An electrically inactive area is one in which ventricular activation does not occur as expected, characterized by the presence of pathological Q waves or equivalents in two contiguous leads. Q waves are usually generated as a consequence of changes produced in infarcted areas (scar/fibrosis).

Electrocardiographic Criteria

  • Any Q wave in V2-V3 > 20 ms or QS complex in V2-V3
  • Q wave ≥ 30 ms and ≥ 1 mm deep or QS complex in I, II, aVL, aVF or V4-V6 in two contiguous leads (I, aVL; V1-V6; II, III, aVF). The same applies to leads V7-V9
  • R wave > 40 ms in V1-V2 and R/S > 1 with a positive T wave in the absence of conduction disturbances

* The criteria apply in the absence of LVH or LBBB.

Topography

Infarct topography based on magnetic resonance imaging

ECG in Electrically Inactive Areas

Electrocardiogram with an anteroapical electrically inactive area (Q wave)

Anteroapical electrically inactive area. Q waves/QS complexes in the anteroapical wall.

Electrocardiogram with a mid-anterior electrically inactive area (Q wave)

Mid-anterior electrically inactive area. Pathological Q waves in the mid-anterior wall (leads I, aVL and V2).

Electrocardiogram with an inferior electrically inactive area (Q wave)

Inferolateral electrically inactive area. ECG with RBBB and pathological Q waves in the inferolateral wall (II, III, aVF, V5 and V6).

References

  1. Samesima N, God EG, Kruse JCL, Leal MG, et al. Diretriz da Sociedade Brasileira de Cardiologia sobre a Análise e Emissão de Laudos Eletrocardiográficos – 2022. Arq Bras Cardiol. 2022;93(3 Suppl 2):2–19.
  2. Thygesen K, Alpert JS, Jaffe AS, Chaitman BR, et al. Fourth universal definition of myocardial infarction (2018). Eur Heart J. 2018;40(3):237–69.