Development and validation of a machine learning model for diagnosis of ischemic heart disease using single-lead electrocardiogram parameters

Table 6 Categorical variables

Index	Factor	Group 1 positive myocardial perfusion on the CTP (n = 31)	Group 2 negative myocardial perfusion on the CTP (n = 49)	P value
Gender	F	17 (54.83)	22 (44.89)	0.387
	M	14 (45.16)	27 (55.10)
Obesity stage	Normal	12 (38.70)	18 (36.73)	0.988363
	Overweight	11 (35.48)	18 (36.73)
	1 degree	8 (25.80)	12 (24.48)
	3 degree	0 (0.00)	1 (2.04)
Smoking	Yes	7 (22.58)	7 (14.28)	0.342
	No	24 (77.41)	42 (85.71)
Concomitant diseases	Yes	15 (48.38)	26 (53.06)	0.835
	No	12 (38.70)	23 (46.93)
	Missing data	4 (12.90)	0 (0.00)
Atherosclerosis of the coronary artery	Yes	16 (51.61)	15 (30.61)	0.061
	No	15 (48.38)	34 (69.38)
Hemodynamically significant coronary artery atherosclerosis on the CTP (> 60% stenosis)	Yes	8 (25.80)	1 (2.04)	0.0021
	No	23 (74.19)	48 (97.95)
Stress induced myocardial perfusion defect on the CTP	Yes	31 (100.00)	0 (0.00)	< 0.0011
	No	0 (0.00)	49 (100.00)
Myocardial perfusion defect before stress ATP on the CTP	Yes	21 (67.74)	5 (10.20408)	< 0.0011
	No	10 (32.25)	44 (89.79)
Atherosclerosis in other arteries	Yes	22 (70.96)	19 (38.77)	0.0061
	No	7 (22.58)	25 (51.020)
	Missing data	2 (6.45)	5 (10.20)
Atherosclerotic vascular (namely)	Carotid	1 (3.22)	0 (0.00)	0.347
	Carotid. brachiocephalic bifurcation	21 (67.74)	19 (38.77)
	Missing data	9 (29.03)	30 (61.22)
Carotid artery atherosclerosis	Yes	20 (64.51)	19 (38.77)	0.0151
	No	8 (25.80)	26 (53.06)
	Missing data	3 (9.67)	4 (8.16)
Brachiocephalic artery atherosclerosis	Yes	18 (58.06)	19 (38.77)	0.067
	No	10 (32.25)	26 (53.06)
	Missing data	3 (9.67)	4 (8.16)
Arterial hypertension	Yes	19 (61.29)	21 (42.85)	0.109
	No	12 (38.70)	28 (57.142)
Stage of arterial hypertension	I	4 (13.55)	1 (2.04)	0.079756
	II	6 (19.35)	14 (28.57)
	III	9 (29.03)	7 (14.28)
Degree of hypertension	Degree 1	10 (32.25)	9 (18.36)	0.098908
	Degree 2	3 (9.67)	10 (20.40)
	Degree 3	6 (19.35)	3 (6.12)
Risk of cardiovascular disease	Low	10 (32.25)	19 (38.77)	0.449429
	Moderate	8 (25.80)	16 (34.70)
	High	8 (25.80)	10 (20.40)
	Very high	5 (16.12)	3 (6.12)
SCAD from anamnesis	Yes	4 (12.90)	1 (2.04)	< 0.0011
	No	2 (6.45)	25 (51.02)
	Missing data	25 (80.64)	23 (46.93)
Blood pressure reaction type on stress test	Asthenic	2 (10.50)	2 (4.08)	0.072076
	Hypotonic	3 (15.80)	1 (2.04)
	Hypertonic	1 (5.30)	4 (8.16)
	Mild hypertonic	1 (5.30)	0 (0.00)
	Normotonic	12 (63.20)	42 (85.71)
Functional class by Watt	FC-I	1 (3.22)	7 (14.28)	0.313
	FC-II	3 (9.67)	6 (12.24)
	No SCAD	27 (87.09)	36 (73.46)
Functional class by METs	FC-I	1 (3.22)	5 (10.20)	0.5568
	FC-II	3 (9.67)	7 (14.28)
	FC-III	0 (0.00)	1 (2.04)
	No SCAD	27 (87.09)	36 (73.46)
Reaction type to stress test (positive/negative)	Negative	16 (51.61)	26 (53.06)	0.191007
	Suspected	11 (35.45)	10 (20.40)
	Positive	4 (12.90)	13 (26.53)
Reason for discontinuation of the stress test	Horizontal ST depression > 1 mm	2 (6.45)	6 (12.24)	0.385
	Reach goal HR	29 (93.54)	42 (88.11)
Tolerance to exertion on stress test	Low	1 (3.22)	1 (2.04)	0.416079
	Moderate	20 (64.45)	23 (46.93)
	Close to high	3 (9.67)	5 (10.20)
	High	3 (9.67)	13 (26.53)
	Very high	4 (12.90)	7 (14.28)
CAVI degree	Normal (< 8)	9 (29.03)	27 (55.10)	0.073757
	Borderline (8-9)	11 (35.48)	11 (22.44)
	Pathological (> 9)	11 (35.48)	11 (22.44)
ABI degree	Normal	29 (93.54)	47 (95.91)	0.89381
	Borderline	1 (3.22)	1 (2.04)
	Abnormal	1 (3.22)	1 (2.04)
Biological estimated vascular age	Normal	16 (51.61)	29 (59.18)	0.507
	High	15 (48.38)	20 (40.81)
CKD stage	I	12 (38.70)	23 (46.93)	0.285103
	II	16 (51.61)	25 (51.02)
	IIIa	3 (9.67)	1 (2.04)

¹Values of statically significant differences.

Data were presented as n (%). The χ² test was used for the analysis of categorical variables. F: Female; M: Male; CTP: Computed tomography myocardial perfusion; SCAD: Stable coronary artery disease; FC: Functional classification of angina; METs: Metabolic equivalent; CAVI: Cardio-ankle vascular index; ABI: Ankle-brachial index; CKD: Chronic kidney disease.