lot of heart diseases

  13. Coronary Heart Disease 冠心病 • Account for more than 80% of SCDs in western countries • First manifestation in 25% of CHD patients • LVEF<30% is a strong predict factor for SCD in patients with coronary heart disease • Atherosclerosis of multiple coronary arteries is the underlying pathophysiologic changes in such patients

  14. Major Risk factors for CHD冠心病的主要危险因素 • Risk factors of atherosclerosis • Not well confirmed, but lots of evidence prove that there are some factors might be related to CHD • Multiple factors work together but at different aspects to cause CHD to happen

  15. Age • >40 years • older than 49 years — speed up • some young people

  16. Gender • more male suffer than female,2:1 • female suffer after menopause (绝经期后) because of decrease of Estrogens(雌激素) in the circulation, with resulted in a drop of HDL (high density lipoprotein) (Estrogens) provides a protection for women against CHD?

  17. Abnormal in blood lipid 血脂异常 Hyperlipedamia 高脂血症 • Total cholesterol 总胆固醇 • Triglyceride 甘油三酯 • Low density lipoprotein LDL 低密度脂蛋白 • Very low density lipoprotein 极低密度脂蛋白 • Apoprotein B载脂蛋白B • Apoprotein A载脂蛋白A • High density lipoprotein 高密度脂蛋白

  18. Hypertension • 60-70%CHDpatients have hypertension • 4 times than normal blood pressure pts • both SBP and DBP are significant

  19. Smoking 吸烟 • risk raises 2-6 times

  20. Diabetes mellitus 糖尿病 • 2 times danger than the non-diabetes patient

  21. Body weight 体重 (Obesity肥胖)

  22. Occupation 职业 • Diet 饮食 • Heredity 遗传 • Others

  23. Cardiomyopathies • Idiopathic dilated cardiomyopathy • Hypertrophic cardiomyopathy • Hypertensive cardiomyopathy • Arrhythmogenic right ventricular dysplasia (致心律失常性右室发育不良)

  24. Valvular heart disease • Mitral valve prolapse syndrome 二尖瓣脱垂综合征 • Other valvular heart diseases • Aortic stenosis(主动脉瓣狭窄)

  25. Inflammatory myocardial disease • Myocarditis 心肌炎 several kind of arrhythmia might develop atrioventricular block

  26. Congenital heart disease先天性心脏病 • Arrhythmia • Hemodynamic changes 血流动力学改变

  27. Long QT syndrome • Congenital • Acquired torsades de points (TDP, 尖端扭转性室速)twisting (扭转) of the peaks and troughs of the QRS complexes in relation to the baseline

  28. Brugada Syndrome • Died suddenly during night • Young patient without any evidence of heart disease • Family histroy • Elevated ST segment (V1-3) with right bundle block • Some defect in certain gene

  29. Wolff-Parkinson-white syndrom • Accessory AV pathway 房室旁路 • Also called “preexciteation syndrome”

  30. paroxysmal supraventricular tachycardia 阵发性室上性心动过速

  31. Atrail fibrillation ----ventricular fibrillation

  32. Idiopathic ventricular fibrillation原发性室颤

  33. Drugs and other toxic agents Proarrhythmia 致心律失常作用 • Antiarrhythmic agents quinidine(奎尼丁) flecainide (氟卡尼) encainide(恩卡尼) CAST(Cardiac Arrhythmia Suppression Trail) Evidence Based Medicine

  34. Evidence Based Medicine循症医学 • Multicenter • Randomized • Double blind • Placebo controlled

  35. Cocaine and alcohol 可卡因及酒精 • Drug abuse:Cocaine Marihuana(大麻) • Alcoholic :excessive drinking

  36. Electrolyte abnormalities 电解质紊乱  • Hypokalemia 低钾血症 • Magnesium deficiency 低镁 • Increase in intracellular calcium

  37. Pathology of SCD Caused by CHD • The coronary arteries • Extensive atherosclorosis • Acute atherothrombosis • Coronary arteries spasm

  38. What is Atherothrombosis? • Atherothrombosis is characterized by a sudden (unpredictable) atherosclerotic plaque disruption (rupture or erosion) leading to platelet activation and thrombus formation Plaque rupture1 Plaque erosion2 1. Falk E et al. Circulation 1995; 92: 657–71. 2. Arbustini E et al. Heart 1999; 82: 269–72.

  39. Atherothrombosis is the underlying condition that results in events leading to myocardial infarction, ischemic stroke, and vascular death

  40. Atherothrombosis

  41. Acute syndrome: • coronary • cerebrovascular • peripheral Occlusive thrombus Plaque rupture Platelet activation and aggregation Non-occlusive thrombus Healing and resolution Plaque growth The Development of Atherothrombosis – a Generalized and Progressive Process Adapted from: Drouet L. Cerebrovasc Dis 2002; 13(suppl 1): 1–6.

  42. Atherothrombosis and Microcirculation Plaque rupture Microvascular obstruction Embolization Adapted from: Topol EJ, Yadav JS. Circulation 2000; 101: 570–80, and Falk E et al. Circulation 1995; 92: 657–71.

  43. Major Clinical Manifestations of Atherothrombosis Ischemic stroke Transient ischemic attack Myocardial infarction • Angina: • Stable • Unstable • Peripheral arterial • disease: • Intermittent claudication • Rest Pain • Gangrene • Necrosis Adapted from: Drouet L. Cerebrovasc Dis 2002; 13(suppl 1): 1–6.

  44. The myocardium(of sudden cardiac death by autopsy) • Healed myocardial infarction is a common finding of autopsy in the victims • Frequency ranging from 40-70% • Acute myocardial infarction is about 20%

  45. Mechanism and Pathophysiology of SCD • Mechanism of tachyarrhythmias resulted from coronary atherosclorosis is not clear • Coronary artery disease caused the blood flow to myocardium decrease, which resulted in metabolic change and electrophysiological(电生理) instability, both could lead to ventricular fibrillation

  46. Long term left ventricle overload (负荷过重)and ischemic injury could cause the disturbance of cellular electrophysiology, resulted in ventricular fibrillation

  47. At the level of myocyte, acute ischemia cause : • Loss of integrity of cell membranes • Efflux of K+ • Influx of Ca2+ • Acidosis • Reduction of transmembrane resting potentials • Alpha- and/or beta-adrenocepter and autonomous never activity alteration As the result, the electrical instability increased

  48. Ischemia increases the dispersion (离散度)of repolarization(复极) between the normal and diseased tissue, induces afterpolarization(后除极) as triggering response for Ca2+-dependent arrhythmia, finally leads to ventricular fibrillation