Currently, there is poor scientific evidence about the effects of the method on survival. There is moderate scientific evidence that patients, mainly those with moderately severe chronic heart failure, would experience fewer symptoms in the short term (6 months) with biventricular pacemaker therapy. Findings from long-term followups of the effects on symptoms have not been reported. There is poor scientific evidence that the method would reduce the need for hospital care associated with heart failure. There is no scientific evidence about the cost effectiveness of biventricular pacemaker therapy.