Disorders Cardiac Conduction/Rhythm

electrical system of the heart in order

1. Sa Node

2. AV Node

3. Bundle of His

4. R/L Bundle Branches

5. Purkinje Fibers

Electrocardiogram- EKG

a graphic recording of the electrical activity of the heart

• documents both disturbances in rhythm (dysrhythmia/arrythmia) and disturbances in conduction (heart block)

EKG order when looking at the waves

PQRST

depolarization

contracting (lub)…systole

repolarization

filling (dub)…diastole

P Wave

Represents atrial depolarization on an ECG.

PR interval

time from firing of SA node to the beginning of depolarization of ventricles

QRS Complex

Represents ventricular depolarization on an ECG.

T Wave

Represents ventricular repolarization on an ECG.

cardiac dysrhythmias

Abnormal electrical conduction or automaticity

what causes cardiac dysrhythmias

Acid-base imbalance, hypoxia, drugs, electrolyte imbalance, stress, MI, caffeine, nicotine, congenital disorders, medications

automaticity

the ability of specialized cardiac cells to spontaneously initiate an electrical impulse

conductivity

ability to conduct impulses

SA node conductivity

60-100 bpm

AV node conductivity

40-60 bpm

Purkinje fibers

15-40 bpm

what are the 2 types of atrial disturbances

atrial flutter and atrial fibrillation

atrial flutter

rapid regular contractions of the atria but its not normal looking; 250-350 bpm

atrial fibrillation

extremely irregular and chaotic looking; irregular, uncoordinated contractions of the atria

• Predisposes patient to clot formation!

Sinus Node Dysrhythmias

Due to disturbances in automaticity and conductivity, slow or fast

• not life threatening

• bradycardia (<60 bpm); tachycardia (>100 bpm)

ventricular dysrhythmias

Interfere with the pumping action of the heart

• can be life threatening

heart blocks

Occur when conduction between the atria and ventricles is interrupted

diagnostic tools used with the cardiovascular system (3)

EKG, Holter monitor (wear for 7-14 days), exercise stress test

12 lead EKG

a painless test that measures the electrical activity of your heart, providing a detailed view of its rhythm and function, often used to detect heart problems or assess how well certain treatments are working. 

electrophysiology ablation

a procedure that treats certain types of arrhythmia by destroying problematic heart tissue