Ischemic electrocardiographic abnormalities and prognosis in decompensated heart failure

Background — Identification of coronary ischemia may enable targeted diagnostic and therapeutic strategies for acute heart failure (AHF). We determined the risk of 30-day mortality associated with ischemic ECG abnormalitiesin patients with AHF.

Methods and Results — Among 8772 patients (53.4% women, median 78 years [Q1,Q3 68,84]) presenting with AHF to 86 hospital emergency departments in Ontario, Canada, Q-waves, T-wave inversion, or ST-depression were present in 51.8% of subjects. However, presence of ST-depression was the only finding associated with 30-day mortality with adjusted odds ratio 1.24 (95% CI; 1.02-1.50). Using continuous net reclassification improvement, addition of ST-depression to the Emergency Heart failure Mortality Risk Grade (EHMRG) model reclassified 16.9% of patients overall, and 29.3% of those with a history of ischemic heart disease (both p<0.001). By adding ST-depression to the model, the EHMRG was extended to predict 30-day death with high discrimination (c-statistic 0.801), with mortality rate in the lowest risk decile of 0.57%. Adjusted odds ratios for 30-day mortality were 2.81 (95% CI; 1.48-5.31; p=0.002) in quintile 2, 7.41 (95% CI; 4.13-13.30; p<0.001) in quintile 3, and 14.47 (95% CI; 8.20-25.54; p<0.001) in quintile 4 compared to the lowest risk quintile. When the highest risk quintile was subdivided into two equally-sized risk strata (deciles 9 and 10), the adjusted odds ratios for 30-day mortality were 27.20 (95% CI; 15.33-48.27; p<0.001) in decile 9 and 58.96 (95% CI; 33.54-103.65; p<0.001) in highest risk decile 10.

Conclusions — Presence of ST-depression on the ECG reclassified risk of 30-day mortality in patients with AHF, identifying both high- and low-risk subsets.