Progression of heart failure in right univentricular pacing compared to biventricular pacing

Progression of heart failure symptoms in the right univentricular pacing group was more pronounced compared to the CRT group, despite the fact that patients assigned to the CRT group had more severe symptoms of heart failure at baseline. Biventricular pacing relieved symptoms of heart failure, whereas right univentricular pacing with subsequent conduction delay of the left ventricle further deteriorated pre-existing heart failure. Therefore, patients with an indication for pacemaker therapy because of bradycardia and co-existing mild to moderate heart failure might benefit from early implantation of a CRT system.