Insights into the importance of the electrocardiogram in patients with acute heart failure

Abstract

Background: Patients presenting to the emergency department (ED) with acute heart failure (AHF) are at an increased risk of morbidity and mortality. The electrocardiogram (ECG) is a routine investigation in patients with AHF used to identify potential causes and/or complications. It is unclear whether 12-lead ECG characteristics can serve as a prognostic indicator in this population.

Methods and results: Patients with AHF from four hospital EDs were prospectively enrolled into the AHF - Emergency Management cohort. In addition to baseline data collection, the first available ECG was read in a core laboratory. Clinical outcomes (all-cause mortality and readmission) were recorded and risk models were developed. Of 937 enrolled patients, 816 had a diagnosis of AHF and an available ECG. Median age of the population was 77 [interquartile range (IQR) 67-85], 47% were female and median ejection fraction was 45% (IQR 30-55). Abnormalities were common, with only 7.5% of patients having a normal ECG. During the median follow-up of 25.7 months, there were 379 (46%) all-cause deaths and 328 (40%) hospital readmissions. Sinus rhythm was associated with better outcomes [hazard ratio (HR) 0.76; 95% confidence interval (CI) 0.62, 0.94], while paced rhythms (HR 1.51, 95% CI 1.11, 2.05), a wide QRS (HR 1.29, 95% CI 1.04, 1.59) and an ECG with any abnormality (HR 1.57, 95% CI 1.01, 2.44) was associated with poorer outcomes. Other individual ECG characteristics were not related to clinical outcomes after risk adjustment.

Conclusions: Certain ECG abnormalities are common in patients with AHF and associated with poor outcomes. Used in conjunction with other clinical variables, the ECG may be a useful tool in long-term risk stratifying patients.

Keywords: Arrhythmias; Cardiology; Electrocardiology; Heart failure.