Investigations

• followed by serial ECGs ^a

Why?

Abnormalities on serial ECGs help diagnose MI

Patient	Target Disorder and Reference Standard	Diagnostic Test	LR+ (95% CI)	Post-test Probability	LR- (95% CI)	Post-test Probability
chest pain a (pre-test probability: 20%)	myocardial infarction (ECG at 24h, cardiac enzymes)	initial ECG	10 (7.5 to 14)	72%	0.47 (0.40 to 0.55)	11%
		serial ECG	13 (9.7 to 18)	77%	0.34 (0.27 to 0.41)	8%