Prolonged Qt Syndrome Health Article

Treatment

A conventional treatment is the oral administration of beta-blockers, medications that decrease the input from the sympathetic nervous system to the heart. Although beta-blockers do not correct the abnormalities in the ion channels of the heart cells, they do appear to decrease the occurrence of cardiac arrhythmias. However, these medications are not helpful in all cases, and are actually contraindicated in some individuals. Potassium supplementation is also being explored as a treatment in certain cases. As the genetics of LQTS becomes better understood, it should be possible to tailor treatments that will be effective for each of the various gene mutations.

Alternative treatment

In some patients, severing of the sympathetic nerve to the heart has decreased the occurrence of arrhythmias. Pacemakers and defibrillators appear to hold promise as new forms of treatment. As devices of this type are developed that are smaller in size, they may come into more widespread use, either alone or in conjunction with specific medications.

Prognosis

LQTS is a life-long condition. Individuals who are not diagnosed and treated are at an increased risk of syncope and sudden death. Adequate treatment can decrease this risk. There is no cure. Individuals with one of the inherited forms of LQTS are at risk of passing the mutation and the disease to their offspring.

Prevention

The risk of cardiac arrhythmias due to acquired forms of LQTS can be decreased by avoiding the medications and situations that trigger episodes. At present there is no genetic therapy to correct the gene mutations present in the inherited forms of LQTS, but individuals who are known to have an inherited form may also be able to lessen the risk of a life-threatening episode by avoiding such environmental triggers and by taking the appropriate medications.

BOOKS

Keating, Mark T. and Sanguinetti, Michael C. "Familial Cardiac Arrhythmias." In The Metabolic & Molecular Bases of Inherited Disease, ed. C.R. Scriver et al. New York: McGraw-Hill Press, 2001

PERIODICALS

Towbin, Jeffrey A. and Vatta, Matteo. "Molecular Biology and the Prolonged QT Syndromes" American Journal of Medicine 110 (April 2001): 385–398.

Vizgirda, Vida M. "The Genetic Basis for Cardiac Dysrhythmias and the Long QT Syndrome J. Cardiovasc Nursing 13 no. 4 (1999): 34–45.

ORGANIZATIONS

Sudden Arrhythmia Death Syndromes Foundation. 540 Arapeen Drive, Suite 207, Salt Lake City, Utah 84108. (800) STOP SAD. <http://www.sads.org>. or <http://www.ihc.com/research/longqt.html>.

OTHER

NORD (National Organization for Rare Disorders, Inc.). <http://www.rarediseases.org/cgi-bin/nord>.

American Heart Association. <http://www.americanheart.org/Heart_and_Stroke_A_Z_Guide/longqt.html>.

Sallie Freeman, PhD

KEY TERMS

Anorexia nervosa—A loss of appetite for food not explainable by local disease. It is thought to have a psychological basis.

Autosomal dominant—A pattern of inheritance in which only one of the two copies of an autosomal gene must be abnormal for a genetic condition or disease to occur. An autosomal gene is a gene that is located on one of the autosomes or non-sex chromosomes. A person with an autosomal dominant disorder has a 50% chance of passing it to each of their offspring.

Autosomal recessive—A pattern of inheritance in which both copies of an autosomal gene must be abnormal for a genetic condition or disease to occur. An autosomal gene is a gene that is located on one of the autosomes or non-sex chromosomes. When both parents have one abnormal copy of the same gene, they have a 25% chance with each pregnancy that their offspring will have the disorder.

Diuretic—An agent that increases the production of urine.

Electrocardiogram—A record of the electrical activity of the heart showing certain waves called P, Q, R, S, and T waves. The Q, R, S, T waves are associated with contraction of the ventricles, the lower two chambers of the heart.

Sympathetic nervous system—A division of the autonomic nervous sytem, the portion of the nervous system that controls involuntary bodily functions such as heart rate.

Syndactyly—A fusion of two or more toes or fingers.