disorders of cardiac conduction and rhythm

electrical system of the heart

SA node → AV node → bundle of his → R/L bundle branches → purkinjie fibers

electrocardiogram

a graphic recording of the electrical activity of the heart

documents disturbances in rhythm and disturbances in conduction

can identify myocardial ischemia

cardiac dysrhythmias

abnormal electrical conduction or automaticity

vary in severity

can atrial or ventricular (more severe)

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

diagnosis- EKG, lab tests, stress test, electrophysiology

automaticity

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

conductivity

ability to conduct impulses

SA node

60-100 bpm

AV node

40-60 bpm

purkinje fibers

15-40 bpm

atrial disturbances

atrial flutter- very, very regular rhythm

atrial fibrillation- very chaotic and irregular

predisposes patient to clot formation

ventricular dysrhythmias

interfere with the pumping action of the heart

can be life threatening

heart blocks

abnormalities of impulse conduction

can be normal or pathologic

occurs when conduction between the atria and ventricles is interrupted

can be life threatening