Dysrhythmias and Interpreting EKG Flashcards
A 6-second cardiac strip shows a rhythm characterized by 7 evenly-spaced p-waves and QRS complexes in a 1:1 ratio with consistent PR intervals of 0.2 seconds. Nurses commonly refer to this rhythm as
Normal Sinus Rhythm (NSR)
Depolarization of the cardiac muscle causes a contraction. Immediately following depolarization, the heart enters a(n) ___________ during which it cannot be stimulated, prior to a(n) ___________ during which a significantly strong impulse may excite it. With repolarization, the heart muscle enters a period of ___________.
Absolute refractory phase, relative refractory period, full excitability
Which of the following are common causes of dysrhythmias?
- stimulants like caffeine and tobacco
- myocardial infarction
- heart failure
- alcohol consumption (ETOH)
- acid-base imbalance like sepsis
- hypoxia
A brief lapse in consciousness accompanied by a loss in postural tone is known as
Syncope
What does the P wave represent?
Firing of the SA node, depolarization of the atria
What should a normal P wave look like and what is the normal duration?
Upright
Normal duration = 0.06-0.12 seconds
What is the PR interval?
It is measured from beginning of P wave to beginning of QRS complex
What does the PR interval represent?
time taken for impulse to spread through the atria, AV node and bundle of His, bundle branches, and Purkinje fibers, to a point immediately before ventricular contraction
What is the normal duration for PR interval?
0.12-0.2 seconds
What is the QRS interval?
it is measured from beginning to end of QRS complex
What does the QRS interval represent?
The time taken for depolarization of ventricles (systole)
What is the normal duration of QRS interval?
less than 0.12 seconds
What is the Q wave?
The first negative (downward) deflection after the P wave
Short and narrow
What is the normal duration of the P wave?
less than 0.03 seconds
What does the T wave represent?
The time for ventricular repolarization.
