Utility of the combination of simple electrocardiographic parameters for identifying mid-septal pacing

The electrocardiograms (ECG) criteria to anchor the lead to the right ventricular septum have not been established. This study aimed to identify ECG criteria of pacing at the right ventricular mid septum (RVMS) and investigate whether the paced QRS duration (pQRSd) from the RVMS was narrow.

In 42 patients, ECG pacing at the basal anterior wall (BA), mid-anterior wall (MA), apex (AP), and mid septum (MS) was recorded. The pacing sites were validated by using right ventriculography and computed tomography. We estimated the ECG parameters and compared them among the four pacing sites. The combination of simple four paced-ECG parameters could reliably confirm the pacing at the RVMS. The area under the receiver-operating characteristics curve for the number of positive findings among the following: (a) positive QRS in lead aVL, (b) QRS notching in lead I, (c) precordial leads transition at less than V5, and (d) presence of isoelectric QRS in the inferior leads was 0.95 (95% confidence interval, 0.91-0.98) and the number of positive findings (≥3) had a sensitivity of 83.3% and a specificity of 93.7% for discriminating MS from the other sites. The pQRSd with three or more positive findings was significantly narrower than that with less than three positive findings (≥3: 137.4 ± 9.2 ms, <3: 151.8 ± 13.1 ms, P ≤ .05).

The combination of ECG parameters can help identify right ventricular mid-septal pacing. The use of these parameters may enable the implantation of the pacing lead in the RVMS accurately and obtain a narrower QRS duration.