Po-03-011 left bundle branch area defibrillation (lbbad): evaluation of acute defibrillation performance

Conduction system Pacing (CSP) is a promising technique to prevent pacing-induced cardiomyopathy and is a valuable additional tool in cardiac-resynchronization therapy. Patients requiring an ICD for underlying structural heart disease often have a concomitant bradycardia pacing indication. As RV pacing is to be avoided in these patients, CSP is a promising option. A combined left bundle branch area (LBBA) pacing/defibrillation lead would be desirable over an additional CSP pacing lead. We evaluated defibrillation threshold testing (DFT) with a classical ICD lead (Boston Scientific Reliance 4-Front 0693/64cm) positioned in the LBBA. In our LBBAD feasibility pilot trial we evaluated the implantability of an ICD lead in the LBBA and looked at the acute performance of an ICD lead temporarily implanted in this position. One of the tests performed was DFT testing by VF induction using a shock-on-T with decreasing energy (ULV). This value was subsequently used to program the energy of the first shock to treat the induced VF (see Figure). After all tests were performed the lead was removed from the septum and implanted in a conventional location. We present the DFT results of the first 3 successfully implanted LBBAD leads. All three patients received an ICD in primary prevention for ischemic cardiomyopathy (mean EF of 25 ± 3.3%). Induction shock to initiate VF (ULV) was 14 ± 2.4 J (mean induced VF heart rate of 259 ± 13.9 bpm). Time to VF detection was 5.5 ± 1.2 s with a mean capacitor charging time of 4.9 ± 1.0 s to deliver 28 ± 4.7 J. All VF episodes were successfully terminated by the first programmed shock. The impedance over the shock-lead measured 68 ± 4,99 Ω. No complications occurred. Our LBBAD pilot trial is the first experience in man with ICD leads (temporarily) implanted in an LBBA position. Besides evaluation of the implant feasibility of an ICD lead in the LBBA, we also looked at the acute electrical performance of the lead in this position.