Cardiovascular conditions Flashcards
What is angina?
Mismatch between supply of oxygenated blood to the heart versus myocardial demand causing pain to the chest.
What causes angina?
Usually a narrowing of the coronary vasculature (reduced blood flow)
May also be caused by reduced perfusion pressure (low blood pressure, low MAP) or poor collateral blood supply
What type of chest pain is angina?
Ischaemic type chest pain.
Often described as a pressure/tightness but can fluctuate
What forms is angina generally split into?
Stable (pectoris)
Unstable (type of ACS)
Prizmetal (spasmodic)
What is angina pectoris?
Stable angina
What typically causes angina pectoris?
Atherosclerosis of the coronary arteries
What is stable angina often a first sign of?
Developing ishaemic heart disease/coronary heart disease
What is the main difference between stable and unstable angina?
Unstable angina presents symptoms at rest versus at exertion as with stable angina
Why is unstable angina treated as an emergency?
May be a precursor to/symptom of myocardial infarction
What is primzmetal angina due to?
The etiology is not well understood but due to cornary spasm - potentially from overreaction from vasoconstrictive stimuli with or without stenosis
May be associated with patients with other vasoconstrictive disorders such as raynauds or migraines
What external factor is the main cause of prinzmetal angina?
Recreational drug use (cocaine, amphetamines, cannabis)
What are the similarities and differences between the symptoms of prinzmetal angina and unstable/stable angina?
Prinzmetal angina presents with similar ischaemic chest pain.
Rest doesn’t usually relieve symptoms and it similarly is not thought to be caused by exertion
What is atherosclerosis?
The process of lipid accumulation (plaque formation), scarring and inflammation of the vascular wall resulting in narrowing of vasculature due the vasculature wall thickening, weakening of the vessel walls and a reduction of vessel elasticity. It may also result in thrombosis
What can atherosclerosis cause?
ACS
CVA
AAA
Peripheral vascular disease
Significant cause of hypertension, which can worsen it.
How does atherosclerosis develop?
Damaged endothelium
Fatty streaks
Fibrous plaques
Complicated lesions
What is the mechanism of atherosclerosis?
Damaged endothelium causes lipid accumulation (LDLs build up), platelet attachment, and migration of smooth muscle into the intima.
WBCs activate several positive feeback loops which cause build up of fat.
The build up of fat develops a fibrous cap and absorbs calcium salts and hardens.
How do atherosclerosis plaques become fibrous?
The lipid pool becomes covered with collagen
What are most common causes of endothelial damage that increases risk of atherosclerosis?
Hypertension
Smoking
Diabetes mellitus
High cholesterol
What do atherosclerosis plaques consist of?
A combination of cholesterol, calcium and WBCs
What can cause sinus tachycardia?
Shock
PE
Pyrexia
Anxiety
Exercise
Drugs
Pain
Dehydration
Hypoxia
Hyperthyroidism
What can cause sinus bradycardia?
Inferior/posterior MI
Vagal stimulation
Arrhythmia medication
Hypothermia
Hypo/hyperkelaemia
SA node disease
Raised ICP
Post heart transplant
Hypothyroidism
What can cause sinus arrhythmias?
DISCS HEMP
Drug toxicity
Infection
Scar tissue
Coronary heart disease
Stress
Hormones
Electrolyte imbalance
Medication
Post heart surgery
What are the three main types of atrial conduction abnormalities?
Atrial fibrillation
Atrial flutter
Premature atrial complexes (PACs)
What kind of rhythm does atrial fibrillation follow?
Irregularly irregular
What secondary treatments are AF patients usually given and why?
Anti-coagulant medication as the inadequate contractions and therefore inadequate emptying of the atria can cause blood pooling and clotting which can create embolisms
What is atrial flutter?
A re-entrant arrhythmia where an impulse circles around a large area of tissue (such as the entire right atrium) regularly at a high rate
What are premature atrial complexes, are they cause for concern?
An area of the atria (not the SA or AV node) prematurely produces an impulse. They can be asymptomatic or come with a palpitation or ‘jolt’ feeling and can happen in healthy people and not be cause from concern. Can be concerning if there are several in a row (bigeminy or trigeminy), this can cause a decrease in cardiac output and lead to other arrhythmias
What are the main types of ventricular conduction abnormalities?
Bundle branch blocks
Ventricular tachycardia
Ventricular fibrillation
PVCs
What are premature ventricular complexes?
An area of the ventricles (not the His or purkinje fibres) prematurely produces an impulse.
How is ventricular tachycardia defined?
Defined as an episode of three or more PVCs at a rate of >100bpm. Can occur with or without a pulse
What are the most common causes of ventricular tachycardia?
Previous MI
Electrolyte imbalances
Congenital heart diseases
Coronary heart disease
Side effects of medication
Drug use
What treatments are given for ventricular tachycardia?
Anti-arrhythmics
Ablation
Cardioversion
Implantable Cardioverter Defibrillator
Overdrive pacing
What are bundle branch blocks?
A disruption in impulse conduction from the bundle or His through either the right or left bundle branch to the purkinje fibres.
What are the most common causes of bundle blocks?
Myocardial infarction
Hypertension
Pulmonary embolism
Infections
Cardiomyopathy
Congenital heart diseases
Can be idiopathic
Why are bundle branch block patients often taken to the cath lab?
MIs can be hidden by BBBs
What are the two types of heart failure?
Systolic heart failure - Can’t pump hard enough
Diastolic heart failure - Can’t fill enough
What is congestive heart failure?
When heart failure causes fluid build up (congestion) around the body
Caused by blood backing up, forcing fluid through the capillary walls which builds up around the body (ankles, feet, arms, lungs and/or other organs)
What are the main causes of heart failure?
Coronary heart disease
Heart inflammation (myocarditis, rheumatic heart fever)
High blood pressure
Cardiomyopathy
Irregular heartbeat.
What are the main risk factors of heart failure?
Poor lifestyle habits e.g. poor diet, smoking, drug use, heavy alcohol use, and lack of physical activity.
Heart or blood vessel conditions
Serious lung disease
Infections e.g. HIV or SARS-CoV-2
Obesity
Hypertension
Diabetes
What is ejection fraction?
The fraction of total left ventricle blood volume that is ejected every pump, expressed as a percentage.
What do the different ranges for ejection fraction indicate?
50%-70% = Normal
40%-50% = Borderline
<40% = Systolic heart failure
What is cardiomyopathy?
An umbrella term for a disorder of the heart muscle. May be stiffening, stretching, enlarging or constricting.
What are the 4 main types of cardiomyopathy?
Hypertrophic cardiomyopathy
Arrhythmic Right Ventricle Dysplasia (ARVD)
Restrictive cardiomyopathy
Dilated cardiomyopathy
How does atherosclerosis or ischaemic heart disease lead to heart failure, and what kind?
Atherosclerosis or ischaemic heart disease causes a reduction of blood flow and oxygen to the myocardium causing damage or cell death. Damaged, dead or scar tissue cannot contract properly causing systolic heart failure.
How does long standing hypertension lead to heart failure, and which kind?
An increase in mean arterial pressure means the ventricles have to pump harder to eject enough blood. This increased workload causes the myocardium to hypertrophy. This in turn increases the demand for oxygen and places pressure on the coronary vessels restricting blood flow. This leads to tissue damage and weaker contractions, systolic heart failure.
Similarly, long standing hypertension can cause concentric hypertrophy where the extra myocardium crowds into the ventricles reducing the space for blood, this causes diastolic heart failure as the ventricles cannot fill adequately
How does dilated cardiomyopathy cause heart failure, and what kind?
Dilated cardiomyopathy is an attempt to increase preload to help with ejection and increase the stretch on the ventricular walls to help with contractions (frank-starling effect). However overtime the muscles get thinner and weaker causing ineffective contractions and systolic heart failure
What are common causes of concentric ventricular hypertrophy?
Long term hypertension
Aortic stenosis (narrowing)
Hypertrophic cardiomyopathy (genetic)
How does restrictive cardiomyopathy lead to heart failure, and what kind?
Restrictive cardiomyopathy means stiffer and less compliant myocardium. The ventricles can’t stretch and fill leading to diastolic heart failure
How does decreased blood flow to the kidneys affect patients with heart failure?
Reduced blood flow to the kidneys caused by heart failure actives the RAAS system increasing fluid retention. This increases preload and thereby contraction strength (frank-starling effect). This can compensate in the short term but in the long term the increased fluid can cause the heart failure to become congestive.
How does heart failure lead to pulmonary oedema?
Decrease cardiac output from heart failure can cause blood to back up into the lungs. Increasing the pressure in the pulmonary veins and pulmonary artery. Fluid moves from the blood to the interstitial spaces in the lungs causing pulmonary oedema.
How does pulmonary oedema lead to its signs and symptoms?
The build up of fluid in the alveoli make diffusion of oxygen and carbon dioxide (and thereby gas exchange) a lot harder. This causes difficulty breathing (dyspnoea) especially when lying down (orthopnea) and crackles. A substantial increase in pulmonary capillary wedge pressure can cause ruptures in the pulmonary capillaries, blood leaks into the alveoli, causing pink frothy sputum. Alveolar macrophages digest these blood cells and turn brown from the iron, they are then referred to as “heart failure cells”.
What is the most common cause of right sided heart failure?
Left sided heart failure
What can cause isolated right sided heart failure?
Cardiac shunt caused by atrial or ventricular septal defects
Chronic lung disease
How can cardiac shunt cause right sided heart failure?
Septal defects cause shunts where blood moves from the left side of the heart to the right. This increase in blood volume can cause right ventricular hypertrophy which can lead to:
-ischaemia causing systolic dysfunction
-myocardium crowding, reduced volume and reduced compliance causing diastolic dysfunction
How do chronic lung diseases cause isolated right sided heart failure?
Chronic lung diseases make gas exchange difficult causing hypoxia. In response to this hypoxia the pulmonary arterioles constrict increasing the pulmonary artery pressure increasing the workload on the right side of the heart. This leads to hypertrophy and heart failure. This whole process is referred to as cor pulmonale.
What is cor pulmonale?
When chronic lung disease leads to right sided ventricular hypertrophy and heart failure
Explain the congestion that occurs with right sided heart failure
With right sided heart failure blood backs up to the body and the systemic vasculature becomes congested and fluid leaks out the blood vessels into interstitial spaces of the body. Pitting oedema occurs in the legs and sacrum as gravity naturally pulls fluid here when patients are stood and laying down respectively. The jugular vein will also become distended and enlarged. Fluid leaking into the interstitial spaces within organs such as the liver and spleen (hepato spleno megaly) which can cause pain. Long term congestion can cause cirrhosis (called cardiac cirrhosis in this instance) which can lead to organ failure. Long term congestion can also cause fluid to leak through the surface of these organs into the peritoneal space causing ascites, the peritoneal space is large therefore a large amount of fluid can leak into this space before there is a significant change in pressure.