cardiovascular disorders
Short QT Interval Syndromes
Diagnosis of SQTS
Specific clinical and electrocardiographic criteria Genetic testing Screening of first-degree family members Diagnosis should be considered in patients with unexplained cardiac arrest or syncope or a family history of such when the affected people do not have structural heart disease. It should also be considered in people who are discovered to have a short QT interval when ECG is done for other reasons. Diagnosis is by ECG showing shortening of the rate-corrected QT interval (QTc). The degree of shortening of the QTc required is debated but ranges from < 0.36 second to ≤ 0.33 second; the longer durations may be more appropriate when patients or family members have a known mutation, documented VT/VF, or unexplained cardiac arrest. Genetic testing has a low yield (approximately 20%). A set of diagnostic criteria have been proposed ( Diagnosis reference ). Additional testing may include ambulatory cardiac rhythm monitoring and cardiac imaging. First-degree family members of patients should have clinical evaluation (ie, to detect symptoms suggestive of arrhythmia) and ECG. Genetic testing of family members is done when the patient has an identified mutation. 1.Gollob MH, Redpath CJ, Roberts JD: The short QT syndrome: proposed diagnostic criteria.J Am Coll Cardiol57:802–812.2011. doi: 10.1016/j.jacc.2010.09.048 