week 5 patho Flashcards
what does the term ischemia mean
inadequate blood supply to things due to blockage of blood vessels
what is infarction
injury/death to tissue
what is unstable angina
there’s an MI coming on
what happens when you block angio 2
vasodilation and fluid secretion, high potassium
what is depolarisation
when the heart goes from negatively charged to positive resulting in contraction
what is the pathway for heart conduction
SA - AV- bundle of HIS, L and R bundle branches, purkinjie fibres
what are the four properties of cardiac cells
automaticity, contractility, conductivity, excitability
what kinds of things can an ECG detect
abnormalities in cardiac conduction, ischemia, infarction, hypertrophy, electrolyte abnormalities
what would the sinus rhythm of cardiac conduction generated by the AV node be like
60-40 beats per minute, using AV as backup pacemaker means it’ll be a little delayed
whats the difference between a 12 lead ECG and a continuous
12 lead will be for diagnosing and getting a rlly in depth look at the heart, continuous will be more for superficial monitoring
what would an ECG look like in a patient with an NSTEMI
you will see ST depression (the space after QRS will be dipped_
what would an ECG look like in a patient with full STEMI
you will see ST elevation, the space after QRS will be v high
what should an ECG look like in a patient with high potassium
high and pointy T wave, wave is more spread out
what should and ECG look like in a patient with low potassium
An additional U wave, long q wave, low or inverted T wave
how does potassium affect heart contractility
high potassium can affect the ability to depolarise
what could cause sinus bradycardia
vagal stimulation, medications, hypothermia
how could sinus tachycardia lead to angina
coronary arteries fill during diastole, since diastole is shorter they aren’t filling enough, meaning the heart isn’t getting enough oxygen
whats similar with all sinus rhythms (normal, tachycardia, brady)
waves don’t change, just the space in between them
what is atrial fibrillation
heart goes haywire, atria pump at 600bpm, ventricles pump anywhere from 50-180 bpm, blood doesn’t actually move foreward
why is there risk of blood clots with atrial fibrillation
blood doesn’t actually more foreward, thrombous may form due to venous stasis
define heart failure
heart isn’t pumping as effectively as it should
what are the 5 factors of cardiac output
contractility, HR, preload, afterload, blood volume
what is a normal cardiac output
3-6 L/min
what are the two biggest risk factors of heart failure
CAD because it reduces blood flow to the myocardium (responsible for cardiac pump)
HTn: resistance during afterload overworks ventricles
what are two chronic causes of heart failure associated with contractility
CAD: impaired blood flow to myocardium
cardiomyopathy: disease to heart
what are two acute causes of heart failure associated with contractility
acute MI (side backflow of blood to the heart)
myocarditis: inflammation of the heart muscle
what are three causes of heart failure associated with afterload
HTN: heart has to work harder to overcome resistance
Pulmonary disease: same as HTN in terms of heart needs to try and push blood through lungs
hypertensive crisis: BP goes up quickly, heart can’t overcome
what do valvular disease and rupture of papillary muscle have in common
- both affect preload
- valvular disease: valves aren’t working
- rupture: this muscle is involved with the opening and closing of valves, when it ruptures it causes regurgitation and back flow
what are the two issues in valvular diseases
stenotic valves: too tight
loose valves: don’t close properly (can cause regurgitation)
what is myocarditis
inflammation of heart muscle, affects contractility
what is ejection fraction
the percentage of blood during end diastolic volume that actually ejected from the heart during diastole (there’s always a bit remaining)
what is a critical number for ejection fraction that could mean that the heart is failing
less than 40%
what are some characteristics of heart failure with reduced injection fraction
it means there’s a pumping problem, left ventricle cannot contract strong enough to pump blood effectively
heart muscle damaged from being overworked
usually includes an ejection fraction less than 40 %
what are characteristics of heart failure with preserved injection fraction
means there’s a filling problem, inability for ventricles to relax and fill during diastole
usually from ventricular hypertrophy
what are the four compensatory mechanisms for heart failure
- SNS activation
- neurohormonal response (RASS)
- ventricular dilation
- ventricular hypertrophy
what are the two cardiac enzymes that work against all compensatory mechanisms of the heart
ANP and BNP (they increase urinary output and trigger vasodilation)
what is the difference between right sided and left sided heart failure
left sided: blood backs up into lungs
right sided: blood backs up into organs
what is biventricular failure
failure of one pump with eventually cause other pump to fail
what is the difference between hypertrophy and dilation
hypertrophy: LV is stiff, can’t pump as effectivelly
dilation: wider, looser
what does blocking the RAAS do for a patient in heart failure
it can prevent cardiac remodelling!
what is the atrial kick
puts significant volume towards ventricular preload, essential for adequate ventricular filling
(basically atria kick block into ventricles so they can fill)
