Electrocardiogram Flashcards
atrial depolarization-> atrium contracts
Pwave
interval AV nodal delay
allows last 20% of blood
P-R interval
isovulmetric contraction
R wave
where do impulses go once released from AV node
down bundle of his into purkinjie fibers
what is a moderator band
right bundle of his in septomarginal recess of right ventricle
describe the purkinjie system in the ventricle
150 times faster than AV node in heart due to increased intercalated discs and gap junctions
ventricular depolarization-> ventricle contracts
QRS
stroke volume 70 ml
1st downward deflection
Qwave
where is atrial depolarization hidden
under the QRS complex
what prevents the AV valves from blowing back from ventricular contraction
chordae tindinae + papillary muscles
ventricular repolarization
Twave
repolarization of papillary muscle
u wave
isovolumetric relaxation
S-T segment
how many ml of blood in ventricles during isovolumetric relaxation
50 ml
what does an inverted T-wave or an altered ST-segment indicate
myocardial infarction
acute heart failure
what prevents the heart from tetany
slow calcium channels
what are slow calcium channels aka
long absolute refractory period
plateaus
(impossible to fire heart again)
what is auto rhythmicity aka
automatic conductivity
how can the heart beat on its own
due to leaky sodium channels
how many beats can the SA node keep the heart at
45 bpm
what speed up the ehart
sympathetics
what slows down the heart
parasympthetics
hwat is a primary heart block (bundle branch blood)
elongation of PR interval
what is a secondary heart block
winkebocks phenomena
elongation of PR till 2 atria depolarization show up
what is a complete heart block
no pattern to the EKG, random EKG
what sit eh first heart sound
AV valves closed during isometric contraction
what is the second heart sound
semilunars closed
what is the 3rd heart sound
ventricular gallop in CHF
what is the 4th heart sound
similar to 3rd=heard in diastole atrial gallop (CHF)
what occurs in the heart during diastole
arms and prts
Aortic Regurgitation and Mitral Stenosis
Pulmonic Regurgitation and Tricuspid Stenosis
what is diastole
relaxation
what is systole
contraction
when does end diastolic filling time occur
before systole
what is the purpose of an echocardiogram
detect murmurs
