Term
| what is the cardiac dipole? |
|
Definition
| an electric vector force going from the SA node that first goes anteriorly and then posteriorly as it heads inferior along the angle toward the L foot |
|
|
Term
| what is the sequence of events as the heart depolarizes? |
|
Definition
| SA node fires -> atria depolarizes -> AV node activated -> bundle of His activated -> purkinje fibers activated -> excitation-contraction coupling occurs |
|
|
Term
| what deflection do you get when a positive charge goes to a positive electrode? |
|
Definition
|
|
Term
| what deflection do you get when a positive charge goes away from a positive electrode? |
|
Definition
|
|
Term
| what do you get when a positive charge going toward and then going past a positive electrode? |
|
Definition
|
|
Term
| what do you get when the positive charge is coming directly at a positive electrode? |
|
Definition
| an isoelectric line (need to switch leads) |
|
|
Term
| how long should the PR interval be? |
|
Definition
|
|
Term
| how long should the QRS interval be? |
|
Definition
|
|
Term
| how much time does a single box on the EKG represent? electricity? |
|
Definition
|
|
Term
| what does the P wave represent? |
|
Definition
|
|
Term
| what is happening in the PR interval? |
|
Definition
| the atria are pushing blood into the ventricles |
|
|
Term
| what is happening in the QRS complex? |
|
Definition
| the ventricles are depolarizing |
|
|
Term
| what does the T wave represent? |
|
Definition
| repolarization (it is upright b/c it is going away from the electrode at this point) |
|
|
Term
| what is the interpretation scale for EKGs? |
|
Definition
| when the R wave lands on the heavy black line, the next heavy line should be 300, the next should be 150, the next should be 100, the next should be 75, the next should be 60, and the next should be 50. therefore if the pt's next R wave is between 3 and 4 heavy lines out, their HR is between 100 and 75 bpm (or 6 of them = 60 sec) |
|
|
Term
|
Definition
|
|
Term
| what are you analyzing when you look at an EKG? |
|
Definition
| the rate, rhythm (regular or irregular?), axis (depolarizing between L arm & foot?), hypertrophy (large complexes?), ischemia (flipped T waves), MI (ST segment elevation?) |
|
|
Term
|
Definition
|
|
Term
| what is bradycardia? why is it so important? |
|
Definition
| HR < 60 bpm, important b/c HR x SV = CO and TPR can go up |
|
|
Term
| what is the spectrum of regularity when talking about heart rhythm? |
|
Definition
| heart beats can be regularly irregular or irregularly irregular. it is seen on the rhythm strip |
|
|
Term
| what will give you an irregularly irregular heart rhythm? |
|
Definition
|
|
Term
| how should the ST segment appear? |
|
Definition
|
|
Term
| how should the QT interval appear? |
|
Definition
| not prolonged b/c if it is an abberant beat can cause a lethal dysrhythmia (can happen with interacting medications, such as those prescribed for fungal/bacterial infections) |
|
|
Term
| what are U waves important for? |
|
Definition
|
|
Term
| how much electricity is 10 boxes on an EKG? |
|
Definition
|
|
Term
| where might you see an EKG, but no heart beat? |
|
Definition
| in electromechanical dissociation pulseless electrical activity (PEA) |
|
|
Term
| where is atrial depolarization? |
|
Definition
|
|
Term
| where is atrial repolarization? |
|
Definition
| hidden in the QRS complex |
|
|
Term
| where is ventricular depolarization? |
|
Definition
|
|
Term
| where is ventricular repolarization? |
|
Definition
|
|
Term
|
Definition
| when the T wave is more than half the distance between 2 R waves/closer to the 2nd R (the heart is then vulnerable to dysrhythmia) |
|
|
Term
| what is the progression of ion movement during the cardiac action potential? |
|
Definition
| Na+ in, K+ out, Ca+ in, more K+ out, less Ca+ in |
|
|
Term
| what are the important things to scan for on an EKG? |
|
Definition
| PR ~5 boxes, QRS ~3 boxes, insignificant Q, decent R wave, ST isoelectric, QT not longer than ½ distance b/w R waves |
|
|
Term
| are upright T waves normal? |
|
Definition
| yes - elevated or inverted = ischemia |
|
|
Term
| what speed should the EKG paper be at? |
|
Definition
|
|
Term
| what directly stimulates the ventricles? |
|
Definition
| purkinje fiberes (stimulated by the bundle of his) |
|
|
Term
| if there is a block between the SA and AV node, what will get bigger? |
|
Definition
|
|
Term
| if there is a block in the QRS, what must be the problem? |
|
Definition
| something must be blocking the conduction tissue |
|
|
Term
| where is the SA anatomically? |
|
Definition
| where the crista terminalis is in the RA |
|
|
Term
|
Definition
|
|
Term
| where is the bundle of his? |
|
Definition
| in the interventricular septum |
|
|
Term
|
Definition
| any part of the heart that initiates an impulse without waiting for the SA node. they can develop into PVCs (premature ventricular contractions) |
|
|
Term
| what is the AV node if the PR interval is longer than .2 sec? what might cause this situation? |
|
Definition
| the AV node is refractory, meaning that there is an AV block because the PR interval should be 5 boxes (or .2 sec @ .04 sec a block). problems with vasculature, an MI, an rx could all cause this. |
|
|
Term
| what is seen in a 2nd degree wenckeback or mobitz I block? |
|
Definition
| the PR interval gets longer and longer, then drops |
|
|
Term
| what is seen in a 2nd degree mobitz type II block? |
|
Definition
| the SA node is firing regularly and the AV is responding intermittently |
|
|
Term
| what is seen in a 3rd degree A/V block? |
|
Definition
| there is no relationship between SA firing and AV response (each have their own rate) |
|
|
Term
| what is wolff-parkinson-white syndrome w/ aberrant pathway? how does it appear on an EKG? what might be problematic in treating this? |
|
Definition
| when there is an abberant and faster pathway between the atria and the ventricles around the outside of the heart that leads to a faster depolarization of the ventricles. this appears on the EKG as a delta wave, which looks like a longer, slower slope heading up to the QRS. blocking the A/V node will worsen this problem |
|
|
Term
| what does an atrial flutter appear as? what is a danger unique to this? |
|
Definition
| an atrial flutter appears "sawtoothed" - meaning that it is depolarizing many more times than the ventricles (which respond irregularly), and a particular risk with this is beating the blood up to the point where the coagulation cascade is activated and clots form |
|
|
Term
| what happens in junctional rhythym? |
|
Definition
| the AV node fires rather than the SA, and therefore there is no P wave. this can happen when the pt has excessively high vagal tone. the beat is usually regular. |
|
|
Term
|
Definition
| a lot of extra waves being picked up on the EKG due to shivering due to hypothermia. the HR will also be low. there are P waves, so it can't be atrial fibrillation |
|
|
Term
| what is atrial fibrillation? |
|
Definition
| lack of P waves, constant depolarization of atria |
|
|
Term
| what is a first degree block? |
|
Definition
| just if the PR interval gets beyond 5 boxes (.2 sec) |
|
|
Term
| what is a right bundle branch block? |
|
Definition
| when the right ventricle is not directly activated by impulses travelling from the SA -> AV through the right bundle branch - and the L stimulates it, creating a delay. so instead of the normal P-QRS-T, RBBB has P, R, S, R’. V1 and V2 have 2 R waves while V6 is pretty normal. there is also an inverted T |
|
|
