Antiarrhythmics

Class IA

(7)

• Sodium Channel Blockers 
• Prolong QT interval;    
• Slow to intermediate kinetics
• Drugs
• procainamide (Pronestyl)
• quinidine (Quinidex)
• disopyramide (Norpace)

Antiarrhythmics

Class IA

Sodium Channel Blockers (Prolong QT interval;    Slow to intermediate kinetics)

Procainamide (Pronestyl)

Clinical Uses

(3)

• Acute and chronic treatment of 
• ventricular tachycardia
• ventricular fibrillation (VF)
•  supraventricular arrhythmias

Antiarrhythmics

Class IA

Sodium Channel Blockers (Prolong QT interval;    Slow to intermediate kinetics)

Procainamide (Pronestyl)

Toxicities

(5)

• Common
• 40% of patients discontinue within 6 months of therapy due to side effects: hypotension, nausea.
• Torsades de pointes
• Unique; Clinically Important
• Lupus-like syndrome (25-50% with chronic) that can be fatal; starts with rash and mild arthralgia

Antiarrhythmics

Class IA

Sodium Channel Blockers (Prolong QT interval;    Slow to intermediate kinetics)

quinidine (Quinidex)

Clinical Uses

(2)

• Chronic treatment of atrial flutter/fibrillation (AF)
• Chronic treatment of ventricular tachycardia and VF

Antiarrhythmics

Class IA

Sodium Channel Blockers (Prolong QT interval;    Slow to intermediate kinetics)

quinidine (Quinidex)

Toxicities

(9)

• Common
• Diarrhea (30-50%)
• Cinchonism: 
• CNS, 
• hypotension, 
• syncope, 
• GI
• Unique; Clinically Important
• Long QT (torsades de pointes)

Antiarrhythmics

Class IA

Sodium Channel Blockers (Prolong QT interval;    Slow to intermediate kinetics)

disopyramide (Norpace)

Clinical Uses

(2)

• Chronic treatment of atrial flutter/AF
• Chronic treatment of ventricular tachycardia and VF

Antiarrhythmics

Class IA

Sodium Channel Blockers (Prolong QT interval;    Slow to intermediate kinetics)

disopyramide (Norpace)

Toxicities

(5)

• Common
• Anticholinergic effects
• Unique; Clinically Important
• Can worsen heart failure
• Long QT (torsades de pointes)

Antiarrhythmics

Class 1B

(6)

• Sodium Channel Blockers
• Little effect on ECG;
• fast kinetics
• Drugs
• lidocaine (Xylocaine)
• mexiletine (Mexitil)

Antiarrhythmics

Class 1B

Sodium Channel Blockers (Little effect on ECG; fast kinetics)

lidocaine (Xylocaine) 

Clinical Uses

Chronic treatment of ventricular tachycardia and VF

Antiarrhythmics

Class 1B

Sodium Channel Blockers (Little effect on ECG; fast kinetics)

lidocaine (Xylocaine)  

Toxicities

(9)

• Common
• CNS: 
• seizures and 
• tinnitus 
• Unique; Clinically Important
• CNS:
•  tremor, 
• hallucinations, 
• drowsiness, 
• coma
• Severe interactions with other anti-arrhythmics

Antiarrhythmics

Class 1B

Sodium Channel Blockers (Little effect on ECG; fast kinetics)

mexiletine (Mexitil) 

Clinical Uses

Chronic treatment of ventricular tachycardia and VF

Antiarrhythmics

Class 1B

Sodium Channel Blockers (Little effect on ECG; fast kinetics)

mexiletine (Mexitil)  

Toxicities

(3)

• Common
• Tremor and 
• nausea
• Unique; Clinically Important
• Severe interactions with other anti-arrhythmics

Antiarrhythmics

Class IC

(6)

• Sodium Channel Blockers 
• Prolong PR & broaden QRS intervals; 
• slow kinetics
• Drugs
• flecainide (Tambocor)
• propafenone (Rythmol)

Antiarrhythmics

Class IC

Sodium Channel Blockers (Prolong PR & broaden QRS intervals; slow kinetics)

flecainide (Tambocor)

Clinical Uses

(2)

• Chronic treatment of AV nodal reentry in patients w/o structural heart disease
• Chronic treatment of life-threatening ventricular arrhythmias 

Antiarrhythmics

Class IC

Sodium Channel Blockers (Prolong PR & broaden QRS intervals; slow kinetics)

flecainide (Tambocor)

Toxicities

(3)

• Common
• Blurred vision
• Can worsen heart failure 
• Unique; Clinically Important
• Life-threatening CAST proarrhythmia in patients with MI

Antiarrhythmics

Class IC

Sodium Channel Blockers (Prolong PR & broaden QRS intervals; slow kinetics)

propafenone (Rythmol) 

Clinical Uses

• Chronic treatment of AV nodal reentry (PSVTs) and AF
• Chronic treatment of ventricular arrhythmias (modest efficacy)

Antiarrhythmics

Class IC

Sodium Channel Blockers (Prolong PR & broaden QRS intervals; slow kinetics)

propafenone (Rythmol) 

Toxicities

(2)

• Common
•  Beta-adrenergic blocking effects (worsening of heart failure and bronchospasm)
• Unique; Clinically Important
• Can increase frequency or severity of ventricular tachycardias

Class II

(5)

• Beta-Adrenergic Antagonists
• Drugs
• propranolol (Inderal)
• sotalol (Betapace)
• esmolol (Brevibloc)

Class II

Beta-Adrenergic Antagonists

Propranolol (Inderal)

Clinical Uses

(2)

• Chronic treatment of torsades de pointes
• Rate control in AF

Class II

Beta-Adrenergic Antagonists

Propranolol (Inderal)

Toxcities

(1)

• Common
• Beta-adrenergic blocking effects (worsening of heart failure and bronchospasm)
• Unique; Clinically Significant

Class II

Beta-Adrenergic Antagonists

Sotalol (Betapace)

Clinical Uses

Class II

Beta-Adrenergic Antagonists

Sotalol (Betapace)

Toxcities

(2)

• Common
• Beta-adrenergic blocking effects
• Unique; Clinically Significant
• Long QT (torsades de pointes)

Class II

Beta-Adrenergic Antagonists

Esmolol (Brevibloc)

Clinical Uses

Class II

Beta-Adrenergic Antagonists

Esmolol (Brevibloc)

Toxcities

(1)

• Common
• Beta-adrenergic blocking effects (dissipate rapidly when drug is removed)
• Unique; Clinically Significant

Class III

(7)

• Increase Refractory Period (Prolong QT)
• Drugs
• Amiodarone (Cordarone)
• Dronedarone (Multaq)
• Sotalol (Betapace)
• Dofetilide (Tikosyn)
• Ibutilide (Corvert)

Class III

Increase Refractory Period (Prolong QT)

Amiodarone (Cordarone)

(7)

• Clinical Uses
• Acute and chronic treatment of ventricular tachycardia
• *Acute and chronic treatment of VF
• Chronic treatment of AF
• Toxicities
• Common
• Hypotension and depressed ventricular function with IV
• Unique; Clinically Important
• Pulmonary fibrosis with chronic therapy which can be fatal (requires periodic monitoring of lung function)
• Many other AEs: corneal microdeposits, hepatotoxicity, neuropathies photosensitivity, thyroid dysfunction
• Note: Tissue half life of several months

Class III

Increase Refractory Period (Prolong QT)

Dronedarone (Multaq)

Clinical Uses

Chronic treatment of atrial flutter/AF

Class III

Increase Refractory Period (Prolong QT)

Dronedarone (Multaq)

Toxicities

(5)

• Common
• GI disturbances
• Less than amiodarone
• Unique; Clinically Important
• Increases mortality in patients with severe heart failure

Class III

Increase Refractory Period (Prolong QT)

Sotalol (Betapace)

Clinical Uses

(2)

• Chronic treatment of ventricular tachycardia
• Chronic treatment of atrial flutter/AF      

Class III

Increase Refractory Period (Prolong QT)

Sotalol (Betapace)

Toxicities

(2)

• Common
• Beta-adrenergic blocking effects
• Unique; Clinically Important
• Long QT (torsades de pointes)

Class III

Increase Refractory Period (Prolong QT)

Dofetilide (Tikosyn)

Clinical Uses

Class III

Increase Refractory Period (Prolong QT)

Dofetilide (Tikosyn)

Toxicities

(1)

• Common
• Unique; Clinically Important
• Long QT (torsades de pointes)

Class III

Increase Refractory Period (Prolong QT)

Ibutilide (Corvert)

Clinical Uses

Class III

Increase Refractory Period (Prolong QT)

Ibutilide (Corvert)

Toxicities

• Common
•  
• Unique; Clinically Important
• Long QT (torsades de pointes)

Class IV

(6)

• Ca2+ Channel Blockers 
• Non-dihydropyridine; 
• Inhibit SA and AV nodes; 
• Prolong PR
• Drugs
• Diltiazem (Cardizem)
• Verapamil (Calan)

Class IV

Ca2+ Channel Blockers (Non-dihydropyridine; Inhibit SA and AV nodes; Prolong PR)

Diltiazem (Cardizem)

Clinical Uses

(2)

• Acute and chronic treatment of AV nodal reentry (PSVTs)
• Acute and chronic control of  ventricular rate in atrial flutter/AF

Class IV

Ca2+ Channel Blockers (Non-dihydropyridine; Inhibit SA and AV nodes; Prolong PR)

Diltiazem (Cardizem)

Toxicities

(2)

• Common
• Hypotension       
• Unique; Clinically important
• Sinus bradycardia or AV block in combination with beta-blockers

Class IV

Ca2+ Channel Blockers (Non-dihydropyridine; Inhibit SA and AV nodes; Prolong PR)

Verapamil (Calan)

Clinical Uses

(2)

• Acute and chronic treatment of AV nodal reentry (PSVTs)
• Acute and chronic control of  ventricular rate in atrial flutter/AF         

Class IV

Ca2+ Channel Blockers (Non-dihydropyridine; Inhibit SA and AV nodes; Prolong PR)

Verapamil (Calan)

Toxicities

(2)

• Common
• Constipation
•  Unique; Clinically important
• Sinus bradycardia or AV block in combination with beta-blockers

Adenosine (Adenocard)

(7)

• Class
• Miscellaneous:Adenosine receptor agonist
• Clinical Uses
• *Acute treatment of AV nodal reentry
• Toxicities
• Common
• Asystole (<5 seconds)
• Dyspnea
• Unique; Clinically important
• Short half-life (< 5 seconds) minimizes toxicities

Magnesium sulfate

(2)

• Class
• Miscellaneous: Unknown mechanism   
• Clinical Uses
• Acute treatment of torsades de pointes

Digoxin (Lanoxin) 

(8)       

• Class
• Miscellaneous: Na+,K+ -ATPase inhibitor that increases vagal tone
• Clinical Uses
• Ventricular rate control in atrial fibrillation       
• Toxicities
• Common
• GI, 
• vision, 
• cognitive dysfunction
• Unique; Clinically important
• Arrhythmias
• Sinus bradycardia and AV block
• Severe toxicities can be treated w/ antibody (Digibind)