electric conduction of the heart

What is the order of conduction of the heart

SA node, AV node, AV bundle, bundle branches, subendocardial conducting network

Sinatrial node

pacemaker, generates impulses

Atrioventricular node

impulses pause for 0.1 second

Atrioventricular bundle

bundle of His, conducts impulse to bundle branches, in interventricular septum

Bundle branches

conduct impulses through interventricular septum

Subendocardial conducting network (purkinge fibers)

depolarizes contractile cells of both ventricles

What happens when AV node-bundle pathway is damaged

stops SA node from interacting with ventricles

Intrinsic conduction system

cardiac pacemaker cells, depolarizes heart sequentially

Segment

region between 2 waves

Interval

segment and one or more waves

What does P hump represent

atrial depolarization

What does R on ecg represent

Ventricular depolarization

What does T represent

ventricular repolarization

Tachycardia

over 100 beats/min

Bradycardia

lower than 60 beats/min

Fibrillation

rapid, uncoordinated heart contractions

Why is bradycardia good in athletes

indicates stroke volume has increased

What is stroke volume

amount of blood ejected by ventricle

How many leads are used to record an ECG standard how many are bipolar and how many are unipolar

12, 3 bipolar 9 unipolar

What does enlarged R wave mean

enlarged ventricles

What does prolong P-R interval mean

1st degree heart block, signal from SA node to AV node is delayed longer than normal

What does prolonged Q-T interval mean

increased risk of arrhythmias, interval corresponds to beginning if ventricular depolarization and repolarization

What does elevated S-T segment mean

myocardial infarction