ABSTRACT
Changes induced by intrauterine growth restriction (IUGR) in cardiovascular anatomy and function that persist throughout life have been associated with a higher predisposition to heart disease in adulthood. Together with cardiac morphological remodelling, evaluated through the ventricular sphericity index, alterations in cardiac electrical function have been reported by characterization of the depolarization and repolarization loops, and their angular relationship, measured from the vectorcardiogram. The underlying relationship between the morphological remodelling and the angular variation of QRS and T-wave dominant vectors, if any, has not been explored. The aim of this study was to evaluate this relationship using computational models based on realistic heart and torso in which IUGR-induced morphological changes were incorporated by reducing the ventricular sphericity index. Specifically, we departed from a control model and we built eight different globular heart models by reducing the base-to-apex length and enlarging the basal ventricular diameter. We computed QRS and T-wave dominant vectors and angles from simulated pseudo-electrocardiograms and we compared them with clinical measurements. Results for the QRS to T angles follow a change trend congruent with that reported in clinical data, supporting the hypothesis that the IUGR-induced morphological remodelling could contribute to explain the observed angle changes in IUGR patients. By additionally varying the position of the ventricles with respect to the torso and the electrodes, we found that electrode displacement can impact the quantified angles and should be considered when interpreting the results.
ABSTRACT
Traditional methods of posture evaluation carried out by physical therapists manually measure or test the alignments of body segments, investing a long time for its development and adding an error percentage related to the level of professional expertise. The present study uses a system of two dimensions photogrammetry to investigate its applicability on measurement of posture parameters and the variation of the measurements using different photographic cameras locate at different distances from the subject. The "marker automatic measurement" system (LAM) filters and segments body markers on photographic images. Data were collected using a semi-professional, a mid-range cellphone and a sports camera. Tests were recorded by placing the camera at 2.50, 2.00 and 1.80 meters from the subject, and the lens at a height of 1.10, 1.00 and 0.97 meters with an illuminance of 29.92 lux. Subsequently, 30 volunteers participated in the postural tests. The Measurements were made on frontal, anterior and posterior planes as well as sagittal plane. The maximum absolute error on the measuring of distances was 0.64 cm. On angles related to the horizontal was 0.70 degrees and for angles concerning the vertical was 0.76 degrees.Clinical Relevance-By utilizing LAM system all three views were evaluated in less than a minute without counting the time for putting on the markers. The results obtained suggest that the system presents trustworthy results, which reduce considerably the time of carrying out posture evaluations where results are measurable, repeatable and away from the evaluator's subjectivity.
