Background and aim of the study Guidelines on myocardial revascularization indicate for type V myocardial infarction (MI) that postoperative troponin elevations need not be exclusively ischemic but may also be caused by direct epicardial injury. Additional complexity arises from the introduction of high-sensitive troponin markers. The present study attempts to contribute to the understanding of postoperative high-sensitive cardiac troponin T (hs-cTnT) increase. Methods Type of surgery, potential factors affecting the postoperative hs-cTnT increase, and possible thresholds indicative of type V MI were analyzed. Results Among 400 included patients, 2.8% had intervention-related ischemia analogous to the type V MI definition. Receiver-operating characteristics confirmed good discriminatory power for hs-cTnT and creatine kinase myocardial band (CK-MB), with ischemia indicating thresholds for hs-cTnT (1705.5 ng/l) and for CK-MB (113 U/l). The median postoperative hs-cTnT/CK-MB increase differed significantly depending on the type of surgery, with the highest increase after mitral valve and the lowest after off-pump coronary surgery. Regression analysis confirmed Maze procedure (p<0.001), cardiopulmonary bypass time (p=0.03), emergency indications (p= 0.01) and blood transfusion (p=0.02) as significant factors associated with hs-cTnT increase. In contrast, CK-MB increase was also associated with mortality (p=0.002). Intra-pericardial defibrillation was the only ischemia-independent factor additionally associated with proposed thresholds (p<0.001). Conclusions The present results confirm the influence of the type of surgery and other intervention-related parameters on the postoperative hs-cTnT increase. Type V MI-indicating thresholds may require reassessment, especially using high-sensitive markers.

Rationale, aims and objectives: Postoperative atrial fibrillation (POAF) is the most common complication occurring after cardiac surgery. Guidelines for the management of this complication are scarce, often resulting in differences in treatment strategy use among patients. The aims of this study were to evaluate the management of POAF in a cardiac surgery department, characterise the extent of its variability and develop a standardised protocol. Methods: Data from patients who underwent cardiac surgeries with subsequent POAF between 1 January 2017 and 1 June 2018 were analysed in this single-centre observational retrospective study. The primary outcome was the difference in the proportions of patients whose first POAF episodes were treated with a rate control (RaC) strategy, a rhythm control (RhC) strategy and both among hospital units (intensive care unit [ICU], intermediate care unit [IMCU] and general ward [GW]). Secondary outcomes included the mean duration of POAF episodes, POAF recurrences, and the management of anticoagulation. Results: Data from 97 patients were included in this study. The POAF management strategy differed significantly among hospital units (ICU: RhC 75.0%, RhC and RaC 19.4%, RaC 0.0%; IMCU: RhC 40.4%, RhC and RaC 34.6%, RaC 13.5%; GW: RhC 22.2%, RhC and RaC 33.3%, RaC 44.4%; p = 0.001). Ninety-five (97.9%) patients converted to sinus rhythm after the first POAF episode; 51.2% of these conversions occurred within 8 h after onset. POAF recurred in 56.7% of patients. Considering all POAF episodes, 83 (85.6%) patients received amiodarone as part of the RhC strategy. Based on these results, a hospital working group developed a standardised protocol for POAF management. Conclusions: POAF management was heterogeneous at our institution. This paper highlights the need for clear practice guidelines based on large prospective studies to provide care according to best practices for all patients undergoing cardiac surgery.