Endocardial left ventricular pacing across the interventricular septum for cardiac resynchronization therapy: Clinical results of a pilot study

Cardiac resynchronization therapy (CRT) is an effective treatment for selected patients with heart failure, but it can be limited by the inability to place the left ventricular (LV) lead via the coronary sinus. The purpose of this study was to develop an alternative approach, placing the LV lead endocardially via an interventricular septal puncture, and to assess the feasibility and safety of this technique. All patients were anticoagulated with warfarin (international normalized ratio 2.5–3.5). A superior approach ventricular transseptal puncture using radiofrequency energy was performed. An active fixation pacing lead was delivered to the mapped site of latest electrical activation on the endocardial LV. Twenty patients were recruited, 15 with failed transvenous LV lead placement and 5 nonresponders to CRT. Mean (± SD) age was 67 ± 12, with 80% male, QRS duration 157 ± 14 ms, ischemic etiology 45%, New York Heart Association functional class 2.9 ± 0.4, and LV ejection fraction 28% ± 7%. The procedure was successful in all, with no serious complications. Clinical composite score improved at 6 months in 65% and worsened in 35%. LV ejection fraction improved >5% in 88%, from 28% ± 7% to 41% ± 9%. Six-minute walking distance improved >10% in 64%, from 248 ± 125 m to 316 ± 109 m. One patient suffered a lacunar ischemic stroke after 5 months with partial neurological recovery, associated with labile international normalized ratios. After 2.0 ± 1.0 years of follow-up, 3 patients died (2 pneumonia, 1 heart failure), and 2 patients suffered transient ischemic attacks. LV endocardial pacing via interventricular septal puncture in patients for whom standard CRT is not possible is similarly effective and durable, with significant but potentially acceptable risks.