Pathophysiology of Cardiovascular Disease
Lecture Overview
Lecture 5 (Part I) on Pathophysiology of Cardiovascular Disease
Course: KHPM324 Chronic Diseases of Modern Society
Instructor: Hannah Oh
Institution: Division of Health Policy & Management, College of Health Sciences, Korea University
Normal Heart Function
Healthy Heart Mechanics
The normal heart is a robust, muscular pump.
Approximately the size of a fist.
Composed of:
Blood vessels
Muscle tissue
Valves
Conduction systems
It consists of four chambers:
Two Atria (upper chambers)
Two Ventricles (lower chambers)
Normal Blood Flow Pathway
Blood circulates in the following order:
Body → Heart → Lungs → Heart → Body
Heart Anatomy
Chambers and Valves
Right Atrium
Right Ventricle
Pulmonary Valve
Left Atrium
Left Ventricle
Mitral Valve (Bicuspid) and Tricuspid Valve
Aortic Valve
Diagrams illustrating the heart chambers and valves can enhance understanding here. Refer to images included in the slides.
Circulatory Systems
Systemic and Pulmonary Circulation
Blood Flow Dynamics
Pulmonary Circuit:
Consists of pulmonary arteries and pulmonary veins.
Right atrium receives deoxygenated blood from the body through the venae cavae.
Right ventricle pumps the blood to the lungs for oxygenation.
Systemic Circuit:
Oxygen-rich blood returns to the left atrium via pulmonary veins.
Left ventricle pumps oxygenated blood through the aorta to all body tissues.
Gas exchange occurs in capillary beds throughout the body and lungs.
Blood Flow Distribution
Distribution Metrics
Resting and exercising blood flow distribution:
Blood is directed differently depending on physical activity.
During heavy exercise, total cardiac output increases significantly from 5 L/min (rest) to 25 L/min (exercise).
Body's Mechanisms for Blood Redistribution
Vasoconstriction: Narrowing of blood vessels to reduce flow to certain areas.
Vasodilation: Expansion of blood vessels to increase flow to essential areas during activities such as exercise.
Cardiovascular Disease (CVD)
Overview
Leading cause of death worldwide.
In 2021, about 20.5 million deaths attributed to CVD, with approximately 85% due to heart attacks and strokes.
Most CVD deaths occur in low- and middle-income countries.
Many cases amenable to prevention through managing behavioral risk factors:
Tobacco use
Unhealthy diet and obesity
Physical inactivity
Harmful alcohol use
Types of Cardiovascular Disease
Disorders of the Heart and Blood Vessels
Coronary Heart Disease: Affects blood vessels supplying the heart muscle.
Cerebrovascular Disease: Affects blood vessels supplying the brain.
Peripheral Arterial Disease: Affects blood vessels supplying arms and legs.
Rheumatic Heart Disease: Damage from rheumatic fever due to streptococcal bacteria.
Congenital Heart Disease: Structural malformations present at birth.
Deep Vein Thrombosis (DVT) and Pulmonary Embolism: Clots that can dislodge.
Conditions Related to CVD
Heart Disease: General term for heart and vessel diseases.
Heart Attack: Occurs when blood flow to heart muscle is blocked, leading to tissue death.
Stroke Types:
Ischemic Stroke: Blockage from a blood clot.
Hemorrhagic Stroke: Burst blood vessel often due to hypertension.
Heart Failure: Inability of the heart to pump sufficient blood.
Arrhythmias: Abnormal heart rhythms.
Bradycardia: Heart rate < 60 bpm.
Tachycardia: Heart rate > 100 bpm.
Heart Valve Problems: Stenosis (narrowing) and Regurgitation (leakage).
Atherosclerosis
Characterized by plaque buildup in artery walls.
Narrows arteries and restricts blood flow.
Plaque rupture can trigger clot formation, leading to heart attacks or strokes.
Chronic condition that develops slowly, often without symptoms.
Spectrum of Coronary Heart Disease
Progression:
Atherosclerosis → Plaque stability → Plaque rupture → Thrombosis → Arrhythmia → Angina → Myocardial Infarction / Acute Coronary Syndrome → Death
Timeframe from stable coronary artery disease to critical events varies from years to seconds.
Angina Pectoris
Most common symptom of coronary artery disease.
Triggers with activity or stress; relief with rest.
Characterized by:
Local vessel narrowing.
Intermittent chest pain due to reversible myocardial ischemia.
No tissue damage unless progresses to infarction.
Myocardial Infarction (Heart Attack)
Defined as localized necrosis (cell death) from ischemia.
Primarily caused by thrombosis at plaque sites.
Severe reduction or complete cut-off of oxygenated blood flow results in heart muscle damage.
Symptoms of CVD Events
Heart Attack Symptoms:
Chest pain or discomfort.
Pain in arms, shoulders, jaw, back.
Stroke Symptoms:
Numbness in face, arm, leg.
Confusion or difficulty communicating.
Vision issues.
Walking difficulties and severe headache.
FAST Method for Stroke Recognition:
Face drooping
Arm weakness
Speech difficulties
Time to call emergency services (911) immediately.
Treatment Options for Cardiovascular Disease
Lifestyle Changes
Basic yet effective initial treatment strategy.
Medications
Beta-blockers: Prescribed for hypertension and heart failure; reduces heart's oxygen demand by slowing heart rate.
Statins: Cholesterol-lowering agents; useful for stabilization of plaques and primary prevention of CVD.
Aspirin: Anti-platelet therapy to prevent clot formation; should not be taken casually by low-risk individuals.
Nitrates: Induce vasodilation to reduce stress on the heart.
Surgical Operations
Coronary Artery Bypass Surgery: Restores blood flow by bypassing blocked arteries.
Balloon Angioplasty: Opens narrowed arteries using a balloon catheter.
Valve Repair/Replacement: Address issues in heart valves, including biological and mechanical options.
Heart Transplantation: For severe cases where other methods fail.
Questions
Open forum for addressing any uncertainties or clarifications related to cardiovascular diseases and treatments.