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Patient
77-year-old woman with non-ischemic dilated cardiomyopathy (normal coronary angiography 15 years earlier at time of diagnosis); asymptomatic, with follow-up visit with her cardiologist;
Trace
Sinus rhythm, normal PR interval; typical pattern of complete left bundle branch block: wide QRS (140 ms), delayed intrinsicoid deflection in V6, exclusive positive deflection in V6, QS pattern in V1, V2 without delayed intrinsicoid deflection, left axis; the repolarization disorders appear to be aspecific with weak elevation from V1 to V3 and depression in V6 with negative T-wave; negative Sgarbossa and Smith criteria (elevation in V2 < 5mm with negative QRS in V2);
Trace
Emergency hospitalization a few weeks after this first tracing for typical retrosternal, uninterrupted chest pain since 3 hours; significant change in the ECG compared to the previous recording with a left bundle branch block pattern and significant elevation from V1 to V3, less pronounced in leads III and aVF; depression in V5-V6 and negative deep T-waves in leads I, aVL, inferior territory and from V4 to V6; Sgarbossa criterion at the limit of positivity in V2: elevation at 5 mm in V2; Smith criterion (modified Sgarbossa) at the limit of positivity in V2 (S wave: 20 mm, elevation 5 mm ; ratio: 0.25);
Trace
This patient underwent emergency coronary angiography, which showed thrombosis of the median LAD treated by thromboaspiration, angioplasty and stent placement; this tracing was recorded upon return to the room following coronary angiography; a left bundle branch block pattern is found with a significant decrease in the amplitude of the elevation; negative Sgarbossa and Smith criteria;
Exergue
In a patient with a left bundle branch block, the diagnosis of acute myocardial infarction should be evoked in the presence of 1) a clinical situation indicative of infarction 2) a significant increase in cardiac enzymes 3) ST-segment abnormalities of «abnormal» magnitude for a left bundle branch block. The Sgarbossa criteria are based on the loss of appropriate discordance. They have a limited sensitivity and should be used with caution; the presence of a characteristic symptomatology should warrant performing a coronary angiography.
Upon arrival at the emergency ward for the evaluation of chest complaints, the electrocardiogram usually allows classifying myocardial infarctions as either an acute coronary syndrome with hyperacute ST-segment elevation requiring immediate reperfusion or acute coronary syndrome without hyperacut