Heart failure (HF) is a cardiovascular disease affecting about 26 million people worldwide costing about $100 billons per year. HF activates several compensatory mechanisms and neurohormonal systems, so we hypothesized that the concomitant monitoring of a panel of potential biomarkers related to such conditions might help predicting HF evolution. Saliva analysis by point-of-care devices is expected to become an innovative and powerful monitoring approach since the chemical composition of saliva mirrors that of blood. The aims of this study were (i) to develop an innovative procedure combining MEPS with UHPLC-MS/MS for the simultaneous determination of 8-isoprostaglandin F2α and cortisol in saliva and (ii) to monitor lactate, uric acid, TNF-α, cortisol, α-amylase and 8-isoprostaglandin F2α concentrations in stimulated saliva samples collected from 44 HF patients during their hospitalisation due to acute HF. Limit of detection of 10 pg/mL, satisfactory recovery (95-110%), and good intra- and inter-day precisions (RSD ≤ 10%) were obtained for 8-isoprostaglandin F2α and cortisol. Salivary lactate and 8-isoprostaglandin F2α were strongly correlated with NT-proBNP. Most patients (about 70%) showed a significant decrease (a factor of 3 at least) of both lactate and 8-isoprostaglandin F2α levels at discharge, suggesting a relationship between salivary levels and improved clinical conditions during hospitalization.