[Alteration of the QRS complex in electrocardiograms of healthy people in the course of test loading].
QRS amplitudes were analyzed in ECG records obtained from exercising healthy people to evaluate the sensitivity of QRS waves to exaggerated pulmonary ventilation, blood pressure (BP) and heart rate (HR). Seventeen normal subjects aged >35 years were involved in a series of three test loading sessions aimed to define QRS alterations caused by shifting and rotation of the heart, and changes in conductivity of thoracic organs and tissues as a consequence of a different respiration pattern. They also participated in a second series of three loading sessions aimed to trace QRS alterations stemming from changes in central hemodynamics (systolic and diastolic BP and HR). Both series demonstrated a reliable S-wave rise that did not relate to the heart rotation caused by the diaphragm displacement due to deep respiration and change in body positioning but correlated with increases in systolic BP. These observations could have been induced by growth of the transmural myocadial pressure produced by isovolumic contractions during heavy test loading.
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Saltykova
D000328:Adult; D001794:Blood Pressure; D004562:Electrocardiography; D005080:Exercise Test; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D056888:Patient Positioning; D012119:Respiration