Heart Healthy Women Logo

Heart Rhythm Drugs

What are heart rhythm problems (arrhythmias)?

An arrhythmia, or heart rhythm disturbance, is a change in the regular beat of the heart. The heart is divided into four chambers: two atria on top and two ventricles on the bottom. Arrhythmias are classified by their location as ventricular or atrial (sometimes called supraventricular meaning above the ventricle) and whether they slow the heart rate: bradycardia (heart rate less then 60 beats per minute); or speed it up: tachycardia (heart rate more than 100 beats per minute).

Are arrhythmias serious?

Heart rhythm disturbances can occur in people without heart disease and in many cases they are harmless. However, some heart rhythm disturbances affect the heart’s ability to pump blood around the body. In 2002, arrhythmias caused nearly 38,000 deaths.1 Arrhythmias can lead to sudden cardiac death, or SCD, often brought on by cardiac arrest, when the heart abruptly stops beating. If the heart is not restarted immediately with an electric shock ( defibrillation), death can occur. Most cases of SCD occur in people with heart disease, and SCD accounts for half the deaths from cardiovascular disease.2 Each year, three to four times more men experience SCD than women, but the gender gap closes with older age.1

Who should take medication for heart rhythm problems?

This section will focus on the use of antiarrhythmic medications in people with heart disease (fatty plaque buildup in the arteries of the heart), particularly heart attack patients. Heart rhythm disturbances are common early after heart attack symptoms develop.3 Previously, antiarrhythmic medications were given to heart attack patients to help prevent heart rhythm problems from occurring in the first place. Now it is known that in most cases, these drugs do more harm than good when used preventively (beta blockers are the exception).

Currently, heart rhythm medications are reserved for occasionally treating serious heart rhythm problems when they arise. Implantable cardioverter defibrillators (ICDs) and pacemakers are safer and better than drugs for the long-term treatment of serious heart rhythm problems. Some people with ICDs also take antiarrhythmic medication to reduce the likelihood of shocks.

There are four classes of antiarrhythmic medications categorized according to how they affect heart rhythm disturbances.4 A fifth group exists for drugs that do not fit into the other categories. Some medications have properties from more than one class (e.g., amiodarone). The heartbeat is controlled by an electrical conduction system that sends electrical charges to the heart muscle causing it to expand and contract. Antiarrhythmics work by slowing down the electrical signals in the heart so the heart can resume a regular rhythm.


Do sodium channel blockers prevent heart rhythm problems?

In the past, class I antiarrhythmics were routinely given to heart attack patients to prevent heart rhythm disturbances. However, many studies now show that these medications are not beneficial and actually increase the risk of dying because they often trigger heart rhythm disturbances.5-9 In a combined analysis of 138 studies involving 98,000 heart attack survivors, men and women treated with class I antiarrhythmics had a significantly higher risk of dying compared with patients given dummy pills.8 For these reasons, class I medications are no longer routinely prescribed to heart attack patients. Some of these medications may be injected through an IV line to treat continuing arrhythmias in hospitalized heart attack patients.

Prescribed Class I Antiarrhythmics

Class I Antiarrhythmics – Sodium Channel Blockers
(check with manufacturer for specific information on each drug)

Generic

Disopyramide / Flecainide / Mexiletine / Moricizine / Procainamide / Propafenone / Quinidine / Lidocaine

Brand:

Norpace / Tambocor / Mexitil / Ethmozine / Procanbid / Rhythmol / Quinidex Extentabs

Administration:

Oral

What are they used for:
  • Treatment of life-threatening ventricular arrhythmias
  • Delay the recurrence of:
  • Occasional atrial fibrillation/flutter
  • Occasional supraventricular tachycardia

You should not take these medications if:

  • If you have been diagnosed with:
  • Cardiogenic shock (the heart muscle is so damaged it cannot pump properly, causing a shock-like state)
  • Second- or third-degree heart block (the electrical signals between the upper and lower chambers of the heart are impaired)
  • Lupus
  • Torsade de pointes (a type of rapid heart beat that may be caused by a birth defect or by some medications)

Common side effects:
  • Arrhythmias (which can be fatal, particularly in people who have heart disease), digestive upset, dizziness, lightheadedness, tremor, retention of urine, and dry mouth

Pregnancy/nursing:
  • The safety of these medications during pregnancy is unknown
  • Women who are nursing should not use these medications; if the treatment is essential, then nursing should be discontinued

 


Do beta blockers prevent heart rhythm problems?

Class II antiarrhythmics, beta blockers, are the only heart rhythm medications used to prevent heart rhythm problems from occurring in the first place. In people who have had a heart attack, beta blockers reduce the risk of dying, having another heart attack, or experiencing sudden cardiac death.10-14 The risk of dying is reduced by 25% to 40%, and sudden cardiac death specifically is lowered by 30% to 45%.11-14 This survival benefit continues for up to 6 years after the heart attack.10 It is not fully understood how beta blockers prevent heart rhythm problems: they may have a direct antiarrhythmic effect, or their ability to widen arteries and increase blood flow to the heart may indirectly lower the risk of certain heart rhythm disturbances, particularly ventricular tachyarrhythmia (a rapid irregular heart beat originating in the lower chambers of the heart).

You may be given beta blockers shortly after heart attack symptoms begin. These medications should not be used in some patients including those with a slow heart rate or signs of heart failure, so doctors often wait 24 to 48 hours to rule out these conditions before giving patients beta blockers.3 A combined analysis of studies involving nearly 54,000 men and women who had a heart attack found that taking beta-blockers for up to four years reduced the chances of dying by 23%.15 If you had a heart attack, you will likely continue to take beta blockers for the rest of your life.

Prescribed Class II Antiarrhythmics

Class II Antiarrhythmics – Beta Blockers
(check with manufacturer for specific information on each drug)

Generic

Atenolol / Betaxolol / Bisprolol / Carvedilol / Metoprolol / Nadolol / Propanolol / Timolol

Brand:

Tenorim / Kerlone / Zebeta / Coreg / Toprol-XL / Corgard / Inderal LA / Blocadren

Administration:

Oral

What are they used for:
  • Management of high blood pressure
  • Long-term management of angina (chest pain)
  • To reduce the risk of dying or having another heart attack in stable heart attack patients

You should not be treated with these medications:
  • If you have been diagnosed with:
  • Cardiogenic shock (the heart muscle is so damaged it cannot pump properly, causing a shock-like state)
  • Second- or third-degree heart block (the electrical signals between the upper and lower chambers of the heart are impaired)
  • Very slow heart beat (bradycardia)
  • Heart failure
  • Asthma

Common side effects:
  • Excessive slowing of the heartbeat, fatigue, vivid dreams, depression, increased blood sugar and cholesterol levels

Pregnancy/nursing:
  • Pregnant women should not take atenolol because it can harm the fetus. The safety of the other beta blockers during pregnancy is not known
  • Women who are nursing should not use beta blockers; if the treatment is essential, then nursing should be discontinued.

 

Are beta blockers underprescribed?

Many heart attack patients who are eligible for beta blockers do not receive prescriptions,16 particularly women and the elderly.17, 18 A 1999 study of more than 15,000 patients (nearly half were women) found that among the 5,453 heart attack patients older than 66 years of age who were eligible for beta blockers, women were significantly less likely than men to be prescribed them at hospital discharge.19 More recent studies note that people who have had a heart attack are more likely to receive recommended medications, including beta blockers, than in previous years; however, the gender gap remains.20


Are potassium channel blockers beneficial?

Unlike some of the other heart rhythm drugs, class III antiarrhythmics do not increase the risk of dying early in men or women with heart disease.21-23 A version of sotalol increased the risk of dying from heart rhythm disturbances when used to prevent arrhythmias in heart attack patients.24 This risk was higher for women than men.25 That formulation of sotalol is no longer used. The current version of sotalol (Betapace) does not increase the risk of dying from heart rhythm problems when given to people with heart disease.26 Class III antiarrhythmic medications are not used to prevent heart rhythm problems because it is not clear whether they are beneficial in that situation. These medications may be used to treat arrhythmias in men and women with heart disease who are taking beta blockers but continue to experience heart rhythm problems, including atrial fibrillation. Atrial fibrillation is a rapid, disordered contraction of the heart muscles whereby the heart flutters in an uncontrolled manner.

Prescribed Class III Antiarrhythmics

Class III Antiarrhythmics – Potassium Channel Blockers
(check with manufacturer for specific information on each drug)

Generic:

Amiodarone

Dofetilide

Sotalol

Brand:

Cordarone
Pacerone

Tikosyn

Betapace
Betapace AF

Administration:

Oral, intravenous

What is it used for:
  • Treatment of life-threatening recurrent ventricular fibrillation and recurrent ventricular tachycardia that affects blood flow to the heart when these have not responded to available doses of other antiarrhythmic medications
  • Maintenance of normal heart rhythm in patients with atrial fibrillation/flutter for more than 1 week that was corrected to normal heart rhythm; should be reserved for patients with symptoms
  • Correction of atrial fibrillation/flutter to normal heart rhythm

You should not take this medication:
  • When episodes of slow heart rate have caused fainting
  • If you have been diagnosed with:
  • Cardiogenic shock (the heart muscle is so damaged it cannot pump properly, causing a shock-like state)
  • Second- and third-degree heart block (the electrical signals between the upper and lower chambers of the heart are impaired)
  • Abnormally slow heartbeat
  • Uncontrolled congestive heart failure
  • Long QT syndrome—the electrical activation and deactivation of the ventricles takes longer than usual
  • Asthma

Common side effects:

  • Arrhythmias, scarring in the lungs ( pulmonary fibrosis), and low blood pressure

Pregnancy/nursing:
  • Pregnant women should not take amiodarone because it can harm the fetus
  • Women who are nursing should not use these medications; if the treatment is essential, then nursing should be discontinued

 

Choice of Medication

Amiodarone (Pacerone or Cordarone) is better than sotalol for correcting heart rhythm disturbances;27 however, it has a higher risk of very serious side effects. In two major studies, many heart attack patients prescribed amiodarone stopped taking it because of side effects, including serious lung and liver problems.21, 22 In one study of elderly heart attack patients with atrial fibrillation, women treated with amiodarone had a higher risk of developing a slow irregular heartbeat (bradyarrhythmia) requiring permanent pacemaker than men taking amiodarone.28 Because of these risks, sotalol is generally the first choice.29 Dofetilide (Tikosyn) is newer and has not been studied as much as the other class III antiarrhythmics. Both amiodarone and dofetilide have been shown to benefit men and women with heart failure.30, 31 Sotalol and dofetilide may trigger a potentially dangerous rapid heart beat (torsade de pointes), particularly in women.

Amiodarone or sotalol may also be given to people with ICDs to reduce the number of shocks.


Are calcium channel blockers beneficial?

In general, class IV agents, (calcium channel blockers, or CCBs), do not reduce the risk of dying in people who have had a heart attack or have unstable angina (chest pain), and in some cases they do more harm than good. For this reason they are no longer routinely prescribed after a heart attack. There are two types of CCBs: the dihydropyridines (such as amlodipine and nifedipine) are harmful in heart attack patients.32 The other type, non-dihydropyridines (such as verapamil and diltiazem) may be harmful in patients who have chronic heart failure, a very slow irregular heartbeat (bradyarrhythmia), or lung problems.33-36 In heart attack patients who do not have these conditions, verapamil (Covera or Verelan) reduces the risk of dying or suffering further heart problems,37 and diltiazem (Cardizem or Tiazac) lowers the risk of having another heart attack.38, 39 These particular CCBs may be used for the short-term treatment of arrhythmias in heart attack patients who cannot take beta blockers.3 Many CCBs come in a short-acting and a long-acting (sustained release) form. Short-acting CCBs increase the risk of heart attack and stroke when used over an extended period.40

Prescribed Class IV Antiarrhythmics

Class IV Antiarrhythmics – Calcium Channel Blockers
(check with manufacturer for specific information on each drug)

Generic:

Diltiazem

Verapamil

Brand:

Cardizem
Tiazac

Covera HS
Verelan

Administration:

Oral

What is it used for:
  • Treatment of high blood pressure
  • Treatment of stable chest pain (angina)
  • Treatment of chest pain caused by spasm

You should not take these medications:
  • If you have been diagnosed with:
  • Second- or third-degree heart block (the electrical signals between the upper and lower chambers of the heart are impaired) unless pacemaker present
  • Sick sinus syndrome (the heart’s natural pacemaker, the sinus node, does not work properly) except when a pacemaker is present
  • Low blood pressure
  • Patients with cardiogenic shock (the heart muscle is so damaged it cannot pump properly, causing a shock-like state), severe damage to the left side of the heart, or atrial fibrillation or flutter associated with Wolff-Parkinson-White syndrome should not take verapamil

Common side effects:

  • Headaches and swelling of the ankles
  • Verapamil can cause constipation and excessive slowing of the heartbeat

Pregnancy/nursing:
  • The safety of these medications during pregnancy is unknown
  • Women who are nursing should not use calcium channel blockers; if the treatment is essential, then nursing should be discontinued

 


Are class V antiarrhythmics beneficial?

In people with heart disease, the class V antiarrhythmics are used to treat certain heart rhythm disturbances affecting the upper chambers of the heart (the atria).3 They are not used to prevent arrhythmia. These antiarrhyhmics should be used with caution since men and women taking digoxin (Lanoxin) after having a heart attack have an increased risk of dying early.41-43 Digoxin may be used to relieve symptoms of atrial fibrillation (see below) in people with heart failure or severe damage to the left side of the heart.29

Prescribed Class V antiarrhythmics

Miscellaneous Antiarrhythmics
(check with manufacturer for specific information on each drug)

Generic:

Adenosine

Digoxin

Brand:

Adenocard IV

Lanoxin

Administration:

Oral, intravenous

Indications:
  • To restore normal heart rhythm in people with occasional supraventricular tachycardia including that associated with Wolff-Parkinson-White syndrome
  • Treatment of mild to moderate heart failure
  • Control of chronic atrial fibrillation

You should not be treated with these medications:
  • If you have been diagnosed with:
  • Second- or third-degree heart block (the electrical signals between the upper and lower chambers of the heart are impaired) except when a pacemaker is present
  • Sick sinus syndrome (the heart’s natural pacemaker doesn’t function properly) or abnormally slow heartbeat
  • Ventricular fibrillation
  • Asthma

Common side effects:
  • Weight loss, nausea, vomiting, serious heart rhythm disturbances, tightening or narrowing of the airways (bronchospasm), and flushing

Pregnancy/nursing:
  • The safety of these medications during pregnancy is not known
  • Women who are nursing should not take digoxin; if the treatment is essential, then nursing should be discontinued

 

What are the risks of heart rhythm drugs?

With the exception of beta blockers, the benefits of antiarrhythmic medications must be carefully balanced against the risk of triggering a fatal heart rhythm disturbance. These medications are generally reserved for people with life-threatening arrhythmias. Therapy is usually initiated in the hospital where you can be monitored.

Women taking antiarrhythmic medications have a higher risk than men of developing the life-threatening rapid heartbeat torsade de pointes (TdP), particularly with class IA medications and sotalol (Betapace), a class III antiarrhythmic.44-46 Women have a higher risk of TdP to begin with because the time between electrical activation and deactivation of the lower chambers of the heart is longer for women than men (called the QT interval in reference to the pattern produced on the ECG). Two-thirds of heart medication-induced TdP cases occur in women,45 and it is estimated that TdP accounts for 5% of the 300,000 sudden cardiac deaths each year.47

Magnesium

Low blood levels of magnesium increase the risk of heart rhythm disturbances. Older studies suggested that heart attack patients benefited from intravenous injections of magnesium.48, 49 Contemporary studies where most heart attack patients are treated with balloon angioplasty or clot busting drugs do not show a benefit for IV magnesium in men or women.50, 51 IV magnesium may help treat some life-threatening ventricular arrhythmias, including torsade de pointes (see Risks).3 It is not known whether dietary magnesium or supplements lower the risk of developing heart rhythm problems.


Ventricular Fibrillation

Rapid, disordered contraction of the heart muscles whereby the heart flutters in an uncontrolled manner (fibrillation) is the most serious type of arrhythmia. Ventricular fibrillation (VF) is thought to be responsible for many of the 335,000 sudden cardiac deaths reported each year.1 Because reduced blood flow to the heart often causes or contributes to this heart rhythm disturbance, VF is a concern for heart attack patients.52

>Most cases of VF occur in the first four hours after a heart attack. The risk of dying from this heart rhythm disturbance has declined with improved heart attack treatments, but VF can cause death in the first day after a heart attack.53 Heart attack patients used to be given the class I antiarrhythmic lidocaine to prevent VF, but this is no longer done because there is no clear evidence that it reduces the risk of dying and some evidence suggets that it may be harmful.54, 55 Intravenous beta blockers help prevent ventricular fibrillation early after a heart attack and are given to patients who can tolerate beta blockers. When VF occurs, it is treated with cardioversion; an electric shock is delivered to the heart using paddles placed on the chest (as commonly seen on television medical dramas). VF that is not corrected by shock may be treated with amiodarone, a class III antiarrhythmic. If VF occurs more than 2 days after a heart attack, you may need to have an ICD implanted.56

Ventricular Tachycardia

Ventricular tachycardia (VT) is a rapid heartbeat affecting the lower chambers of the heart. Most cases of VT occur within the first 48 hours after a heart attack. Often, this rhythm disturbance will correct itself without needing treatment. VT that does not impair blood flow to the heart may be treated with medication, preferably amiodarone.57 VT that impairs blood flow to the heart requires electric shock treatment (cardioversion). People who experience VT that impairs blood flow to the heart more than 2 days after a heart attack have a poor prognosis and may need to have an ICD implanted.56, 58

Atrial Fibrillation

The most common cardiac arrhythmia is atrial fibrillation (AF), a rapid, disordered contraction of the heart muscles whereby the heart flutters in an uncontrolled manner. Atrial fibrillation affects 2.2 million people in the US, and approximately 55% of people discharged with a diagnosis of AF are women.1 Heart attack patients who experience AF have a higher risk of dying or experiencing other heart problems both in the hospital and in the long-term than heart attack patients who do not suffer this heart rhythm disturbance.59-61 When medical therapy is required, intravenous beta blockers slow the heart rate. The calcium channel blockers verapamil (Covera or Verelan) and diltiazem (Cardizem or Tiazac) may be used for controlling the rapid heart rate in the short-term in patients who cannot take beta blockers; however, calcium channel blockers increase the risk of dying after a heart attack when used for longer periods of time.40 Digoxin (Lanoxin) is no longer the first-choice medication for the management of AF, but it may be used in patients with heart failure or severe damage to the left side to the heart. 3, 62 Sotalol (Betapace) or amiodarone (Cordarone or Pacerone) may be used for intermediate or long-term treatment of AF after a heart attack.63 Sotalol is generally the first choice because it has fewer serious side effects than amiodarone.29

Bradycardia

Heart attack patients who develop a dangerously slow heartbeat (bradycardia or bradyarrhythmia) are best treated with a pacemaker. When medication is needed, amiodarone (Cordarone or Pacerone) or sotalol (Betapace) may be used.

References

1. Heart Disease and Stroke Statistics: 2005 Update. Dallas, Texas: American Heart Association; 2004.
2. Zipes DP, Wellens HJJ. Sudden Cardiac Death. Circulation. November 24, 1998 1998;98(21):2334-2351.
3. Antman EM, Anbe DT, Armstrong PW, et al. ACC/AHA Guidelines for the Management of Patients With ST-Elevation Myocardial Infarction. A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Revise the 1999 Guidelines for the Management of Patients With Acute Myocardial Infarction). 2004;Available at www.acc.org/clinical/guidelines/stemi/index.pdf.
4. Vaughan Williams EM. A classification of antiarrhythmic actions reassessed after a decade of new drugs. J Clin Pharmacol. Apr 1984;24(4):129-147.
5. Echt DS, Liebson PR, Mitchell LB, et al. Mortality and morbidity in patients receiving encainide, flecainide, or placebo. The Cardiac Arrhythmia Suppression Trial. N Engl J Med. Mar 21 1991;324(12):781-788.
6. Larsen JA, Kadish AH, Schwartz JB. Proper use of antiarrhythmic therapy for reduction of mortality after myocardial infarction. Drugs Aging. May 2000;16(5):341-350.
7. MacMahon S, Collins R, Peto R, Koster RW, Yusuf S. Effects of prophylactic lidocaine in suspected acute myocardial infarction. An overview of results from the randomized, controlled trials. Jama. Oct 7 1988;260(13):1910-1916.
8. Teo KK, Yusuf S, Furberg CD. Effects of prophylactic antiarrhythmic drug therapy in acute myocardial infarction. An overview of results from randomized controlled trials. Jama. Oct 6 1993;270(13):1589-1595.
9. Effect of the antiarrhythmic agent moricizine on survival after myocardial infarction. The Cardiac Arrhythmia Suppression Trial II Investigators. N Engl J Med. Jul 23 1992;327(4):227-233.
10. Pedersen TR. Six-year follow-up of the Norwegian Multicenter Study on Timolol after Acute Myocardial Infarction. N Engl J Med. Oct 24 1985;313(17):1055-1058.
11. Timolol-induced reduction in mortality and reinfarction in patients surviving acute myocardial infarction. N Engl J Med. Apr 2 1981;304(14):801-807.
12. A randomized trial of propranolol in patients with acute myocardial infarction. I. Mortality results. Jama. Mar 26 1982;247(12):1707-1714.
13. Cucherat M, Boissel JP, Leizorovicz A. Persistent reduction of mortality for five years after one year of acebutolol treatment initiated during acute myocardial infarction. The APSI Investigators. Acebutolol et Prevention Secondaire de l'Infarctus. Am J Cardiol. Mar 1 1997;79(5):587-589.
14. Hjalmarson A, Elmfeldt D, Herlitz J, et al. Effect on mortality of metoprolol in acute myocardial infarction. A double-blind randomised trial. Lancet. Oct 17 1981;2(8251):823-827.
15. Freemantle N, Cleland J, Young P, Mason J, Harrison J. beta Blockade after myocardial infarction: systematic review and meta regression analysis. BMJ. June 26, 1999 1999;318(7200):1730-1737.
16. Brand DA, Newcomer LN, Freiburger A, Tian H. Cardiologists' practices compared with practice guidelines: use of beta-blockade after acute myocardial infarction. J Am Coll Cardiol. Nov 15 1995;26(6):1432-1436.
17. McLaughlin TJ, Soumerai SB, Willison DJ, et al. Adherence to national guidelines for drug treatment of suspected acute myocardial infarction: evidence for undertreatment in women and the elderly. Arch Intern Med. Apr 8 1996;156(7):799-805.
18. Everly MJ, Heaton PC, Cluxton RJ, Jr. Beta-Blocker Underuse in Secondary Prevention of Myocardial Infarction. Ann Pharmacother. February 1, 2004 2004;38(2):286-293.
19. Rochon PA, Anderson GM, Tu JV, et al. Use of beta-blocker therapy in older patients after acute myocardial infarction in Ontario. Cmaj. Nov 30 1999;161(11):1403-1408.
20. Eagle KA. Guidelines Applied in Practice. Paper presented at: ACC Annual Scientific Sessions, 2005; Orlando, FL.
21. Julian DG, Camm AJ, Frangin G, et al. Randomised trial of effect of amiodarone on mortality in patients with left-ventricular dysfunction after recent myocardial infarction: EMIAT. European Myocardial Infarct Amiodarone Trial Investigators. Lancet. Mar 8 1997;349(9053):667-674.
22. Cairns JA, Connolly SJ, Roberts R, Gent M. Randomised trial of outcome after myocardial infarction in patients with frequent or repetitive ventricular premature depolarisations: CAMIAT. Canadian Amiodarone Myocardial Infarction Arrhythmia Trial Investigators. Lancet. Mar 8 1997;349(9053):675-682.
23. Kober L, Bloch Thomsen PE, Moller M, et al. Effect of dofetilide in patients with recent myocardial infarction and left-ventricular dysfunction: a randomised trial. Lancet. Dec 16 2000;356(9247):2052-2058.
24. Waldo AL, Camm AJ, deRuyter H, et al. Effect of d-sotalol on mortality in patients with left ventricular dysfunction after recent and remote myocardial infarction. The SWORD Investigators. Survival With Oral d-Sotalol. Lancet. Jul 6 1996;348(9019):7-12.
25. Pratt CM, Camm AJ, Cooper W, et al. Mortality in the Survival With ORal D-sotalol (SWORD) trial: why did patients die? Am J Cardiol. Apr 1 1998;81(7):869-876.
26. Julian DG, Prescott RJ, Jackson FS, Szekely P. Controlled trial of sotalol for one year after myocardial infarction. Lancet. May 22 1982;1(8282):1142-1147.
27. Roy D, Talajic M, Dorian P, et al. Amiodarone to Prevent Recurrence of Atrial Fibrillation. N Engl J Med. March 30, 2000 2000;342(13):913-920.
28. Essebag V, Hadjis T, Platt RW, Pilote L. Amiodarone and the risk of bradyarrhythmia requiring permanent pacemaker in elderly patients with atrial fibrillation and prior myocardial infarction. J Am Coll Cardiol. Jan 15 2003;41(2):249-254.
29. Fuster V, Ryden LE, Asinger RW, et al. ACC/AHA/ESC guidelines for the management of patients with atrial fibrillation: executive summary. A Report of the American College of Cardiology/ American Heart Association Task Force on Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines and Policy Conferences (Committee to Develop Guidelines for the Management of Patients With Atrial Fibrillation): developed in Collaboration With the North American Society of Pacing and Electrophysiology. J Am Coll Cardiol. Oct 2001;38(4):1231-1266.
30. Doval HC, Nul DR, Grancelli HO, Perrone SV, Bortman GR, Curiel R. Randomised trial of low-dose amiodarone in severe congestive heart failure. Grupo de Estudio de la Sobrevida en la Insuficiencia Cardiaca en Argentina (GESICA). Lancet. Aug 20 1994;344(8921):493-498.
31. Torp-Pedersen C, Moller M, Bloch-Thomsen PE, et al. Dofetilide in Patients with Congestive Heart Failure and Left Ventricular Dysfunction. N Engl J Med. September 16, 1999 1999;341(12):857-865.
32. Held PH, Yusuf S, Furberg CD. Calcium channel blockers in acute myocardial infarction and unstable angina: an overview. Bmj. Nov 11 1989;299(6709):1187-1192.
33. Held PH, Yusuf S. Effects of beta-blockers and calcium channel blockers in acute myocardial infarction. Eur Heart J. Oct 1993;14 Suppl F:18-25.
34. Gheorghiade M. Calcium channel blockers in the management of myocardial infarction patients. Henry Ford Hosp Med J. 1991;39(3-4):210-216.
35. Verapamil in acute myocardial infarction. The Danish Study Group on Verapamil in Myocardial Infarction. Eur Heart J. Jul 1984;5(7):516-528.
36. The effect of diltiazem on mortality and reinfarction after myocardial infarction. The Multicenter Diltiazem Postinfarction Trial Research Group. N Engl J Med. Aug 18 1988;319(7):385-392.
37. Effect of verapamil on mortality and major events after acute myocardial infarction (the Danish Verapamil Infarction Trial II--DAVIT II). Am J Cardiol. Oct 1 1990;66(10):779-785.
38. Gibson RS, Boden WE, Theroux P, et al. Diltiazem and reinfarction in patients with non-Q-wave myocardial infarction. Results of a double-blind, randomized, multicenter trial. N Engl J Med. Aug 14 1986;315(7):423-429.
39. Wong SC, Greenberg H, Hager WD, Dwyer EM, Jr. Effects of diltiazem on recurrent myocardial infarction in patients with non-Q wave myocardial infarction. J Am Coll Cardiol. Jun 1992;19(7):1421-1425.
40. Moss AJ, Oakes D, Benhorin J, Carleen E. The interaction between diltiazem and left ventricular function after myocardial infarction. Multicenter Diltiazem Post-Infarction Research Group. Circulation. Dec 1989;80(6 Suppl):IV102-106.
41. Kober L, Torp-Pedersen C, Gadsboll N, Hildebrandt P, Hoilund-Carlsen PF. Is digoxin an independent risk factor for long-term mortality after acute myocardial infarction? Eur Heart J. Mar 1994;15(3):382-388.
42. Leor J, Goldbourt U, Rabinowitz B, et al. Digoxin and increased mortality among patients recovering from acute myocardial infarction: importance of digoxin dose. The SPRINT Study Group. Cardiovasc Drugs Ther. Oct 1995;9(5):723-729.
43. Reicher-Reiss H, Jonas M, Boyko V, Shotan A, Goldbourt U, Behar S. Are coronary patients at higher risk with digoxin therapy? An ongoing controversy. Int J Cardiol. Feb 28 1999;68(2):137-143.
44. Ebert SN, Liu XK, Woosley RL. Female gender as a risk factor for drug-induced cardiac arrhythmias: evaluation of clinical and experimental evidence. J Womens Health. Jun 1998;7(5):547-557.
45. Makkar RR, Fromm BS, Steinman RT, Meissner MD, Lehmann MH. Female gender as a risk factor for torsades de pointes associated with cardiovascular drugs. Jama. Dec 1 1993;270(21):2590-2597.
46. Lehmann MH, Hardy S, Archibald D, quart B, MacNeil DJ. Sex difference in risk of torsade de pointes with d,l-sotalol. Circulation. Nov 15 1996;94(10):2535-2541.
47. Bessette M. Torsade de Pointes. emedicine.com, Inc. [html]. September 17, 2004. Available at: http://www.emedicine.com/EMERG/topic596.htm. Accessed January 12, 2005, 2005.
48. Shechter M, Hod H, Chouraqui P, Kaplinsky E, Rabinowitz B. Magnesium therapy in acute myocardial infarction when patients are not candidates for thrombolytic therapy. Am J Cardiol. Feb 15 1995;75(5):321-323.
49. Shechter M, Hod H, Marks N, Behar S, Kaplinsky E, Rabinowitz B. Beneficial effect of magnesium sulfate in acute myocardial infarction. Am J Cardiol. Aug 1 1990;66(3):271-274.
50. ISIS-4: a randomised factorial trial assessing early oral captopril, oral mononitrate, and intravenous magnesium sulphate in 58,050 patients with suspected acute myocardial infarction. ISIS-4 (Fourth International Study of Infarct Survival) Collaborative Group. Lancet. Mar 18 1995;345(8951):669-685.
51. Early administration of intravenous magnesium to high-risk patients with acute myocardial infarction in the Magnesium in Coronaries (MAGIC) Trial: a randomised controlled trial. Lancet. Oct 19 2002;360(9341):1189-1196.
52. Wiesfeld AC, Crijns HJ, Hillege HL, Tuininga YS, Lie KL. The clinical significance of coronary anatomy in post-infarct patients with late sustained ventricular tachycardia or ventricular fibrillation. Eur Heart J. Jun 1995;16(6):818-824.
53. Thompson CA, Yarzebski J, Goldberg RJ, Lessard D, Gore JM, Dalen JE. Changes over time in the incidence and case-fatality rates of primary ventricular fibrillation complicating acute myocardial infarction: perspectives from the Worcester Heart Attack Study. Am Heart J. Jun 2000;139(6):1014-1021.
54. Antman EM, Berlin JA. Declining incidence of ventricular fibrillation in myocardial infarction. Implications for the prophylactic use of lidocaine. Circulation. Sep 1992;86(3):764-773.
55. Alexander JH, Granger CB, Sadowski Z, et al. Prophylactic lidocaine use in acute myocardial infarction: incidence and outcomes from two international trials. The GUSTO-I and GUSTO-IIb Investigators. Am Heart J. May 1999;137(5):799-805.
56. The Antiarrhythmics versus Implantable Defibrillators (AVID) Investigators. A Comparison of Antiarrhythmic-Drug Therapy with Implantable Defibrillators in Patients Resuscitated from Near-Fatal Ventricular Arrhythmias. N Engl J Med. November 27, 1997 1997;337(22):1576-1584.
57. Guidelines 2000 for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Part 6: advanced cardiovascular life support: section 5: pharmacology I: agents for arrhythmias. The American Heart Association in collaboration with the International Liaison Committee on Resuscitation. Circulation. Aug 22 2000;102(8 Suppl):I112-128.
58. Moss AJ, Hall WJ, Cannom DS, et al. Improved Survival with an Implanted Defibrillator in Patients with Coronary Disease at High Risk for Ventricular Arrhythmia. N Engl J Med. December 26, 1996 1996;335(26):1933-1940.
59. Crenshaw BS, Ward SR, Granger CB, Stebbins AL, Topol EJ, Califf RM. Atrial fibrillation in the setting of acute myocardial infarction: the GUSTO-I experience. Global Utilization of Streptokinase and TPA for Occluded Coronary Arteries. J Am Coll Cardiol. Aug 1997;30(2):406-413.
60. Pizzetti F, Turazza FM, Franzosi MG, et al. Incidence and prognostic significance of atrial fibrillation in acute myocardial infarction: the GISSI-3 data. Heart. Nov 2001;86(5):527-532.
61. Wong CK, White HD, Wilcox RG, et al. New atrial fibrillation after acute myocardial infarction independently predicts death: the GUSTO-III experience. Am Heart J. Dec 2000;140(6):878-885.
62. Rawles JM, Metcalfe MJ, Jennings K. Time of occurrence, duration, and ventricular rate of paroxysmal atrial fibrillation: the effect of digoxin. Br Heart J. Apr 1990;63(4):225-227.
63. Connolly SJ, Gent M, Roberts RS, et al. Canadian implantable defibrillator study (CIDS) : a randomized trial of the implantable cardioverter defibrillator against amiodarone. Circulation. Mar 21 2000;101(11):1297-1302.


SEO by AceSEF