Cardiovascular Disease Flashcards
Circulatory system components
- Pump (heart)
- Distribution system (arteries)
- Oxygenation system (lungs)
- Exchange system (capillaries)
- Collecting system (veins)
Heart anatomy
The heart has 4 chambers with valves between them to maintain unidirectional blood flow
The coronary artery supplies the heart with blood, although flow can only occur during diastole
Has a high energy demand
Cardiac conduction
The heart has intrinsic rhythm provided by the sinoatrial node (SAN)
The SAN releases an action potential with depolaries the both atria and then both ventricles, causing them to contract
The SAN is delayed at the AV node, causing a delay between atrial and ventricular contraction
ECG
An ECG trace measures electrical conduction of the heart
P wave = atrial depolarisation
QRS complex = ventricular depolarisation
T wave = ventricular repolarisation
Arrhythmia
Arrhythmia refers to conduction defects of the heart
They lead to non-uniform and inefficient contraction of the heart
Compensatory mechanisms of the heart
- Frank-Starling mechanism
- Noradrenaline
- RAAS system
- Atrial natriuretic peptide
Hypertension
Hypertension indicates high pressure within the arterial system
Diastole >89mmHg
Systole >139mmHg
Symptoms of hypertension
- Persistent headache
- Blurred vision
- Nosebleeds
- Shortness of breath
Essential hypertension
Idiopathic hypertension
A complex disorder with multiple causes
Secondary hypertension
Occurs due to renal failure, endocrine dysfunction, vascular problems or neurological disorders
Complications of hypertension
- Stroke
- Myocardial infarction
- Chronic renal failure
- Retinopathy
Treatments for hypertension
- ACE inhibitors
- Beta blockers
- Calcium channel blockers
- Diuretics
Ventricular hypertrophy
Hypertension can also lead to ventricular hypertrophy
- Systemic hypertension causes left heart hypertrophy
- Pulmonary hypertension causes right heart hypertrophy
Can progress to heart failure or ischaemic heart disease
Atherosclerosis
Atherosclerosis describes the thickening and hardening of arterial walls leads to a loss of elasticity
Characterised by plaques
Atherosclerotic plaques
Consist of a raised lesion with a soft, yellow core of lipid
Covered with a white fibrous cap
Leukocytes accumulate around the lesion and the plaque will also have a necrotic core of foam cells
Pathogenesis of atherosclerosis
- Endothelial injury
- Accumulation of lipoproteins (LDL)
- Monocyte adhesion
- Platelet adhesion
- Factor release
- Lipid accumulation
Complications of atherosclerosis
- Rupture of the plaque, leading to thrombosis
- Haemorrhage into a plaque
- Atheroembolism
- Aneurysm formation
Ischaemic heart disease
The leading cause of death worldwide
Usually a result of atherosclerotic lesions in the coronary artery
May lead to angina pectoris, myocardial infarctions, heart failure and sudden cardiac death
Angina pectoris
Chest pain characterised by transient myocardial ischaemia
Recognised by an ECG as ST depression
Myocardial infarction
The death of cardiac muscle due to severe prolonged ischaemia of the coronary artery
Symptoms of myocardial infarction
- Severe chest pain
- Sweating
- Nausea
- Vomiting
- ST elevation
Heart failure
Occurs when the heart lacks the ability to pump properly
