The FDA’s Circulatory System Devices Panel voted 4-3 in favor of expanding indications for Medtronic cardiac resynchronization therapy (CRT) pacemakers and defibrillators.

The CRT devices have been approved for use in patients with marked to severe heart failure (New York Heart Association [NYHA] Functional Class III or IV) and left ventricular ejection fraction (LVEF) of 35 percent or less and prolonged QRS duration. The defibrillators are approved for patients at risk of developing life-threatening ventricular arrhythmias and who have either NYHA Functional Class III or IV heart failure and LVEF of 35 percent or less and prolonged QRS duration or NYHA Functional Class II heart failure and left bundle branch block with a QRS duration 130 ms or more and LVEF of 30 percent or less.

Minneapolis-based Medtronic asked to expand the indications for both types of devices to include patients with mild to marked heart failure who are at risk because of a need for right ventricular pacing. It defined these patients as having atrioventricular block, LVEF of 50 percent or less and NYHA Functional Class I, II, or III heart failure.

The panel voted 4-3 with one abstention that that the biventricular pacing devices’ overall benefits outweighed their risks, based on results from the Block HF study. Block HF was a prospective, randomized, controlled, double-blinded multicenter trial that compared biventricular pacing to right ventricular pacing.

The study was designed to assess whether biventricular pacing slowed the onset or progression of heart failure measured by a composite endpoint of all-cause mortality, heart failure urgent care events and an increase in left ventricular end systolic volume index 15 percent or greater. Results showed 45.8 percent of the biventricular-pacing group and 55.6 percent of the right-ventricular pacing group experienced a primary outcome event.

The FDA often, but not always, follows the recommendations of its advisory panels.