ET&P EKG

what is the normal pacemaker of the heart? where is it located?

the sinoatrial node

right atrium

where does depolarization spread from?

the SA node across atria and results in the P-wave

how many tracts within the atria conduct depolarization to atrioventicular node (AV)? where does conduction slow?

3

→ slows in the AV node to allow atria to empty blood into ventricles before ventricular systole

what connect the AV to the bundle branches?

Bundle of His

what are the Purkinje Fibers?

terminal bundle branches

what place on the EKG shows if someone had a heart attack?

ST segment

knowt how to label the EKG

slide r of ECG sldies

mV number that is instantly ahcieved upon depolarization

+30mV

what kinds of things can effect electrical reading tests?

• skin prep

• body composition

• placement of nodes

know this

Phase 0	Rapid Depolarization	Rapid Inflow of Na+
Phase 1	Initial Repolarization	Rapid Outflow of K+
Phase 2	Plateau State	Inward flow of Ca2+
Phase 3	Final Rapid Repolarization	Inward flow of Ca stops Outward flow of K+ accelerated
Phase 4	Resting or Polarized State	Na+/K+ pump Return to Normal

what is the normal mV threshold at beore depolarization?

-90mV

refractory periods; def and types

Ionic composition during different phases (allow differing RXN’s to stimuli)nothing can happen!/reset

• Absolute refractory period- cells cannot respond to stimuli Phase 0,1,2 and ½ of 3
  

• Relative Refractory Period- Repolarization is almost complete, a strong depolarization could occur second half of phase 3-close but may wait
  

• Non-Refractory Period- Cells are in resting polarized state Phase 4

rate (R-R) represents:

between Rs (ex.beats per min)

looking at P-waves (PR interval length)

are they equal?

QRS complex (length of complex)

how high

how does fat % increase effect R?

makes it short

what to look for in EKGs

•Rate (R-R)

•Are there P-Waves (PR interval Length)

•QRS Complex (Length of Complex)

•T-Wave (QT Interval)

•Little boxes and big boxes

•ECG stripes are 6 seconds in length

•In 12-lead look at transition

know what normal sinus rhythym looks like

PVC-pre ventricular contraction- throws a QRS waves

multifocal PVC- (signals) originates in a different spot

look at A-FIB

sinus tachycardia

trial flutter- lots of P, not many QRS (travel in a loop). AV =more disorganized and faster (is worse)

trigeminy (PVC occurs every third beat). rare. has QRS

ventricular flutter(some QRS)

V-fib ventricular fibrillation-not quite as bad

sinus bradycardia

VT-ventricular tachycardia- no pwaves, all QRS

• first degree block

• AKA first degree AV block

• AV- ventricles delayed

• prolonged PR interval

• more p than QRS

bigeminy (can be atrial or ventricular) every other beat extra contraction 9PVC or 9PAC)

second degree block (AV-ventricles is intermittently blocked

SVT- supraventricular tachycardia. impulse originates is above ventricular

mild ST depression (lead II)partial or tempoary blockage needs immediate help

3rd degree AV block

absense of any conduction between atria andventricles

ST elevation- worst case tissue dealth from MI- (lead I and AVL and V2)