Acute myocarditis or idiopathic dilative cardiomyopathy? A six-month-follow up of NT-proBNP and left ventricular diameters in children presenting with left ventricular dilatation and dysfunction

  • Dr Farnaz Darbandi-Mesri, Department of Pediatric Cardiology, Medical University of Vienna, Austria
  • Dr Doris Luckner, Department of Pediatric Cardiology, Medical University of Vienna, Austria
  • Dr Ulrike Salzer-Muhar, Department of Pediatric Cardiology, Medical University of Vienna, Austria

    • Objectives
    To evaluate plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels and echocardiographic left ventricular (LV) parameters at initial presentation and after 6 months in children with heart failure, left ventricular dilatation/dysfunction due to acute myocarditis or idiopathic dilative cardiomyopathy (DCM).
    Methods
    Retrospective study performed in a tertiary pediatric cardiology centre from 2004 to 2006. Ten children with acute myocarditis (n=6) or idiopathic DCM (n=4) were included. NT-proBNP values (in pg/ml)and left ventricular (LV) measurements were retrieved from medical records.
    Values of enddiastolic/endsystolic LV diameters (LVEDD, LVES) were expressed as percentages of mean normal reference values. A p-value <0.05 was considered significant.
    Results
    Median NT-proBNP level was 20241 pg/ml initially and 522.95 pg/ml after 6 months (p<0.05). Patients with acute myocarditis had higher initial NT-proBNP levels (29813.7 ± 3113.8) than children with DCM (7813.8 ± 2192.3). This difference was noticeable, but not statistically significant.In patients with myocarditis, plasma NT-proBNP levels dropped after initiation of therapy and were normal or mildly elevated in all after 6 months.
    Mean LVEDD was 167.6% of the mean normal reference value initially and decreased to 149.6 % after 6 months,when 8/10 patients still had enlarged LVEDD. Mean LVES was 243.3 % of normal initially and decreased to 197.3 % (p < 0.05)
    Conclusion
    Children with myocarditis had higher NT-proBNP levels at presentation than children with DCM and showed a rapid decrease after initiation of treatment. Despite clinical improvement and normal/mildly elevated NT-proBNP values, marked left ventricular dilatation was still found in two thirds after 6 months.