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45 Cards in this Set
- Front
- Back
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precipitating factors for arrhythmia
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ischemia,
pH and electrolyte abnormalities, excessive mycardial fiber stretch, excessive release or sensitivity to neurotransmitters, drugs/toxins |
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electrolyte abnormalities causing arrhythmia: "the big one"
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pottassium
also, fad diets |
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condition caused by drugs that prolong the QT interval
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Torsades de pointes
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mechanisms of arrhythmogenesis
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altered automaticity,
re-entry, after depolarizations |
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automaticity is altered b/c the slope of phase ___ is altered
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4
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decrease in phase 4 slope of pacemaker cell allows ______cell to become dominant
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another pacemaker
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increase in phase 4 slope of nonpacemaker cell allows dominant to ______cell
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normal pacemaker cell
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conditions nec. for re-entry
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1-unidirectional block,
2-electrical recovery of tissue adjacent to site of unidirectional block to allow conduction of re-entering impulse |
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conditions favoring developent of re-entry arrhythmias
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1-long conductin pathways
2-short ERPs (effective refractory period) 3-slowed conduction |
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what do antiarrhythmic drugs attempt to do.
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converting unidirectional block to bidirectional block
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Wolff-Parkinson-White syndrome
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conduction problem where atrial signals reach the ventricle without going thru AV node
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QT_c?
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corrected
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etiology of sinus bradycardia
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1-young, athletic
2-incr. vagal tone (Vom, naus) 3-pharm. (Ca ch or beta blockers) 4-inferior MI |
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Ca ch blocker causing sinus bradycardia
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verapamil
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causes of sinus tachycardia
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pain, fever, stress
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SVT?
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supraventricular tachycardia
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EKG sign of SVT
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narrow QRS, rapid
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cause of SVT
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reentry or an ectopic pacemaker above the bifurcation of the His bundle
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atrial BPM of atrial flutter
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250-350 bpm
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atrial flutter is common in what disease?
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IHD
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EKG characteristics of atrial flutter
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sawtooth waves best in II, III, aVF
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quinidine is bad for atrial flutter why?
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quinidine facilitates AV node conduction
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treatment of atrial flutter that is > 48 hrs
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anticoag + Ca ch or beta blockers
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treatment of unstable atrial flutter
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electrocardioversion
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holiday heart?
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alcoholic induced arrhythmias or cardiomyopathy
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- disorganized multiple ectopic discharges
- loss of atrial kick |
atrial fibrillation
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atrial fib chance of stroke?
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incr. 5% yearly and 25% lifetime
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what drugs are used for rated control in atrial fib?
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beta blockers and digoxin
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pt age that decides anticoag therapy during atrial flutter
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<75 : aspirin
>75 : coumadin |
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EKG sign of 1st degree block
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prolonged PR interval greater than 0.2s (5 blocks)
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is 1st degre block clinically significant?
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no
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Dropped QRS and
increasing PR interval shortening RR intervals constant PP interval |
2nd degree AV block
(Mobitz type I or Wenckebach) |
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dropped QRS
fixed PR interval PRS slightly wide |
2nd degree AV block
(Mobitz type II) |
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No AV condution
ventricular escape rhythm narrow QRS |
3rd degree AV block
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which is more dangerous Mobitz 1 or 2?
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2
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No p wave
wide QRS |
PVC
(preventricular contractions) (premature ventricular contractions) |
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ventricular bigeminy
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PVCs alternating with sinus beats
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treatment for PVC and ventricular bigeminy
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none, usually benign
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"monomorphic" EKG (no p waves)
wide QRS high rate |
ventricular tachycardia
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no p waves or QRS waves
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ventricular arrhythmias
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Major MOA
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Na channel blockade
SNS blockade ERP prolongation Ca channel blockade |
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Antiarrhythmic Drug Actions Decrease automaticity of _________ more than SA node
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ectopic pacemakers
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Antiarrhythmic Drug Actions Reduce conduction and excitability in depolarized tissue more than normally polarized tissue
Selective blockade of ______channels of depolarized tissue |
Na and Ca
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Antiarrhythmic Drug Actions:
ERP increased more in depolarized tissue than in ____________ |
normal polarized tissue
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Ca blockers have greater affinity for activated channels (phase 0) or inactivated channels (phase 2) and low affinity for ____________ [use-dependent or state dependent action]
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rested channels
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