Metabolomic signature of cardiac resynchronization therapy (CRT). A, Changes in plasma metabolomic profiles of patients with heart failure (HF) after CRT by orthogonal partial least squares discriminant analysis (OPLS-DA). 3M indicates 3-month follow-up. B, Most important metabolites in metabolomic signature of CRT by variable importance in the projection (VIP). C, Pattern of plasma metabolite changes in HF patients after CRT (N=19, **P<.001). D, Metabolic pathways most affected after CRT as deduced from an altered plasma metabolomic profile.