Prognostication in acute heart failure and cardiogenic shock : focus on electrocardiography and biomarkers

Acute heart failure (AHF) is a leading cause of hospitalizations in patients over the age of 65 worldwide, and is associated with high mortality. Cardiogenic shock (CS), the most severe form of AHF, is characterized by hypotension and end-organ hypoperfusion. Acute coronary syndrome (ACS) precipitates a third of all cases of AHF, and up to 80% of CS. Objective and timely risk assessment in AHF is challenging due to the heterogeneity in its pathophysiology and clinical picture. Risk assessment has traditionally relied on clinical parameters, which may remain subjective or become evident too late, after end-organ dysfunction has become irreversible. Considering the costs and possible adverse effects, application of the most aggressive therapies should be limited to those that most likely procure benefit. The aim of this thesis is to evaluate the prognostic value of electrocardiographic changes and biomarkers in AHF and CS. The patient data come from three cohorts of AHF and two cohorts of CS. All cohorts are independent, prospective, observational, investigator-initiated European cohorts. Study I compared the prognostic value of ventricular conduction blocks (VCB) in patients with new-onset (de novo) AHF and in patients with acutely decompensated chronic heart failure (ADCHF). Study II investigated the role of VCBs in ACS-related CS. Half the patients had a VCB in their baseline ECG, and the presence of any VCB predicted mortality independently of baseline clinical variables or angiographic findings. Studies III-IV investigated the role of two novel biomarkers, sST2 and bio-ADM, in cariogenic shock. Study III showed that sST2 provide strong and complementary prognostic value to NT-proBNP in ACS-related CS, and can help in stratification of patients into low, intermediate and high-risk groups as early as 12 hours after detection of shock. Study IV evaluated in CS patients the prognostic value and association with haemodynamic parameters of bio-ADM compared to lactate. Whereas lactate had good prognostic value in the early phase, its levels normalized during the first 24 hours in the majority of patients, with a decreasing prognostic value thereafter. In contrast, levels of bio-ADM stayed elevated in non-survivors during the first 4 days of intensive care, and bio-ADM had good prognostic value when measured on days 2 to 4. In conclusion, in patients with AHF or CS, electrocardiographic alterations may prove useful in early risk assessment on top of clinical parameters. In addition, biomarkers provide a novel approach in CS risk assessment.