Prognosis

The risk of dying is increased with an abnormal admission ECG (the more abnormalities present, the greater the risk of dying) ^a

• abnormal QRS complexes ^a
• ST elevation ^b particularly if present in many leads ^b
• bundle-branch block ^b  
  
• specifically for an inferior MI 
  • precordial ST depression ^b  
  • evidence of right ventricular infarction (ST elevation 0.1 mV or more in lead V _4R ) ^a

Why?

ST elevation and bundle-branch block increases the risk of dying in hospital

Patient	Prognostic Factor	Outcome	CER	OR (95% CI)	NNF+ (95% CI)
myocardial infarction b	ST elevation without bundle-branch block independent	death at uncertain duration	13%	1.53 (1.49 to 1.58)	18 (16 to 19)
first myocardial infarction b	increased number of leads with ST elevation (6-7) independent	death at uncertain duration	4.0%	1.86 (1.26 to 2.74)	31 (16 to 100)
myocardial infarction b	left bundle-branch block independent	death at uncertain duration	13%	1.34 (1.28 to 1.39)	27 (24 to 33)
myocardial infarction b	right bundle branch block independent	death at uncertain duration	13%	1.64 (1.57 to 1.71)	15 (14 to 17)

A right ventricular infarction increases the risk of dying

Patient	Prognostic Factor	Outcome	CER	OR (95% CI)	NNF+ (95% CI)
inferior myocardial infarction a	right ventricular infarction independent	death at uncertain duration	19%	7.70 (2.60 to 23.0)	1 (1 to 3)