What is the base of the heart?
where the right ventricle meets the pulmonary artery
-at the R and L 2nd interspaces
what is the apex of the heart?
the tapered tip of the left ventricle
posterior to the RV
what is the apical impulse?
also called PMI (point of maximal impulse)
found at 5th interspace lateral to the midsternal line
where is the inferior border of the heart?
below the junction of the sternum and the xiphoid process
what is the PMI over the left ventricle?
it is more muscular and produces more pressure
what is the posterior border of the heart?
the border of the left atrium
systole
ventricular contraction
diastole
ventricular relaxation
atrial systole
atrial contraction
atrial diastole
atrial relaxaion
what is S1?
mitral and tricuspid valve closing
-you mostly hear mitral
should valve make a noise when it opens?
no!
what is S2?
aortic and pulmonic valve closing
-you mostly hear the aortic valve
what happens during systole?
ventricles start to contract AV valves close = S1 semilunar valves open (can't hear) atrial relaxation and filling ventricular pressure falls (blood is leaving) semilunar valves close = S2
what happens during diastole?
semilunar valves close = S2 AV valves open ventricular relaxation and filling atrial contraction AV valves close = S1
what is cardiac output?
amount of blood ejected from each ventricle in 1 minute
CO = HR x SV
what is stroke volume?
amount of blood ejected with each heartbeat
-tested by the echocardiogram (gives a percentage of blood that comes out with each beat)
what is the average CO?
60-80 mL
what happens when CO falls?
body is not getting appropriately oxygenated
preload
load that stretches the cardiac muscle prior to contraction
-the volume of blood in the R/L ventricle at the end of diastole (how much blood is in this space before it contracts)
afterload
vascular resistance against which the ventricle must contract
-resistance to which preload has to go against
what causes increased afterload?
HTN (vasoconstriction), atherosclerosis, aortic stenosis
-heart has to work harder to pump against small pipes
myocardial contractility
ability of the cardiac muscle when given a load to shorten
when does myocardial contractility increase?
sympathetic stimulation
when does myocardial contractility decrease?
decreased oxygen delivery to myocardium
sinoatrial node (SA node)
“pacemaker” sets up how fast the heart is going to beat
60-100 pulses per minute
atrioventricular node (AV node)
delayed briefly
40-60 pulses per minute
Bundle of His (AV Bundle)
interventricular bundle
20-40 bpm
(has a R and L branch)
what is the P wave
atrial depolarization (atrial contraction)
what is the QRS wave?
ventricular depolarization (ventrical contraction)
what is the T wave?
ventricular repolarization (ventricular relaxation)
what is the most important thing when you are dealing with CV complaint?
history
