Preprocessing Methods for Ambulatory HRV Analysis Based on HRV Distribution, Variability and Characteristics (DVC)

. 2022 Mar 3;22(5):1984. doi: 10.3390/s22051984

Algorithm 1 HRV filtering procedure

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for each $R R_{i}$ < 0.3 s do
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Compute $R R_{r} = R R_{i} + R R_{i + 1}$ , $E R_{r}$ (Equation (4)), $E R_{l}$ (Equation (5)) and $E t o t_{r}$ (Equation (7))
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if $R R_{r} <$ 1.3 s and $E R_{l} \leq E_{10}$ and $E R_{r} \leq E_{10}$ then
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Right merge: Replace $R R_{i + 1}$ by $R R_{r}$ and delete $R R_{i}$ and its timestamp
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else Compute $R R_{l} = R R_{i} + R R_{i - 1}$ , and $E L_{r}$ (Equation (4)), $E L_{l}$ (Equation (5)) and $E t o t_{l}$ (Equation (7))
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if $R R_{l} <$ 1.3 s and $E L_{l} \leq E_{10}$ and $E L_{r} \leq E_{10}$ then
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Left merge: Replace $R R_{i}$ by $R R_{l}$ and delete $R R_{i - 1}$ and its timestamp
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else if $R R_{r}$ > 1.3 s and $R R_{l}$ > 1.3 s then
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Delete both $R R_{i}$ and $R R_{i + 1}$
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else if $R R_{r}$ < 1.3 s and $R R_{l}$ > 1.3 s then
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Replace $R R_{i + 1}$ by $R R_{r}$ and delete $R R_{i}$ and its timestamp
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else if $R R_{r}$ > 1.3 s and $R R_{l}$ < 1.3 s then
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Replace $R R_{i - 1}$ by $R R_{l}$ and delete $R R_{i}$ and its timestamp
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else if Both $R R_{l}$ and $R R_{r}$ < 1.3 s but errors $E t o t_{r}$ and $E t o t_{l}$ are higher than 0.4 then
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Keep the one with the smaller error
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end if
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end if
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end for