Delayed onset of tricuspid valve flow in repaired tetralogy of Fallot: an additional mechanism of diastolic dysfunction and interventricular dyssynchrony

Abstract

BackgroundDiastolic dysfunction of the right ventricle (RV) is common after repair of tetralogy of Fallot. While restrictive physiology in late diastole has been well known, dysfunction in early diastole has not been described. The present study sought to assess the prevalence and mechanism of early diastolic dysfunction of the RV defined as delayed onset of the tricuspid valve (TV) flow after TOF repair.MethodsThe study population consisted of 31 children with repaired TOF (mean age ± SD, 12.3 ± 4.1 years) who underwent postoperative cardiovascular magnetic resonance (CMR). The CMR protocol included simultaneous phase-contrast velocity mapping of the atrioventricular valves, which enabled direct comparison of the timing and patterns of tricuspid (TV) and mitral (MV) valve flow. The TV flow was defined to have delayed onset when its onset was > 20 ms later than the onset of the MV flow. The TV and MV flow from 14 normal children was used for comparison. The CMR results were correlated with the findings on echocardiography and electrocardiography.ResultDelayed onset of the TV flow was observed in 16/31 patients and in none of the controls. The mean delay time was 64.81 ± 27.07 ms (8.7 ± 3.2% of R-R interval). The delay time correlated with the differences in duration of the TV and MV flow (55.94 ± 32.88 ms) (r = 0.90, p < 0.001). Delayed onset was associated with prolongation of the RV ejection time in 9 and delayed onset and cessation of the pulmonary arterial flow in 4. Delayed onset was not associated with timing changes in the pulmonary artery in 3. The patients with delayed onset showed reduced RV ejection fraction (p = 0.01). However, the two groups did not show significant differences in TV E/A ratio, ventricular end-diastolic volumes, left ventricular ejection fraction, pulmonary regurgitant fraction, heart rate, PR interval and QRS duration.ConclusionsEarly diastolic dysfunction with delayed onset of TV flow is common after TOF repair, and is associated with reduced RV ejection fraction. It is a further manifestation of interventricular dyssynchrony and represent an additional mechanism of ventricular diastolic dysfunction.

Atrial Mechanics after Surgical Repair of Tetralogy of Fallot

“…25,26 Atrioventricular diastolic interaction is further reflected by the association between atrial SR ed and the corresponding ventricular early diastolic strain rate on both sides. An additional component of RV diastolic dysfunction reported recently is delayed onset of tricuspid flow, 30 which shortens RV diastolic filling time and may perhaps account in part for our finding of increased maximum RA area. Apart from the diminished magnitude and rate of atrial deformation, we also found delay in EMC of both atria in repaired TOF patients.…”

Influence of RV Restrictive Physiology on LV Diastolic Function in Children after Tetralogy of Fallot Repair

“…A recent MRI study from our group showed that in about 50% of patients after TOF repair, the onset of TV inflow was delayed compared with mitral valve inflow. 26 In patients with delayed tricuspid inflow, RV filling starts after LV early filling. This could explain why LV early filling would be less affected by RV dilatation, and the fast filling of the right ventricle mainly affects late diastolic LV filling.…”

Improved Cardiac MRI Volume Measurements in Patients with Tetralogy of Fallot by Independent End-Systolic and End-Diastolic Phase Selection

“…Previous echocardiographic and cardiac MRI studies reported on the electromechanical delay of the RV compared to the LV in patients with congenital heart disease and normal subjects [8]–[10], [17], [18]. The main focus of the echocardiographic studies was to assess intra- and interventricular dyssynchrony and their predictors.…”