CRAT Study Guide Exam 38 Questions with Verified Answers
Normal PRI interval - CORRECT ANSWER 0.12-0.20
Normal QRS interval - CORRECT ANSWER 0.11 or
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What does the P wave represent? - CORRECT ANSWER Atrial depolarization
What does the QRS complex represent? - CORRECT ANSWER Atrial repolarization and ventricular depolarization
Q wave indicates what? - CORRECT ANSWER Dead myocardial tissue. Always a negative deflection
What is the natural pacemaker of the heart? - CORRECT ANSWER SA node
3 types of pacemakers - CORRECT ANSWER 1) single (either RA or RV)
2) dual chamber (RA and LV)
3) bi-ventricular (RV and LV --> Congestive Heart Failure)
Which HB would you NOT need a pacemaker for? - CORRECT ANSWER First-degree AV block (prolonged PRI >0.20 seconds)
Define intrinsic beats - CORRECT ANSWER The patient's own heart beat
What is sensing? - CORRECT ANSWER The ability for the heart to sense and respond to the electrical activity of the heart
What is capture? - CORRECT ANSWER The pacemaker sends a stimulus to the heart which causes the heart to depolarize
Failure to sense - CORRECT ANSWER Lack of pacemaker spikes where they should have been. Battery can be dead.
Failure to capture (loss of capture) - CORRECT ANSWER No P or QRS after the pacemaker spike
Undersensing - CORRECT ANSWER Pacemaker spikes in areas where they should not be (i.e. in the T wave, an ST segment, or on top of another QRS)
Cardioversion vs. Defibrillation - CORRECT ANSWER Cardioversion: to change the heart rhythm (usually from SVT to sinus)
Defibrillation: only used for pulseless VT and v-fib
Pacemaker inhibition - CORRECT ANSWER Pacemaker doesn't work because it senses the heart is beating at or above the programmed rate
A-V sequential pacing - CORRECT ANSWER When the pacemaker paces both the atrium and the ventricle
No pacemaker spikes is... - CORRECT ANSWER Failure to sense
Pacemaker spikes with no P wave or QRS following it... - CORRECT ANSWER Failure to capture
Causes of wandering baseline - CORRECT ANSWER Respiration or by lotion/sweat on the skin interfering with the signal
Causes of 60-cycle interference - CORRECT ANSWER Electrodes not properly applied, EKG machine not properly grounded, r by too many electrical devices nearby.
How to fix 60-cycle interference - CORRECT ANSWER Unplug and re-plug somewhere else.
What does 60-cycle interference look like? - CORRECT ANSWER Fat highlighter marks on baseline
Causes of somatic tremor artifact - CORRECT ANSWER Patient keeps moving, Parkinson's disease
How to fix somatic tremor artifact - CORRECT ANSWER Make sure leads are not placed over muscle and instead placed on bone, help patient relax, give a blanket.
What causes leads reversed? - CORRECT ANSWER When the leads are placed on opposite limbs (i.e. left arm and right arm are switched)
Lead I connects what? - CORRECT ANSWER Right arm to left arm
Lead II connects what? - CORRECT ANSWER Right arm to left leg
Lead III connects what? - CORRECT ANSWER Left arm to left leg
Lead I, II, and III are what kind of leads? - CORRECT ANSWER Bipolar (also frontal because they only show the front of the heart)
What makes Einthoven's Triangle? - CORRECT ANSWER Connecting leads I, II, and III at their ends
Memory method for calculating heart rate - CORRECT ANSWER 300-150-100-75-60-50-43-37-33-30
Length of time for one small box - CORRECT ANSWER 0.04 seconds
Amplitude for one small box - CORRECT ANSWER ?
Chart speed - CORRECT ANSWER 25 mm/s
Gain - CORRECT ANSWER Normally set to 1
While in the resting state, myocytes are polarized and the interior of the cell becomes ________-ly charged - CORRECT ANSWER Negative
When cells contract, they become _______. (Negative or positive) - CORRECT ANSWER Positive [Show Less]