Background: Acute coronary syndromes (ACS) occurring on rest days have been associated with higher mortality, but the current literature remains inconsistent in this regard. This study included ACS patients presenting with acute decompensated heart failure (ADHF) investigating the relationship between time of coronary catheterization and outcomes.

Methods: Analyses were performed from the prospective, multicentric Special Program University Medicine Acute Coronary Syndromes and Inflammation (SPUM-ACS) Cohort. Patients were divided into two groups according to time of coronary catheterization on either workdays (Monday, 00:00 to Friday, 23:59) or rest days (Saturday, 00:00 to Sunday, 23:59 and public holidays). ADHF was defined by Killip Class III or IV upon presentation. Patients were followed over 1 year.

Results: Out of 4787 ACS patients enrolled in the SPUM-ACS Cohort, 207 (4.3%) presented with ADHF. 52 (25.1%) and 155 (74.9%) patients underwent coronary angiography on rest days or workdays, respectively. Baseline characteristics were similar among these groups. ACS patients with ADHF showed increased 1-year mortality on rest days (34.6% vs. 17.4%, p-value = 0.009). After correction for baseline characteristics, including the GRACE 2.0 Score, rest day presentation remained a significant predictor for 1-year mortality (adjusted hazard ratio = 2.42 [95% confidence interval: 1.14-5.17], p-value = 0.022).

Conclusions: One-year all-cause mortality was high in ACS patients with ADHF and doubled for patients admitted on rest days. The present data support the association of a rest day effect and long-term patient survival and indicate a need for further investigations.