Asymmetry of RR intervals and ECG amplitudes in LQTS patients

Abstract

A system which responds strongly to stimuli is more asymmetric in time. We show this effect in RR intervals and also in amplitudes of QRS and T complex of the ECG in the groups of 67 long QT syndrome (LQTS) patients and 128 healthy controls from THEW database. We claim that it reflects a diminished response to inotropic and chronotropic control of cardiac effector in this pathology. Measured based on difference of amplitudes between consecutive beats are the best, especially the D index (Hou et al.), which utilizes poor overlap between paired variables. Clinical Relevance-Clinical indices of asymmetry differen-tiate between LQTS and healthy individuals and may be used to stratify risk in LQTS and other patients threatened by arrhythmia