ABSTRACT
BACKGROUND: Current guidelines recommend avoiding apical left ventricular (LV) pacing for cardiac resynchronization therapy (CRT). AIMS: We investigated the feasibility of nonapical pacing with the current quadripolar LV lead technology. METHODS: We analyzed consecutive patients who received CRT with an LV quadripolar lead. The post--implantation position of each electrode of the LV lead was designated as basal, mid, or apical. The pacing capture threshold (PCT) and phrenic nerve stimulation (PNS) threshold were assessed for each electrode. RESULTS: We enrolled 168 patients. A total of 8 CRT defibrillators were from Biotronik (with Sentus OTW QP leads), 98 were from Boston Scientific (with 21 Acuity X4 Spiral and 77 Acuity X4 Straight leads), and 62 from St. Jude Medical (with Quartet leads). The median (interquartile range) number of electrodes at nonapical segments per patient was 3 (1-4) with Biotronik Sentus leads, 4 (3-4) with spiral -design Boston Scientific leads, 4 (3-4) with straight Boston Scientific leads, and 3 (3-4) with St. Jude Medical Quartet leads (P = 0.045). Three patients (38%) with Biotronik Sentus leads, 21 (100%) with spiral -design Boston Scientific leads, 69 (90%) with straight -design Boston Scientific leads, and 49 (79%) with St. Jude Medical Quartet leads (P <0.001) had at least 1 electrode located at nonapical segments linked with a PNS -PCT safety margin of more than 2 V. During the 6-month follow -up, PNS was detected in 4 patients and was eliminated with reprogramming. No significant changes in PCT were detected during follow -up. CONCLUSIONS: Quadripolar leads allowed nonapical pacing with acceptable electrical parameters in the majority of CRT recipients, although differences were found among the currently available devices.
