Isolation of the Phrenic Nerve to Suppress Diaphragmatic Contraction Induced by Cardiac Resynchronization

Postoperative performance of the Quartet® left ventricular heart lead

INTRODUCTION

The Quartet(®) left ventricular (LV) lead is the first with 4 pacing electrodes (tip and 3 rings) that enables pacing from 10 different pacing vectors. Postoperative performance of this lead was evaluated in a prospective, nonrandomized, multicenter IDE study.

METHODS

Patients with standard indications for CRT-D were enrolled. Electrical performance and presence of phrenic nerve stimulation (PNS) were assessed during pacing from each of 10 vectors at predischarge (within 7 days), 1 month, and 3 months postimplant.

RESULTS

The Quartet LV lead was implanted successfully in 170 patients (95.5% implant success rate, 68 ± 11 years, 68.5% male, LVEF: 25 ± 7%, NYHA class III: 98.3% and class IV: 1.7%). Mean follow-up was 4.7 ± 1.9 months. Capture threshold and impedance for each of the 10 LV lead pacing vectors remained stable during follow-up. LV lead dislodgement occurred in 6 (3.5%) patients and PNS was observed in 23 (13.5%) patients. PNS was resolved noninvasively in all 23 (100%) patients, either by reprogramming to pace from the additional LV lead pacing vectors alone (13 pts, 56.5%), reprogramming to pace from the additional LV lead pacing vectors and reprogramming pacing output (4 pts, 17.4%), or by reprogramming pacing output alone (6 pts, 26.1%).

CONCLUSIONS

The Quartet LV lead electrical performance was stable and was associated with a high implant success and low dislodgement rate during 3-month follow-up. In all patients with PNS, the 10 pacing vectors combined with reduced output programming enabled the elimination of PNS noninvasively.