ekg class

1500 method

• This method is the most precise, and the best method to use with fast rhythms.

• The rhythm must be regular to use this method.

• Count the small squares between qrs complex and take that number and 1500/# of small boxes

Sequence method

• not as accurate

• quick calculation

• heart rate is regular

• qrs complex starts on solid line, count big boxes

• 300/ number of big boxes

6 second method

irregular rhythm

3 black lines, 30 big boxes

qrs complex *10

maxium heart rate

220 - patients age

target heart rate

maximum heart rate * percentage to limit the rate = target

P wave

atrial depolarization

when SA node fires

positively deflected

QRS complex

ventricular depolarization

end of PR interval to the end of the J point

0.04 to 0.10 seconds

J point

where ventricular depolarization stops and ventricular repolarization starts

myocardial ischemia

• J point elevate/ depress

T wave

ventricular repolarization

should be uniform

U wave

not always visible

repolarization of the Bundle of his and Purkinje fibers

PR interval

• time it takes for the SA node to fire, atria to depolarize and electrivity to travel through the AV node

• beginning of P wave to beginning of Q wave

• 0.12-0.20 seconds

RR interval

amount of time between atrial depolarization cycles

QT interval

• one complete ventricular cycle

• beginning of the q wave to the end of the t wave

segments

flat lines

PR segment

• begins at the end of the P wave and goes to the beginning of the Q wave

ST segment

• early phase of ventricular repolarization

• shape is important when looking for patterns of ischemia

• end of S wave beginning of t wave

• time from end of ventricular depolarization to beginning of repolarization

positive deflection

wave that rises above the isoelectric line

negative deflection

wave below the isoelectric line

p wave and PR interval abnormalities

atrial dysfunction

QRS and t wave abnormalities

ventricular dysfunction

low levels of potassium and high levels

• heart rate decrease

• abnormal rate or rhythm

low levels of calcium and high levels

slower heart rate

longer than normal contractions

pacemakers

an artifact

Normal sinus rhythm

• P wave present, upright, and rounded

• amplitude is less than 2.5 mm

• duration is less than 110 milliseconds

• QRS complex is narrow

Sinus Brachycardia

less than 60 bpm

Sinus tachycardia

more than 100 bpm

Sinus dysrhythmia

slight irregularity in rhythm

Sinus arrest

break in normal EKG

SA node failed in fire

not significant unless arrest last longer than 6 seconds

Atrial flutter

more sever than sinus arrhythmias

atria contracts faster than ventricles

Atrial fibrillation

• no organized contraction of the atria

• quivering state

• blood clot forms because of stagnation of blood in ventricles

Junctional arrhythmias

occur at AV node

inverted P wave configuration

SA node damaged

Premature junctional complex

• early impulse that occurs before next beat

• P wave can occur before, after, or during QRS complex

Junctional escape rhythm

• absent P wave

• impulse from AV node

• atria and ventricles receive impulse simultaneously

• heart rate does not exceed 60 bpm

Accelerated junctional rhythm

• escape rhythm but 60-100 bpm

Junctional tachycardia rhythm

escape rhythm but 100-150 bpm