Block 7: Cardiology (Week 1.1)

Front 1

after premature heart beat, is the next beat stronger or weaker? what is this due to?

Back 1

stronger; due to both better filling and contractility

Front 2

tell me about the right ventricle

Back 2

thin outer wall & septum; during contraction, the wall moves toward the interventricular septum with a bellowslike action and shortens toward the apex.

Front 3

tell me about what happens with the PMI

Back 3

base and apex move toward each other with the systolic descent of base more important. there's also an anterior swing of the apex, which causes the actual beat of the heart on the chest wall (which you can feel)

Front 4

name the 3 key determinants of cardiac fxn:

Back 4

preload, afterload, contractility (these are all determinants of myocardial fiber shortening)

Front 5

define preload.
what does Starling's law say about preload in relation to cardiac performance?

Back 5

preload = the blood volume in ventrice at end-diastole

important in starling's law: increase preload, increase cardiac performance (CO and SV) because of the increased amount of stretching in the cardiac muscle

Front 6

what are the main determinants of preload? (4)

Back 6

1) intravascular volume (hypovolemia or hypervolemia)
2) venous return (how much blood returns to the heart)
3) atrial contraction (ie. atrial kick)
4) pericardial fxn (increase in intra-pericardial pressure due to accumulation of fluid in pericardial space, decrease preload, decrease CO/SV)

Front 7

define afterload

Back 7

tension/force acting on ventricular fibers after onset of contraction; influenced by BP (anything the blood has to beat to get out of the heart)

Front 8

name two things that can cause INCREASED afterload

Back 8

hypertension (high BP)
aortic stenosis

Front 9

name 2 examples of things that causing DECREASED afterload

Back 9

mitral regurgitation
ventricular septal defect

Front 10

T or F. after mitral regurgitation repair, cardiac performance generally goes up.

Back 10

F. due too afterload rising after MR repair, cardiac performance usually goes down. REMEMBER THAT LOWER AFTERLOAD IN MR INCREASES EF NOT CONTRACTILITY!!

Front 11

what is wall stress?
how does wall stress affect cardiac performance?

Back 11

-generated by contractile event which causes pressure in cavity to rise...determines extent and velocity of fiber shortening according to force-velocity relation
-adversely, just like afterload

Front 12

how does wall stress affect oxygen consumption?

Back 12

higher wall stress increases oxygen consumption (so clinical goal = decrease wall stress)

Front 13

what are 3 determinants of wall stress?

Back 13

wall stress = pressure x radius of cavity / 2(wall thickness)

(laPlace's law)

Front 14

pressure overload = ________ hypertrophy; give examples

volume overload = ________ hypertrophy; give examples

Back 14

concentric (hypertension; aortic stenosis); eccentric (mitral valve regurgitation or other leaky valves)

Front 15

describe the ventricle size and wall thickness changes in both eccentric and concentric hypertrophy

Back 15

eccentric = dilated ventricles, thin walls (think water filling up balloons)

concentric = normal ventricles, thick walls

Front 16

explain the 2 components of post-extrasystolic potentiation (where contraction after a pause that follows premature beat is more forceful than normal)

Back 16

greater contractility
greater preload

Front 17

name the 4 controls of contractility

Back 17

- sympathetic nervous system (ie. norepi)
- circulating catecholamines (ie. epi)
- exogenous substances (ie. caffeine)
- diseases affecting myocardium

Front 18

name the four phases of diastole

Back 18

IVR - RAPID EARLY FILLING OF LV - SLOW LV FILLING - ATRIAL KICK

Front 19

contrast contractility vs. cardiac performance

Back 19

contractility = abstract, load- independent

cardiac performance = load dependent, measureable at bedside

Front 20

name the 3 positive waves of atrial waveform

name the 2 negative waves of atrial waveform

Back 20

a,c,v waves

x,y descents

Front 21

name the 3 measures of cardiac performance

Back 21

stroke volume (end diastolic volume - end systolic volume), cardiac output (SV x HR), ejection fraction (ratio of SV to end-diastolic volume)

Front 22

vascular resistance is ratio of what over what?

Back 22

pressure over flow

Front 23

1) diastolic pressure is HIGHER/LOWER in PA than in RV
2) in diastole, pressuree is EQUAL/NOT EQUAL in RV and RA (or LV and LA)
3)RV systolic pressure is EQUAL/NOT EQUAL to PA systolic pressure

Back 23

higher; equal; equal

Front 24

in atrial pressure waveform:
v =
y =
a =
c =
x =

Back 24

v wave = atrial fully filled and ready to be ejected (also point of MV opening)
y descent = rapid early filling of ventricle, early atrial emptying as mitral valve opens
A = atrial kick (last portion of ventricular filling)
C = MV closing
x = atrial relaxation

Front 25

what is the normal left ventricular ejection fraction? what will happen to the EF in a pt with leaky valves?

Back 25

above 50%; pt with leaky valves will have lower EF

Front 26

how do you account for differences in body size when measuring cardiac output?

Back 26

have to use cardiac index (CO/body surface area)

Front 27

2 ways to measure cardiac output are...

Back 27

thermodilution method using Swan Ganz catheter

doppler echocardiography (method of obtaining blood flow velocity)

Front 28

how does one assess LA pressure reliably?

Back 28

insertion of Swan Ganz catheter into a branch of the pulmonic artery

Front 29

define regional ventricular fxn

Back 29

the extent of myocardial thickening and wall motion of various myocardial segments (can be measured by echo, radionuclide angiography, cardiac catheterization)

wall motion can be described as normal, hypokinetic (less than normal)to , akinetic (no motion), dyskinetic (reverse motion)

Front 30

why doo we measure ventricular response to stress (isotonic exercise - walking on a treadmill, isometric exercise - handgrip, pharmacological agents)?

what is the hallmark of regional myocardial ischemia?

Back 30

assess overall ventricualr reserve and determine fxnal sign of coronary stenosis in pts with CAD

THE DEVELOPMENT OF NEW SEGMENTAL WALL MOTION ABNORMALITIES DURING ANY STRESS IS HALLMARK OF REGIONAL MYOCARDIAL ISCHEMIA

Front 31

4 main hemodynamic measurements of cardiac fxn

Back 31

ventricular volume
ejection fraction
cardiac output
vascular resistance