Association of the Heart Rate Variability Response to Active Standing with the Severity of Calcific Aortic Valve Disease: Novel Insights of a Neurocardiovascular Pathology

Figures

• 

  Figure 1. Example of HRV time series from one NAV subject (upper panels), one AVSc patient (middle panels) and one AVSt patient (lower panels) while they were in supine position (left panels) and active standing (right panel). The NAV subject is a 46-year-old man with a BMI of 25.565 kg/m2, a Vmax of 1.2 m/s, an AVA of 3.9 cm2, an AVAi of 2.02 cm2/m2, a PGmean of 2 mmHg, a PGmax of 5 mmHg and an LVEF of 60%. The AVSc patient corresponds to a 30-year-old-man with a BMI of 26.3 kg/m2, a Vmax of 1.05 m/s, an AVA of 4.2 cm2, an AVAi of 2.2 cm2/m2, a PGmean of 2 mmHg, a PGmax of 4 mmHg and an LVEF of 68%. The AVSt patient is a 53-year-old man with a BMI of 30.191 kg/m2, a Vmax of 5.6 m/s, an AVA of 0.5 cm2, an AVAi of 0.25 cm2/m2, a PGmean of 57 mmHg, a PGmax of 97 mmHg and an LVEF of 55%. MeanNN: mean value of all NN intervals in the time series, NAV: normal aortic valve, AVSc: aortic valve sclerosis, AVSt: aortic valve stenosis. ΔmeanNN: the difference between meanNN values at the supine position minus values at active standing.

• 

  Figure 2. Conceptual framework of the studied variables. Vmax: maximum aortic valve transvalvular velocity; PGmean: mean pressure gradient, PGmax: maximum pressure gradient; AVA: aortic valve area, AVAi: aortic valve area indexed to body surface area; Δ: the difference between values of heart rate variability (HRV) indices at the supine position minus values at active standing; meanNN: mean value of all NN intervals (RR intervals from sinus rhythm); SDNN: standard deviation of all NN intervals; RMSSD: root mean squared of the successive differences; pNN20: percentage of successive NN intervals with differences greater than 20 ms; LF: low-frequency band spectral power; HF: high-frequency band spectral power, n.u.: normalized units; LF/HF: ratio between low-frequency and high frequency spectral powers; α1: short-term scaling exponent, SampEn: sample entropy; MMPs: matrix metalloproteinases; TIMP1: tissue inhibitor of metalloproteinase-1.

• 

  Figure 3. Schematic representation of hierarchical partitioning analysis applied to each of the 11 dependent variables (HRV indices). The pre-selected variables were distinctive for each of the 11 HRV indices. * A multiple linear stepwise regression model was applied for each category of independent variables and covariables as described in Figure 2.