TABLE 2.

eSKNA and HRV parameters.

	(1) Non-AMI		(2) AMINCA		(3) AMICA		(1) vs. (2)	(2) vs. (3)	(1) vs. (3)
Parameters HRV (time domain)	Median	(Q1–Q3)	Median	(Q1–Q3)	Median	(Q1–Q3)	p-value	p-value	p-value
Linear
pNN50 (%)	4.535	(2.262–19.300)	5.991	(0.593–11.111)	3.439	(1.390–18.458)	0.563	0.849	0.706
SDNN (ms)	46	(33–70)	0.056	(26–73)	45	(31–62)	0.710	0.569	0.706
RMSSD (ms)	26.465	(21.868–40.380)	26.310	(13.700–31.21)	25.990	(18.735–44.195)	0.433	0.569	0.925
HRV (frequency domain)
LF power (ms2)	382.420	(133.120–1,070.762)	501.466	(46.742–1,329.760)	229.602	(92.829–678.625)	0.741	0.790	0.278
Normalized LF (%)	72.906	(57.447–83.637)	79.834	(64.789–86.776)	65.246	(59.437–70.647)	0.215	0.044*	0.322
HF power (ms2)	158.298	(64.490–251.699)	101.671	(17.937–164.380)	135.524	(53.379–360.903)	0.083	0.184	0.777
Normalized HF (%)	27.094	(16.363–42.553)	20.166	(13.224–35.211)	34.754	(29.353–40.563)	0.215	0.044*	0.322
LF/HF	2.691	(1.351–5.451)	3.959	(1.840–6.562)	1.877	(1.483–2.413)	0.215	0.044*	0.322
eSKNA
Average (μV)	0.680	(0.617–0.728)	1.024	(0.852–1.399)	0.972	(0.852–1.161)	<0.001	0.676	<0.001***

AMI, acute myocardial infarction; AMI_CA, AMI subjects with cluster appearing; AMI_NCA, AMI subjects with non-cluster appearing; eSKNA, envelope of SKNA; HF, high frequency; HRV, heart rate variability; LF, low frequency; LF/HF, the ratio of LF to HF; pNN50, the proportion of the number of pairs of successive R–R intervals that differ by more than 50 ms divided by the total number of R–R intervals; Q1, 25th percentile; Q3 75th percentile; RMSSD, the square root of the mean of the squares of the successive differences between adjacent R–R intervals; SDNN, standard deviation of R–R intervals.

*Statistically significant (p < 0.05). ***Statistically significant (p < 0.001).