CV Medicine - 2 Flashcards
blood vessel narrowing VS blood vessel occlusion
Blood vessel narrowing
* ischaemia developing in the tissues supplied by the affected blood vessel causing cramp felt as pain
* over many years specialised cardiac tissue will become fibrotic and muscle tissue will reduce
Blood vessel occlusion
* no oxygen delivery - tissue death
* more severe pain
* loss of function of tissue
Where in the vessels does atherosclerosis occur?
occurs at areas where there is turbulent bloodflow i.e. areas with increased stress
At what time does permanent damage occur if there is total occlusion?
reversible <20 min
permanent >20 min
What are the 3 main forms of acute ischaemic events affecting the heart?
atherosclerosis with blood clot
atherosclerosis
spasm
What are the characteristics of stable angina?
pain develops where there is increased demand in the setting of a stable atherosclerotic plaque.
vessel is unable to dilate enough to allow adequate blood flow to meet the myocardial demand
mostly due to exercise
lactic acidosis
normal troponin levels and ECG
What are the characteristics of unstable angina?
plaque ruptures and a thrombus forms around ruptured plaque causing partial occlusion of the vessel. angina pain occurs at rest or progresses rapidly over a short period of time
can happen at any time i.e. sitting
troponin levels are normal
ECG can show inverted T waves, ST depresssion or just normal
no cardiac tissue death but ischaemia
What are the characteristics of NSTEMI?
non-elevated st
during an nstemi, the plaque rupture and thrombus formation causes partial occlusion to the vessel that results in injury and infarct to the subendocardial myocardium (damage has happened to heart muscle)
troponion level is elevated
ECG can show inverted T waves, ST depression or normal
What are the characteristics of STEMI?
complete occlusion of the blood vessel lumen, resulting in entire wall (transmural0 injury and infarct to myocardium which is reflected by ECG changes and elevated troponins
ECG shows hyperacute T waves or ST elevation
What are the steps to diagnosing ACS?
History - (PMH may show patient has has central crushing chest pain)
ECG findings (STEMI, NSTEMI)
Biomarkers (troponin)
When testing troponin what is recommened?
tested on admission then 24 hours later because troponin levels can change
What do all angina pectoris symptoms share?
- All describe ‘central crushing chest pain’
– radiation to arm, back, jaw possible (embryological)
coronary artery narrowing (mostly due to plaque)
What are the symptoms of classic angina?
- No pain at rest
- pain with certain level of exertion
– worse with cold weather/emotion - pain relieved by rest
- patient lives within limits of tolerance
- gradual deterioration
What conditions can worsen angina?
– anaemia
– hyperthyroidism
– hypovolaemia
What are the tests for angina?
- ECG -resting and exercise
– shows area of myocardial ischaemia - Test and eliminate other disease
– thyroid, anaemia, valve - Angiography
- Echocardiography
- Isotope studies (function assessment)
What is an exercise ECG?
- Tests ischaemia of the heart in real time
- Allows changes to be seen and stopped at the ’reversible’ stage
- ST- segment depression increases as ischaemia increases – asymptomatic to the patient
- ECG changes resolve when exercise stops
How are blood vessels visualised?
with an injection of dye
What are the two ways angina can be treated?
reduced oxygen demands of the heart
increase oxygen delivery to the tissues
How can oxygen demands be reduced?
– reduce afterload (blood pressure)
– reduce preload (venous filling pressure, starling’s law)
– Correct mechanical issues – failing heart valves, septal defects