Cardio Flashcards
Which three conditions is atherosclerosis the principal cause of?
Stroke, heart attack and gangrene
What are the 7 risk factors for atherogenesis?
- Age
- Tobacco smoking
- High serum cholesterol
- Obesity
- Diabetes
- Hypertension
- Family history
What is the term for a new plaque?
Neointima
What are the 4 components of an atherosclerotic plaque?
- Lipid
- Necrotic core
- Connective tissue
- Fibrous cap
What are the two ways that atheroma can cause problems?
- Rupture which precipitates a thrombus that occludes the vessel
- The plaque can grow so big that it occludes the vessel. This leads to the tissue being supplied to become ischaemic
How is an atheroma caused by injury?
- Endothelium is injured- “endothelial dysfunction”
- Signals sent to circulating leukocytes which then accumulate and migrate into the vessel wall.
- Inflammation ensues
What happens when LDL is present in the blood in excess?
It accumulates in the arterial wall and then undergoes oxidation and glycation
What happens after inflammation is initiated after injury?
Chemoattractants are released from the endothelium and they send signals to the leukocytes
What are the 7 inflammatory cytokines found in plaques?
- IL-1
- IL-6
- IL-8
- IFN-gamma
- TGF- beta
- MCP-1
- C reactive protein
What are the 5 stages of leukocyte recruitment to vessel walls?
- Capture
- Rolling
- Slow rolling
- Firm adhesion
- Transmigration
When do fatty streaks begin to appear?
Under 10 years
What do fatty streaks consist of?
Lipid-laden macrophages and T lymphocytes within the intimal layer of the vessel wall.
What do intermediate lesions consist of? (5)
- Lipid laden macrophages called foam cells
- Vascular smooth muscle cells
- T lymphocytes
- Adhesions and aggregations of platelets on the cell wall
- Isolated pools of extracellular lipid
What is the fibrous cap made up of in an atheroma?
Collagen and elastin
What causes a plaques to rupture?
A fibrous cap needs to constantly be resorbed and redeposited. If the balance shifts in favour of inflammatory conditions then the cap becomes weak and the plaque ruptures.
How do you treat coronary heart disease?
PCI- percutaneous coronary intervention
How do some stents reduce the chances of restenosis?
They are drug eluting
How does aspirin work?
It is an irreversible inhibitor of platelet cyclo-oxygenase
How does Clopidogrel/ Ticagrelor work?
Inhibits the P2Y12 ADP receptor on platelets
How do statins work?
Inhibit HMG CoA reductase, reducing cholesterol synthesis
Which node is the dominant pacemaker node?
SA
What is the intrinsic rate of the SA node?
60-100 bpm
What is the intrinsic rate of the AV node?
40-60 bpm
What is the intrinsic rate of ventricular cells?
20-45 bpm
What is the standard calibration of an ECG?
25 mm/s
0.1mV/mm
What does an upright deflection in an ECG signify?
An electrical impulse that is travelling towards the electrode
What is the sequence of impulse conduction in the heart?
SA node- AV node- Bundle of His- Bundle branches- Purkinje fibres
What does the P wave signify on an ECG?
Atrial depolarisation
What does the QRS complex signify on an ECG?
Ventricular depolarisation
What does the T wave signify on an ECG?
Ventricular repolarisation
What does the PR interval signify on an ECG?
Atrial depolarisation and the delay in the AV junction
What makes up a 12 lead ECG?
3 standard limb leads, 3 augmented limb leads, 6 precordial leads
Which anatomical group of the heart does lead I monitor?
Lateral
Which anatomical group of the heart does lead aVR monitor?
None
Which anatomical group of the heart does lead V1 monitor?
Septal
Which anatomical group of the heart does lead V4 monitor?
Anterior
Which anatomical group of the heart does lead II monitor?
Inferior
Which anatomical group of the heart does lead aVL monitor?
Lateral
Which anatomical group of the heart does lead v2 monitor?
Septal
Which anatomical group of the heart does lead V3 monitor?
Lateral
Which anatomical group of the heart does lead III monitor?
Inferior
Which anatomical group of the heart does lead aVF monitor?
Inferior
Which anatomical group of the heart does lead V3 monitor?
Anterior
Which anatomical group of the heart does lead V6 monitor?
Lateral
How long should a PR interval be?
120 to 200 miliseconds. 3 to 5 little squares
How long should the QRS complex be?
No bigger than 110ms, 3 little squares
In which leads should the QRS complex be upright?
I and II
What is special about lead aVR?
all waves are negative
What is the difference in R waves between leads V1 and V4?
They grow in magnitude
What is the trend in S waves V1- V6?
The S wave must grow from V1 to at least V3 and then disappear in V6
What is the rule regarding the ST segment in a normal ECG?
The ST segment should start isoelectric except in v1 and v2 where it may be elevated
In which leads should the P wave be upright?
I, II, v2 and v6
What is the rule regarding Q waves?
There should be no Q wave or a very small one in I, II, V2-6
What is the rule regarding T waves?
Must be upright in I, II, V2-6
how does right atrial enlargement present on an ECG?
Tall, pointed P waves (P pulmonale)
How does left atrial enlargement present on an ECG?
Notched P wave (P mitrale) in the limb leads
What does a short PR interval indicate?
Wolff-parkinson-white syndrome.
What does a long PR interval indicate?
First degree heart block
What does an tall QRS complex in V1-6 mean?
Left or right ventricular hypertrophy
How do you calculate heart rate?
- Divide 300 by the number of big boxes between QRS complexes
- Count the number of beats in the 10 second strip and x6
What is the normal weight of a heart in a male?
280-340g
What is the normal weight of a heart in a female?
230- 280g
What is heart failure?
failure to transport blood out of the heart
What is cardiogenic shock?
Severe heart failure
Which parts of the heart does the right coronary artery supply?
Right ventricle, posterior part of the intraventricular septum and part of the posterior wall of the left ventricle
What does the left coronary artery supply?
The left ventricle and the anterior part of the intraventricular septum
Where is ANP produced in the heart?
In the right atrial wall
What does increased sympathetic tone cause?
tachycardia
What are the signs of left heart failure?
pulmonary congestion and oedema
What are the signs of right heart failure?
prominent systemic venous congestion, raised jugular venous pressure, enlargement of the liver
What does cor pulmonae mean?
Describes right heart failure second to lung disease
What is the most common cause of cor pulmonae?
chronic obstructive airway disease
What is dysponea?
subjective symptom of shortness of breath
What is orthponea and what does it suggest?
Dysponea when lying down. It suggests left heart failure because it is a result of oedema in the legs returning to the lungs.
What are the 4 principle causes of heart of heart failure?
- Ischaemic heart disease
- systemic hypertension
- Valvular heart disease
- lung disease leading to right then congestive heart failure
Why is there increased fluid retention by the kidney in heart failure?
It is a compensatory mechanism
What does increased fluid retention by the kidney lead to?
Increased venous return, increased in ventricular preload and volume overloading of the ventricles
Why is the liver enlarged in congestive heart failure?
because the centrilobular veins and hepatic sinusoids are engorged.