Table 1.
Holter-based measures significantly different by cardiovascular risk category for T1 or T2 (cross-sectional analyses)
| T1 | T2 | |
|---|---|---|
| Lower risk = 182 | Lower risk = 153 | |
| Higher risk = 403 | Higher risk = 432 | |
| (n = 585) | (n = 585) | |
| Mean ± SE | Mean ± SE | |
| Age | ||
| Lower risk | 70 ± 0.3 | 75 ± 0.3 |
| Higher risk | 71 ± 0.2 | 76 ± 0.2 |
| P-value | 0.001 | 0.022 |
| Heart rate (HR) | ||
| Lower risk | 75 ± 1 | 74 ± 1 |
| Higher risk | 73 ± 1 | 73 ± 1 |
| P-value | 0.027 | 0.054 |
| Number of VPCs* | ||
| Lower risk | 10 [57] | 12 [97] |
| Higher risk | 13 [93] | 32 [223] |
| P-value | 0.180 | 0.001 |
| Ln ULF | ||
| Lower risk | 9.5 ± 0.04 | 9.4 ± 0.1 |
| Higher risk | 9.3 ± 0.03 | 9.2 ± 0.03 |
| P-value | 0.002 | 0.014 |
| Ln LF | ||
| Lower risk | 5.9 ± 0.1 | 5.7 ± 0.1 |
| Higher risk | 5.8 ± 0.04 | 5.6 ± 0.04 |
| P-value | 0.019 | 0.408 |
| Normalised LF | ||
| Lower risk | 65 ± 0.8 | 63 ± 0.8 |
| Higher risk | 63 ± 0.5 | 59 ± 0.5 |
| P-value | 0.002 | <0.001 |
| Normalised HF | ||
| Lower risk | 22 ± 0.6 | 24 ± 0.7 |
| Higher risk | 24 ± 0.4 | 26 ± 0.5 |
| P-value | 0.024 | 0.006 |
| LF/HF ratio | ||
| Lower risk | 4.8 ± 0.2 | 4.4 ± 0.2 |
| Higher risk | 4.4 ± 0.1 | 3.8 ± 0.1 |
| P-value | 0.014 | 0.003 |
| DFA1 | ||
| Lower risk | 1.10 ± 0.01 | 1.07 ± 0.01 |
| Higher risk | 1.06 ± 0.01 | 1.01 ± 0.01 |
| P-value | 0.023 | 0.001 |
| Lower risk = 147 | Lower risk = 124 | |
| Higher risk = 325 | Higher risk = 379 | |
| (n = 472) | (n = 503) | |
| Turbulence slope | ||
| Lower risk | 7.7 ± 0.6 | 6.5 ± 0.5 |
| Higher risk | 6.6 ± 0.3 | 5.1 ± 0.2 |
| P-value | 0.043 | 0.006 |
| Turbulence onset | ||
| Lower risk | −0.015 ± 0.002 | −0.012 ± 0.002 |
| Higher risk | −0.011 ± 0.001 | −0.008 ± 0.001 |
| P-value | 0.085 | 0.047 |
Heart rate (HR) beats/min = 60,000/average of normal-to-normal (N–N) intervals; ULF = ultra-low frequency power (1.15 × 10−5–0.003–0.0033 Hz); VLF = very low frequency power (0.0033–0.04 Hz); LF = low frequency power (0.04–0.15 Hz), average of 5-min values; HF = high frequency spectral power (0.15–0.4 Hz), average of 5-min values; normalised LF (%) = LF/(TP−VLF), average of 5-min values; normalised HF (%) = HF/(TP−VLF), average of 5-min values; LF/HF ratio = LF/HF for average of 5-min values; DFA1 = short-term fractal scaling exponent; power-law slope = slope of a line fitted to a plot of log spectral power versus log of underlying frequency between 10−2 and 10−4 Hz; turbulence slope (TS) in ms/beat = maximum slope of any 5 beats in the 15-beat interval after a VPC; turbulence onset (TO) = average ratio of the difference in the N–N interval of the two beats before each VPC and the N–N interval of the two beats after each VPC divided by the N–N interval before each VPC. P < 0.05 in bold.
*P-values based on ln transformed values.