[Electrocardiogram for diagnosing myocardial infarction in patients with left bundle branch block or a pacemaker].

Effective management of myocardial infarction with ST segment elevation depends on rapid diagnosis. The presence of a left bundle branch block or of an electrically driven rhythm limits the interpretation of the initial electrocardiogram, potentially causing damaging delays. The Sgarbossa's score is well fit for those situations allowing when positive to opt for an immediate reperfusion strategy. However, its low sensitivity requires that it be combined with other diagnostic tools when negative.