Objectives: The isovolumetric relaxation time of the right ventricle (RV-IVRT) can be assessed using a method based on ECG and pulsed wave Doppler (PW). Recently pulsed wave Doppler tissue imaging (PW-DTI) has been introduced in the assessment.
Design: RV-IVRT obtained by the two methods was compared in 20 consecutive patients as was the time from the R wave on the ECG to the onset of tricuspid flow (R-T), to the closure of the pulmonic valve (R-P), to the onset of early diastolic motion of the tricuspid annulus tissue (R-E) and to the end of the systolic motion (R-S).
Results: RV-IVRT obtained by the PW method was significantly (p < 0.001) shorter than RV-IVRT obtained by PW-DTI. R-S had significantly (p < 0.001) shorter duration than R-P, while there was no significant difference between R-E and R-T.
Conclusions: The methods are not measuring the same interval. Only the PW method measures RV-IVRT according to the usual definition. Different reference values have to be used if the methods are used in the assessment of RV diastolic function.