Electrocardiographic changes in the differentiation of ischemic and non-ischemic ST elevation

Figures & data

Table 1. Baseline characteristics.

	STEMI patients (n = 85)	Non-ischemic patients (n = 94)	Pericarditis (n = 38)	Takotsubo (n = 21)	ERS (n = 35)
Age, years, mean (SD)	65 (13)	46 (18)	38 (16)	68 (10)	42 (14)
Sex, % women	34	33	18	100	9
MaR, mean % (SD)	31 (11)	–	–	–	–
ECG variables
HR, bpm (median (IQR))	71 (60–87)	73 (64–85)	80 (67–90)	76 (69–96)	65 (58–73)
Pathological Q waves, n (%)	22 (26)	8 (9)	1 (3)	4 (19)	3 (9)
Max STE (mV), mean (SD)	0.33 (0.22)	0.18 (0.08)	0.20 (0.09)	0.17 (0.07)	0.17 (0.08)
STE in V2–V4, n (%)	43 (51)	74 (79)	22 (58)	17 (81)	35 (100)
Max STE typical lead (%)	III (39)	V2 (39)	V2 (24) V3 (24)	V3 (33)	V2 (66)
STE in II/aVF/III, n (%)	40 (47)	28 (30)	23 (61)	3 (14)	2 (6)

ERS: early repolarization syndrome; SD: standard deviation; MaR: myocardium at risk; bpm: beats per minute; IQR: inter-quartile range; HR: heart rate; STE: ST elevation.

Table 2. Prevalence of ECG findings in patients with different ST-elevation etiology.

ECG finding	STEMI patients	Non-ischemic patients	p Value
All patients	N = 85	N = 94
Convex STE, n (%)	19 (22)	8 (9)	.01
J waves, n (%)	23 (27)	59 (63)	<.001
J waves in leads with STE, n (%)	22 (26)	53 (56)	<.001
PR depression any lead, n (%)	26 (31)	42 (45)	.06
PR depression limb leads, n (%)	25 (29)	40 (43)	.09
PR depression chest leads, n (%)	10 (12)	36 (38)	<.001
Patients without pathological Q waves	N = 63	N = 86	–
Absent S and J in V2/V3, n (%)	5 (8)	2 (2)	.13
TQRSD, n (%)	25 (40)	6 (7)	<.001

STE: ST elevation; TQRSD: terminal QRS distortion.

Table 3. Reciprocal ST-segment changes in patients with anterior or inferior ST elevation.

	STEMI patients	Non-ischemic patients	p Value
Anterior STE; STE V2–V4	N = 43	N = 74
STD in aVR  ≥0.025 mV, n (%)	13 (30)	59 (80)	<.001
≥0.05 mV, n (%)	5 (12)	36 (49)	<.001
STE in aVR
≥0.025 mV, n (%)	11 (26)	0 (0)	<.001
≥0.05 mV, n (%)	7 (16)	0 (0)	<.001
STD in II
≥0.25 mV, n (%)	17 (40)	0 (0)	<.001
≥0.05 mV, n (%)	9 (21)	0 (0)	<.001
STD in aVF
≥0.25 mV, n (%)	15 (35)	6 (8)	<.001
≥0.05 mV, n (%)	11 (26)	0 (0)	<.001
STD in III
≥0.25 mV, n (%)	20 (47)	12 (16)	.001
≥0.05 mV, n (%)	9 (21)	4 (5)	.01
Inferior STE; STE in II, aVF, III	n = 40	(n = 28)	–
STD in aVL
≥0.25 mV, n (%)	40 (100)	6 (21)	<.001
≥0.05 mV, n (%)	40 (100)	3 (11)	<.001
STD in I
≥0.25 mV, n (%)	33 (83)	0 (0)	<.001
≥0.05 mV, n (%)	30 (75)	0 (0)	<.001
STD in V2
≥0.25 mV, n (%)	34 (85)	2 (7)	<.001
≥0.05 mV, n (%)	32 (80)	1 (4)	<.001
STD in V3
≥0.25 mV, n (%)	25 (63)	0 (0)	<.001
≥0.05 mV, n (%)	23 (58)	0 (0)	<.001

Max: maximal; STE: ST elevation; STD: ST depression.

Table 4. ECG findings to be used to detect patients with STEMI: Sensitivity, specificity and likelihood ratio for an ischemic etiology.

	Sensitivity	Specificity	LR+/LR−
Any STEMI
Convex STE	22 (14–33)	91 (84–96)	2.6/0.9
TQRSD	40 (28–53)	93 (85–97)	5.7/0.7
Anterior STEMI
Convex STE	14 (4–32)	93 (83–98)	1.9/0.9
STD in lead II^a	40 (25–56)	100 (95–100)	b/0.6
TQRSD	21 (8–41)	96 (87–99)	4.8/0.8
Inferior STEMI
Convex STE	26 (12–43)	90 (76–97)	2.5/0.8
STD in lead I^a	83 (67–93)	100 (88–100)	b/0.2
TQRSD	61 (42–78)	81 (61–93)	3/0.5

A true positive test is defined as presence of the ECG finding AND a STEMI diagnosis, a true negative result is defined as absence of the ECG finding AND a non-ischemic diagnosis.

STE: ST elevation; TQRSD: terminal QRS distortion; STD: ST depression; LR+: positive likelihood ratio; LR−: negative likelihood ratio.

^a ≥0.025 mV.

^b LR + cannot be calculated since specificity is 100 %.

Table 5. ECG findings to be used to detect non-ischemic patients: Sensitivity, specificity and likelihood ratio for a non-ischemic etiology.

ECG finding	Sensitivity	Specificity	LR+/LR−
Non-ischemic etiology and any STE pattern
Chest lead PR depression	38 (28–49)	88 (79–94)	3.2/0.7
STD in aVR^a	80 (69–88)	70 (54–83)	2.6/0.3
Non-ischemic etiology and anterior STE
Chest lead PR depression	38 (27–50)	86 (72–95)	2.7/0.7
STD in aVR^a	80 (69–88)	70 (54–83)	2.6/0.3
Non-ischemic etiology and inferior STE
Chest lead PR depression	46 (30–63)	83 (66–93)	2.7/0.7
STD in aVR^a	77 (61–89)	66 (48–81)	2.2/0.4

A true positive test is defined as presence of the ECG finding AND a non-ischemic diagnosis, a true negative result is defined as absence of the ECG finding AND a STEMI diagnosis.

STE: ST elevation; TQRSD: terminal QRS distortion; STD: ST depression; LR+: positive likelihood ratio; LR−: negative likelihood ratio.

^a ≥0.025 mV.

Table 6. Univariate and multivariable predictors of ischemic STE.

	Model 1 Unadjusted OR (CI 95)	p Value	Model 2 PR depression in chest leads, reciprocal STD, convex STE, TQRSD, STD in aVR	Model 3 PR depression in chest leads, reciprocal STD, convex STE, TQRSD, STD, in aVR, age, sex
PR depression limb leads	0.6 (0.3–1.0)	.069	–	–
PR depression chest leads	0.2 (0.1–0.5)	<.001	0.2 (0.1–0.4)	0.2 (0.05–0.5)
Reciprocal STD^a	12.5 (6.2–25.6)	<.001	8.7 (3.8–19.9)	9.9 (3.5–28.1)
Convex STE	3.0 (1.2–7.3)	.017	2.8 (0.9–8.6)	2.2 (0.5–9.2)
TQRSD	6.7 (2.6–17.3)	<.001	4.6 (1.4–15.5)	3.9 (0.9–17.0)
STD in aVR^b	0.2 (0.09–0.04)	<.001	0.2 (0.08–0.5)	0.2 (0.06–0.5)

a Reciprocal STD is defined as presence of either STD ≥ 0.025 mV in lead II in patients with anterior STE or STD ≥ 0.025 mV in lead I in patients with inferior STE.TQRSD, Terminal QRS distortion.

b ≥0.025 mV.

Figure 1. ECGs (25 mm/s) from four patients with different ST elevation etiologies. (A) Patient with STEMI. ECG shows PR depression ≥0.05 mV in the limb leads, but not in the chest leads, and slight ST elevation in aVR. (B–D) Non-ischemic patients with ST elevation (B: perimyocarditis; C: takotsubo cardiomyopathy; D: ERS). Both (B) and (C) show PR depression in both limb leads and chest leads, in (D) minor PR depression is present in the limb leads, and PR depression ≥0.05 mV in lateral chest leads. All non-ischemic patients show some degree of ST depression in aVR.

Figure 2. ECGs (25 mm/s) from two STEMI patients. (A) ECG shows concave ST elevation in V1 – V4 and ST depression in aVL, I and II. ST elevation is present in aVR. PR depression is absent in both limb leads and chest leads. Terminal QRS distortion is present in leads V2 and V3 (absent S and J wave in leads with ST elevation (Rs configuration)). (B) ECG shows concave ST elevation in inferior leads (II, aVF, III) with reciprocal ST depression in leads aVL and I, as well as precordial leads. PR depression is absent in both limb leads and chest leads. Terminal QRS distortion is present in aVF and III (ST elevation ≥50% of R-wave amplitude).