• right heart catheterization
• diastolic dysfunction
• cardic magnetic resonance
• tetralogy of Fallot

Background: In patients with repaired Tetralogy of Fallot (rTOF) biventricular disfunction is associated with poor outcome. Diastolic dysfunction (DD) represents a challenge topic in the clinical and scientific scenario of rTOF, relating not only to its definition but also to the predictive role in cardiovascular adverse events. Diagnosis of right ventricular diastolic disfunction (RVDD) is performed by invasive right heart catheterization (CC) that is not routinely performed, unlike cardiac magnetic resonance (CMR), that is recommended in the follow-up.
Aim: The aims of our study are the following: 1) to evaluate CMR parameters of right and left diastolic function in repaired TOF patients, in comparison with a group of age- and sex-matched healthy volunteers; 2) to study the association of CMR parameters of diastolic function with catheter-based RV end-diastolic pressure (RVEDP); 3) to define the predictors of major adverse cardio-vascular events (MACE) during follow-up.
Method: we identified patients with rTOF who underwent CC and CMR. In addition to standard CMR parameters, we analyzed parameters of diastolic function from the right and left atrial and ventricular volume/time (V/t) curves, and corresponded derivative dV/dt curves and correlated them with RVEDP and with event at follow-up. A population of age-and sex-matched healthy subjects was enrolled as control group.
Results: Population study was composed by 35 patient (18 males, age 31 ± 15 years) with rTOF and 14 controls (10 males, age 37 ± 13 years).
The comparison between patients and controls, shown that in patients left atrium (LA)-emptying volume, reservoir, conduit, booster LAVi and LA early-peak emptying rate (LA-PER-E), were significantly lower than controls. On contrast, the isovolumetric pulmonary transit volume (IPTV) and isovolumetric pulmonary transit ratio (IPTR) were significantly higher in patients. Among parameters of LV diastolic function, patients had higher early-peak filling ratio (PFR-E), E/A and lower atrial-peak filling rate (PFR-A).
Among all parameters, a significant inverse linear relation with RVEDP was found only for cardiac index, isovolumetric caval transit volume (ICTV), right ventricle (RV PFR-A), right ventricle elastance.
Patient with RVEDP >=12 presented a significantly lower RA-EF, lower ICTV, but having a higher absolute value of RA PER-A, RV PFR-A
About follow-up, the only parameters significantly associated with MACE were RAVi and LAVi max, LAVi peak reservoir, LAVi peak conduit, LAVi peak booster, IPTV.
ROC curve analysis allowed to identify the best cut-off of each of these quantitative parameters to predict events. Finally, a score system was created using these parameters with the respective cut-off. Survival curves demonstrated that all the events occurred in patients with a score >1, achieving a negative predicting value of 100%.
Conclusion and clinical relevance: the analysis of right and left atrial-ventricular volume/time curves by CMR may allow a non-invasive and non-ionizing comparison with a population of controls and evaluation of diastolic dysfunction in rTOF, predicting high RVEDP and MACE at follow-up. Further studies are needed to validate the technique in a larger population.