Time-domain remarks on the cycle-to-cycle variability in some quantities measured on the vectorcardiogram magnitude

Traces from five patients with different pathophysiological conditions were considered. For each of them more than ten successive cardiac cycles were observed. In each cycle, fourteen temporal intervals were measured. Diagrams were prepared with all values from many measurements made on the electrocardiogram of a patient. Means, variances and coefficients of variation were also computed. A consistent variability was detected in all measurements on every patient. The causes of such a situation have to be studied in detail. However, the coefficient of variation appears make it possible by itself, to distinguish some pathological cases (infarcts and conduction defects) from all others considered here.