Peripheral Resistance Baroreflex During Incremental Bicycle Ergometer Exercise: Characterization and Correlation With Cardiac Baroreflex

Figures

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  FIGURE 1. The conventions for the construction of HP, SAP, DAP, and PR variability series from ECG (A), AP (B), and SBF (C) are shown. MAP and MSBF are computed within two consecutive diastolic values and their combination, denoted by red double arrows, allows the computation of PR. The associations between HP and SAP values at the same cardiac beat and between PR and DAP values at the same cardiac beat are made evident via blue and green double arrows, respectively. Association might be varied according with the selected value of τHP-SAP and of τPR-DAP (here τHP-SAP = τPR-DAP = 0). The dotted lines identify the positions of the QRS complex on the ECG trace and the diastolic values on the AP trace.

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  FIGURE 2. The line plots show examples of HP (top panels) and SAP (middle panels) beat-to-beat variability recorded at R (A,F), during E10 (B,G), E20 (C,H), E30 (D,I), and RC (E,J). The line plots (bottom panels) show the linearly-interpolated spontaneous HP-SAP +/+ and –/– patterns in the [SAP(i), HP(i + τHP-SAP°)] plane at R (K), during E10 (L), during E20 (M), during E30 (N), and during RC (O) extracted from the HP and SAP variability series depicted, respectively, in (A–J).

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  FIGURE 3. The line plots show examples of PR (top panels) and DAP (middle panels) beat-to-beat variability recorded at R (A,F), during E10 (B,G), E20 (C,H), E30 (D,I), and RC (E,J). The line plots (bottom panels) show the linearly-interpolated spontaneous PR-DAP +/– and –/+ patterns in the [DAP(i), PR(i + τPR-DAP°)] plane at R (K), during E10 (L), during E20 (M), during E30 (N), and during RC (O) extracted from the PR and DAP variability series depicted, respectively, in (A–J).

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  FIGURE 4. The bar graphs show tHP-SAP° (A) and tPR-DAP° (B) as estimated individually in all experimental conditions (i.e., R, E10, E20, E30, and RC). Values are given as mean plus standard deviation.

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  FIGURE 5. The bar graphs show BRScBR (A), SEQ%cBR (B), and EIcBR (C) as a function of the experimental condition (i.e., R, E10, E20, E30, and RC). Values are given as mean plus standard deviation. The symbol ∗ denotes p < 0.05 versus R.

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  FIGURE 6. The bar graphs show BRSprBR (A), SEQ%prBR (B), and EIprBR (C) as a function of the experimental condition (i.e., R, E10, E20, E30, and RC). Values are given as mean plus standard deviation. The symbol ∗ denotes p < 0.05 versus R.

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  FIGURE 7. Linear regression analyses of SEQ%prBR on SEQ%cBR (A) and EIprBR on EIcBR (B) during incremental light-to-moderate bicycle ergometer exercise. Individual pairs (open circles) in the (SEQ%cBR, SEQ%prBR) and (EIcBR, EIprBR) planes are shown after pooling all subjects together regardless of the experimental condition. The linear regression (solid line) and its 95% confidence interval (dotted lines) are plotted as well if the slope of the regression line is significantly larger than zero with p < 0.05.