Flashcards in Clinical Treatment of Arrhythmias Deck (50):
If the rhythm is too slow, where in the conduction system is it affected?
-below the av node
Sinus node dysfunctions
Failure of sinus node discharge resulting in the absence of atrial depolarization and periods of ventricular asystole
Bradycardia-Tachycardia (Brady-Tachy) Syndrome
Intermittent episodes of slow and fast rates from the SA node or atria
AV node dysfunctions
- first degree AV block
- Mobitz I 2nd degree AV block (Wenkebach)
1st degree AV block
AV conduction is delayed, and the PR interval is prolonged (> 200 ms or .2 seconds). each atrial signal is conducted to the ventricles (1:1 ratio).
Second-Degree AV Block – Mobitz I (Wenckebach)
Progressive prolongation of the PR interval until a ventricular beat is dropped
-Ventricular rate: irregular
below the AV node dysfunctions
- Mobitz II 2nd degree AV block
- complete heart block
Second-Degree AV Block – Mobitz II
-Intermittently dropped ventricular beats preceded by constant PR intervals
-The infranodal (His bundle) tissue is most commonly the site of Mobitz II block.
Third-Degree AV Block
-No impulse conduction from the atria to the ventricles
-PR interval = variable
-also referred to as complete heart block
When should you be concerned about a bradyarrhythmia pt?
1. When the patient is symptomatic, no matter which part of the conduction system is affected.
2. When the rhythm is infranodal (below the AV node).
Treatment of bradyarrhythmia?
-Find and treat reversible causes– ischemia/infarction, hypothyroidism, neurologic causes, Lyme disease
-Stop offending medications, if possible: antiarrhythmics, clonidine, lithium, among others.
-Acute treatment for unstable patient: beta-agonists (dopamine or isoproterenol), transcutaneous pacing, temporary transvenous pacing.
-Long term: Permanent pacemaker
Types/origins of tachyarrhythmias
-Supraventricular Tachycardias (SVT)
Acute treatment of irregular SVT
If unstable: shock
Stable: can control their rates, use antiarrhythmics, or cardioversion
5 C's of A. Fib management
antiCoagulation (I know, no C there)
Common causes of A. Fib
Mitral valve Disease
Lone AF 14%
Immediate Tx of A Fib
Control the Rate
Pharmacological rhythm control in A fib
Does not require sedation
Class III agents- ibutilide, amiodarone, dofetilide, sotalol
Class IC agents- flecainide, propafenone
Electrical rhythm control in A Fib
DC Shock 70-90% success
Day procedure in hospital
T or F: Patients with recurrent AF may require long term maintenance medications to control rhythm
True, especially if they are symptomatic in AF.
When are Class IC agents contraindicated?
in CAD and structural heart disease
Should Patients with a rhythm control agent should still be anticoagulated?
Yes, risk still present for thromboembolism, as rhythm control is not a cure.
T or F: Digoxin controls rate during exercise well
Rate control medications
Amiodarone: can be used as a rate-controlling agent, especially in setting of decompensated heart failure.
Which medications control HR during exercise?
Betablockers and rate limiting Ca Antagonists
T or F: Use of medications in combination can develop heart block
Tx strategies for atrial flutter
-Similar to A Fib
-Catheter ablation more successful than medications, 95% cure rate
-with successful catheter ablation, anticoagulation no longer necessary
-Lower ablation risk when compared to A fib