The influence of mental load and physical load on the interventricular synchronous depolarization

The influence of mental load and physical load on the synchronous depolarization of the left and right ventricles in healthy persons was examined by the morphology of R wave peaks in Electrocardiogram (ECG). The R waves which have two peaks within 5 milliseconds´ interval near the R peak were defined as Two Peaks R waves (TPR), and R waves with only single peak as One Peak R waves (OPR). A number of totally 30 healthy subjects were examined during relaxation state, from whom subjects with Percent of Two Peaks R waves to total R waves (PTPR) higher than 20% were extracted. And then the mental load of reading and the physical load of running was imposed on them in-order. There were 3 subjects (10%) whose PTPR was higher than 20% during relaxation state, who were noted as subject A, B and C, respectively. Change of the morphology of R wave peaks induced by mental load and physical load was found by Analysis of Variance (ANOVA) in these three subjects. PTPR decreased significantly (P<;0.001 for subject B and C) during mental load period in comparison with relaxation state, while increased significantly (P<;0.001 for all subjects) during recovery period when compared with mental load. Similarly, PTPR decreased significantly (P<;0.001 for all subjects) during physical load in comparison with relaxation state, while increased significantly (P<;0.001 for subject A and B) during recovery period when compared with physical load. Both mental load and physical load could increase the level of interventricular synchronous depolarization for healthy persons with PTPR higher than 20 % in relaxation state.