Electrocardiographic localization of leads that exhibit right bundle branch block morphologies during pacing
| Frontal axis | Precordial transition | Location | Sensitivity (%) | Specificity (%) | Positive predictive value (%) |
|---|---|---|---|---|---|
| 0° to –90° | By V3 | RV septum or apex | 86 | 99 | 95 |
| By V4 | RV septum or apex | 100 | 92 | 64 | |
| By V4 | Posterior LV or coronary vein | 26 | 83 | 36 | |
| After V4 | Posterior LV or coronary vein | 72 | 100 | 100 | |
| −90° to –180° | By V3 | LV apex and distal anterior LV | 85 | 100 | 100 |
| 90° to 180° | Proximal anterior and anterolateral LV | 100 | 97 | 90 | |
LV = left ventricular; RV = right ventricular
Reprinted from reference 6 with permission.