Lead aVR in ACS- neglected but informative!!

The lead aVR is usually not taken into consideration while interpreting ECGs, even complicated ones. This is because of the fact that aVR displays reciprocal information covered by II, aVL, V5 & V6. But it has been shown recently by various authors that careful evaluation of lead aVR can give a lot of valuable information in patients with ACS that can help in therapeutic decision making.

In patients with STEMI:

Presence of ST elevation in aVR in patients with acute AWMI strongly predicts proximal LAD occlusion proximal to the first septal perforator.

Also, in the presence of evolved IWMI, presence of an initial 'r' wave > 1.5 mm in aVR suggests additional infaction of the apical lateral wall, either due to occlusion of LCX or larger RCA involving a large posterolateral branch of LV.

In patients with NSTE-ACS:

Presence of ST elevation in aVR in the presence of ST depression in 7 or more leads indicates incomplete occlusion of the LMCA or its equivalent (very proximal LAD plus LCX)

Thus, careful evaluation of lead aVR in the ECG of patients with ACS may provide additional information regarding the artery involved, site of occlusion and its extent and help plan interventions.