Flashcards in antiarrhythmia drugs 2 Deck (23):
1
direct results of block of L-type Ca2+ channels are?
1. Slowed upstroke
2. reduced AP amplitude
2
What results indirectly from L channel block?
Slowed repolarization (phase 3)
3
In SA and AV node, adenosine (via A1 adenosine receptor) works to?
1. ↑ K+ current
2. ↓ L-type Ca2+ current (dihydropyridine-sensitive, slow inward current)
3. ↓ If in SA and AV nodes
4
adenosine action
similar to β-adrenergic receptor blockers, but adenosine is not a β-blocker.
5
Adenosine-induced changes in membrane currents:
↓ SA node and AV node firing rate
↓ conduction rate in the AV node
6
Antiarrhythmic drugs are primary therapy for
1. atrial fibrillation only
2. Ablation or ICD equal or superior in management of all other arrhythmias
7
PSVT: tx acute with
adenosine (short half-life is advantageous)
8
PSVT: tx chronic with
1. AV nodal blockers
2. Class II (β-blockers)
3. Class IV (Ca2+ channel blockers)
4. Class III (amiodarone, sotalol)
5. catheter ablation of ectopic focus
9
Ventricular tachycardias/fibrillation pathophysiology via
afterdepolarizations + re-entry
10
Ventricular tachycardias/fibrillation: treat acute with
1. amiodarone
2. lidocaine
11
esmolol metabolize by
blood esterase
12
amiodarone side effects
1. heart block
2. thyroid dysfunction
3. corneal deposits
4. pulmonary fibrosis
13
Drug prevention of sudden cardiac death:
Proven benefit
1. β-blockers
2. angiotensin converting enzyme (ACE) inhibitors
3. aspirin
4. statins
14
Drug prevention of sudden cardiac death:
perhaps benefit
1. amiodarone
2. digoxin
15
Drug prevention of sudden cardiac death:
perhaps harmful
1. Class I drugs (Na+ channel blockers)
2. Class IV drugs (Ca2+ channel blockers)
16
Procainamide major side effect
1. Lupus syndrome (occurs in 1/3 of patients on long-term therapy).
2. class Ia
17
Lidocaine major side effects
1. Least cardiotoxic agent of Class I drugs.
2. Side effects: paresthesia, tremors, seizures, agitation, confusion.
3. class Ib
18
Flecainide and Propafenone Major side effects
1. Highly pro-arrhythmic, particularly with ventricular tachycardia.
2. class Ic
19
B-blocker major side effects
1. Hypotension
2. aggravation of heart failure
3. bronchospasm
4. impotence.
20
amiodarone major side effects
1. Cardiac problems include bradycardia and heart block.
2. Dose-related effects include:
a. thyroid dysfunction,
b. corneal deposits,
c. pulmonary fibrosis and
d. skin discoloration.
3. Problems with side effects are exacerbated by the very long half-life of amiodarone (13-100 days).
4. Class 3
21
sotalol major side effects
1. Structurally, this drug is a β-adrenergic receptor ligand.
2. Principal side effects are similar to those of the other β-blockers.
3. class 3
22
verapamil major side effects
1. The major adverse effect of these drugs is hypotension
(via action on vascular smooth muscle.)
2. Negative cardiac inotropy
3. class 4
23