6 lead ecg reading. Need feedback. Thanks guys


Forum Deputy Chief
What's your concern?

The reason R waves, S waves, and the size/amplitude of these waves is because of the direction of the mean QRS vector. Each lead has a different view of the mean QRS vector. When the lead has a better view, the R or S wave will be bigger. When it has a poor view, it'll be smaller. That's it.

In this case, it looks like the mean QRS vector is a little bit more rightward than most people. It's pointing straight down, inferior, about +90 degrees. Since it points straight down towards the inferior leads (II, III, and aVF), it makes the R wave in the inferior leads tall. Since it points down and away from lead aVR and avL (these leads points up). Since lead I is perpendicular to the inferior leads, it's got the poorest view and is biphasic. In some cases, lead I would be super small like what you see in right ventricular outflow tract ventricular tachycardia (RVOT VT) simply because of the mean QRS vector/axis (+90 degrees).

So the question is what is causing this mean QRS vector to be +90 degrees? It could be normal variant. It could be an indication of a respiratory issue (chronic or old), torso positioned limb leads (Mason-Likar), right ventricular hypertrophy, etc.

A lot of ECG stuff tend to not be very specific and you need to consider "the company it keeps". There isn't anything here that strikes me as concerning or interesting.