Exploring cardiac vector propagation in acute myocardial infarction: a spatial velocity perspective.

Aims: To objectively characterize the spatial-velocity dynamics of the QRS-loop in the vectorcardiogram (VCG) of patients with acute myocardial infarction (AMI).

Methods: VCG was constructed as a space curve directly with three quasi-orthogonal leads I, aVF and V2 recorded by conventional ECG of 25 healthy individuals and 50 AMI patients. Spatial velocity (SV) of the dynamic QRS loop, spatial distance (SD), and spatial magnitude (SM) were recorded, along with axis-specific component attributes of vector magnitude such as ΔX, ΔY, and ΔZ.

Geometry of the Poincaré plot can segregate the two arms of autonomic nervous system - A hypothesis.

Autonomic Nervous System (ANS) operates to achieve the optimum physiological functioning and maintains homeostasis in a tonic and continuous manner. Evaluation of ANS profile is crucial in assessing autonomic dysfunction. Conventional ANS evaluation procedures fail to capture minute dynamic alterations of ANS activities.

Spatial velocity of the dynamic vectorcardiographic loop provides crucial insight in ventricular dysfunction.

Vectorcardiogram (VCG) represents the trajectory of the tip of cardiac vectors in three dimensional space with varying time. It is a recurring, near-periodic pattern of cardiac dynamics that is constructed by drawing the instantaneous vectors from a zero reference point according to direction, magnitude and polarity in the space. Being a three dimensional entity, it is more informative and more sensitive than conventional ECG as an evaluation tool of the physiology of cardiac dynamics, because of its extra degree of freedom.

An evaluation of planarity of the spatial QRS loop by three dimensional vectorcardiography: Its emergence and loss.

Aims: To objectively characterize and mathematically justify the observation that vectorcardiographic QRS loops in normal individuals are more planar than those from patients with ST elevation myocardial infarction (STEMI).

Methods: Vectorcardiograms (VCGs) were constructed from three simultaneously recorded quasi-orthogonal leads, I, aVF and V (sampled at 1000 samples/s). The planarity of these QRS loops was determined by fitting a surface to each loop.

Understanding clay minerals with fuzzy mathematics.

A long-existing geochemical problem is the lack of a means of chemically defining non-stoichiometric complex minerals such as clays, which have no distinct composition and no clear compositional boundaries. We propose here a novel approach for describing the chemical nature of clay minerals using fuzzy logic. This non-conventional mathematical approach allows us to quantify compositional vagueness in such systems.