Results:
Among the 93 patients who had undergone successful LBBP during the study period, 11 satisfied the inclusion criteria. Successful LBBP could be performed in 10 out of 11 patients (91% acute success rate). In one patient with AV block, lead could not be penetrated deep and conventional RV lead was placed. Baseline and procedural characteristics are shown in table 1. Mean age of the study population was 82.1 ± 2.5 years. 6 patients were men and 5 had associated coronary artery disease. The indication for pacemaker implantation was AV block in 5 patients (50%), LBBB with low EF in 4 patients (40%) and symptomatic sinus node dysfunction in one patient. The baseline QRS duration was 145.9 ± 27.7ms. Pre-procedural echocardiography showed mean EF of 47.6 ± 11.2% and septal thickness of 11.1 ± 0.7mm. The mean duration of follow up was 4.7 ± 1.9 months
The fluoroscopic time for LB lead placement was 17.9 ± 8.2 minutes. Non-selective to selective LB capture could be demonstrated during unipolar threshold measurement (fig 1B). LB potential was noted in one patient as other patients had either AV block or complete LBBB. QRS duration was reduced to 107.1 ± 9.5ms (measured from the onset to the end) (p value 0.00001). The pLVAT as measured in lead V5 (from pacing spike to peak of R wave) was 72.2 ± 5.3ms. The unipolar pacing threshold was 0.58 ± 0.22V at 0.5ms pulse width. The mean R wave amplitude was 17.35 ± 6.6mV. The unipolar pacing impedance was 773.6 ± 112.9ohms. All 4 patients with LBBB and low EF had complete correction of LBBB at low and stable threshold (fig 1C and 1D). No acute procedural complications noted.