Dual-chamber CRT-D using ICD lead implantation in the LBBAP position

Abstract Background Interest in conduction system pacing (CSP) has increased in recent years. For left bundle branch area pacing (LBBAP), 4F and 6F pacing leads have been shown to be effective and safe. No information is available on the potential use of ICD leads for LBBAP. Aim The objective of the study was to demonstrate the feasibility of implanting an ICD lead in the LBBAP position to reduce the number of leads for CRT-D therapy. Patients and Methods We implanted the 7F ICD lead in the LBBAP position through a new 10F CSP delivery sheath in ten consecutive patients. Periprocedural data, QRS morphology and degree of QRS reduction were analyzed. Results Ten consecutive patients (one female) aged 69.5±9.2 years were treated with the above-mentioned method. Eight patients had ischemic cardiomyopathy and two patients had nonischemic cardiomyopathy. All patients had a CRT-D indication. Eight patients had a wide QRS complex with complete LBB and a QRS complex of 184.8±25.8 ms. Two patients had a narrow QRS complex but first-degree AV block with a PR interval greater than 240 ms. Left ventricular ejection fraction was 31.8±8.6%. Operative and fluoroscopy times were 103.6±30.3 minutes and 10.5±6.1 minutes, respectively. On average, 1.7 ± 0.6 screwing attempts were required per patient. The intraprocedural LBBAP threshold was 0.78±0.6V/1.0ms, the impedance was 530.8±86.5 ohm, and the R-wave amplitude was 9±3.3mV. The unipolar paced QRS complex was 123.6±15.9ms, the bipolar paced QRS complex was 129.5±12.8ms, and the bipolar paced QRS complex on the next day was 133.3±11.7. The mean duration from stimulus to R-wave peak in lead V6 was 82.9 ± 19.7 ms. The R-wave interpeak interval between leads V6 and V1 was 43.4 ± 9.7 ms. All but one patient received an effective defibrillation threshold test at 30J (n=8) and 36J (n=1). One patient was not tested during the procedure due to high risk. Conclusion This first-in-human study of ICD lead implantation in the LBBAP position demonstrated its feasibility and efficacy in achieving conduction system stimulation. This approach may lead to a reduction in the number of leads implanted for cardiac resynchronization therapy. Figure 1. A- RAO view, angiography of the RV for verification of the TVA-summit. B- LAO view, angiography from the CSP- sheath after reaching final position of the LBBAP lead (right sided interventricular septum - yellow dotted line). C – 12 lead ECG (speed 50mm/sec) demonstrating paced and native QRS complexes. D – Fluoroscopy in RAO view, final result. E – Fluoroscopy in LAO view, final result. F – Transthoracic echocardiography the next day (4Ch view) demonstrates optimal LBBAP lead position.. RAO – right anterior oblique; LAO – left anterior oblique; TVA – tricuspid valve anulus; CSP – conduction system pacing; LBBAP – left bundle branch area pacing.Figure 1.