Quantification of Pulmonary Regurgitation by Vector Flow Mapping in Congenital Heart Patients after Repair of Right Ventricular Outflow Obstruction: A Preliminary Study.

BACKGROUND: Vector flow mapping (VFM) enables direct visualization of flow pattern and estimation of flow volume. The aim of this study was to determine its accuracy in the quantification of pulmonary regurgitation (PR) in congenital heart patients after repair of right ventricular (RV) outflow obstruction. METHODS: This study comprised two parts: (1) validation of VFM in the quantification of PR in patients with repaired tetralogy of Fallot by cardiac magnetic resonance and (2) clinical application of VFM to determine PR in patients after biventricular repair of pulmonary atresia and stenosis with intact ventricular septum. PR was quantified by calculation of VFM-derived pulmonary regurgitant ratio (PRVFM), defined as ratio of backward to forward flow volume. RESULTS: Coefficients of variations for intra- and interobserver variability in the measurements of PRVFM were 7.0% and 10.4%, respectively. Fourteen patients with repaired tetralogy of Fallot aged 31.3 ± 7.3 years were studied. Their PRVFM correlated strongly with cardiac magnetic resonance-derived PR fraction (r = 0.95, P < .001) and RV end-diastolic volume (r = 0.84, P < .001). In the second part, 14 patients with pulmonary atresia with intact ventricular septum aged 25.6 ± 6.0 years, 14 patients with pulmonary stenosis aged 24.2 ± 7.0 years, and 14 healthy control subjects were studied. PRVFM was found to increase across groups of subjects with absent (4.6 ± 3.3%), mild (11.1 ± 7.1%), moderate (29.6 ± 7.8%), and severe (50.1 ± 8.2%) PR as defined semiquantitatively by color flow mapping. Furthermore, PRVFM correlated strongly with the ratio of PR color jet to width of RV outflow (r = 0.92, P < .001). CONCLUSIONS: VFM is a reproducible technique for accurate quantification of PR in congenital heart patients after repair of RV outflow obstruction.

Right Atrial Mechanics Long-Term after Biventricular Repair of Pulmonary Atresia or Stenosis with Intact Ventricular Septum.

BACKGROUND: This study tested the hypothesis that right atrial (RA) mechanics are altered in patients after repair of pulmonary atresia with intact ventricular septum (PAIVS) and pulmonary stenosis (PS) and to explore their relationships with right ventricular (RV) diastolic function and P-wave indices. METHODS: Thirty-six adult patients, 16 with PAIVS and 20 with PS patients, and 20 age-matched healthy subjects were studied. Right atrial mechanics were assessed using speckle tracking echocardiography (STE) with quantification of positive, negative, and total strain, and strain rates at ventricular systole (aSRs ), early diastole (aSRed ), and atrial contraction (aSRac ). Right ventricular diastolic function was assessed by Doppler interrogation and STE. Maximum P-wave duration and P-wave dispersion were measured. RESULTS: Compared with controls, PAIVS and PS patients had significantly lower RA positive and total strain, aSRs and aSRed (all P < 0.05). Parameters of RV diastolic function including transtricuspid early (E) and late (A) diastolic inflow velocities, E/A ratio, early diastolic tricuspid annular velocity (e), early to late diastolic annular velocity ratio, E/e ratio, and RV early diastolic strain rate were found to correlate significantly with RA positive and total strain and aSRed (all P < 0.05). Maximum P-wave duration and P-wave dispersion increased progressively across control, PS, and PAIVS groups (P for trend <0.001). Both P-wave indices correlated negatively with RA positive strain, total strain, and aSRed (all P < 0.05). CONCLUSION: Impairment of RA mechanics occurs in patients long term after repair of PAIVS and PS and is associated with RV diastolic dysfunction, longer P-wave duration, and greater P-wave dispersion.