Cardiac Abnormalities Flashcards
What do you call it when valves don’ t open fully?
stenosis
What do you call it when valves don’t close
insufficiency
When do you get hypertrophy of the upstream chamber - in stenosis or insuffiiency?
in stenosis - the upstream chamber has to develop more pressure during systole in order to get a given flow through the stenotic valve, so you get increased pressure work and hypertrophy
When do you get chamber dilation - stenosis or insufficiency?
insufficiency - the regurgitated blood means the chamber gets an additional volume that must be ejected in order to get sufficient forward flow. This icnreases volume work and leads to dilation.
If atrial presure increases due to stenosis or insufificney, this will lead to what in the periphery?
higher pressure there as well - HTN
If capillary hydrostatic pressures are elevated, what happens to fluids?
you get tissue edema in the organs because the oncotic pressure is less than the hydrostatic pressure and water only is filtered out of the blood and never reabsorbed back into the vessel
What are the four common valve defects in the left
mitral stenosis or insufficiency
In aortic stenosis, the valve doesn’t open fully and you hav eincreased resistance to flow. What happens to the pressure difference between the LV and the aorta?
under normal conditions, the pressure difference beterween the two is minimal
however, in stenosis, the pressure in the LV shoots way way high and the pressure in the aorta only rises gradually (since it’s not a large opening anymore) and doesn’t reach the normal peak systolic pressure
What happens to the pulse pressure in aortic stenosis?
since the peak systolic pressure doesn’t get high enough, the pulse pressure is low
What sort of murmur will be heard with aortic stenosis?
Systolic - the high ejection velocity of blood through the stenotic valve as the ventricle contracts
What will happen to the left ventricular muscle mass in aortic stenosis? What does this do to the axis deviation?
it will hypertrophy, causing a left axis deviation
What’s increasing in aortic stenosis - ventricular preload or afterload
afterload, reducing cardiac output
What happens to the pressure differenc eacross the mitral valve during diastole?
under normal conditions it shouldn’t be more than a few mmHg, but in mitral stenosis it will be
What happens to left atrial pressure in mitral stenosis?
increases because the blood can’t get out into the ventricle as well
What sort of murmur will you hear with mitral
diastolic murmur
Where will muscle hypertrophy take place with mitral stenosis?
left atrial
Why do you get pulmonary edema with mitral stenosis?
because you have increased pressure in the left atrium, you also get a back up of increased presure in the pulmonary capillary beds. THis leads to increased pulmonary edema
What will you see different about the aortic pressure with aortic insufficiency?
blood reguritates back into the left ventricle during diastole, so aortic pressure falls faster and farther than normal duing diastole - body’s taking more blood than the aorta can give
Does aortic insufficiency therefore lead to a low diastolic pressure or a low systolic pressure?
low diastolic
Is the pulse pressure increased or decreased in aortic insufficiency?
the same but diastolic pressure decreases, so you have an increased pulse pressure
What happens to ventricular EDV and EDP in aortic insufficiency?
they are higher then normal because extra blood reenters the chamber
WHat sor tof murmur will you hear with aortic insufficiency?
blood flows back in a turbulent fashion during diastole, so you’ll hear a diastolic murmur
If you hear both a systolic and diastolic murmur, what’s likely wrong with the aortic valve?
it’s common to have stenosis and insuffieicnecy of the aortic valve at the same time
What will you see in left atrial pressure with mitral regurgitation?
THe mitral leaflets don’t seal, soyou get blood regurgitating back intot he left atrium during systole
this means the left atrial pressure will be abnormally high
What happen to left ventricular EDV and EDP?
they both increase ?
What sort of murmur will you hear with mitral regurgitation?
systolic (since blood regurgitates during during systole)
Why do you get pulmonary effects with mitral regurgitation?
because pressure in the left atria is high, you’ll get back up into the pulmonary capillary beds with edema and SOB
What is the most common form of mitral regurgitation?
mitral valve prolapse (evert into the left artium during systole)
What lead is the most helpful on EKG to diagnost cardiac problems?
lead II
What happens in supraventricular tachycardia (paroxysmal atrial tachycardia)?
the atria abnormally excite and drive ventricles at a rapid rate - begin and end abruptly
What will you see on EKG with supraventricular tachycardia?
the QRS is normal but frequent and the P and T wave may be superimposed because of the high heart rate
What will blood pressure look like in supraventricular tachycardia?
low because the ventricles don’t have enough time to fil appropriately and you get a decrease in CO.
What happens in a first degree conduction block?
unusually slow conduction - you’ll see an abnormally long PT interval, but the EKG is otherwise normal
What happens in a second degree conduction block?
Some, but not all atrial impulses transmit through the AV node due to slower than normal conduciton
You’ll see seom but not all P waves accompanies by QRST
What happens in third degree block?
no impulses are transmitted through the AV node so the pacemaker defaults to His and atrial and ventricular rates become independent. so the P wave s and the QRS are totally dissociated. the ventricular rate will be slower than normal because of the different pacemaker
What happens in atrial fibrillation?
repolarization happening trandomly through the atria, so it’s a complete loss of the normally close synchrony of excitation and resting phases between individual atrial cells
What does the EKG look like in atrial fibrillation?
no P waves will appear in the EKG and the ventricular ratewill be irregular
Is atrial fibrillation immediately lethal?
No - atrial contraction plays very little role in ventricular filling so it can be well tolerated as long as the ventricular rate is sufficient to maintain CO
Bundle branch blocks are also called what?
hemiblocks
What is the often cause of bundle branch blocks?
myocardial infarction
What will you see on EKG with a bundle branch block?
widening of the QRS because ventricular depolarization is less synchronous on the side of the block
What happens in premature ventriculr contractions?
you have action potentials initiated and propagated away from an ectopic focus in a ventricle, causing earrly ventricular depolarization
What will yo see on EKG with PVCs?
large amplitude, long duration QRS deflection on EKG (shapes are variable depending on where the ectopic site of origin is)
Why do PVCs often have a missing beat afterwards?
because the ventricular cells are still refractory at the next normal SA impulse, so you don’t get the contraction
What happens in ventricular tachycardia?
tthe ventricles are driven at high rates, usually by a ventricular ectopic focus
What does V tach often precede?
V fib
What causes a prolonged QT?
delayed ventricular myocyte repolarization - maybe due to inappropriate opening of Na+ channels or prolonged closure of K+ channels during phase 2
Long QT is defined as what percentage of cardiac cycle duration?
over 50%
What type of V-tac occurs in associateion with prolonged QT?
torsades de pointes
What happens in ventricular fibrillation?
various areas of the ventricle are excited and contract asynchronously (similar to a-fib)
What do you see on EKG in ventricular fibrillation?
no discernable waves, rate or rhythm
Ventricles are particularly susceptible to fibrillation when premature excitation aoccurs at the end of what wave?
the T wave
Why is V-fib fatal?
no pumping action occurs so the body doesn’t get perfused
