Inaccuracy of various proposed electrocardiographic criteria in the diagnosis of apical myocardial infarction — a critical review

The diagnostic accuracy of the standard electrocardiogram (ECG) in apical myocardial infarction (MI) was evaluated in 112 consecutive patients with recent MI and wall-motion abnormalities limited to the left ventricular (LV) apex on two-dimensional echocardiography, performed at rest 21 to 84 days after MI. The following patterns of abnormal (≥30 ms) Q waves were found: anteroseptal (Q V1–V4) in 44 patients (39.3%), anterolateral (Q V1–V6 and/or I, aVL) in 22 (19.6%), inferior (Q III, aVF or II, III, aVF) in five (4.5%), lateral (Q I, aVL and/or V5–V6) in five (4.5%), anteroinferior in six (5.3%); non-Q MI was present in 30 patients (26.8%). By applying various proposed ECG criteria, the presence of apical MI was correctly identified in very few (24, 21%) patients. LV apex was extensively asynergic in 85 patients (76%) and partially asynergic in 27 (24%). All the patients with Q waves in lateral leads and 47% of the patients with non-Q MI had partially asynergic LV apex, while in the other ECG patterns, extensively asynergic LV apex was predominant. The presence of both ≥ 30 ms Q waves and loss of R in left precordial leads and I strongly suggests extensive apical asynergy; normal QRS in the same leads, however, does not exclude extensive apical involvement. Patients with extensively asynergic LV apex had higher end-diastolic volume (58±23 vs 46±15 mlm−2 P < 0.01), lower ejection fraction (52±5 vs 58±6%, P < 0.001) and a greater incidence of abnormal Q waves (3.2±1.8 vs 1.2±1.1, P<0.01) than patients with partially asynergic LV apex. In conclusion; various proposed ECG criteria are insensitive (21% success rate) in detecting apical MI diagnosed by 2D ECHO; the most common ECG pattern is anterior Q waves, and the ECG may simulate a large infarction even when the asynergy is limited to the LV apex. However a greater infarct size on ECG is associated with greater apical involvement.