Clin Med- Cardiac 1

kelseyfmeyer's version from 2015-11-30 13:52


Question Answer
congestive heart failure (CHF) is what kinda disease?TRICK QUESTION: it is not a disease!!!! It is the END PRODUCT of just about every cardiac dz ever
Do NOT confuse an action potential with an ECG. look at slide 3 for a action potentialresting-->depolarizing (rapid influx of Na)-->repolarizing phase (rapid efflux of K)--> undershoot--> resting state
look at slide 4 for a CARDIAC action potential (NOT THE SAME AS AN ACTION POTENTIONAL)start with resting phase 4, rapid depol with Na is 0, 1 is the little hook where it goes up and then goes down slightly to flatten out, the flattened plateau is 2, the slightly more gradual decline is 3, back to 4 where it's resting
what allows the cardiac action potential to have a plateau?Ca++!!!
which cells are pacemakers in the heart?ALL CELLS have inherent pacemaker potential
how is it physiologically possible that a cell can work like a pacemaker?they have leaky Ca and K channels
explain the difference between the absolute and relative refractory periodin the absolute period, the Na channels are closed tight, and no matter how big the signal, they will not open to create another action potential. In the relative refractory period, however, a stimulus which is BIG enough will overcome the closed Na+ gates to cause an action potential
how does the sympathetic nervous system affect the heart?It can INC things, of course. BUT, it can also turn things down-- it all depends ON WHICH RECEPTOR the sympathetic system acts on (so symp will turn things on with B1, but turn them down with B2)
what factors is cardiac output composed of?CO= SVxHR (stroke volume times heart rate)
how does L heart CO compare to R heart CO?THEY ARE EQUAL! (L might be more distance but the lungs are a TON of space)
what factors is MAP (mean arterial pressure) composed of?CO x SVR (cardiac output times systemic vascular resistance)
explain starlings lawfluid movement= a constant([capillary hydrostatic pressure - interstitial hydrostatic pressure] - [capillary oncotic pressure-interstitial oncotic pressure])
what is preload?the amount of blood coming back to the heart! Think of it as a volume- so an inc in preload to the heart is an inc in volume returning to the heart
what is afterload?the pressure the heart has to overcome to get blood out of the heart.
(way to think of things) what are you trying to change by giving furosemide to a CHF patient?pee out fluid volume---> dec preload!
(way to think of things) analylpril (ace inhibitor) is given to CHF patient to change what?vasodilator--> dec BP---dec PRESSURE/work blood has to do to get blood out of heart--> dec afterload
************what is the #1 priority of the heart?Maintain normal systemic arterial pressure!! it will kill itself trying to do this
**explain the priorities of the heart, in the order of if cares the most to cares the least(1) MAINTAIN NORMAL SYSTEMIC ARTERIAL PRESSURE!!!!!! (2) Maintain normal tissue blood flow (3) Maintain normal systemic and pulmonary capillary pressures
(example of how the heart always keeping normal systemic arterial pressure can be a bad thing) pathogenesis of mitral valve insufficiencyThe blood is going backwards through the mitral valve and not getting pushed out, which is INC the PRELOAD (volume) of the L heart. Also, that blood is not getting to the aorta, so there is a dec in CO. They kidney senses this and turns on compensatory mechanisms. The body starts to retain Na+Cl and water. This increases the BP. An inc in BP increases the preload of the right heart, which follows through that the preload of the L heart will be inc also...again. This inc the work the heart has to do more. And the blood is still flowing backwards!
what is the Frank-Starling Mechanism?The ability of the heart to change its force of contraction, and therefore stroke volume, in response to changes in venous return (inc volume--stretch receptors in heart stretched--tell heart to contract harder)
Frank-Starling Mechanism--> check out pic on slide 10!notice how there is the control loop, and how an inc in venous return will lead to inc stroke volume. UNDERSTAND this chart!
inc venous return is basically what happening? what happens, how does the heart compensate, and what is this called?ie, the PRELOAD (end diastolic volume and pressure) INCREASE. but the end systolic volume is the same. This means the heart increases the FORCE OF CONTRACTION, and therefore the STROKE VOLUME to compensate. This is the Frank-Starling Mechanism
explain diagram on slide 10 (Frank-starling mechanism)(remember this means if preload inc, contractility inc to up the stroke volume to compensate) as the left vent fills, the volume inc and the pressure inc a little. Then the valve closes, and there is an inc in pressure (contraction) but no inc in volume. Then the pressure in the LV overcomes the pressure in the aorta, and the aortic valve opens. Then there is a dec in volume in the LV, until the aortic pressure is higher than in the LV, and the aortic valve closes-- this causes a dec in the pressure in the LV with no volume change. This is the blue cycle. In the green, there is more volume entering the LV (preload) but in a healty heart, the heart is just able to contract harder to overcome the aortic valve and still get the blood out
check out graph on slide 11 about frank-starling mechanismsee how that in heart failure, the heart can only be contractile enough for being at rest-- which is why THE FIRST SIGN OF PROBLEMS is often exercise intolerance. Then, in cardiogenic shock, the heart isnt even able to contract enough to meet demands at rest.
WHAT IS USUALLY THE FIRST SIGN OF CARDIAC DZ TO OWNERS? why is this?usually exercise intolerance. The Frank-starling mechanism explains this (see slide 11) because a failing heart cannot compensate by contracting more for an increased volume (if the animal can't even handle resting, it is in cardiogenic shock)
4 types of heart dzs/failuresvolume overload, pressure overload, pump failure, electrical abnormalities
clinical signs of heart dz that owners notice...Syncope (fainting- NOTE: owners might think this is a seizure), exercise intolerance, cough, dyspnea, abdominal distension, cyanosis
clinical signs of heart dz that VETS notice...Pulse abnormalities, murmurs, Arrhythmias, jugular pulses
bad heart are _________BIG
bad hearts usually like to fail in which direction?backwards! so L heart backs into lungs and R heart backs into abdomen/liver
(if you are asking your owner a history about a suspected heart dz, why might you ask about if theyve been to texas?)parasite: trypanosoma (kissing bugs- aka reduvid bugs). end stage trypansoma will look like dilated cardiomyopathy
Signs of Congestive Heart Failure (CHF) are usually...backwards failure!! so respiratory signs, ascites.
Signs of low cardiac output are usually... (what'e the onset like?)usually late onset. This is a FORWARD failure (usually see backwards fail before forward so this is unique) and you will see Exercise intolerance, syncope, pre-renal azotemia, cyanosis
what are 5 major clinical signs you see in CHF?(1) Pulmonary Edema (Canine/Feline Left sided backwards heart failure) (2) Pleural effusion in cats (L OR R sided heart failure) (3) Hepatic congestion/Ascites (Right Sided backwards heart failure) (4) Jugular vein distension (5) Cachexia (only two times you lose weight super fast like this is in cancer or cardiac probs)
whats the difference between pulmonary edema and pulmonary effusions, and who usually gets what?EDEMA= water in lungs (cats or dogs). EFFUSION= water in chest outside of lungs, CATS ONLY.
pulmonary edema in CHF usually occurs from what dz/prob? (who?)Left sided backwards heart failure (dogs and cats)
plural effusion in CHF usually occurs form what dz/prob? (who?)Either left or right sided heart failure, IN CATS ONLY
Hepatic congestion/Ascites in CHF usually occurs from what dz/problem?Right Sided backwards heart failure
Arrhythmias can be due to what kinda things?(1) Structural or pathophysiologic remodeling (like Conduction abnormalities, Automaticity errors) (2) genetic factors (3) environmental stresses (4) ischemia (5) can be modulated by neuroendocrine factors (like epi and norepi)
how does a dog with heart problems appear?Anxious, Open mouth breathing, Orthopneaand elbows abducted, Tachypnea—short and shallow OR Hyperpnea—increased depth
explain Tachypnea vs Hyperpnea, and when you see theseTACHY= short and shallow, usually associated with pulmonary edema. HYPER=increased DEPTH, usually associated with hypoxia, hypercarbia
if a dog comes in presenting with syncope, what should you prolly do first?figure out if it's actually syncope and not a seizure, and vice versa
what clinical signs ARE usually seen with syncope?Fainting, Exertion or excitement, Rear limb weakness, Sudden collapse, Lateral recumbency, Stiffening of the forelimbs and opisthotonos, Micturition, Vocalization, Hypoxia
what clinical signs are NOT usually seen with syncope?Tonic/clonic motion, Facial fits, Defecation, Aura (signs dog might have a sz before it happens), Post-ictal dementia(ictus is a seizure), Neurologic deficits
GOLD STANDARD for working up a heart?MR(I)
pulmonary edema would look like what on a rad?air bronchogram
a dog comes in and is a walking, talking, breathing pure example of a heart problem. first test?RADS BEFORE ECHO. ALWAYS.
4 reasons for why an animal might be coughing?(1) CHF (2) Mainstem bronchi compression (3) Pneumonitis and vascular disease 2°to HWD (4) Non cardiac diseases (airway dz, Parenchymal disease, pleural space dz)
what's a "cowboy sign" and when do you see it?(VD view) the left atrium is pushing the bronchi up and apart, the bronchi look like they are straddling the L atrium. Means enlarged L atrium
why would you always palpate the chest, esp the precordium?(precordium= portion of the body over the heart and lower chest) this is where you might feel a palpable thrill
why on earth would you want to palpate the thyroid?CATS!! hyperthyroidism can cause cardiac issues
if you are examining for Arterial pulse abnormalities, what should you be checking?check Pulse pressure differences in conjunction with ascultation.
why would you want to do an eye exam if you suspected heart problems?BP problems might lead to Hemorrhage and detachment of retina
what is the equation for pulse pressure? why is it good to know this?systolic pressure vs diastolic pressure (my notes say: palpate pulses on dog... there are bounding pulses. pulse pressure is diff between systolic and diastolic. so if sthign that drops diastolic AND inc systolic--> get bounding)
what is the jugular pulsing (general/not specific causes)?INC VENOUS PRESSURE (however, the jug isnt pulsing, its just full and bouncing off of the carotid underneath)
why might you see a jugular pulse?It is due to Increased venous pressures, which can be from (1) Right sided failure (Tricuspid disease, Pulmonary hypertension, Caval syndrome) (2) Pericardial disease (3) Volume overload (4) Cranial mediastinal mass
whats Caval syndrome and what might you see as symptoms of it?worms stop living in pulmonary artery and start living in the heart (bc so many worms). see jugular pulses from inc venous pressure
why do you see R heart signs (like jugular pulses) in Pericardial disease?why signs of R heart failure--- bc R heart smaller and wimpier (so opens up/collapses first)
what kinda mass can cause jugular pulse?Cranial mediastinal mass (in the way so incoming blood to the heart starts backing up)
where do you ascult what valves etc for ascultation?PAM-T. 3-4-5--3/4
which side of the body do you hear a PDA on? why?LEFT side, because the pulmonic valve is assculted on the left and in PDA the aorta has blood backflowing into pulmonic arteries which pushes against the pulmonic valve
which side of the body do you hear a VSD on? why?RIGHT side, because the L ventricle has higher pressure than the right, so the blood is pushed into the R ventricle and hits the R wall, so that's where you hear the turbulence
check out the wigger diagram on slide 26understand the timing of things-- the S1/QRS comes just before the actual inc in LV pressure (contraction)
what's a holosystolic murmur aka? what does it mean?aka plateau. Lasts for entirely of systole and doesnt get quieter (regurgiant or plateau)
(corrigan pro tip) how can you help yourself get better and spot murmurs?mutter lub-dub to yourself repeatedly in rhythem before you even put a steth on the animal
what a creshendo-decreshendo murmur, and what does it mean?gets louder and then quieter during systole. (ejection)
4 types of murmurs?holosystolic, creshendo-decreshendo, diastolic decreshendo, continuous (machinery)
****how would you describe a grade 1 murmur?Very soft, intermittent (like only an expert can hear it)
****how would you describe a grade 2 murmur?Soft murmur, can hear consistently in a quiet room
****how would you describe a grade 3 murmur?Moderate intensity murmur (*if you hear a murmur when you just put the stethoscope on the dog, its a three. IF you can hear it on the other side, it's a 4)
****how would you describe a grade 4 murmur?Loud murmur (if you can hear it on L and R sides
****how would you describe a grade 5 murmur?Loud murmur with a precordial thrill (you can FEEL it!! little tickles on your fingers-- not feeling the beat, but the turbulence)
****how would you describe a grade 6 murmur?Very loud murmur, can hear with stethoscope off of the body wall (if you can remove the steth and still hear it, it's a 6)
if you find out the dog has an anemia, and you can hear a mild murmur, what are you thinking it MIGHT be?anemia can cause physiological murmur bc the blood is thinner and it sloshes more
endocardiosis vs endocarditis?endocardiosis= degenerative valve dz....endocarditis= valve infxn
If you detect a murmur, what is the first thing you wanna do diagnostically?CHEST RADS. ALWAYS FIRST.
when is the only time you don't do chest rads first?arrythmia- do ECG first