Investigations

• exercise ECG
Look for ^a
• horizontal or down sloping ST slope and 1 mm or more of depression in any lead ^b
• angina during test

Why?

Abnormalities on exercise ECG makes coronary artery disease more likely

Patient	Target Disorder and Reference Standard	Diagnostic Test	LR+ (95% CI)	Post-test Probability	LR- (95% CI)	Post-test Probability
probable or definite stable angina a (pre-test probability: 51%)	coronary artery stenosis (coronary angiography)	exercise ECG	3.0 (2.3 to 3.9)	76%	0.65 (0.59 to 0.71)	40%

Exercise ECG: deepening ST segment depression makes coronary artery disease more likely

Patient b	Target Disorder and Reference Standard	Diagnostic Test	LR+ (95% CI)	Post-test Probability
suspected coronary artery disease (pre-test probability: 51%)	coronary artery stenosis (coronary angiography)	Non-sloping ST segment depression exercise ECG ≥ 2.50 mm	39	98%
		2.0 to 2.49 mm	11	92%
		1.5 to 1.99 mm	4.2	81%
		1.0 to 1.49 mm	2.1	69%
		0.5 to 0.99 mm	0.92	49%
		< 0.5 mm	0.23	19%

Exercise ECG is not very helpful at diagnosing restenosis following PTCA

Patient	Target Disorder and Reference Standard	Diagnostic Test	LR+ (95% CI)	Post-test Probability	LR- (95% CI)	Post-test Probability
recent PTCA a (pre-test probability: 51%)	coronary artery restenosis > 50% (coronary angiography)	exercise ECG	1.9	6%	0.71	42%