Ventricular septal pacing: Optimum method to position the lead

Fig. 1. Illustration of the heart highlighting the RV septal anatomy. The right ventricle has been opened from the front with the heart orientated anatomically. The RVOT is bordered by the pulmonary valve above and the superior aspect of the tricuspid apparatus below. The upper part of the septal wall is the conus arteriosus, bordered below by the supraventricular crest. To the anatomical left of the septomarginal trabeculation, this continues into the moderator band. The septoparietal trabeculations are shown with stars (Target site for septal lead position). SC = Supraventricular crest, SMT = Septomarginal trabeculation, APM = Anterior papillary muscle of Tricuspid valve, MB = Moderator band.

Fig. 2. A. Mond’s stylet, B; Burri’s 3D stylet, C. Srivatasa’s stylet, D. Osmanick’s stylet.

Fig. 3. A. Anatomy of different cardiac chambers in Left Anterior Oblique view. Note the orientation of inter-ventricular septum, B. Fluoroscopic 40 ° Left Anterior Oblique view showing different lead tip angulations and different zones of right ventricle.

Fig. 4. Fluoroscopic 40 ° Left Anterior Oblique view: Different lead tip angulations and different template zones.

Fig. 5. Fluoroscopic landmarks for mid-septal lead placement using RAO views. In the RAO 30 ° view, the cardiac Silhouette is divided into thirds from the external border of the heart to the spinal column using an imaginary grid, with the target position of the lead tip being the central third sector (i.e. centre of the cardiac silhouette).

Fig. 6. A, RAO 30 ° view shows RV lead positioned at the middle square of the top row in imaginary 9 square model; B, LAO 40 ° shows posteriorly facing lead tip angulation with the horizontal line of less than 60 ° (Template zone 3); C, Left lateral fluoroscopic view shows posteriorly facing lead tip; D, Final appearance of the lead in LL view after atrial lead positioned in right atrial appendage.

Fig. 7. Pacing from various sites: A; RV apex: Pacing from RV apex results in LBBB pattern. But, the mechanical activation pattern significantly differs from intrinsic LBBB. In pacing induced LBBB the mid and apico-septal region of LV is the earliest and one of the lateral segments (apico, mid, or basal) is the latest activated region with an activation vector directed apical to basal and from right to left. Whereas in intrinsic LBBB, basal septum is the earliest activated region and lateral wall is latest activated in only one third of the patients with activation vector directed from basal to apical and from septal to lateral. B; RVOT septal (Anterior part): Dominant R wave in inferior leads indicate RVOT location of the lead. Narrow paced QRS complex with early precordial transition (at V3) and lack of notching of R wave in inferior leads confirm septal position of the lead. Morphology in lead I suggest location of the pacing lead in the anterior part of the inter-ventricular septum, C; RVOT free wall (Anterior part): Dominant R wave in inferior leads indicate RVOT location of the lead. Notched and wide paced QRS complex in inferior leads with late precordial transition (at V5)…