7/4/23, 12:19 AM SQTS - Textbook of Cardiology SQTS Auteur: Louise R.A. Olde Nordkamp Supervisor: Arthur A.M. Wilde The short QT syndrome is a very rare syndrome characterized by an abnormally short QT interval and increased risk of ventricular fibrillation and cardiac death. Contents Clinical diagnosis Physical examination ECG tests Genetic diagnosis Risk Stratification Treatment References Clinical diagnosis The diagnosis is based on the presence a short QT interval, in which the upper limit is mostly set on 330 ms. Males are more often affected than women. A history of cardiac arrest is present in one-third. for both atrial Patients are at risk ventricular (AF) arrhythmias arrhythmias (VT/VF). and Physical examination Patients can present with symptoms of arrhythmias: Out-of-hospital-cardiac-arrest Syncope, pre-syncope (weakness, lightheadedness, dizziness) ECG tests https://www.textbookofcardiology.org/wiki/SQTS 1/3 7/4/23, 12:19 AM SQTS - Textbook of Cardiology The ECG demonstrates a corrected QT interval significantly below the limit of normal (<330 ms). Additionally, notable ECG findings are the presence of a sharp T-wave beginning at the end of the QRS complex, preceded by a brief or absent ST-segment. Exercise electrocardiographic studies in SQTS patients also characteristically reveal a non-physiologic lack of QT shortening at increased heart rates. Genetic diagnosis In a quarter of the patients a mutation is found, predominantly in the KCNH2 gene (SQTS1). This gain- of-function mutation causes an increase in the potassium efflux and, subsequently, to a decrease of the myocyte refractory period. Mutations in the KCNQ1, KCNJ2 and possibly CACNxxx genes are also associated with the SQTS. Risk Stratification Risk stratification in SQTS is still ill-defined and should be done by a specialized cardio-genetic cardiologist. Treatment Hydroquinidine is suggested for normalization of the QT interval in patients with a KCNH2 mutation. ICD therapy is advised in SQTS patients for secondary prevention of sudden cardiac death and could be considered References 1. Giustetto C, Di Monte F, Wolpert C, Borggrefe M, Schimpf R, Sbragia P, Leone G, Maury P, Anttonen O, Haissaguerre M, and Gaita F. Short QT syndrome: clinical findings and diagnostic-therapeutic implications. Eur Heart J. 2006 Oct;27(20):2440-7. DOI:10.1093/eurheartj/ehl185 | 2. Giustetto C, Schimpf R, Mazzanti A, Scrocco C, Maury P, Anttonen O, Probst V, Blanc JJ, Sbragia P, Dalmasso P, Borggrefe M, and Gaita F. Long-term follow-up of patients with short QT syndrome. J Am Coll Cardiol. 2011 Aug 2;58(6):587-95. DOI:10.1016/j.jacc.2011.03.038 | 3. Patel C, Yan GX, and Antzelevitch C. Short QT syndrome: from bench to bedside. Circ Arrhythm Electrophysiol. 2010 Aug;3(4):401-8. DOI:10.1161/CIRCEP.109.921056 | Retrieved from "http://www.textbookofcardiology.org/index.php?title=SQTS&oldid=2298" This page was last edited on 26 March 2013, at 07:34. https://www.textbookofcardiology.org/wiki/SQTS 2/3 7/4/23, 12:19 AM SQTS - Textbook of Cardiology Content is available under Attribution-NonCommercial-ShareAlike 3.0 Unported unless otherwise noted. https://www.textbookofcardiology.org/wiki/SQTS 3/3