Week 2 Cardiovascular Flashcards
define stable coronary artery disease
a pathological process characterised by atherosclerotic plaque accumulation in the epicardial arteries, whether obstructive or non obstructive
list the symptoms of angina
chest pain
radiating pain to left jaw
dyspnoea
sweating
fatigue
syncope
anxiety
explain chest pain as a symptom of angina
reduced blood flow to the heart muscle due to coronary artery stenosis, leading to ischemia
explain radiating pain to left jaw as a symptom of angina
referred pain due to the convergence of sensory nerve fibres in the spinal chord (commonly seen in myocardial ischemia)
explain dyspnoea as a symptom of angina
decreased oxygen supply to the heart results in inadequate pumping capacity, reducing oxygen delivery to body tissues, including the lungs
explain sweating as a symptom of angina
the body’s sympathetic response to ischemia often accompanied by an adrenaline release
explain fatigue as a symptom of angina
reduced oxygen delivery to the heart muscle, leading to reduced CO and loss of consciousness
explain syncope as a symptom of angina
severe ischemia can cause a sudden drop in CO, leading to loss of consciousness
explain anxiety as a symptom of angina
psychological and physiological reaction to chest pain and fear of cardiac events
Describe how a mismatch between oxygen supply and demand arises
-when an obstruction in the coronary artery occurs, this prevents perfusion, creating a supply demand mismatch, heart can’t receive enough oxygen, leading to ischemia and possible angina
-mild to moderate stenosis due to atherosclerosis is clinically inconsequential
-fixed vessel narrowing over a prolonged period of time can lead to pressure drop and limited vessel flow
what factors impact the haemodynamic significance of stenotic lesions
-extent of stenosis
-degree of compensatory vasodilation
-myocardial oxygen demand
describe how the extent of stenosis can impact stenotic lesions
greater stenosis, means greater narrowing of coronary artery and reduced blood flow to the heart
describe how the degree of compensatory vasodilation can impact stenotic lesions
reflects the ability of the heart to self-regulate blood flow by widening smaller vessels, compensating for reduced flow due to stenosis
describe how myocardial oxygen demand impacts stenotic lesions
determines the stress placed on the heart, with increased demand potentially exacerbating the impact of coronary artery stenosis (by increasing mismatch)
describe the process of anaerobic metabolism in cardiac myocytes during ishcemia and how this process can lead to the accumulation of metabolic by-products and lead to dyspnoea
-myocardial ischemia causes cardiomyocytes to with from oxygen dependent (aerobic) to oxygen-absent (anaerobic) metabolism
-anaerobic metabolism produces more lactic acid and lowers cellular pH, impairing cardiomyocytes function
-damaged cardiomyocytes impair myocardial relaxation and cause decreased left ventricular contractility and cardiac output
-blood backs up into LV and LA and pulmonary vessels
-increased pulmonary capillary pressures pushed fluid into alveoli
-decreased gas exchange (dyspnoea)
describe how myocardial ischemia can lead to stimulation of pain pathways
-myocardial ischemia causes cardiomyocytes to with from oxygen dependent (aerobic) to oxygen-absent (anaerobic) metabolism
-anaerobic metabolism produces metabolites that stimulates cardiac spinal afferent nerves
-myocardial visceral afferent and somatic sensory nerve fibres mix and enter spinal cord via T1-T4 nerve roots
-brain interprets increased nerve signalling as pain coming from skin T1-T4 dermatomes (referred pain)
cardiac chest pain is usually related to which dermatomes
C3 to T5
C3-C4 dermatome is relevant to
neck and upper shoulder pain
C5-T1 dermatome is relevant to
upper chest, shoulder and back pain
what is acute coronary syndrome
used to describe suspicion or confirmation of acute MI
what are the main types of acute coronary syndrome
-ST-elevation myocardial infarction (STEMI)
-non-St-elevation MI
-Unstable angina
describe how spontaneous coronary artery dissection leads to acute coronary syndrome
sudden tearing of the layers in a coronary artery wall, often leading to a blockage
describe how coronary artery spasm can lead to acute coronary syndrome
temporary constriction of a coronary artery, restricting blood flow to the heart
describe how coronary microvascular dysfunction can lead to acute coronary syndrome
impaired function of the small blood vessels in the heart, affecting blood supply to the heart muscle