New Research Paper
Cardiac Resynchronization Therapy With a Quadripolar Electrode Lead Decreases Complications at 6 Months: Results of the MORE-CRT Randomized Trial

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Abstract

Objectives

The aim of this study was to test the hypothesis that a quadripolar left ventricular (LV) lead results in fewer LV lead–related events than a bipolar cardiac resynchronization therapy (CRT) system in a prospective randomized trial.

Background

Bipolar LV leads cannot be implanted at the optimal site in up to 10% of patients who need CRT, because of anatomic or technical challenges (pacing threshold, phrenic stimulation, or mechanical instability).

Methods

The MORE-CRT (More Options Available With a Quadripolar LV Lead Provide In-Clinic Solutions to CRT Challenges) trial enrolled 1,078 patients. Patients with indications for CRT defibrillator therapy were randomized into 2 groups in a 1:2 ratio: a group with a bipolar CRT lead system (the BiP group; any manufacturer) and a group with a quadripolar CRT system (the Quad group; Quartet LV lead). The primary endpoint was freedom from a composite endpoint of intraoperative and post-operative LV lead–related events at 6 months.

Results

A total of 1,074 of 1,078 patients (99%) were randomized and contributed to the primary endpoint. Freedom from the composite endpoint was significantly greater in the Quad than the BiP group (83.0% vs. 74.4%, p = 0.0002). The intraoperative component of the endpoint was met less frequently by Quad group patients (6.26% Quad vs. 12.1% BiP), whereas there was no difference for the post-operative component (7.1% Quad vs. 7.6% BiP).

Conclusions

The Quartet LV system significantly reduced total LV lead–related events at 6 months after implantation compared with a bipolar CRT system. The reduction in events demonstrates the superiority of this quadripolar technology to effectively manage CRT patients. (More Options Available With a Quadripolar LV Lead Provide In-Clinic Solutions to CRT Challenges [MORE-CRT]; NCT01510652)

Key Words

cardiac resynchronization therapy
left ventricular pacing
LV lead complications
phrenic nerve stimulation
quadripolar lead
randomized trial

Abbreviations and Acronyms

BiP
bipolar left ventricular lead group
CRT
cardiac resynchronization therapy
CS
coronary sinus
HF
heart failure
LV
left ventricular
MLWHFQ
Minnesota Living With Heart Failure Questionnaire
PNS
phrenic nerve stimulation
QoL
quality of life
Quad
quadripolar Quartet left ventricular lead group

Cited by (0)

This study was sponsored by St. Jude Medical. Prof. Boriani has received speaking fees from Biotronik, Boston Scientific, Medtronic, and St. Jude Medical. Dr. Connors has received consulting fees from St. Jude Medical; and speaking fees from St. Jude Medical, Biosense Webster, Bristol-Myers Squibb, and Boehringer-Ingelheim. Prof. Kalarus has received speaking fees from Pfizer, Eli Lilly, Boehringer-Ingelheim, Abbott, Bayer, St. Jude Medical, and Adamed; and consulting fees from Boehringer Ingelheim, Amgen, and AstraZeneca. Prof. Lemke has received speaking fees from St. Jude Medical, Medtronic, Biotronik, and Impulse Dynamic. Dr. Osca-Asensi has received consulting fees from St. Jude Medical. Prof. Raatikainen has received consulting fees from Bayer and Bristol-Myers Squibb/Pfizer; speaking fees from Biosense Webster, Bristol-Myers Squibb/Pfizer, Boehringer Ingelheim, and Cardiome; and research support from St. Jude Medical. Mr. Gazzola and Dr. Farazi are employees of St. Jude Medical. Prof. Leclercq has received consulting fees from St. Jude Medical, Medtronic, Sorin, Boston Scientific, and Biotronik. Dr. Leclerq has reported that he has no relationships relevant to the contents of this paper to disclose.

Listen to this manuscript's audio summary by JACC: Clinical Electrophysiology Editor-in-Chief Dr. David J. Wilber.