Sudden cardiac death

1. Sudden cardiac death Ri黃柏樺

2. Sudden cardiac death(SCD) Introduction • Sudden cardiac death (SCD) is used to describe cardiac arrest with cessation of cardiac function, whether or not resuscitation or spontaneous reversion occurs • Patients who do not die after cardiac arrest should be said to have experienced aborted SCD

3. Sudden cardiac death(SCD) Definition by WHO • Sudden collapse of cardiac function occurring within one hour of symptoms

4. Sudden cardiac death(SCD) Symptoms&signs • Chest pain • Dyspnea • Fatigue • Palpitations • Syncope

7. Sudden cardiac death(SCD) Pathophysiology • The vast majority of cases of SCD are due to ventricular arrhythmias • Ventricular tachycardia (VT) or ventricular fibrillation (VF) account for the majority of episodes • This almost always occurs in the setting of underlying myocardial disease • More than 80% of SCD events occur in individuals with coronary artery disease (CAD)

10. Arrhythmic mechanisms • Reentry with unidirectional • Enhanced automaticity • Altered Ca, K hemodynamics • Neurohormonal changes • Mutations resulting in dysfunction of a sodium channel (Na channelopathy)

11. SCD & ischemic heart disease • 65 to 70 % of SCDs are attributable to CAD • SCD accounts for 30 to 50 % of coronary deaths • A peak incidence of VT and VF within the first 48 hours after acute MI has also been noted in other reports

12. SCD & ischemic heart disease(2) Incidence of VT and VF after ST- elevation MI • VF:4.2 % • VT:3.5 % • Both VF and VT:2.7 % • 80 to 85 % of these arrhythmias occurred in the first 48 hours.

13. Hypertrophic cardiomyopathy • Most common cause of SCD in young(age ≤ 35 y/o) • SCD is priimarily related to VT or VF. • The mechanism of arrhythmia in this setting is not clear • Autosomal-dominant inherited disease

14. Hypertrophic cardiomyopathy Symptoms and signs • Dyspnea on exertion • Orthopnea and paroxysmal nocturnal dyspnea • Chest pain • Presyncope and syncope • Palpitation • Postural lightheadedness • Fatigue • Edema (rare)

15. Hypertrophic cardiomyopathy • Autosomal-dominant inherited disease • Mutation in one of the many (>45) genes encoding proteins of the cardiac muscle sarcomere(eg. beta-myosin heavy chains, and cardiac troponin T)

16. Valvular disease • Aortic stenosis (predominate) • The mechanism of sudden death is unclear, and both malignant ventricular arrhythmia and bradyarrhythmia have been documented

17. Absence of structural heart disease • Primary VT and VF • Long QT syndrome • Wolff-Parkinson-White (WPW) syndrome • Commotio cordis • Brugada syndrome • Congenital short QT syndrome

18. Long QT syndrome • Prolonged QT interval • Polymorphic ventricular tachycardia (VT) called torsade de pointes

19. QTc   =   QT interval  ÷  square root of the RR interval (in msec)

22. WPW syndrome • Existence of an atrioventricular accessory pathway • Short PR interval, wide QRS complex, and delta wave on ECG • Atrial fibrillation (AF) with a rapid ventricular response was the most common

25. Commotio cordis • Refers to SCD that most often occurs in young athletes who have been struck in the precordium with a projectile object such as a baseball, hockey puck, or fist • The most common arrhythmia is VF • 62 ％ during exercise VS 32 ％ during routine daily activities

27. Sudden cardiac death in young • 65 to 70 ％ of all sudden deaths are attributable to coronary artery disease • The frequency of CAD is much lower in SCDs occurring under the age of 30 to 40 (eg. 24 ％ under the age of 30 in one report) • Male (65 ％) VS female(35 ％)

29. Sudden cardiac death in young Causes of sudden cardiac death in young Australians MJA 2004; 180: 110–112 Alessandra Doolan, Neil Langlois and Christopher Semsarian

30. Sudden cardiac death in young • Design and setting: A review of all autopsies performed between 1 January 1994 and 31 December 2002 at a major Sydney forensic medicine department serving an area with over 2 million people. • Main outcome measures: Incidence of various types of cardiac disease causing sudden death in those aged ≤ 35 y/o proportion of deaths in which no cause was found at autopsy.

31. Sudden cardiac death in young • Results: 10199 autopsies performed. 2986 (29.2%) deaths occurred in people aged ≤ 35 years 193 were classified as sudden cardiac deaths: 60 (31%) the cause was not established and was presumed to be due to primary arrhythmogenic disorders. 46 (24%), Coronary artery disease 29 (15%), hypertrophic cardiomyopathy 23 (12%). myocarditis

34. Sudden cardiac death in young Of these 193 sudden cardiac deaths • 22% occurred during exercise • 38% during minimal exertion or at rest; • 40% were not witnessed

35. Sudden cardiac death in young Discussion 1. Unlike the reports in the United States and in most of Europe, primary arrrhythmogenic disorders of the heart is the leading cause of SCD in young Australians 2. The incidence of primary arrhythmogenic causes of sudden cardiac death in young people is likely to be underestimated

37. Sudden cardiac death in young Conclusion • The importance of correct diagnosis of genetic cardiac disease • Appropriate family screening of at-risk individual • Initiation of preventive strategies, such as implantable defibrillator(ICD) therapy Above these should be highlight to prevent from sudden cardiac death in young

38. Can the young of SCD be the donor of heart transplantation ? Answer: NO

40. Take home message • The vast majority of cases of SCD are due to ventricular arrhythmias • The causes of SCD is different in different age groups • The most effective strategy for prevention of SCD is implantable cardioverter defibrillator (ICD) • Strictly speaking, most victims of SCD can not be the donor of heart transplantation

41. Thanks for your attention !