Cardiac resynchronization therapy using left ventricular septal pacing: An alternative to biventricular pacing?

Figure 1. Images of the implantation procedure. A: Posteroanterior (PA) fluoroscopy showed the fractured part (white arrow) of the left ventricular (LV) lead. B: His bundle pacing (HBP) was performed in right anterior oblique (RAO) view; the lead tip (black arrow) was in the His bundle region. C: Left ventricular septal pacing (LVSP) was attempted by advancing the sheath 1.5–2 cm towards the ventricle side from the His bundle region. The LVSP lead (black arrow) was positioned perpendicularly against the right ventricular (RV) septum. D: Left anterior oblique (LAO) fluoroscopy showing the tip of the lead (black arrow) resting perpendicular against the RV septum (white arrow) before being screwed in. E: While the lead was being rotated, repeated injections of contrast medium through the guiding catheter against the RV septum (white arrow) were used to assess the penetration depth. The part of the lead tip (black arrow) protruding into the RV septum was not covered by contrast medium. F: Ultrasonography 4-chamber view of the heart showed that the lead tip (yellow arrow) was on the LV septum (white arrow). LA = left atrium.

Figure 2. Electrocardiogram of the implantation procedure. A: The intrinsic rhythm was left bundle branch block (LBBB) and the HV interval was 82 ms. B: A lower output (≥1.5 V @ 0.4 ms) can capture the His bundle and adjacent ventricular tissues but cannot correct LBBB. C: A higher output (≥5.5 V @ 0.4 ms or ≥3.5 V @ 1.0 ms) can correct LBBB and acquire a narrow QRS. D: Right ventricular septum pacing QRS morphology before screwing the lead. E: Paced QRS morphology changed while screwing the lead. F: Paced QRS showed right bundle branch block morphology while the tip of the lead arrived at the left ventricular septum.

Figure 3. The offline analysis showing the regional and overall ventricular longitudinal strain pattern changes at baseline (A) and during 3-month follow-up (B). These regional curves show that the mechanical dispersion was improved during 3-month follow-up.