Impact of myocardial injury on regional left ventricular function in the course of acute myocarditis with preserved ejection fraction: insights from segmental feature tracking strain analysis using cine cardiac MRI.

The aim of this study was to provide insights into myocardial adaptation over time in myocyte injury caused by acute myocarditis with preserved ejection fraction. The effect of myocardial injury, as defined by the presence of late gadolinium enhancement (LGE), on the change of left ventricular (LV) segmental strain parameters was evaluated in a longitudinal analysis. Patients with a first episode of acute myocarditis were enrolled retrospectively. Peak radial (PRS), longitudinal (PLS) and circumferential (PCS) LV segmental strain values at baseline and at follow-up were computed using feature tracking cine cardiac magnetic resonance imaging. The change of segmental strain values in LGE positive (LGE+) and LGE negative (LGE-) segments was compared over a course of 89 ± 20 days. In 24 patients, 100 LGE+ segments and 284 LGE- segments were analysed. Between LGE+ and LGE- segments, significant differences were found for the change of segmental PCS (p < 0.001) and segmental PRS (p = 0.006). LGE + segments showed an increase in contractility, indicating recovery, and LGE- segments showed a decrease in contractility, indicating normalisation after a hypercontractile state or impairment of an initially normal contracting segment. No significant difference between LGE+ and LGE- segments was found for the change in segmental PLS. In the course of acute myocarditis with preserved ejection fraction, regional myocardial function adapts inversely in segments with and without LGE. As these effects seem to counterbalance each other, global functional parameters might be of limited use in monitoring functional recovery of these patients.

Elevated troponin I level assessed by a new high-sensitive assay and the risk of poor outcomes in patients with acute heart failure.

BACKGROUND: The interpretation and clinical usefulness of elevated levels of cardiac troponins in acute heart failure (AHF) remain controversial. We aimed to characterize the relationship between changes in cardiac troponin I (measured using a new high-sensitive immunoassay by single-molecule counting technology, Singulex, Alameda, USA; hs-TnI) during first 48h of hospital stay and patients' characteristics and the outcomes. METHODS AND RESULTS: We measured hs-TnI at baseline, after 24 and 48h in 130 AHF patients (mean age: 65±13years, 77% men). The percentage of patients with elevated hs-TnI (i.e., above the upper reference limit [URL]>10.19pg/mL) were: on admission - 59%, after 24h - 61%, and after 48h - 58%. Elevated baseline level of hs-TnI was associated with more severe dyspnoea on admission but neither peak level nor changes in hs-TnI during first 48h were related to the dyspnoea severity or magnitude of dyspnoea relief. During 1-year follow-up there were 32 (25%) cardiovascular deaths. Neither absolute baseline nor peak values of hs-TnI predicted cardiovascular mortality. Only changes in hs-TnI were independently associated with cardiovascular mortality with the strongest relationship seen in peak change in hs-TnI: patients with an increase vs. remaining patients - hazard ratio (95% confidence interval): 3.22 (1.52-6.82)p=0.002. CONCLUSIONS: Using the new assay (proved to be more sensitive that the other available troponin assays) we observed that approximately 60% of patients with AHF presented elevated hs-TnI above URL during first 48h of hospital stay. Only significant increase in hs-TnI predicted cardiovascular mortality.