Right ventricular dysfunction and B-type natriuretic peptide in asymptomatic patients after repair of tetralogy of Fallot

  • Dr Christian Apitz, Pediatric Cardiology, University Children's Hospital, Tuebingen, Germany, Germany
  • Dr Ludger Sieverding, Pediatric Cardiology, University Children's Hospital, Tuebingen, Germany, Germany
  • Heiner Latus, Pediatric Cardiology, University Children's Hospital, Tuebingen, Germany, Germany
  • Dr Anselm Uebing, Pediatric Cardiology, University Children's Hospital, Kiel, Germany, Germany
  • Dr Stephan Schoof, Pediatric Cardiology, University Children's Hospital, Hanover, Germany, Germany
  • Dr Michael Hofbeck, Germany

    • Background: Early detection of right ventricular (RV) dysfunction is essential in the assessment of patients with repaired tetralogy of Fallot (TOF). Purpose of this study was to assess latent RV dysfunction in asymptomatic patients with TOF, and to determine the predictive value of B-type natriuretic peptide (BNP).

    Methods: Pressure-volume loops were recorded in 16 young patients (NYHA class I) (mean age 15.9 years) by conductance catheter technique. All patients had moderate to severe pulmonary regurgitation (PR) after surgical repair of TOF (mean PR 36.2%) and an increased enddiastolic RV volume of 129.7 ml/m2 on magnetic resonance imaging. Indexes of RV function were derived at baseline level and during dobutamine infusion. Contractility was calculated by the slope of the endsystolic pressure-volume relation (ESPVR). An increase in ESPVR during dobutamine infusion was considered to indicate contractile reserve as a marker for latent RV dysfunction.

    Results: Mean ESPVR was significantly increased from 0.34 mmHg/ml at baseline to 0.60 mmHg/ml during dobutamine (p=0.005). However, in 5 patients no relevant increase in contractility was found indicating impaired RV contractile reserve. There was only a weak, and not significant inverse correlation between contractile reserve and BNP (r=-0.28).

    Conclusions: Even asymptomatic patients with an only mildly enlarged right ventricle can have impaired RV function. BNP is not able to predict early RV dysfunction accurately.