Clinical Treatment of Arrhythmias

Question 1

Sinus bradycardia

Answer 1

• slow HR
• <60 bmp
• does not necessarily indicate pathology

Question 2

Sinus arrest

Answer 2

• lack of sinus node discharge

- absence of p wave and absence

Question 3

Bady-tachy

Answer 3

intermittent episodes of slow and fast rates form SA node or atria

Question 4

Chronotropic incompetence

Answer 4

• HR should normally respond smoothly to excercise/stress

- unable to reach max HR smoothly and unable to maintain

Question 5

First-degree AV block

Answer 5

• no actual block
• AV conduction is delayed
• long PR interval (>.2 secs)
• primarily block occurring w/in AV node

Question 6

Second-degree AV block - Mobitz I

Answer 6

• not every p wave transmits to ventricular contraction

- progressive prolongation of PR interival until ventricular beat is drop

Question 7

Locations w/in conduction system where problems can d\occur

Answer 7

• @ sinus node
• @ AV node
• infranodal (below AV node)

Question 8

Second-degree AV block - Mobitz II

Answer 8

• no progressive prolongation – suddenly dropped QRS wave
• regular PR interval
• block primarily occurs below AV node: w/in His, bundles, or purkinje

Question 9

Third-degree AV block

Answer 9

• no impulse conduction from the atria to the ventricles

- p wave

Question 10

Indications for treating bradyarrhythmias

Answer 10

• patient is symptomatic and arrythymia at from any point in conduction system is detected
• when the rhythm is infranodal (below the AV node)

Question 11

Steps in treatment of bradyarrhythmias

Answer 11

1. Find and treat reversible causes: i.e. ischemia/infarct, hypothyroidism, neurologic causes, lyme disease
2. Stop offending meds
3. Acute tx: beta-agonists (dopamine or isoproterenol), transcutaneous pacing, venous pacing
4. Long term: permanent pacemaker

Question 12

Tachyarrhythmias

Answer 12

• Above ventricle=supraventricular tachycardias (SVTs)

- @ ventricle=ventricular tachycardia, ventricular fibrillation

Question 13

Supraventricular tachycardia types

Answer 13

• 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)

Question 14

Irregular supraventricular tachycardia tx

Answer 14

if unstable –> shock

Question 15

Regular supraventricular tachycardia tx

Answer 15

• give adenosine
• adenosine may slow down rhythm to help dx arrythmia
• adenosine may also slow down AV node and actually treat/terminate tachycardia

Question 16

Atrial fibrillation approach

Answer 16

• 5 C’s:
• Cause: reverse
• Control rate
• antiCoagulation –> @ risk for stroke, must prevent clots
• Control rhythm
• Cure?: ablation

Question 17

Common causes of AF

Answer 17

• hypertension
• mitral valve disease
• alcohol
• cardiomyopathy
• hyperthyroidism
• lone AF
• cardiac surgery

Question 18

Immediate Treatment of Atrial fibrillation

Answer 18

• cardiovert (shock) if close to hemodynamic collapse

- control rate if

Question 19

Rhythm control in Atrial fibrillation

Answer 19

• pharmalogical: less successful, but does not require sedation –> Class IC (flecainide, prpafenone) and Class II anti-arrhythmics (ibutilide, amiodarone, dofetilide, sotalol)
• electrical

Question 20

Maintenance rhythm control in AF

Answer 20

• can use meds at lower doses
• Class IC agents: contraindicated inCAd and structural heart disease
• Class III agents: amiodarone, sotalol, dofetilide, dronedarone

Question 21

Rate control in AF

Answer 21

• 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

Question 22

Rhythm control: catheter ablation

Answer 22

-surgical technique that cauterizes atrium to prevent triggers from pulmonary veins from getting into atrium

Question 23

Atrial flutter treatment approaches

Answer 23

• similar to Afib
• can be more difficult to control rate or rhythm
• catheter ablation more successful than meds (95% cure rate)

Question 24

Other SVTs (3)

Answer 24

• AV nodal reentrant tachycardia
• accessory pathway-mediated tachycardias: abnormal connection between atrium and ventricle
• focal atrial tachycardias: least common, abnormal focus w/increased automaticity

Question 25

Treatment approaches to other SVTs

Answer 25

• individualized tx

- catheter ablation

Question 26

Ventricular Tachyarrhythmias characteristics

Answer 26

• “more Vs than As” = more QRS waves than P waves
• wide complex tachycardia usually indicates ventricular origin
• CAD = 90% of time it is VT

Question 27

Acute tx in stable Vtach

Answer 27

• meds: amiodarone, lidocaine, procainamide

- treat underlying causes

Question 28

Acute tx in unstable Vtach

Answer 28

• shock
• treat underlying causes
• meds

Question 29

Approach to Vtach w/out structural heart disease

Answer 29

• usually idiopathic: focal arrythmogenic trigger
• usually “benign”
• meds or ablation
• defribillator rarely necessary

Question 30

Approach to Vtach w/ structural heart disease

Answer 30

• treat underlying causes
• risk stratify
• defribillator + meds/ablation

Question 31

Reasons for defribrillator in Vtach

Answer 31

• 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