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CARDIAC KQ
Cardiac Dysrhythmias
Question | Answer |
---|---|
Where is the SA node located | upper posterior wall of the right atrium |
If the SA node fails what takes over for pacemaking of the heart? | the AV node |
what rate does the SA node fire at? | 60- 100 bpm |
What rate does the AV node normally fire at | 40 - 60 bpm |
What is the rhythm called when the AV node initiates the impulses? | nodal or junctional rhythm |
If the AV node fails what initiates the impulses for the cardiac cycle? | the ventricles |
At what rate would the ventricles fire if they initiate the cardiac cycle? | 20 -40 bpm |
what is the rhythm called when the ventricles are the initiators in the cardiac cycle? | ventricular escape rhythm |
What is the cycle of firing starting at the SA node to....? | the AV node, down the bundle of His, which divides into right and left bundle branches , through the purkinje fibers (in the ventricles) |
To be considered normal what must a cardiac cycle consist of on an ECG? | a P, QRS and T wave |
What is the most commonly used lead for ECG monitoring? | Lead II |
What do the horizontal lines on ECG paper refer to? | time |
What do the verticle lines on the ECG refer to? | volts |
How much time is a small sqaure on the ECG worth? | .04 seconds |
How many small squares are there to one big square on the ECG? | 5 |
How much time is a large square representative of? | .20 seconds |
What is the straight line or flat line of the ECG representative of? | no electrical activity |
What does the P wave represent? | atrial depolarization |
What happens to the atria when they deplarize? | they contract |
What is the PR interval representative of? | the time it takes for the impulse to travel from the SA node to the AV node |
What does the QRS complex represent? | ventricular depolarization |
What happens to the ventricles during depolarization? | they contract |
What occurs to the atria during the QRS complex | they repolarize |
What is repolarization representative of? | relaxation |
Why can you NOT see the atria repolarization somewhere in the QRS complex? | because the ventricular activity is stronger |
What is the normal time frame for the QRS interval? | .06-.10 seconds |
What does the T wave represent? | ventricular repolarization |
When the ventricles repolarize what are they doing? | relaxing |
What happens to the T wave that is indicative of damage to the heart? | it may be inverted |
What is the U wave representative of? | hypokalemia |
If your T wave is distorted what should you look for? | K levels (U wave is possibly there) |
What does the ST segment represent? | time from completion of a contraction to recovery or repolarization |
What part of the cardiac complexes are examined if the patient is having chest pain? | the ST segment |
If the ST segment is inverted what is this indicating? | ischemia |
What comprises the 5 steps for cardiac rhythm identification? | Regularity, Heart Rate, the P wave, the PR interval, the QRS complex |
How do you measure regularity on the ECG? | R - R interval |
What method to deterimine HR would you use for an irregular rhythm? | the 6 second method |
What method is used for regular rhythm calculation? | counting the small boxes and divinding 1500 into it |
What are the rules for Sinus Rhythm? | Regular rhythm R-R, P, QRS and T wave, uniform waves, HR 60-100 bpm |
What are the rules for sinus brady? | rhythm: regular, HR less than 60, P wave smooth rounded, PR interval .12 to .20 and QRS interval .06-.10 |
What are the rules for sinus tach? | rhythm: regular, HR 101-180, P wave rounded, PR interval .12-.20, QRS interval .06-.10 |
What signs may present with sinus tach? | dyspnea or angina |
What is the treatment dependent on with sinus tach? | the cause |
What is characteristic of an atrial dysrhythmia? | it is usually faster than 100 bpm and can exceed 200 |
What happes to P waves when the impulse occurs outside the SA node? | they look different - flattened, notched or peaked |
What is a PAC | premature atrial contraction |
what is an PAC in layman terms | early beat |
What causes a PAC? | the atria fire before the SA node fires |
How can you see a PAC? | there is a shortened R-R interval |
What are the rules for a PAC? | rhythm: premature beat interrupts the rhythm, HR depends on the underlying rhythm, P wave: early beat is abnormally shaped, PR interval essentially normal, QRS interval is .06 - .10 seconds |
What is atrial flutter? | when the atria contract rapidly |
what is the normal rate for atrial flutter? | 250 - 350 bpm |
What is the differentiation between atrial flutter and atrial fibrillation? | the rate in fibrillation is more rapid and more chaotic than flutter |
What is the rate for atrial fibrillation? | 350-600 bpm |
What causes atrial flutter? | rheumatic or ischemic heart disease, CHF, hypertension, pericarditis, PE and post op CABG |
What are the rules for atrial flutter | rhythm: ventricular rhythm can be regular or irregular, HR varies, P wave : saw toothed, PR interval-none, QRS complex-.06-.10 |
What are the usual symptoms for atrial flutter? | none |
What is the treatment for atrial flutter? | cardioversion |
What meds control atrial flutter? | calcium channel blockers and beta blockers, digoxin, quinidine, propranolol, procainamide |
What causes atrial fibrillation? | aging, rheumatic or ischemic heart disease, heart failure, HTN, pericarditis, PE and post op CABG |
What are the rules for atrial fibrillation? | rhythm-grossly irregular, HR atrial not measureable, ventricular is 100, P wave-none, PR interval-none, QRS .06-.10 |
What is the term used for ventricular rate greater than 100 in atrial fibrillation? | rapid ventricular response |
What is RVR? | rapid ventricular response |
What is the treatment for atrial fibrillation if patient is unstable? | cardioversion |
what treatment is used for stable atrial fibrillation? | medications |
What medications can control atrial fibrillation? | digoxin, beta blockers, calcium channel blockers |
What drugs are used to convert the rhythm in atrial fibrillation? | dofetilide, quinidine, flecainide, propafenone, and ibutilide IV |
What is the Maze procedure used for? | to create a route for electrical impulses to travel through the AV node |
What is a PVC? | premature ventricular contraction |
Where does the impulse originate in a PVC? | in the ventricles |
What is a unifocal PVC? | the PVCs all come from the same irritable ventricular area |
What is a multifocal PVC? | they originate from several irritable areas in teh ventricle |
PVC can look different shapes, why? | it depends on where the impulse originates in the ventricles |
What are the PVC rules? | rhyhtm-depends on the underlying rhythm, HR depends on underlying rhythm, P wave -absent, PR interval-none, QRS complex-if the PVC is greater than .11 it can invert the QRS or T wave |
what are the s/sx of PVCs? | pt may describe as skipped beat or palpitation |
What is the treatment for PVCs? | few require none, more require antidysrhythmic medications |
What is Ventricular Tachycardia? | continuous firing of a ectopic focus the ventricles are the pacemaker |
What causes VT? | myocardial irritability, MI and cardiomyopathy |
What are the VT rules? | rhythm-regular, HR 150 - 250 bpm, P wave absent, PR interval none, QRS greater than .11 sec |
What are the signs and symptoms of VT? | dyspnea, palpitations, light headedness, angina |
What are the VT rules? | Rhythm-regular,HR 150-250 bpm, P wave-absent,PR interval-none,QRS greater than .11 sec |
What are the signs ans symptoms of VT? | sudden onset of rapid HR and dyspnea,palpitations,light headedness and angina |
What is the treatment of VT? | if pulseless - CPR, defibrillation followed by medication : if stable, meds and ACLS protocol |
What medications are used to treat stable VT? | amiodarone, procainamide, sotalol, lidocaine,phenytoin or beta blockers |
When does VFib occur? | when many ectopic foci fire at same time |
What is the ventricular activity like with VFib? | chaotic and the ventricle quivers with complete loss of cardiac output |
Where does a single chamber pacemaker go in the heart? | right atrium or right ventricle |
Where aer dual chamber pacemakers placed? | both in right atrium and ventricle |
what is the usual set rate of a pacemaker? | 72 bpm |
What is seen on an ECG lead with a paced rhythm? | a spike will be seen in the trace |
What is an ICD? | implantable cardioverter defibrillator |
Why are patients with ICDs anxious? | due to the anticipation of receiving a shock or having another cardiac arrest |
What is ablation? | mechanical, chemical or radiofrequency to destroy pathways to stop dysrhythmias |