Treatment of arrhythmias Flashcards
Bradyarrythmias of SA node
- sinus bradycardia * sinus arrest/pause
- tachy-brady syndrome * chronotropic incompetence- inability to
mount age-appropriate HR with exercise - sinus bradycardia * sinus arrest/pause
- tachy-brady syndrome * chronotropic incompetence- inability to
mount age-appropriate HR with exercise
Bradyarrhythmias of AV node
1st degree AV block, Mobitz I 2nd degree AV block (Wenkebach)
Bradyarrhythmias below AV node
Mobitz II 2nd degree AB block, complete heart block
Sinus bradycardia
SA node fires slow (<60BPM)
Sinus arrest
a pause in the rate at which the SA node firesdue to failure of SA node discharge
Bradycardia-tachycardia syndrome
SA node has alternating periods of firing too slowly (< 60 bpm) and too fast (> 100 bpm). Brady-tachy syndrome often manifests itself in periods of atrial tachycardia, flutter, or fibrillation
Chronotropic incompetence
HR response to activity is unstable
1st degreee AV block
delay in AV conduction, but each atrial signal is conducted to the ventricles
2nd degree AV block- mobitz I and II
failure of atrial depolarizations to reach the ventricle. Mobitz I(Wenckebach): Progressive prolongation of the PR interval until a ventricular beat is dropped due to block of AV node. Mobitz II: intermittent dropped beats preceded by constant PR intervals due to block of bundle of His
Mobitz I vs II
Mobitz1: difference in PR intervals before and after beat is >0.02seconds. MobitzII: difference in PR intervals before and after beat is <0.02 seconds
What is advanced second degree block
block of two or more consecutive P waves
3rd degree AV block
The QRS complexes are not caused by conduction of the P waves through the AV node to the ventricles, but rather the QRS is initiated at a site below the AV node (such as in the His bundle or the Purkinje fibers) as an escape rhythm
Treatment for Bradyarrhythmias
- treat reversible causes (ischemia, infarct, hypothyroidism). 2. Stop offending meds (antiarrhythmics, clonidine, lithium). 3. Acute treatment for unstable patient: beta-agonists (dopamine or isoproterenol), transcutaneous pacing, temporary transvenous pacing. 4. Long term: Permanent pacemaker
Describe implantation of pacemaker
generator placed in shoulder with leads that are guided by venous system into heart (atria or ventricle) where sensing of heart rhythm occurs
Two general categories of tachyarrhythmias
Supraventricular tachycardia or ventricular (tachycardia or fibrillation)
Supraventricular tachycardia classifications
irregular: Atrial fibrillation, multifocal atrial tachycardia (3 or more p waves), atrial flutter. Regular: sinus tachycardia, AV nodal reentrant tachycardia, atrioventricular reentrant tachycardia, atrial flutter, atrial tachycardia, and junctional tachycardia
Acute treatment of supraventricular tachycardia
Shock/cardiovert if unstable. If stable: irregular SVT treated with rate control, antiarrhythmics or cardioversion. Regular SVT treated with adenosine (blocks AV node)
Treatment of Atrial fibrillation
reverse cause, control rate, anti-coag, control rhythm and possible cure with ablation
Causes of atrial fibrillation
hypertension, mitral valve disease, alcohol, cariomyopathies, hyperthyroidism, lone AF
List methods for rhythm control in Afib
drugs: class III agents, class IC agents. Electrical: DC shock has good success but requires sedation. Ablation is last resort
Use of anti-coags in afib
risk of thromboembolism from clot in atrium
Methods for rate control in Afib
meds: B blocerks, digoxin, verapamil (IV), Diltiazem (IV), amiodarone
CHAD2 tool
risk assessment tool that weighs the risks and benefits of taking warfarin vs having an embolus. C: CHF, H: hypertension, A: Age>75, D: diabetes, 2: prior stroke/TIA
Atrial flutter treatment
Catheter ablation has high success rate (better than Afib). Targets isthmus in RA btw tricuspid and IVC
Treatment of ventricular tachyarrhythmias
if unstable: shock, treat underlying causes and meds. If stable: Meds (amiodarone, lidocaine, procainamide), treat underlying . If structural heart disease, may require defibrillator. If idiopathic, meds include B blockers, Ca channel blockers, Class IC and Class II agents and ablation.
When does patient need a defibrillator
Secondary prevention: Patient has had sudden cardiac arrest without reversible cause. Primary prevention: No previous cardiac arrest by significant risk due to ischemic heart disease (low Ejection fraction<35% ), ischemic heart disease with EF 35-40% and inducible VT, or structural disease (hypertrophy, etc)
