Critical Care Nursing
Card Set Information
Critical Care Nursing
Conduction System and Introduction to Rhythm Analysis
What are the 4 primary activities of the cardiac cells?
The ability of cardiac muscle cells to generate their own electrical impulses spontaneously
Abilty of the cardiac cells to respond to an impulse
Ability of the cardiac cells to receive an electrical impulse and transmit it to the other cardiac cells
Ability of the cardiac cells to contract
The cardiac cycle is composed of what two activities?
What activity is caused by automaticity?
What activity is the contraction?
What are the 2 phases of the electrical activity?
What phase is depolarization?
What phase is repolarization?
What are the 2 mechanical responses?
During depolarization is it systole or diastole? Is it contraction or resting?
During repolarization is it systole or diastole? Is it contraction or resting?
Resting or filling
What happens before a mechanical activity?
What is happening during ventricle repolarization?
The ventricles are filling with blood
Vulnerable phase (Twave) is when enough cells have repolarized that ____ ____ ________ will cause cells to depolarize leading to _______ ___________
Any weak stimulus
Under normal circumstances, depolarization is followed by what?
Repolarization is the resting state in which the ventricles do what?
fill with blood
The ventricles need enough relaxation time in order for them to do what?
adequately fill before the next depolarization
How do you treat a slow heart rate?
What is the conduction pathway?
Bundle of His
What is the pacemaker of the heart?
SA node (Sinoatrial node)
The SA node has how many beats/min?
The AV node has how many beats/min?
What are the functions of the AV node?
Delays impulses into the ventricle
The back up pacemaker
The bundle of His divides into what ?
The right bundle & left bundle
The left bundle divides into what?
Anterior fascicle and posterior fascicle
How many beats/min in the purkinje fibers?
What does the P wave represent?
What is the normal measurement of a PR interval?
0.12 - 0.20
What is the normal measurement of a QRS interval?
0.04 - 0.10
What does the QRS complex represent?
What does the T wave represent?
A T wave inversion indicates what?
Changes in the ST segment indicates what?
Myocardial injury or ischemia
An elevated ST segment indicates what?
Myocardial injury, the action phase. The patient is having a heart attack
What are the steps to interpret an ECG?
Determine heart rate
Identify and examine the P waves
Measure PR interval
Measure QRS complex
Name the rhythm
What is an abnormal cardiac rhythm
What has an impact on the body's ability to maintain a normal hemodynamic status and adequate cardiac output?
What does a significant Q wave indicate?
first negative deflection
first positive deflections
negative deflection after R wave