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Aims: To study the different QRS patterns in leads V1 and V2 in first inferior, lateral, and combined inferolateral myocardial infarction (MI) to recognize which are the ECG criteria that best define the presence of lesions isolated to the anatomically lateral wall of the left ventricle., Methods and Results: We studied consecutive patients with first inferior (15), lateral (9), or inferolateral (21) MI with reference to contrast enhanced cardiac magnetic resonance (CE-CRM). We measured the R-wave amplitude and duration, the R/S ratio, and the T-wave amplitude and polarity in leads V1 and V2. The specificity of the V1 criteria for lateral MI, that is, R/S amplitude ratio 1 or greater and R duration 40 milliseconds or longer, is very high but its sensitivity is low. We defined 2 new criteria, R/S of 0.5 or greater and R amplitude in V1 greater than 3 mm, with each achieving a sensitivity of 73.3% and specificity of 93.3% for lateral/inferolateral MI location., Conclusions: (1) New ECG criteria for lateral MI (R/S ratio in V1 > or =0.5 and R amplitude in V1 >3 mm) present very high specificity and lower but very acceptable sensitivity for lateral MI. (2) New criteria based on R waves in V2 or T waves in V1 to V2 do not discriminate between inferior and lateral MI. (3) The classical criteria (R/S amplitude ratio > or =1 and R duration > or =40 ms in V1) attain very high specificity but much lower sensitivity than the new criteria.

Q-wave myocardial infarction (MI) location is generally based on a pathologic correlation first proposed >50 years ago. Despite the proved reliability of contrast-enhanced cardiovascular magnetic resonance (CE-CMR) imaging to detect and locate infarcted areas, no global study has been conducted with the aim of correlating the electrocardiographic (ECG) patterns of Q-wave MI with infarct location. We studied this correlation in 51 patients with ST-elevation acute coronary syndrome who presented with Q waves or equivalents during MI. Seven preestablished ECG patterns that matched with high specificity to 7 different MI locations as detected by CE-CMR imaging were used to assess its value in clinical practice to locate an infarcted area. There were 4 ECG patterns in the anteroseptal zone (23 patients; septal, apical, and/or anteroseptal, extensive anterior, and limited anterolateral) and 3 ECG patterns in the inferolateral zone (28 patients; lateral, inferior, and inferolateral). In conclusion, (1) the predefined ECG patterns we used matched well (86% global concordance) with their corresponding infarction areas as detected by CE-CMR imaging and have real value in clinical practice, and (2) the RS morphology in lead V(1) is due to lateral MI and the QS morphology in lead aVL is due to mid-anterior and mid-lateral MI. Therefore, the terms posterior and high lateral infarction are incorrect and should be changed to lateral wall and limited anterolateral wall MI.

Objectives: For over 50 years, Q-wave myocardial infarction (MI) location has been based on pathologic ECG studies. Although contrast-enhanced magnetic resonance (CE-CMR) is currently the "gold standard" technique for location and quantification of necrotic areas, we found no large study in the literature devoted to establish which ECG patterns corresponds to different MI location detected by CE-CMR. We hypothesized that CE-CMR would be very accurate for evaluating different ECG patterns and its sensitivity (SE) and specificity (SP) for locating MI in different LV areas., Methods and Results: CE-CMR/ECG correlation was studied in 48 patients who presented a first MI due to acute coronary syndrome (ACS) with ST-segment elevation and in whom CE-CMR was performed in chronic phase. We evaluated the ECG patterns that best correlated with the 7 prespecified necrotic areas assessed by CE-CMR, 4 in anteroseptal zone (septal, apical/anteroseptal, extensive anterior, and limited anterolateral) and 3 in inferolateral zone (inferior, lateral and inferolateral). The global concordance between CE-CRM and ECG was of 75% and 7 ECG patterns were stablished., Conclusion: The capacity of CE-CMR to detect ECG patterns for necrotic area location presents highly acceptable concordance. Thanks to CE-CMR, we defined 7 ECG patterns for MI detection according to the 7 areas of the LV studied. The areas that present more cases with normal ECG are limited anterolateral and the areas of the inferolateral zone.