More than 50% of Persistent Myocardial Scarring at One Year in “Infarct-like” Acute Myocarditis Evaluated by CMR

Background: Cardiac magnetic resonance (CMR) has emerged as a reference tool for the non-invasive diagnosis of myocarditis. However, its role in follow-up (FU) after the acute event is unclear. The objectives were to assess the evolution of CMR parameters between the acute phase of infarct-like myocarditis and 12 months thereafter and to identify the predictive factors of persistent myocardial scarring at one year. Methods: All patients with infarct-like acute myocarditis confirmed by CMR were included. CMR was performed within 8 days following symptom onset, at 3 months and at one year. One-year FU included ECG, a cardiac stress test, Holter recording, biological assessments, medical history and a quality-of-life questionnaire. Patients were classified according to the presence or absence of complete recovery at one year based on the CMR evaluation. Results: A total of 174 patients were included, and 147 patients had three CMR. At one year, 79 patients (54%) exhibited persistent myocardial scarring on CMR. A multivariate analysis showed that high peak troponin at the acute phase (OR: 3.0—95%CI: 1.16–7.96—p = 0.024) and the initial extent of late gadolinium enhancement (LGE) (OR: 1.1—95%CI: 1.03–1.19—p = 0.006) were independent predictors of persistent myocardial scarring. Moreover, patients with myocardial scarring on the FU CMR were more likely to have premature ventricular contractions during the cardiac stress test (25% versus 9%, p = 0.008). Conclusion: Less than 50% of patients with infarct-like acute myocarditis showed complete recovery at one year. Although major adverse cardiac events were rare, ventricular dysrhythmias at one year were more frequent in patients with persistent myocardial scarring.

Abstract 394: Effect Of Introduction Of Non Invasive Risk Stratification On Cardiac Catheterization Referrals In A Community Hospital.

Background: Appropriate use criteria recommend against unwarranted cardiac catheterization (caths) in low risk patients. Reporting of risk stratification on non-invasive cardiac stress test reports was implemented at our institution to reduce low risk cardiac cath referrals. Methods: We performed a retrospective study to compare the effect of introduction of risk stratification in cardiac stress test reports. The percentages of low risk patients by nuclear stress, who underwent cardiac cath, before and after application of risk stratification were compared. Chi-square and Mann-Whitney-Wilcoxon tests were used for analysis. Results: There were significantly fewer low risk referrals after risk stratification, 43.2% of patients of low-risk patients were referred for catheterization before, compared to 28.3% of low-risk patients after risk stratification (p value 0.01). There was reduction in the percentage of normal cardiac caths in the low risk category after introduction of risk stratification (61.5% vs 33.3%, p value 0.05). Conclusion: Risk stratification led to a decrease in the percentage of low-risk patients referred for cath following a stress test.