RV peak systolic annular velocity (S’)
As a conventional RV function parameter, S’ represents the
tricuspid annulus’ longitudinal velocity at systole and is easy to
estimate, reliable and reproducible . Previous studies show that S’
might be the best predictor of RVEF, and may predict short-term outcome
of heart failure. S’ was also questioned whether the displacement of the
myocardium or the regional velocities in a single segment can truly
represent the entire RV function. However, our observation indicates the
accuracy of S’ in assessing RV systolic dysfunction maybe not as good as
suggested in prior studies . Using a cutoff of < 10 cm/s, the
accuracy (AUC) of S’ in differentiating the severity of RV systolic
dysfunction were in the range of 0.58-0.65 in our study; which is
apparently lower than previously reported 0.7-0.8 range. Of note, the S’
threshold of RV systolic dysfunction varies considerably between studies
while the commonly accepted S’ cutoff for RV dysfunction is <
10 cm/s . In addition, a study showed that S’ detected best at a cut-off
value of 8.8 cm/sec in 10 patients with arrhythmogenic RV dysplasia and
low RVEF. Another study found that S’ between lateral and septal
tricuspid annulus of 7 cm/s was the most accurate means to detect an
RVEF cut-off by MRI of 45%. Overall, our data support that S’ is more
accurate in cases with mild RV dysfunction as reported previously. The
S’ cutoff used in prior studies ranged from 7 cm/s to 11 cm/s , which is
about 30 to 40% variation between different studies. This implies a
single best cutoff threshold may not exist among different patient
cohorts.