Arrhythmias lecture

Question 1

Describe how the heart works in one sentence

Answer 1

Electrical and mechanical properties working in synchrony

Question 2

Counseling point: What are 2 potential negatives of Antiarrhythmic drugs (AADs)?

Answer 2

Proarrhythmic effects and organ toxicities

Question 3

Abnormal conduction: Tachyarrhythmias
Differentiate the two main kinds of tachyarrhythmias

Answer 3

Automatic = impulse generation
Reentrant = impulse conduction

Question 4

What class of antiarrhythmics are more effective in ventricular arrhythmias than supraventricular arrhythmias?

Answer 4

Class Ib (lidocaine and mexiletine)

Question 5

What class of antiarrhythmics’ use for ventricular arrhythmias has been limited by the risk of proarrhythmia effects

Answer 5

Class Ic (flecainide and propafenone)

Question 6

Antiarrhythmics: Out of “Slow on-off” and “fast on-off” drugs, which is more potent?

Answer 6

“Slow on-off”

Question 7

Weak bases: Acidosis will ___________ sodium channel blockade; alkalosis will diminish sodium channel blockade

Answer 7

accentuate; diminish

Question 8

Name a drug with Beta-blocking properties

Answer 8

propafenone

Question 9

Class II: beta-blockers
Inhibit adrenergic activation of _______ and ______ node

Answer 9

SA and AV

Question 10

Class III: potassium channel blockers:
What do Amiodarone and Dronedarone have in common?

Answer 10

1) Both inhibit sodium & calcium and are non-selective beta-blockers
2) Very similar chemical structures

Question 11

Class III: potassium channel blockers:
1) Amiodarone: What can it treat?
2) What’s different about Dronedarone?

Answer 11

1) Supraventricular and ventricular arrhythmias
2) Very similar chemical structure when compared to amiodarone, but w addition of a methylsulfonyl group and the removal of iodine (so no thyroid issues)

Question 12

Class IV: non-dihydropyridine calcium channel blockers:
1) List the 2 members of this class
2) What can they Tx?

Answer 12

1) Verapamil and diltiazem
2) Tachycardias which arise from the SA or AV nodes

Question 13

List some adverse effects of antiarrhythmic drugs

Answer 13

1) Worsening of heart failure with HFrEF
2) Precipitation of ventricular arrhythmias
-All anti-arrhythimics
-QT-prolongation

Question 14

Name a side effect of mexiletine

“probably repeated later (slide 16)”

Answer 14

GI and neurologic toxicity

Question 15

List some side effects of Flecainide

“probably repeated later (slide 16)”

Answer 15

Blurred vision, dizziness, dryness, headache, tremor, nausea, worsening HF, conduction disturbances, ventricular arrythmias

Question 16

List some side effects of Propafenone

“probably repeated later (slide 16)”

Answer 16

Dizziness, fatigue, blurred vison, bronchospasm, headache, taste disturbances, nausea, vomiting, bradycardia or AV block, worsening HF, ventricular arrythmias

Question 17

List some side effects of Amiodarone

“probably repeated later (slide 16)”

Answer 17

Tremor, ataxia, paresthesia, insomnia, corneal microdeposits, optic neuropathy/ neuritis, nausea, vomiting, anorexia, constipation, TdP (<1%), etc

Question 18

List some side effects of Dofetilide

“probably repeated later (slide 16)”

Answer 18

Headache, dizziness, TdP

Question 19

List some side effects of dronedarone

“probably repeated later (slide 16)”

Answer 19

Nausea, vomiting, diarrhea, serum creatinine elevations, bradycardia, worsening HF, hepatotoxicity, pulmonary fibrosis, acute renal failure, etc

Question 20

List some side effects of Sotalol

“probably repeated later (slide 16)”

Answer 20

Dizziness, weakness, fatigue, nausea, vomiting, diarrhea, bradycardia or AV block, TdP, bronchospasm, worsening HF

Question 21

List 5 adverse effects of Amiodarone

Answer 21

Severe bradycardia, hypo or hyperthyroidism, peripheral neuropathy, GI discomfort, photosensitivity

Question 22

List the 3 main groups of interactions with amiodarone

Answer 22

1) CYP3A4 substrate
2) CYP3A4, CYP2D6, CYP2C9 inhibitor
3) P-gp inhibitor

Question 23

1) Amiodarone is a CYP3A4, CYP2D6, CYP2C9 inhibitor; what does this cause it to interact with which drug?
2) What should you do if you’re already taking this other drug and starting amiodarone?
3) What if you’re already taking amiodarone and starting this other drug?

Answer 23

1) Warfarin = increases INR
2) Reduce dose of warfarin by 30%
3) Start warfarin at 2.5mg PO Qday

Question 24

Amiodarone being a P-gp inhibitor causes it to interact with what? What should you do when starting amiodarone while taking this drug?

Answer 24

Digoxin; reduce dose of digoxin by 50% when starting amiodarone

Question 25

True or false: You should recommend a new weekly dose for a patient taking warfarin while starting amiodarone

Answer 25

True

Question 26

Amiodarone vs. dronedarone 1) Which has decreased lipophilicity and half-life? 2) They have similar adverse effects; what are they?

Answer 26

1) Dronedarone 2) Organ toxicities: pulmonary fibrosis, severe hepatic injury or acute kidney injury

Question 27

Amiodarone & dronedarone have similar CYP and P-gp interactions; what should you do with both of these drugs because of it?

Answer 27

Dose reduce digoxin by 50% Monitor warfarin INR

Question 28

What should you do with dronedarone & dabigatran

Answer 28

Increase of dabigatran concentrations in patients with renal impairment Decrease dabigatran to 75mg PO BID is CrCl = 30 – 50 mL / min Contraindicated if CrCl < 30 mL / min Side note: The CrCl dose reduction for secondary stroke prevention is different ↓ dose to 75 mg BID if CrCl = 15 – 30 mL / min

Question 29

True or false: Amiodarone and dronedarone don't require renal dosing

Answer 29

True

Question 30

List the typical maintenance doses for amiodarone and dronedarone

Answer 30

1) Amiodarone: 10g total, and then 200-400mg/day 2) Dronedarone: 400mg BID (w. meals)

Question 31

List 3 clinical situations in which you may use amiodarone

Answer 31

1) Pulseless VT/ VF 2) Stable VT (with a pulse) 3) AF (termination)

Question 32

When may you use diltiazem?

Answer 32

PSVT; AF (rate control)

Question 33

When may you use ibutilide?

Answer 33

AF (termination)

Question 34

When may you use lidocaine?

Answer 34

1) Pulseless VT/ VF 2) Stable VT (with a pulse)

Question 35

When may you use procainamide?

Answer 35

AF (termination); stable VT (with a pulse)

Question 36

When may you use verapamil?

Answer 36

PSVT; AF (rate control)

Question 37

1 in 4 lifetime risk if 40 years or older of what?

Answer 37

Atrial fibrillation and atrial flutter

Question 38

With AF, ventricular rate is usually _____________ and the pulse is irregular

Answer 38

90-170bpm

Question 39

Acute treatment: restoring ventricular rate (rate control) With hemodynamic instability, what is indicated as first-line therapy in an attempt to immediately restore SR (without regard to the risk of thromboembolism)?

Answer 39

Direct current cardioversion (DCC)

Question 40

Acute treatment: restoring ventricular rate (rate control) when hemodynamically stable: 1) What should you do if normal left ventricular funct.? 2) What if the pt has HFrEF? 3) What if the pt has HFpEF? 4) What if the pt has any kind of HF and is acutely decompensated?

Answer 40

1) IV beta-blocker: propranolol, metoprolol or esmolol 2) IV beta-blocker 3) IV non-DHP CCB 4) Amiodarone or digoxin

Question 41

True or false: Many patients with AF spontaneously convert to SR without intervention; obviating the need for therapy to achieve this goal

Answer 41

True

Question 42

Acute treatment for restoring sinus rhythm (rhythm control): What should you do for normal left ventricular function or HFpEF?

Answer 42

Oral beta-blocker or non-DHP CCBs Can consider adding digoxin to lower heart rate to goal of 80 – 110 bpm

Question 43

What is the acute treatment for thromboembolic risk reduction when a pt has had AF for >48 hrs?

Answer 43

Warfarin (INR = 2 – 3)

Question 44

Acute treatment: For thromboembolic risk reduction for AF > 48 hours, what approach should you use?

Answer 44

Transesophageal echocardiogram (TEE) guided approach

Question 45

Acute treatment: For thromboembolic risk reduction for AF > 48 hours, what should you use either inpatient or outpatient at the time of TEE?

Answer 45

1) Inpatient Administer heparin or Lovenox at time of TEE If no thrombus is visualized on the TEE, cardioversion should then be performed within 24 hours of the TEE 2) Outpatient Administer warfarin at time of TEE Cardioversion should then be performed in 5 days If cardioversion is successful, continue warfarin or DOAC for four weeks

Question 46

Describe acute treatment for thromboembolic risk reduction for AF < 48 hours

Answer 46

Heparin or DOAC if high risk prior to cardioversion Men with a CHA2DS2-VASc score of at least 2 or women with a CHA2DS2-VASc score of at least 3 Continue DOAC indefinitely if no high risk of bleeding

Question 47

List the doses for the 2 outpatient “pill-in-the-pocket” drugs (used for pharmacologic cardioversion to sinus rhythm)

Answer 47

1) Propafenone PO > 70 kg = 600 mg < 70 kg = 450 mg 2) Flecainide PO > 70 kg = 300 mg < 70 kg = 200 mg

Question 48

Pharmacologic cardioversion appears to be most effective when initiated within ___ days after the onset of AF

Answer 48

7

Question 49

Describe acute treatment for pharmacologic cardioversion to sinus rhythm in an inpatient setting if: 1) No comorbidities 2) Left ventricular dysfunction or hypertrophy, coronary artery disease or valvular heart disease

Answer 49

1) Flecainide & propafenone 2) Amiodarone & dofetilide

Question 50

How do you determine the need for anticoagulation as a chronic therapy?

Answer 50

CHA2DS2-VASc

Question 51

CHA2DS2-VASc: What score indicates chronic anticoag therapy for males and females?

Answer 51

No antithrombotic therapy is recommended for males with a CHA2DS2-VASc score of 0 and females with a CHA2DS2-VASc score of 1

Question 52

Describe chronic (lifelong) anticoag therapy

Answer 52

1) DOAC are preferred over warfarin unless cost or patient factors preclude use 2) Warfarin (Coumadin) Inexpensive Anticoagulant of choice if patient has mechanical heart valve

Question 53

Chronic therapy – anti-arrhythmic therapy 1) For HFrEF, what are the 2 first line options? 2) What 2 things should you avoid w HFrEF? Why?

Answer 53

1) Amiodarone and dofetilide 2) Avoid dronedarone (increased mortality) and sotalol (worsening heart failure)

Question 54

Chronic therapy – anti-arrhythmic therapy 1) If a pt has LV hypertrophy and no heart failure, you should use what?

Answer 54

amoidarone [or dronedarone?]