Electrical alternans in long QT syndrome resembling a Brugada syndrome pattern.
Isolated T wave alternans (repolarization alternans) is frequently associated with long QT syndrome. However, electrical alternans involving the P wave, QRS complex, ST segment (depolarization alternans), and the T wave is a rare finding. This report describes a 62-year-old woman with long QT syndrome and an electrical alternans occurring after previous syncope. Alternating QRS complexes showed a prolonged PR interval, a Brugada syndrome resembling pattern of the QRS complexes (elevation and downslope of the ST segments), and a T wave alternans. A genetic basis for the long QT syndrome has been ruled out by sequencing of all coding areas of the LQT genes. Potential mechanisms for the electrical alternans are discussed.
D002037:Bundle-Branch Block / Q000150:complications / Q000175:diagnosis* / Q000235:genetics / Q000503:physiopathology; D003937:Diagnosis, Differential; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D008133:Long QT Syndrome / Q000150:complications / Q000175:diagnosis* / Q000235:genetics / Q000503:physiopathology; D008875:Middle Aged; D013575:Syncope / Q000209:etiology