Table 2

Clinical and ECG factors used to derive logistic regression models

Input item	Log₁₀ LR	Notes
The 45 potential input items are listed in descending order of their log₁₀ likelihood ratios (log₁₀ LRs). Data item 45 (chest wall tenderness) was not present in any patient with ACS and log₁₀ LR was set at −2.5. The data items are listed in the same order as they are shown in fig 1.
IHD rhythm was coded as 1 if patient had atrial fibrillation or supraventricular tachycardia.
A, inputs used in the eight factor model; B, inputs used in the 14 factor model; C, items used in the 25 factor model. The 43 factor model used all inputs except two logically redundant inputs (D).
Hypoperfusion	1.6	A B C
ST depression	1.6	A B C
ST elevation	1.5	A B C
New Q waves	1.4	A B C
T wave inversion	1.1	A B C
Added heart sounds	0.93	A B C
Crackles	0.88	A B C
Nausea/vomiting	0.51	A B C
Pain radiating to right arm	0.36	C
Sweating	0.32	C
Age category 3 (>60 years)	0.31	C
Diabetes	0.27	C
Worse than previous angina	0.24	C
Pain radiating to left arm	0.21	C
Cardiac rhythm	0.2	NA
Hypertension	0.19	NA
Pain described as tight	0.18	NA
Former smoker	0.16	NA
Previous angina	0.15	NA
Retrosternal chest pain	0.14	NA
Previous MI	0.12	NA
Duration category 1 (<4 hours)	0.11	NA
Syncope	0.091	NA
Hyperlipidaemia	0.089	NA
Family history of IHD	0.068	NA
Bundle branch block	0.051	NA
Shortness of breath	0.031	NA
Duration category 2 (5–12 hours)	0.022	D
Chest pain is major symptom	0.016	NA
Pain radiating to back	0.004	NA
Sex (male = 1)	0.0015	NA
Smoker	−0.032	NA
Old MI on ECG	−0.11	NA
Age category 2 (41–60 years)	−0.15	D
Duration category 3 (13–48 hours)	−0.26	C
Old ischaemia on ECG	−0.36	C
Pain radiating to left chest	−0.38	C
Pain radiating to right chest	−0.41	C
Duration category 4 (>48 hours)	−0.49	C
Pain described as sharp	−0.56	B C
Episodic pain	−0.79	B C
Worse with changes in posture	−1.0	B C
Age category 1 (⩽40 years)	−1.4	B C
Pain worse on inspiration	−1.5	B C
Chest wall tenderness	−2.5	B C