heart and EKG

flow of blood into the heart

• deoxygenated blood goes into right atrium

  • from superior vena cava (upper body), inferior vena cava (lower body), coronary sinus (myocardium)

• right ventricle pumps that blood to pulmonary trunk artery

  • splits left and right to carry deoxygenated blood to lungs

• oxygenated blood comes from pulmonary veins into left atrium

  • left and right ones

• left atrium pumps oxygenated blood to aorta then all other branching arteries

flow of electrical conduction in the heart

1. SA node

2. AV node

3. Atrioventricular bundle

4. Purkinje fibers

Sinoatrial node

• mass of tissue in upper right atrium wall

• initiates heartbeat and pacemaker

atrioventricular node

tissue mass at bottom of atrial septum

atriventricular bundle

• Specialized cells in the top of interventricular septum

• Fibers travel down sides of septum in bundle branches

purkinje fibers

• Specialized cells for conduction

• Part of bundle branches

• Travel throughout myocardium of ventricles

EKG electrode V1 placement

right of sternum at 4th intercostal space

EKG electrode V2 placement

left of sternum at 4th intercostal space

EKG electrode V3 placement

on 5th rib, between V2 and V4

EKG electrode V4 placement

5th intercostal space at mid clavicular line, placed after V2

EKG electrode V5 placement

On 6th rib at the same level as V6, in middle of V4 and v6, placed after V6

EKG electrode V6 placement

at left mid axillary line, near arm pit, kind of same level as V4

RA wire color

white

LA wire color

black

LL wire color

red

RL wire color

green

V1 color

red

V2 color

yellow

V3 color

green

V4 color

blue

V5 color

orange

V6 color

purple

order of waves on EKG

P wave, QRS interval, T wave

P wave facts

• shows depolarization of atria

• atrial contraction

QRS interval facts

• shows ventricular depolarization —> contraction

• also when atria relax and repolarize

T wave

• when ventricles repolarize —> relax

somatic tremor

artifact caused by shivering muscle movement —> parkinsons, cold, anxious

looks like irregular spikes

interrupted baseline

artifacts caused by loose or dry electrodes, oily skin, disconnected wires, movement

looks like EKG then stops and another line starts from bottom

wandering baseline

artifact caused by patient movement, bad skin prep, bad lead attachment

looks like ekg not staying in the middle

AC interference or 60 cycle interference

artifact caused by electrical activity nearby EKG

looks like normal EKG but very thickened line

atrial rhythm

abnormality where rhythm comes from atria and not SA node

abnormal or missing P waves on EKG

atrial flutter

• area of atrial tissue fires faster than ventricle rate

• looks like mini waves before QRS but at regular intervals

atrial fibrillation

• disorganized firing in multiple sites of atrial tissue

• little waves between QRS complex and irregular distance between QRS complexes

Premature atrial or ventricular contractions

Atria or ventricles stimulated to contract earlier than they should

not a flat line between T and P waves

abnormal if it happens more than 6 times a minute

ventricular tachycardia

• emergency abnormality caused by single area of ventricles firing outside normal pathway

  • Patients usually do not have a pulse

• shows wide and irregular looking QRS complexes

• report immediately

ventricular fibrillation

• emergency abnormality where ventricles twitch or quiver and don’t pump blood to body

  • No pulse and unconcious within seconds

• looks like little irregular waves