ComplicationsBy Mayo Clinic Staff
Sometimes, prolonged QT intervals in people with long QT syndrome never cause problems. However, physical or emotional stress might "trip up" a heart susceptible to prolonged QT intervals. This can cause the heart's rhythm to spin out of control, triggering life-threatening, irregular heart rhythms (arrhythmias) including:
Oct. 27, 2015
Torsades de pointes — 'twisting of the points.' This arrhythmia is characterized by your heart's two lower chambers (ventricles) beating fast, making the waves on an ECG monitor look twisted. When this arrhythmia occurs, less blood is pumped out from your heart. Less blood then reaches your brain, causing you to faint suddenly and, often, without any warning.
If a torsades de pointes episode is short — lasting less than one minute — your heart can correct itself seconds later, and you regain consciousness on your own. However, if a torsades de pointes episode persists, it can lead to a life-threatening arrhythmia called ventricular fibrillation.
Ventricular fibrillation. This condition causes the ventricles to beat so fast that your heart quivers and effectively ceases pumping blood. Unless your heart is shocked back into a normal rhythm by a device called a defibrillator, ventricular fibrillation can lead to brain damage and death.
It's now known that long QT syndrome might explain some cases of sudden death in young people who otherwise appear healthy.
- What is long QT syndrome? National Heart, Lung, and Blood Institute. http://www.nhlbi.nih.gov/health/health-topics/topics/qt. Accessed Aug. 25, 2015.
- Conduction disorders. American Heart Association. http://www.heart.org/HEARTORG/Conditions/Arrhythmia/AboutArrhythmia/Conduction-Disorders_UCM_302046_Article.jsp. Accessed Aug. 25, 2015.
- Seslar SP, et al. Clinical features of congenital long QT syndrome. http://www.uptodate.com/home. Accessed Aug. 21, 2015.
- Zimetbaum PJ, et al. Genetics of congenital and acquired long QT syndrome. http://www.uptodate.com/home. Accessed Aug. 21, 2015.
- Berul CI, et al. Acquired long QT syndrome. http://www.uptodate.com/home. Accessed Aug. 21, 2015.
- AskMayoExpert. Causes of QT prolongation or serial lengthening of the QT interval. Rochester, Minn.: Mayo Foundation for Medical Education and Research; 2014.
- AskMayoExpert. Personal or family history of syncope or sudden death. Rochester, Minn.: Mayo Foundation for Medical Education and Research; 2014.
- What is the heart? National Heart, Lung, and Blood Institute. http://www.nhlbi.nih.gov/health/health-topics/topics/hhw. Accessed Aug. 28, 2015.
- AskMayoExpert. Medical conditions that may prolong the QT interval. Rochester, Minn.: Mayo Foundation for Medical Education and Research; 2014.
- Arrhythmia. National Heart, Lung, and Blood Institute. http://www.nhlbi.nih.gov/health/health-topics/topics/arr/types. Accessed Aug. 28, 2015.
- Seslar SP, et al. Diagnosis of congenital long QT syndrome. http://www.uptodate.com/home. Accessed Aug. 21, 2015.
- Ferri FF. Prolonged Q-T interval syndrome. In: Ferri's Clinical Advisor 2016. Philadelphia, Pa.: Mosby Elsevier; 2016. https://www.clinicalkey.com. Accessed Aug. 31, 2015.
- Zimetbaum PJ, et al. Prognosis and management of congenital long QT syndrome. http://www.uptodate.com/home. Accessed Aug. 21, 2015.
- Ackerman MJ. My approach to treatment of the congenital long QT syndromes. Trends in Cardiovascular Medicine. 2015;25:67.
- Johnson JN, et al. Return to play? Athletes with congenital long QT syndrome. British Journal of Sports Medicine. 2013;47:28.
- Riggin ER. Allscripts EPSi. Mayo Clinic, Rochester, Minn. Sept. 3, 2015.
- Glatter K. Genetic testing for long QT syndrome — Is it a useful tool? EP Lab Digest. http://www.eplabdigest.com/articles/Genetic-Testing-Long-QT-Syndrome-%E2%80%94-Is-it-a-Useful-Tool. Accessed Sept. 9, 2015.
- Genetic testing. Sudden Arrhythmia Death Syndromes Foundation. http://www.sads.org/living-with-sads/Insurance/Genetic-Testing#.VfB_G9iFODZ. Accessed Sept. 9, 2015.
- Fish and omega-3 fatty acids. American Heart Association. http://www.heart.org/HEARTORG/GettingHealthy/NutritionCenter/HealthyEating/Fish-and-Omega-3-Fatty-Acids_UCM_303248_Article.jsp. Accessed Sept. 9, 2015.
- von Schacky C. Omega-3 fatty acids: Anti-arrhythmic, pro-arrhythmic, or both? Frontiers in Physiology. 2012;3:1.
- Behere SP, et al. Recent advances in the understanding and management of long QT syndrome. Current Opinion in Pediatrics. 2014;26:727.
- Loar RW, et al. Sudden cardiac arrest during sex in patients with either catecholaminergic polymorphic ventricular tachycardia or long-QT syndrome: A rare but shocking experience. Journal of Cardiovascular Electrophysiology. 2015;26:300.
- Seth R, et al. Long QT syndrome and pregnancy. Journal of the American College of Cardiology. 2007;49:1092.
- Ackerman MJ (expert opinion). Mayo Clinic, Rochester, Minn. Sept. 28, 2015.
- Ackerman MJ, et al. HRS/EHRA expert consensus statement on the state of genetic testing for the channelopathies and cardiomyopathies: This document was developed as a partnership between the Heart Rhythm Society (HRS) and the European Heart Rhythm Association (EHRA). Heart Rhythm. 2011;8:1308.