CRAT Study Guide All Answers Rated A

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