Cardiac resynchronization with sequential biventricular pacing for the treatment of moderate-to-severe heart failure

Angel R. León, William T. Abraham, Susan Brozena, James P. Daubert, Westby G. Fisher, John C. Gurley, Chang Seng Liang, George Wong

Research output: Contribution to journalArticlepeer-review

172 Scopus citations


OBJECTIVES: The InSync III study evaluated sequential cardiac resynchronization therapy (CRT) in patients with moderate-to-severe heart failure and prolonged QRS. BACKGROUND: Simultaneous CRT improves hemodynamic and clinical performance in patients with moderate-to-severe heart failure (HF) and a wide QRS. Recent evidence suggests that sequentially stimulating the ventricles might provide additional benefit. METHODS: This multicenter, prospective, nonrandomized, six-month trial enrolled a total of 422 patients to determine the effectiveness of sequential CRT in patients with New York Heart Association (NYHA) functional class III or IV HF and a prolonged QRS. The study evaluated: whether patients receiving sequential CRT for six months experienced improvement in 6-min hall walk (6MHW) distance, NYHA functional class, and quality of life (QoL) over control group patients from the reported Multicenter InSync Randomized Clinical Evaluation (MIRACLE) trial; whether sequential CRT increased stroke volume compared to simultaneous CRT; and whether an increase in stroke volume translated into greater clinical improvements compared to patients receiving simultaneous CRT. RESULTS: InSync III patients experienced greater improvement in 6MHW, NYHA functional class, and QoL at six months compared to control (all p < 0.0001). Optimization of the sequential pacing increased (median 7.3%) stroke volume in 77% of patients. No additional improvement in NYHA functional class or QoL was seen compared to the simultaneous CRT group; however, InSync III patients demonstrated greater exercise capacity. CONCLUSIONS: Sequential CRT provided most patients with a modest increase in stroke volume above that achieved during simultaneous CRT. Patients receiving sequential CRT had improved exercise capacity, but no change in functional status or QoL.

Original languageEnglish
Pages (from-to)2298-2304
Number of pages7
JournalJournal of the American College of Cardiology
Issue number12
StatePublished - Dec 20 2005

Bibliographical note

Funding Information:
This study was supported by Medtronic Inc., Minneapolis, Minnesota. Drs. Leon, Abraham, Brozena, Daubert, Fisher, and Gurley have been speakers for Medtronic Inc. Drs. Leon, Abraham, Daubert, and Fisher are consultants to Medtronic Inc.

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine


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