ECG Flashcards
Physiologically what occurs in heart during the P wave?
Atrial depolarization
Physiologically what occurs during the heart in the QRS complex?
Ventricular depolarization
Physiologically what occurs during the heart during the T wave?
Ventricular re-polarization
What does an ECG NOT tell us?
Muscle contraction and how hard the heart is working.
What is the isoelectric line? If the ECG persists along this line what does the patient have?
Baseline. Asystole.
If something abnormal shows on the ECG, what should the nurse initially do?
Assess the patient as the ECG might change and show abnormal things with patient movement etc.
What lead are we usually looking at?
Lead 2
A rise from the baseline (isoelectric line) is what?
Positive deflection
A fall from the baseline (isoelectric line) is what?
A negative deflection.
An ECG will pick up on other ________ _____?
Muscle contractions.
Normally impulses originate from which node?
Sinoatrial Node.
What are the three main ions involved in an action potential?
Na, K, Ca
How many electrodes are placed on the body for a 12 lead ECG?
10
Lead 2 reads from where to where?
Right arm electrode to left foot electrode.
What is the path electrical impulses take through the heart?
SA node - AV node - AV bundle/bundle of His - purkinje fibres
What is a Q wave caused by?
Electrical activity moving across muscle fibres of the septum/depolarization through the septum.
What does ST segment elevation indicate?
STEMI
What does ST segment depression indicate?
NSTEMI
What is the most common dysrhythmia requiring medical treatment?
AFib
What occurs in AFib?
The SA node fails to coordinate atrial muscle contraction and impulses are initiated at different foci in the atria starts a muscle contraction.
What is the atrial rate in AFib usually?
300-500
In Afib what is the ventricular rate usually? Will this beat be regular or irregular? Why?
80-160. Irregular. Because only some impulses from the atria will get through to the ventricle.
What medication is effective in treating a patient with AFib?
Digoxin
In AFib there is no_____ wave.
P
What is the resting electrical potential in the heart?
-90
During an action potential what ions influx? Which ones efflux?
K. Na.
What ion is involved with contractility of the heart?
Ca
