Dysrhythmias

Question 1

Sinus Pause/Sinus Arrest Treatment

Answer 1

Possible pacemaker insertion

Atropine 1mg IV may be given if hemodynamic instability is noted

Question 2

Sinus Bradycardia Treatment

Answer 2

Symptomatic and hemodynamically unstable:
Atropine 1mg IV
Temporary Pacer

No tx. if symptomatic!

Question 3

Sinus Tachycardia Treatment

Answer 3

Treat underlying cause
Calcium channel blockers: Diltiazem, verapamil
Beta Blockers in Symptomatic tachycardia

Question 4

SVT causes

Answer 4

digitalis, asthma medications, or cold remedies
Caffeine, ephedra
Cocaine, meth

Question 5

EKG in PSVT

Answer 5

Heart rate 140-240
Regular rhythm
P wave different from the normal sinus rhythm
P wave often buried in QRS (can't see)
QRS is narrow and of normal morphology

Question 6

Supraventricular Tachycardia (SVT) treatment

Answer 6

Vagal Maneuvers:
Carotid massage, start at R side
Adenosine (Adenocard) 6mg IV

Question 7

Supraventricular Tachycardia (SVT) treatment If adenosine is unsuccessful:

Answer 7

Consider cardioversion if patient is hemodynamically unstable (requires sedation)
Or IV Beta or calcium channel blocker

Question 8

Wolff-Parkinson-White Syndrome (WPW)

Answer 8

Form of SVT
Accessory pathway that bypasses the AV node (Bundle of Kent)
heart rate is typically greater than 200
PR interval is short <.12ms
The upstroke of the QRS wave is slurred (delta wave)

Question 9

delta wave

Answer 9

The upstroke of the QRS wave is slurred, seen in WPW

Question 10

Paroxysmal Atrial Tachycardia(PAT)

Answer 10

Atrial rate150-250/min: may conduct to ventricles but the AV node will try to block impulses.
P wave - morphology usually varies from sinus
Originates from an irritable atrial focus

Question 11

Premature Atrial Contractions (PACs)

Answer 11

Discharge from non-sinus atrial pacemakers
P-wave preceding may not look like the P waves that originate from the sinus node
Very frequent PACs may be a precursor to the development of atrial fibrillation

Question 12

Most common encountered arrhythmia in clinical practice

Answer 12

Atrial Fibrillation

Question 13

Class 1A antiarrythmics To restore sinus rhythm if necessary

Answer 13

Pronestyl (Procainimide)

Quinidine (Cardioquin)

Question 14

Class III antiarrhythmics

Answer 14

Sotalol (Betapace)120-160mg po BID
Ibutilide (Corvert) IV only
**Amiodarone – titrated up to 400mg po qday
**Long-term toxicity issues, lungs, thyroid, liver and eyes need monitoring.

Question 15

Class IC antiarrhythmics

Answer 15

Propafenone (Rythmol) 300-600mg po qday

Flecainide (Tambocor) 50-100mg po BID

Question 16

Cardioversion for Atrial Fibrillation

Answer 16

Less than 48-72hours of a-fib:
Safe to cardiovert (May need to R/O LA thrombus…TEE to see if atrial thrombus present prior to cardioversion)

If duration unknown:
Rate control
Anticoagulate x 4-6 weeks then cardiovert
Anticoagulants x 6 weeks after successful cardioversion or indefinitely if patient was unaware that they were in atrial fibrillation

Question 17

Junctional Escape, Accelerated Junctional Rhythm EKG findings

Answer 17

Narrow complex QRS

Retrograde P wave

Question 18

Junctional Tachycardia Rhythms Treatment

Answer 18

Acute Treatment:
Vagal maneuvers
Adenosine

Long term treatment:
Beta Blockers
Calcium Channel Blockers
Class 1A, 1C and III antiarrythmics for resistant cases

Question 19

1st degree AV Block EKG

Answer 19

PR interval greater than 0.20

Question 20

2nd degree AV Block-Mobitz Type I(Wenckebach)

Answer 20

occurs in the AV node above the Bundle of His
often transient and may be due to acute inferior MI or digitalis toxicity
Treatment is usually not indicated as this rhythm usually produces no symptoms
PR interval gets progressively longer until a QRS is dropped (or blocked)

Question 21

2nd degree AV Block-Mobitz Type II

Answer 21

occurs below the Bundle of His and may progress into a higher degree AV block.
Out of the blue drops a Q for type II, PR is normal until dropped QRS
Treatment = permanent pacemaker

Question 22

3rd degree heart block EKG findings

Answer 22

Atrial rate is normal
Ventricular rate is less than 70/bpm
Atrial rate is always faster than ventricular rate.
P waves: normal with constant P-P intervals, but not “married” to the QRS complexes.
QRS: may be normal or widened

Question 23

Premature Ventricular Contractions(PVC’s)

Answer 23

Rate: variable
P wave – usually obscured by the QRS with the PVC
QRS: Wide > 0.12, morphology is bizarre

Question 24

Premature Ventricular Contractions Treatment

Answer 24

Lidocaine - Class 1B antiarrhythmic
Procainamide (Pronestyl) - Class 1A antiarrythmic
Amiodarone (Cordorone) – Class III antiarrhythmic
Replace Magnesium, potassium if appropriate