When the Cardiovascular System Goes Wrong - Lecture 15 Flashcards
What are the figures for cardiovascular disease?
○ Affects 1 in 14 people worldwide
○ Kills 1 in 3 people worldwide
○ Kills 45% of Europeans: biggest single cause of death
○ Death rates in the UK are falling
○ 4 out of 5 deaths from CVD are associated with modifiable risk factors
What diseases does hypertension put you at risk of?
○ Coronary heart disease & myocardial infarction
○ Aneurysms
○ Stroke
○ Chronic kidney disease
○ Heart failure
How does hypertension give coronary heart disease & myocardial infarction?
Accelerates atherosclerosis by increasing stress and damage to endothelial walls of coronary arteries
How does hypertension give aneurysms?
Increased wall stress can lead to aneurysms and increase the risk of rupture
How does hypertension give stroke?
Damage to endothelial cells in cerebral arteries increases the risk of haemorrhagic or ischaemic stroke
How does hypertension give chronic kidney disease?
Can narrow the renal arteries and reduce the blood supply to the kidney which damages the nephron and kidney function declines
How does hypertension give heart failure?
○ Puts more strain on the ventricles by increasing afterload and reducing cardiac output
○ To compensate the heart remodels and hypertrophies to increase contractility but this deteriorates over time
What is the difference between primary and secondary hypertension?
○ Primary: of unknown medical cause
○ Secondary: of known medical cause
What are the likely contributing factors to primary hypertension?
○ Genetic predisposition
○ High alcohol consumption
○ Sedentary lifestyle
○ Obesity
○ Diabetes
○ Intrauterine environment
What are some examples of secondary hypertension?
○ Chronic kidney disease
○ Endocrine disorders
○ Adrenal tumour
What are the treatments for hypertension?
○ Thiazide Diuretic
○ Ca2+ channel blocker
○ RAAS inhibition
How does thiazide diuretic work?
○ Inhibits renal Na+ reabsorption to increase water loss to urine
○ Venous return and end diastolic volume decrease
○ Cardiac output decreases
How does Ca2+ channel blocker work?
○ Inhibits Ca2+ entry in cardiac and vascular muscle cells
○ Decreases contractility and stroke volume
○ Decreases vasoconstriction
○ Decreases cardiac output
How does RAAS inhibition work?
○ Decreases vasoconstriction
○ Decreases Na+ & water absorption
○ Decreases cardiac output
What are the three treatments for RAAS inhibition?
○ Angiotensin converting enzyme inhibitor
○ Angiotensin II receptor blocker
○ Aldosterone antagonist
What is athersclerosis?
Triggering factors:
○ Endothelial damage
○ High LDL cholesterol
Plaque formation:
○ Macrophage and lipid accumulation
○ Narrow lumen
What are the risks for atherosclerosis?
○ Stroke
○ Vascular dementia
○ Coronary heart disease
○ Increases the likelihood of thromboembolism
What is a treatment for atherosclerosis?
Statins:
○ Inhibit cholesterol synthesis -> decreases LDL
GTN spray:
○ Nitric oxide -> vasodilation
What is thrombosis?
Blood clots forming in the circulation
Why can thrombosis increase the risk for?
○ Stroke
○ Myocardial infarction
○ Pulmonary embolism
What are the treatments for thrombosis?
○ Anticoagulants e.g. warfarin
○ Anti-platelet therapy e.g. aspirin
What are the main risk factors for coronary heart disease & myocardial infarction?
○ Atherosclerosis of coronary artery: restricts myocardial blood flow
○ Atherothrombosis: Vessel occlusion cuts off myocardial blood flow
What is myocardial infarction?
○ Muscle distal to blockage starts to die
○ Left anterior descending coronary artery most commonly affected
What are the treatments for myocardial infarction?
○ Percutaneous coronary intervention: stent inserted into blocked artery to reopen it
○ Thrombolytics: to break up clot
What is stenosis?
○ Valvular disease
○ Thick/stiff valves fail to open properly
○ Increases afterload reducing ejection
○ Leads to LV hypertrophy and eventually failure
What is regurgitation?
○ Valvular disease
○ Valves fail to close properly
○ Results in backflow of blood
○ Reduces SV & CO
What treatment can be used on valvular disease?
Surgery to repair or replace damaged valves
What is heart failure?
○ When CO is inadequate to meet the body’s demands
○ Heart can’t fill: stiff and thick chamber so decrease in filling & EDV & SV
○ Heart can’t pump: stretched and thin chambers so decrease in contractility and SV
What can cause heart failure?
○ Diseases increasing workload: hypertension
○ Damage to myocardium: myocardial infarction
What happens in right sided failure?
○ Blood pools in periphery due to increased pressure in systemic veins
○ Peripheral oedema
What happens in left sided failure?
○ Congestion in lungs due to pressure in pulmonary veins
○ Pulmonary oedema
What happens if both sides fail?
Congestive heart failure
How to treat heart failure?
○ Beta blockers: reduces SNS activity to reduce workload and prevents desensitisation
○ Anti-hypertensives: reduce fluid, vasoconstriction and workload
○ Heart transplant: low availability, surgical risks, immunorejection
○ Left ventricular assist device: mechanical heart, surgical risks, immunorejection
What is arrhythmia?
A deviation of the heart’s normal sinus rate or rhythm
What is bradycardia and its treatment?
○ <60bpm
Causes:
○ Slow signal from SA node (sinus bradycardia)
○ Block of signal due to SA node, AV node or conductive tissue damage
○ Treatment: pacemaker
What is tachycardia?
○ >100bpm
Causes:
○ Cogenital, cardiomyopathy, ischaemia
Types:
○ Sinus tachycardia: Drugs or hormones
○ Non-sinus tachycardia: additional abnormal impulses in ECG
