Inaccuracy of radiological and ECG criteria for right ventricular outflow tract implantation of pacemaker leads.

We present three cases of active fixation pacemaker lead implantation, where the leads were believed to be inserted in the right ventricular outflow tract (RVOT) septal position, using established radiological criteria. However, when the exact location of the leads was documented by three-dimensional echocardiography, true septal RVOT position was achieved in only one patient. In the other two patients, the leads were, in fact, implanted into the RVOT anterior free wall. The electrocardiogram criteria were not able to identify the septal position from the anterior RVOT free wall position.