Brain Natriuretic Peptides and QRS Duration in Repaired TOF Patients with QRS Duration < 180msec

Abstract

Background: Several studies from Western countries have demonstrated that QRS prolongation is related to right ventricular (RV) dysfunction and that the B-type natriuretic peptide is a good marker for RV enlargement based on dysfunction after repair tetralogy of Fallot (TOF). Since the prevalence of patients with QRS duration >180ms may be less in Japan than in Western countries, it remains unclear whether the same relations are observed in Japanese patients.
Methods: Sixty-two repaired TOF patients who had narrow QRS (<180msec) underwent cardiac MRI or catheterization for assessment of RV function and blood sampling for BNP and NT-pro BNP.
Results: Median age at study was 18.9 years (2.5-64.2 years) and more than half of patients had narrow QRS <120 ms. Median right ventricular end-diastolic volume index (RV-EDVI), end-systolic volume index (RV-ESVI) and ejection fraction (EF) were 127 mL/m² (63-286 mL/m²), 73mL/m² (27-172mL/m²) and 46% (27% to 63%), respectively. No relationship was found between B-type natriuretic peptides and RV volume (RV-EDVI and ESVI) or between B-type natriuretic peptides and EF, but the QRS duration (64-176 ms) correlated positively with RV-EDVI, ESVI and negatively with RV-EF.
Conclusion: The QRS duration is a good marker to predict the RV volume overload and RVEF, but not levels of B-type peptide in repaired TOF patients with narrow QRS.