Diagnostic potentials of the T-loop morphology in VCG

In the present work, the characterization and quantification of heterogeneous cardiac repolarization have been considered, and different studies of the authors considering particular aspects of the T-loop morphology have been reviewed. In particular, the longitudinal modifications, the age and gender influences and the diagnostic relations have been reported. The population based ECG-ILSA (Italian Longitudinal Study on Aging) database has been used in all studies. The orthogonal Frank leads were synthesized from the standard 12 lead electrocardiogram. Depending on the different studies, six to ten parameters have been obtained from the vectorcardiograms with two different methods of considering the zero point. The resulting conclusions were: 1. The modified parameters calculated towards the major axis of the T-loop proved to yield higher discriminative power. 2. The mean values of all parameters of the T-loop morphology of the healthy subjects group are statistically different from those of ischemia or myocardial infarction groups. 3. Stability of the T-loop morphology measurements made in a temporal interval of 5 years (longitudinal modifications) for one and the same patient is observed. The Angina Pectoris group characterized in general by a high "clinical instability" shows the most significant longitudinal modifications. 4. Age (< 75 years and >= 75 years old) and gender (male/female) have different T-loop morphology impact in the three considered groups (healthy, cardiac diseases, and hypertension). The gender influences the healthy and patients with hypertension, while age influences mainly the patients with cardiac diseases.