Clinical Treatment of Arrhythmias Flashcards
Sinus bradycardia
- slow HR
- <60 bmp
- does not necessarily indicate pathology
Sinus arrest
- lack of sinus node discharge
- absence of p wave and absence
Bady-tachy
intermittent episodes of slow and fast rates form SA node or atria
Chronotropic incompetence
- HR should normally respond smoothly to excercise/stress
- unable to reach max HR smoothly and unable to maintain
First-degree AV block
- no actual block
- AV conduction is delayed
- long PR interval (>.2 secs)
- primarily block occurring w/in AV node
Second-degree AV block - Mobitz I
- not every p wave transmits to ventricular contraction
- progressive prolongation of PR interival until ventricular beat is drop
Locations w/in conduction system where problems can d\occur
- @ sinus node
- @ AV node
- infranodal (below AV node)
Second-degree AV block - Mobitz II
- no progressive prolongation – suddenly dropped QRS wave
- regular PR interval
- block primarily occurs below AV node: w/in His, bundles, or purkinje
Third-degree AV block
- no impulse conduction from the atria to the ventricles
- p wave
Indications for treating bradyarrhythmias
- patient is symptomatic and arrythymia at from any point in conduction system is detected
- when the rhythm is infranodal (below the AV node)
Steps in treatment of bradyarrhythmias
- Find and treat reversible causes: i.e. ischemia/infarct, hypothyroidism, neurologic causes, lyme disease
- Stop offending meds
- Acute tx: beta-agonists (dopamine or isoproterenol), transcutaneous pacing, venous pacing
- Long term: permanent pacemaker
Tachyarrhythmias
- Above ventricle=supraventricular tachycardias (SVTs)
- @ ventricle=ventricular tachycardia, ventricular fibrillation
Supraventricular tachycardia types
- regular (consistent QRS intervals w/P waves) vs. irregular
- regular: sinus tachycardia
- irregular: atrial fibrillation (no discrete Ps); multifocal atrial tachycardia (3+ Ps); atrial flutter (flutter waves)
Irregular supraventricular tachycardia tx
if unstable –> shock
Regular supraventricular tachycardia tx
- give adenosine
- adenosine may slow down rhythm to help dx arrythmia
- adenosine may also slow down AV node and actually treat/terminate tachycardia
Atrial fibrillation approach
- 5 C’s:
- Cause: reverse
- Control rate
- antiCoagulation –> @ risk for stroke, must prevent clots
- Control rhythm
- Cure?: ablation
Common causes of AF
- hypertension
- mitral valve disease
- alcohol
- cardiomyopathy
- hyperthyroidism
- lone AF
- cardiac surgery
Immediate Treatment of Atrial fibrillation
- cardiovert (shock) if close to hemodynamic collapse
- control rate if
Rhythm control in Atrial fibrillation
- pharmalogical: less successful, but does not require sedation –> Class IC (flecainide, prpafenone) and Class II anti-arrhythmics (ibutilide, amiodarone, dofetilide, sotalol)
- electrical
Maintenance rhythm control in AF
- can use meds at lower doses
- Class IC agents: contraindicated inCAd and structural heart disease
- Class III agents: amiodarone, sotalol, dofetilide, dronedarone
Rate control in AF
- medications: beta blockers, digoxin, verapamil, diltiazem, amiodarone as rate-control in decompensated HF
- Digoxin=not good during exercise
- Beta-blockers and Ca channel blockers control HR during exercise
Rhythm control: catheter ablation
-surgical technique that cauterizes atrium to prevent triggers from pulmonary veins from getting into atrium
Atrial flutter treatment approaches
- similar to Afib
- can be more difficult to control rate or rhythm
- catheter ablation more successful than meds (95% cure rate)
Other SVTs (3)
- AV nodal reentrant tachycardia
- accessory pathway-mediated tachycardias: abnormal connection between atrium and ventricle
- focal atrial tachycardias: least common, abnormal focus w/increased automaticity
Treatment approaches to other SVTs
- individualized tx
- catheter ablation
Ventricular Tachyarrhythmias characteristics
- “more Vs than As” = more QRS waves than P waves
- wide complex tachycardia usually indicates ventricular origin
- CAD = 90% of time it is VT
Acute tx in stable Vtach
- meds: amiodarone, lidocaine, procainamide
- treat underlying causes
Acute tx in unstable Vtach
- shock
- treat underlying causes
- meds
Approach to Vtach w/out structural heart disease
- usually idiopathic: focal arrythmogenic trigger
- usually “benign”
- meds or ablation
- defribillator rarely necessary
Approach to Vtach w/ structural heart disease
- treat underlying causes
- risk stratify
- defribillator + meds/ablation
Reasons for defribrillator in Vtach
- secondary prevention: pt who has already had sudden cardiac arrest due to VT/VF w/out a reversible cause
- primary prevention:pt w/out previous cardiac arrest but is at significant risk
