eMedicine Specialties > Cardiology > Arrhythmias

Multifocal Atrial Tachycardia: Treatment & Medication

Author: Neeraj Tandon, MB, BS, Chief, Cardiology Section, Associate Professor of Medicine, Medical Service, Overton Brooks Veterans Affairs Medical Center
Coauthor(s): Pratap Reddy, MD, Director, Electrophysiology Service, Professor, Department of Medicine, Section of Cardiology, Louisiana State University Health Sciences Center
Contributor Information and Disclosures

Updated: May 11, 2009

Treatment

Medical Care

  • General: Treatment of multifocal atrial tachycardia (MAT) involves treatment and/or reversal of the precipitating cause. This may be all that is required; however, the arrhythmia may recur when the underlying condition worsens. Treatment of underlying diseases may sometimes have arrhythmia-promoting effects; for example, theophylline and beta-agonist drugs used in patients with COPD produce an increased catecholamine state. These therapies should be used judiciously.
  • Calcium channel blockers: Diltiazem3 and verapamil4,5,6,7,8,9 decrease the atrial activity and slow atrioventricular (AV) nodal conduction, thereby decreasing ventricular rate, but they do not return all patients to normal sinus rhythm. Transient hypotension is the most common adverse effect, which may often be avoided by pretreating the patient with 1 g of intravenous calcium gluconate (10 mL of 10% calcium gluconate). Diltiazem may be used as a 20-45 mg intravenous bolus and then as a 10-25 mg/h continuous infusion. Verapamil may worsen hypoxemia by negating the hypoxic pulmonary vasoconstriction in underventilated alveoli; this is usually not clinically significant.
  • Beta-blockers: Metoprolol10,11,12,6,8 has been used to lower the ventricular rate. More patients convert to a normal sinus rhythm when treated with beta-blockers. Both oral and intravenous dosage forms have been used. The oral dosage is 25 mg q6h until the desired effects are obtained. Intravenous bolus dosing has been administered to as much as 15 mg over 10 minutes. Although no controlled studies have evaluated the use of short-acting beta-blockers in treatment of MAT, esmolol can also be used to control the ventricular rate as an intravenous infusion. It has a very short half-life and can be terminated quickly in the event of an adverse reaction. The use of beta-blockers is limited by transient hypotension and bronchospastic adverse effects since lung disease is commonly associated with MAT.
  • Magnesium: In a small number of patients, high-dose magnesium13,14,6,15,16 causes a significant decrease in the patient's heart rate and conversion to normal sinus rhythm. The dosage is 2 g intravenously over 1 minute, followed by 2 g/h infusion over 5 hours.
  • Antiarrhythmics: Oral and intravenous amiodarone17,18,19 (300 mg PO tid or 450-1500 mg IV over 2-24 h) has been used and has been reported to be associated with conversion to normal sinus rhythm. The success rate was 40% at 3 days with oral dosing and 75% on day 1 with intravenous dosing; however, this has been evaluated in a very small number of patients. Recent data support the use of amiodarone prophylactically postoperatively in patients with COPD. Case reports have also supported the use of ibutilide20 and flecainide21 for cardioversion.
  • Digitalis and cardioversion: Despite the urge to use digoxin, it has not been found to be effective in controlling the ventricular rate or restoring normal sinus rhythm. Digoxin promotes afterdepolarizations, which may promote the arrhythmia. Ventricular arrhythmias, AV block, and death have been reported when excessive digoxin has been administered to patients who were incorrectly diagnosed to have atrial fibrillation. Direct current (DC) cardioversion is not effective in conversion to normal sinus rhythm and can precipitate more dangerous arrhythmias.

Surgical Care

In patients who have persistent and recurrent episodes of MAT and problems with rate control, the AV node may be ablated using radiofrequency energy and a permanent pacemaker implanted.22

Medication

The goals of pharmacotherapy are to reduce morbidity and to prevent complications. Calcium channel blockers are used as the first line of treatment. Antiarrhythmics are usually not indicated for treatment of MAT. Consider using antiarrhythmics when the arrhythmia is symptomatic and does not respond to correction or treatment of underlying diseases.

Calcium channel blockers

Diltiazem and verapamil have been used to control the ventricular rate.


Diltiazem (Cardizem, Dilacor, Tiazac)

During depolarization, inhibits calcium ions from entering the slow channels and voltage-sensitive areas of vascular smooth muscle and myocardium.

Adult

10-20 mg IV bolus, followed by 5-15 mg/h continuous infusion; alternatively, 120-360 mg PO divided tid/qid or qd in long-acting preparations

Pediatric

Not established

May increase carbamazepine, digoxin, cyclosporine, and theophylline levels; when administered with amiodarone, may cause bradycardia and a decrease in cardiac output; when administered with beta-blockers, may increase cardiac depression; cimetidine may increase diltiazem levels

Documented hypersensitivity; severe CHF, sick sinus syndrome, second- or third-degree AV block, hypotension (<90 mm Hg systolic)

Pregnancy

C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions

Caution in impaired renal or hepatic function; may increase LFT levels, and hepatic injury may occur


Verapamil (Calan, Covera, Verelan)

During depolarization, it inhibits the calcium ion from entering slow channels or voltage-sensitive areas of the vascular smooth muscle and myocardium. By interrupting reentry at AV node, verapamil can occasionally restore normal sinus rhythm.

Adult

0.075-0.15 mg/kg IV bolus over 5-10 min, followed by 0.005 mg/kg/min continuous infusion for 1 h; alternatively, 240-480 mg PO divided tid/qid

Pediatric

<2 years: Not established
>2 years: 0.075-0.15 mg/kg IV bolus over 2 min, followed by 0.005 mg/kg/min infusion

May increase carbamazepine, digoxin, and cyclosporine levels; coadministration with amiodarone can cause bradycardia and a decrease in cardiac output; when administered concurrently with beta-blockers, may increase cardiac depression; cimetidine may increase verapamil levels; may increase theophylline levels

Documented hypersensitivity; severe CHF, sick sinus syndrome, second- or third-degree AV block, hypotension (<90 mm Hg systolic)

Pregnancy

C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions

Hepatocellular injury may occur; transient elevations of transaminases with and without concomitant elevations in alkaline phosphatase and bilirubin have occurred (elevations have been transient and may disappear with continued verapamil treatment); monitor liver function periodically

Antiarrhythmic agent

These agents promote the conversion of arrhythmia to normal sinus rhythm.


Magnesium sulfate

Used IV or IM, found to significantly slow the ventricular rate and to convert patients to normal sinus rhythm.

Adult

2 g IV over 1 min followed by 2 g/h over 5 h continuous infusion; 1g IM q6h

Pediatric

25-50 mg/kg IV

Concurrent use with nifedipine may cause hypotension and neuromuscular blockade; may increase neuromuscular blockade seen with aminoglycosides and potentiate neuromuscular blockade produced by tubocurarine, vecuronium, and succinylcholine; may increase CNS effects and toxicity of CNS depressants, betamethasone, and cardiotoxicity of ritodrine

Documented hypersensitivity; heart block; Addison disease; myocardial damage; severe hepatitis

Pregnancy

A - Fetal risk not revealed in controlled studies in humans

Precautions

Magnesium may alter cardiac conduction, leading to heart block in patients who are digitalized; monitor respiratory rate, deep tendon reflex, and renal function when electrolytes are administered parenterally; caution when administering magnesium dose because it may produce significant hypertension or asystole; in overdose, a 10-20 mL IV of 10% calcium gluconate solution can be administered as an antidote for clinically significant hypermagnesemia

More on Multifocal Atrial Tachycardia

Overview: Multifocal Atrial Tachycardia
Differential Diagnoses & Workup: Multifocal Atrial Tachycardia
Treatment & Medication: Multifocal Atrial Tachycardia
Follow-up: Multifocal Atrial Tachycardia
Multimedia: Multifocal Atrial Tachycardia
References
Further Reading
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References

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  2. Esperer HD, Esperer C, Cohen RJ. Cardiac arrhythmias imprint specific signatures on Lorenz plots. Ann Noninvasive Electrocardiol. Jan 2008;13(1):44-60. [Medline].

  3. Adcock JT, Heiselman DE, Hulisz DT. Continuous infusion diltiazem hydrochloride for treatment of multifocal atrial tachycardia (abstract). Clin Res. 1994;42:430A.

  4. Aronow WS, Plasencia G, Wong R. Effect of verapamil versus placebo on PAT and MAT. Current Ther Res. 1980;27:823-29.

  5. Hazard PB, Burnett CR. Verapamil in multifocal atrial tachycardia. Hemodynamic and respiratory changes. Chest. Jan 1987;91(1):68-70. [Medline].

  6. Kastor JA. Multifocal atrial tachycardia. N Engl J Med. Jun 14 1990;322(24):1713-7. [Medline].

  7. Levine JH, Michael JR, Guarnieri T. Treatment of multifocal atrial tachycardia with verapamil. N Engl J Med. Jan 3 1985;312(1):21-5. [Medline].

  8. Parillo JE. Treating Multifocal Atrial Tachycardia (MAT) in a critical care unit: new data regarding verapamil and metoprolol. Update Crit Care Med. 1987;2:3-5.

  9. Salerno DM, Anderson B, Sharkey PJ, Iber C. Intravenous verapamil for treatment of multifocal atrial tachycardia with and without calcium pretreatment. Ann Intern Med. Nov 1987;107(5):623-8. [Medline].

  10. Arsura E, Lefkin AS, Scher DL, et al. A randomized, double-blind, placebo-controlled study of verapamil and metoprolol in treatment of multifocal atrial tachycardia. Am J Med. Oct 1988;85(4):519-24. [Medline].

  11. Arsura EL, Solar M, Lefkin AS. Metoprolol in the treatment of multifocal atrial tachycardia. Crit Care Med. Jun 1987;15(6):591-4. [Medline].

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  15. McCord JK, Borzak S, Davis T, Gheorghiade M. Usefulness of intravenous magnesium for multifocal atrial tachycardia in patients with chronic obstructive pulmonary disease. Am J Cardiol. Jan 1 1998;81(1):91-3. [Medline].

  16. Ho KM. Intravenous magnesium for cardiac arrhythmias: jack of all trades. Magnes Res. Mar 2008;21(1):65-8. [Medline].

  17. Kouvaras G, Cokkinos DV, Halal G, et al. The effective treatment of multifocal atrial tachycardia with amiodarone. Jpn Heart J. May 1989;30(3):301-12. [Medline].

  18. Kuralay E, Cingoz F, Kilic S, et al. Supraventricular tachyarrythmia prophylaxis after coronary artery surgery in chronic obstructive pulmonary disease patients (early amiodarone prophylaxis trial). Eur J Cardiothorac Surg. Feb 2004;25(2):224-30. [Medline].

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  27. Levine JH, Michael JR, Guarnieri T. Multifocal atrial tachycardia: a toxic effect of theophylline. Lancet. Jan 5 1985;1(8419):12-4. [Medline].

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Keywords

MAT, chaotic atrial rhythm, chaotic atrial tachycardia, chaotic atrial mechanism, repetitive paroxysmal multifocal atrial tachycardia, intracellular calcium overload, catecholamine excess, phosphodiesterase inhibition, acidosis, hypoxemia, electrolyte imbalances associated with severe underlying illnesses, COPD, congestive heart failure, metabolic disorders, diabetes mellitus, hypokalemia, azotemia, postoperative infections, sepsis, pulmonary embolism, respiratory acidosis, coronary artery disease, valvular heart disease, hypomagnesemia, azotemia, multifocal atrial rhythm, multifocal atrial bradycardia, wandering atrial pacemaker

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Contributor Information and Disclosures

Author

Neeraj Tandon, MB, BS, Chief, Cardiology Section, Associate Professor of Medicine, Medical Service, Overton Brooks Veterans Affairs Medical Center
Neeraj Tandon, MB, BS is a member of the following medical societies: American College of Cardiology and Society of Cardiac Angiography and Interventions
Disclosure: Nothing to disclose.

Coauthor(s)

Pratap Reddy, MD, Director, Electrophysiology Service, Professor, Department of Medicine, Section of Cardiology, Louisiana State University Health Sciences Center
Pratap Reddy, MD is a member of the following medical societies: American College of Cardiology, American College of Physicians, American Federation for Medical Research, American Heart Association, and American Medical Association
Disclosure: Nothing to disclose.

Medical Editor

Alan D Forker, MD, Professor of Medicine, Program Director of Cardiovascular Fellowship, University of Missouri at Kansas City School of Medicine; Director, Outpatient Lipid Diabetes Research Center, MidAmerica Heart Institute of St Luke's Hospital
Alan D Forker, MD is a member of the following medical societies: Alpha Omega Alpha, American College of Cardiology, American College of Physicians, American Heart Association, American Medical Association, American Society of Hypertension, and Phi Beta Kappa
Disclosure: Research Grant Grant/research funds Hospital contracts to do research; I am a hospital employee with no personal profit; Speakers Bureau Honoraria Speaking and teaching

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: Nothing to disclose.

Managing Editor

Frank M Sheridan, MD, Cardiology, Providence Everett Medical Center
Frank M Sheridan, MD is a member of the following medical societies: American College of Cardiology, American Heart Association, and Society for Cardiac Angiography and Interventions
Disclosure: Nothing to disclose.

CME Editor

Amer Suleman, MD, Consultant in Electrophysiology and Cardiovascular Medicine, Department of Internal Medicine, Division of Cardiology, Medical City Dallas Hospital
Amer Suleman, MD is a member of the following medical societies: American College of Physicians, American Heart Association, American Institute of Stress, American Society of Hypertension, Federation of American Societies for Experimental Biology, Royal Society of Medicine, and Society of Cardiac Angiography and Interventions
Disclosure: Nothing to disclose.

Chief Editor

Jeffrey N Rottman, MD, Professor of Medicine and Pharmacology, Director, Clinical Cardiac Electrophysiology Fellowship Program, Vanderbilt University School of Medicine; Chief, Department of Cardiology, Nashville Veterans Affairs Medical Center
Jeffrey N Rottman, MD is a member of the following medical societies: American Heart Association and North American Society of Pacing and Electrophysiology (NASPE)
Disclosure: Nothing to disclose.

 
 
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