Young_Heart_Attacks_Module1_Epi_Pathophys.pptx

young heart attcks

1. Young Heart Attacks & Cardiac Arrest – Module 1 Epidemiology & Pathophysiology

2. Who is 'Young'? Premature CAD: <45–50 years Young MI registries: ≤40 years SCD literature: athletes typically <35 years

3. Why This Matters in India India: rising premature CAD burden South Asians present younger – INTERHEART trial ICMR priority: unexplained sudden deaths in the young

4. NORIN-STEMI Registry ~33% STEMI <50 years ~9% STEMI <40 years High prevalence of smoking/tobacco

5. ACS-QUIK & YOUTH Registry ACS-QUIK: 22% ACS 'young'; 42% smokers YOUTH registry (≤40y): 93% male, ~50% tobacco use Key risk factors: smoking, diabetes, dyslipidemia

6. Young STEMI – NORIN Data

7. Global vs Indian Perspective SCD incidence in young: 0.5–1.2/100,000 person-years Athlete SCD: ~1 per 40,000–80,000 athlete-years India: under-reported but rising awareness

8. Normal Coronary Anatomy Epicardial coronary arteries supply myocardium Three major vessels: LAD, LCX, RCA Coronary dominance influences risk patterns

9. Initiation of Atherosclerosis Endothelial dysfunction → increased permeability LDL entry into intima → oxidation Monocyte adhesion → foam cell formation

10. Progression of Atherosclerosis Fatty streaks → intermediate lesions Fibrous cap forms over necrotic core Smooth muscle proliferation and calcification

11. Pathophysiology of Atherosclerosis

12. Plaque Rupture vs Erosion Rupture: thin fibrous cap → thrombosis Erosion: endothelial denudation → platelet aggregation Erosion more common in young women

13. Acute Thrombosis Cascade Plaque rupture/erosion Platelet adhesion & activation Coagulation cascade → fibrin clot Complete occlusion → STEMI

14. Mechanisms of Sudden Cardiac Arrest Ischemia → ventricular fibrillation (VF) Arrhythmogenic cardiomyopathy (substrates) Electrical–mechanical dissociation Brain ischemia: irreversible after 4–6 minutes

15. Arrhythmic Substrates – HCM Hypertrophic cardiomyopathy Myocyte disarray → reentry arrhythmias Risk: unexplained syncope, family history, LV thickness >30mm

16. Arrhythmic Substrates – ARVC Arrhythmogenic right ventricular cardiomyopathy Fibro-fatty replacement → VT/VF Often presents in athletes

17. Channelopathies Brugada syndrome: sodium channel defect → VF Long QT syndrome: repolarization abnormality CPVT: stress-induced polymorphic VT

18. Structural & Acquired Causes Anomalous coronary arteries Myocarditis in young adults Substance use: cocaine, amphetamines

19. Sudden Cardiac Arrest – Chain of Survival

20. Module 1 Summary Premature CAD and SCD are rising in young Indians Atherosclerosis: initiation, progression, rupture/erosion SCD mechanisms: ischemia, arrhythmias, cardiomyopathies, channelopathies Prevention starts with recognition of pathophysiology