Atrial flutter antiarrhythmics

The uses of the antiarrhythmic drug are given in the Summaiy Drug Table Antiarrhythmic Drug3. In general these drugp are used to prevent and treat cardiac arrhythmias, such as premature ventricular contractions (PVCs), ventricular tachycardia (VT), premature atrial contractions (PACs), paroxysmal atrial tachycardia (PAT), atrial fibrillation, and atrial flutter. Some of the antiarrhythmic dru are used for other... 

Indications. Verapamil is used as an antiarrhythmic drug in supraventricular tachyarrhythmias. In atrial flutter or fibrillation, it is effective in reducing ventricular rate by virtue of inhibiting AV-conduction. Verapamil is also employed in the prophylaxis of angina pectoris attacks (p. 308) and the treatment of hypertension (p. 312). Adverse effects Because of verapamil s effects on the sinus node, a drop in blood pressure fails to evoke a reflex tachycardia Heart rate hardly changes bradycardia may even develop. AV-block and myocardial insufficiency can occur. Patients frequently complain of constipation. 

Procainamide is an effective antiarrhythmic agent when given in sufficient doses at relatively short (3-4 hours) dosage intervals. Procainamide is useful in the treatment of premature atrial contractions, paroxysmal atrial tachycardia, and atrial fibrillation of recent onset. Procainamide is only moderately effective in converting atrial flutter or chronic atrial fibrillation to sinus rhythm, although it has... 

The antiarrhythmic actions and uses of diltiazem (Cardizem see Chapter 19) are similar to those of verapamil. Diltiazem is effective in controlling the ventricular rate in patients with atrial flutter or atrial fibrillation. The pharmacology of diltiazem is discussed in detail in Chapter 19. 

Ohmura K, Kobayashi Y, Miyauchi Y, et al. Electrocardiographic and electrophysiological characteristics of atrial fibrillation organized into atrial flutter by oral administration of class I antiarrhythmic agents. Pacing Clin Electrophysiol. 2003 26 692-702. 

Stambler BS, Wood MA, Ellenbogen KA. Antiarrhythmic actions of intravenous ibutilide compared with procainamide during human atrial flutter and fibrillation electrophysiological determinants of enhanced conversion efficacy. Circulation 1997 96( 12) 4298-4306. 

FIGURE 6-1. Algorithm for the treatment of atrial fibrillation (AF) and atrial flutter. °lf AF <48 hours, anticoagulation prior to cardioversion is unnecessary may consider transesophageal echocardiogram (TEE) if patient has risk factors for stroke. Ablation may be considered for patients who fail or do not tolerate one antiarrhythmic drug (AAD). Chronic antithrombotic therapy should be considered in all patients with AF and risk factors for stroke regardless of whether or not they remain in sinus rhythm. (BB, 8-blocker CCB, calcium channel blocker p.e., verapamil or diltiazem] DCC, direct-current cardioversion.)... 

Natale A, Newby KH, Pisano E, Leonelli F, Fanelli R, Potenza D, Beheiry S, Tomassoni G. Prospective randomized comparison of antiarrhythmic therapy versus first-line radiofrequency ablation in patients with atrial flutter. J Am Coll Cardiol 2000 35(7) 1898-904. 

Brembilla-Perrot B, Houriez P, Beurrier D, Qaudon O, Terrier de la Chaise A, Louis P. Predictors of atrial flutter with 1 1 conduction in patients treated with class I antiarrhythmic drugs for atrial tachyarrhythmias. Int J Cardiol 2001 80(1) 7-15. 

Suttorp MJ, Polak PE, van t Hof A, Rasmussen HS, Dunsehnan PH, Kingma JH. Efficacy and safety of a new selective class III antiarrhythmic agent dofetilide in paroxysmal atrial fibrillation or atrial flutter. Am J Cardiol 1992 69(4) 417-19. 

Schumacher B, Jung W, Lewalter T, Vahlhaus C, Wolpert C, Luderitz B. Radiofrequency ablation of atrial flutter due to administration of class IC antiarrhythmic drugs for atrial fibrillation. Am J Cardiol 1999 83(5) 710-13. 

MackstaUer LL, Marcus FI. Rapid ventricular response due to treatment of atrial flutter or fibrillation with Class I antiarrhythmic drugs. Arm Noninvasive Electrocardiol 2000 5 101. ... 

Kawabata M, Hirao K, Horikawa T, Suzuki K, Motokawa K, Suzuki F, Azegami K, Hiejima K. Syncope in patients with atrial flutter during treatment with class Ic antiarrhythmic drugs. J Electrocardiol 2001 34(l) 65-72. 

Amman EM, Beamer AD, Cantillon C, McGowan N, Friedman PL. Therapy of refractory symptomatic atrial fibrillation and atrial flutter a staged care approach with new antiarrhythmic drugs. J Am Coll Cardiol 1990 15(3) 698-707. 

Ibutilide. Ibutilidc, A - 4- 4-(cthylheptylaminoH-hy-droxybutyllphenyllmethanesulfonamidc (Corvert), a class III antiarrhythmic belonging to the mcthancsulfonanilidc class of agents, is indicated for rapid conversion of atrial Hbrillation or atrial flutter to normal sinus rhythm. Unlike dofetilide, it is not highly. specific for the delayed a clificr potassium currents (Ikr) and does have some affinity for. sodium channels. 

FIGURE 17-6. Algorithm for the treatment of atrial fibrillation and atrial flutter. Sx = symptoms AVN = AV node DCC = direct-current cardioversion CCB = calcium channel antagonist (verapamil or diltiazem) BB = jS-blocker ASA = aspirin OHD = organic heart disease AADs = antiarrhythmic drugs INR = international normalized ratio MVD = mitral valve disease CHF = congestive heart failure HTN = hypertension DM = diabetes mellitus. 

Dofetilide is an antiarrhythmic agent that causes blockade of the cardiac ion channel carrying the rapid component of the delayed rectifier potassium currents. Dofetilide is indicated in maintenance of normal sinus rhythm (delay in time to recurrence of atrial fibrillation/atrial flutter [AF/AFl]) in patients with AF/AFl of more than 1 week duration who have been converted to normal sinus rhythm and in conversion of AF/AFl to normal sinus rhythm. 

Esmolol is a class 11 antiarrhythmic agent with ultra-short-acting beta-adrenergic-blocking activity that is used (50 to 200 mcg/kg/minute) to treat supraventricular tachycardia such as atrial fibrillation or atrial flutter. It is rapidly metabolized by erythrocyte esterases via hydrolysis of the methyl ester. Unlike succinylcholine, esmolol is not metabolized by plasma cholinesterase (see also Eigures 67 and 83). 

Ibutilide is an antiarrhythmic agent that prolongs atrial and ventricular action potential duration and refractoriness by activation of a slow inward current (predominantly sodium). It is indicated for rapid conversion of recent onset atrial fibrillation or atrial flutter to sinus rhythm. 

Quinidine (200 to 600 mg t.i.d.), a cinchona alkaloid with antiarrhythmic properties, is indicated in premature atrial, AV junctional, and ventricular contractions paroxysmal atrial (supraventricular) tachycardia paroxysmal AV junctional rhythm atrial flutter paroxysmal and chronic atrial fibrillation established atrial fibrillation when therapy is appropriate paroxysmal ventricular tachycardia not associated with complete heart block and maintenance therapy after electrical conversion of atrial fibrillation or flutter (see Figure 103). 

Another important indication for antiarrhythmic therapy is to reduce ventricular rate in atrial flutter or fibrillation. Rare forms of ventricular tachycardia appear to be DAD-mediated and respond to verapamil. Parenteral verapamil and diltiazem are approved for rapid conversion of PSVTs to sinus rhythm and for temporary control of rapid ventricular rate in atrial flutter or fibrillation. Oral verapamil may be used in conjunction with digoxin to control ventricular rate in chronic atrial flutter or fibrillation and for prophylaxis of repetitive PSVT Unlike adrenergic receptor antagonists, Ca + channel blockers have not been shown to reduce mortality after myocardial infarction. 

Dofetilide is a Type III antiarrhythmic agent used in the treatment of chronic atrial fibrillation or atrial flutter. Physicians and hospital staff need to complete a dofetilide education program before the drug can be received by the hospital and prescribed. Dofetilide can cause fife-threatening ventricular arrhythmias and should therefore be used in select patients. 

When intravenous ibutilide 2 mg was used for cardioversion of atrial fibrillation or flutter in 70 patients taking long-term amiodarone the QT interval was further prolonged (iiom 371 to 479 milliseconds). However, only one patient had an episode of non-sustained torsade de pointes. Ibutilide was effective within 30 minutes of infusion in 39% of patients with atrial flutter, and 54% of patients with fibrillation. Both amiodarone and ibutilide are class III antiarrhythmics and prolong the QT interval, with the consequent risk of torsade de pointes. The manufacturer recommends that they should not be used concurrently. However, the authors of the above report suggest that ibutilide may be useful for cardioversion in those already taking amiodarone. Combined use should be very well monitored. 

Cosio, F.G., and Delpon, E. New Antiarrhythmic Drugs for Atrial Flutter and Atrial Fibrillation A Conceptual Breakthrough at Last Circulation 10S(3) 276-78, January 2002. 

Impulses originating at loci outside the sinus node are seen in supraventricular or ventricular extrasystoles, tachycardia, atrial or ventricular flutter, and fibrillation. In these forms of rhythm disorders, antiarrhythmics of the local anesthet-Ltillmann, Color Atlas of Pharmacology... 

Tikosyn Dofetilide 125, 250, 500 (jig Capsule Maintenance of normal sinus rhythm and conversion of atrial fibrillation/ flutter Cardiac ion channel blocker/ antiarrhythmic drug MCC, corn starch, silicon dioxide, magnesium stearate Pfizer... 

Frost L, Mortensen PE, Tingleff J, Platon ES, Christiansen EH, Christiansen N. Efficacy and safety of dofetilide, a new class III antiarrhythmic agent, in acute termination of atrial fibrillation or flutter after coronary artery bypass surgery. Dofetilide Post-CABG Study Group. Int J Cardiol 1997 58(2) 135 0. 

Falk RH, Poliak A, Singh SN, Friedrich T. Intravenous dofetilide, a class III antiarrhythmic agent, for the termination of sustained atrial fibrillation or flutter. Intravenous Dofetilide Investigators. J Am CoU Cardiol 1997 29(2) 385-90. 

Indications Atrial fibrillation and flutter Category Antiarrhythmic class III Half-life 2-12 hours... 

Flecainide, is an antiarrhythmic agent that is indicated for prevention of paroxysmal supraventricular tachycardia including atrioventricular nodal reentrant tachycardia, atrioventricular reentrant tachycardia, and paroxysmal atrial fibrillation and flutter (see also Figure 84). 

---