EKG NHA Certification Exam

Lead 1

records impulses between left and right arms

Lead 2

records impusles between right arm and left leg

Lead 3

records impulses between left arm and left leg

AVL

left leg and right arm assist with left arm tracing

AVR

left arm and left le with right arm tracing

AVF

right and left arms assist with left leg tracing

V1

fourth intercostal space right sternum (red)

V2

fourth ICS, left of sternum, directly across from V1 (yellow)

V3

Midway between V2-V4

V4

5th intercostal space midclavicular line

V5

Midway between V4-V6

V6

5th intercostal space midaxillary line

Augmented leads

Consider unipolar because of a single electrode in combination with limb leads.They record the electrical activity along the frontal plane of the heart.

Bipolar Leads:

have two poles. One positive and one negative.

AC Interference

small uniform spikes caused by electricity radiated from other machines. Common sources: improper grounding, lead wires crossed, corroded or dirty electrodes

Wandering baseline

usually cause by improper electrode application

Somatic Tremors

Large spikes caused by muscle movement

Broken recording

corroded lead wires, damaged or faulty wires

P wave

atrial depolarization, SA Node fires, Atrium contracts, P is a positive deflection

PR Interval

time it takes for SA impulse to travel across atrium

QRS Complex

Ventricular depolarization

J Point

exact point where ventricular repolarization starts

T wave

ventricular repolarization

U wave

not always visible, repolarization of Bundle of HIS

PP Interval

measures atrial rate

RR Interval

measures ventricular rate

QT Interval

one ventricular cycle, depolarization to repolarization

PR Segment

end of atrial contraction to beginning of ventricular contraction

ST Segment

end of ventricular depolarization to the beginning of ventricular repolarization

Sinus Rhythm

normal rhythm with all components

Sinus Bradycardia

slow normal rhythm with all components

Sinus Tachycardia

fast normal rhythm with all components

Sinus Dysrhythmia

slight irregularity usually related to breathing

Sinus Arrest

break in normal components

Atrial Fibrillation

atria quiver, no organized contraction, multiple P waves, irrregular

Atrial flutter

atria contracts faster then ventricles, multiple P waves, sawtooth appearance

Junctional rhythms

SA Node is not working, AV Node generates impulse, P wave is negative

Premature Junctional beat

early impulse before the next expected beat

Junctional Escape

Heartbeat is escaping the SA Node, usually no wave P wave, rate less than 60

Accelerated Junctional

same as escape, rate 60-100

Junctional tachycardia

same as escape, rate 100-150

Premature Ventricular Contraction (PVC)

ventricles contract outside of the normal sequence

Ventricular Tachycardia

3 or more PVCs, poor cardiac output

Ventricular Fibrillation

ventricles are quivering, no cardiac output

3rd Degree Heart Blocks

complete heart block

Idioventricular

ventricles are pacing heart, all other fail, SA and AV node stop working

Bundle Branch Block

impulse cannot make it down one of the branches, wide QRS

First Degree Block

delay between SA node to the AV node, all components are present, prolonged PR interval

Second Degree Block Type 1

P waves prolonged until dropped

Second Degree Block Type 2

P wave present and then drops a QRS

Third Degree block

complete heart block

Ischemia

persisted decrease in O2 to myocardium, tissue is dying, st segments is depressed

S (SALLI)

Septum: V1 and V2

A (SALLI)

Anterior wall: V3 and V4

L (1) (SALLI)

Lateral wall:V5 and V6

L (2) (SALLI)

Lateral High: Lead 1 and aVL

I (SALLI)

Inferior wall: Lead 2, 3, aVF, and V4 if used