Respiratory Variations of R-Wave Amplitude in Lead II Are Correlated With Stroke Volume Variations Evaluated by Transesophageal Doppler Echocardiography

Heart rates, heart rate profiles, and electrocardiograms in three killer whales, a beluga, and a pilot whale: An exploratory investigation

“…, Lorne et al . ), and with exercise in horses (Marlin and Nankervis , Hiraga and Sugano ), such changes were limited to one or the other waveforms and were small relative to the two‐ to three‐fold changes observed in the entire ECG signals of the whales. Most probably, the changes observed in the whales were secondary to a change in the relationship of the electrical vector of the heart to the location of the suction cup electrodes.…”

Effects of psychological stress test on the cardiac response of public safety workers: alternative parameters to autonomic balance

“…The increases observed in the BI and in the relative area LF to LF + HF between the initial stage and the test stage indicate that, according to [5] and [15], the Stroop test generates a response of the sympathetic nervous system of the subjects. As a consequence, the medians of the total areas LF + HF shift to the LF region, where the SNS dominates, as is shown in the box plot of figure 2c.…”

“…Another parameter, among others, that is usually extracted from the ECG, although strongly influenced by the thoracic movements during respiration, is the height of the R-wave with respect to the baseline of the signal. This parameter is known as R-wave amplitude, and is related to changes on the volume of the left ventricle [4,5]. The ECG signals are mediated by the autonomic nervous system (ANS) through the sympathetic (SNS) and parasympathetic (PSNS) nervous system [6].…”

Comparison of automated vs. manual determination of the respiratory variations in the EKG R wave amplitude for the prediction of fluid responsiveness during surgery

“…A receiver operating characteristic (ROC) curve analysis was then performed for EKGv auto varying the discriminating threshold of this parameter to determine the ability of EKGv auto to discriminate between patients with an EKGv man > 15% and EKGv man ≤ 15%. This threshold was chosen based on a previous study by Lorne et al which determined that the inconclusive limits of changes in stroke volume (ΔSV) ranged from 13% to 15%, and that EKGv > 15% was able to accurately predict ΔVTI > 15% [10]. In all cases, a P value less than 0.05 was considered statistically significant.…”

“…For a preload-dependent patient, the large changes in cardiac volume induced by respiration will result in a corresponding large change in the measured QRS wave amplitude for the same reasoning. Since changes in R wave amplitude from lead II are induced by significant rapid LV preload changes and have been shown to correlate well with PPV and SVV [9,10], the EKGv for this study was calculated from lead II R wave amplitude (RDII) variations.…”