Different Ventricular Arryhthmias

Question 1

Which drugs are used for rhythm control?

Answer 1

Class I: Disopyramide, Qunidine, Procainamide

Class III: Amidarone (Pacerone), Dronedarone (Multaq), Dofetilide (Tikosyn), Sotalol (Betapace)

Question 2

Which drugs are used for rate control?

Answer 2

Class II: Beta-blockers

Class 4: non-DHP-CCBs

Question 3

Main Atrial Arrhythmias

Answer 3

-Afib: irregularly irregular rhythm

-Aflutter: can be regularly irregular rhythm (AV nodal conduction in consistent ratio)
-> Treatment is the same as is in Afib: Rate control versus rhythm control

Question 4

Supraventricular tachycardia (SVT)

Answer 4

-Atrioventricular reentrant tachycardia above the bundle of His

-typically initial depolarization from the SA node, then reentry from the ventricle
-reentry circuit from the ventricle back to the atrium

-patient presents with extreme tachycardia
-narrow complex

Question 5

Which arrhythmias are considered narrow VS wide?

Answer 5

-narrow (QRS) complex -> atrial arrhythmias

-wide (QRS) complex -> ventricular arrhythmias

Question 6

Which drug is used to treat SVT?

Answer 6

Adenosine
-blocks conduction through the AV node -> resulting in a reset of the reentry pathway

Question 7

How is Adenosine administered?

Answer 7

-6 mg over 1-2 sec -> immediately rapid flush of 20 ml NS

-if ineffective: increase to 12 mg -> NS flush
-if ineffective: DC -> cardioversion (shock back to a normal rhythm)

-after that, a rate-controlling agent is needed: Class II or IV (Metoprolol succinate or CCB)

Question 8

Ventricular Arrhythmias

Answer 8

-Premature ventricular complexes (PVCs)
-Ventricular tachycardia (Vtach)
-Ventricular fibrillation (Vfib)
-Torsades de pointes (TdP) - polymorph Vtach
-Sinus bradycardia
-Atrioventricular node block (AVB

Question 9

How are PVC patients managed?

Answer 9

-benign: young healthy asymptomatic

-when benign -> symptoms treatment with BB

-concerning if: with structural heart disease or ischemic event -> may lead to ventricular tachycardia
-> treat with AAD

Question 10

In the CAST trial, which drugs were associated with post-MI and HF - increased mortality?

Answer 10

-Class Ic: Encainide, Flecainide, Morizicine

-worked well: Amiodarone (pacerone), Dronedarone (Multaq)
-> Dronedarone is NOT safe for patients with HF and Afib

Question 11

Which arrhythmic disease is referred to as polymorphic Vtach (ventricular tachycardia)?

Answer 11

Torsades de Pointes (Tdp)

Question 12

What are potential causes of Torsades de Pointes?

Answer 12

-Hypokalemia (may caused by diuretic) -> replenish K+
-Hypomagnesia -> replenish
-Hypoxia
-Digoxin toxicity
-Acute MI
-CCB (prolong the QT interval -> higher risk for Tdp)

Question 13

Other drugs causing Tdp

Answer 13

QT-prolonging drugs
Class Ia: Qunidine
Class III

Question 14

When might a Bradyarrhtmia be concerning?

Answer 14

-in elderly patients:
SA node dysfunction
tachy-brady syndrome: run high and low

-pacemaker therapy: patients may be treated with a BB/CCB and a pacemaker at the same time

Question 15

AV node block

Answer 15

-interruption of impulse transmission from the atria to the ventricles
-may need atropine

Question 16

Where to avoid Class Ic drugs?

Answer 16

in patients with a history of MI (post-MI) and LV dysfunction (CAST trial)

Encainide
Flecainide
Morizicine

Question 17

In which patient population should Dronedarone (Multaq) be avoided?

Answer 17

patients with HF and Afib

Question 18

Which drug should be initiated inpatient?

Answer 18

Dofetilide (Tikosyn)

Class I/III are safer when initiated inpatient

Question 19

Complexitiy of Amiodarone

Answer 19

-blocks K+ channel (primarily) -> QTc prolonging!
-blocks Na+ channel
-Beta-blocker activity: slows HR

Question 20

ADR of Amiodarone (pacerone)

Answer 20

-Hepatoxicity
-Pulmonary fibrosis
-Hyperthoiridsm/Hypothyroidism
-Eye and skin toxicity
-somewhat QTc

Question 21

What class does Sotalol belong to?

Answer 21

-Class III -> prolongs QT
-L-isomer with Class II beta-blocking activity
-renal elimination

Question 22

What to monitor when using Dofetilide

Answer 22

-given PO inpatient

-monitor QT interval
-monitor electrolytes and ECG
-monitor renal function

Question 23

Common QT-prolonging drugs

Answer 23

-Class III: amiodarone, dofetilide, sotalol
-FQ
-azoles
-antipsychotics (quetiapine)
-macrolides: azithromycin, clarithromycin
-ondansetron
-methadone

levels of 450-500 are high and should be monitored closely

Question 24

Which drug classes can cause AV nodal blockade?

Answer 24

-non-DHP-CCB
-BB