Discussion
The ”TAPSE-slope” index was proposed and measured in 84 healthy persons. In our study group, TAPSE-slope was 7.0±1.0, TAPSE-slope was 7.3±1.0 in men, and TAPSE-slope was 6.9±0.9 in women. A significant difference (P value=0.001) was observed between the mean TAPSE-slope in men and women.
Slope signifies the ratio of the longitudinal systolic movement to the time change. In other words, it shows an object’s acceleration. Neither height nor time alone determines slope, but a combination of these parameters.
TAPSE-t actually shows the systolic interval (SI) 5that consists of isovolumic contraction time (IVCT) and ejection time (ET). In the left ventricle (LV), systolic interval and diastolic interval (DI) and their ratio not only depend on heart rate (HR) but also depend on diurnal variations6, Valsalva maneuver7, and medications8. Also, multiple studies have shown that LVET increases from infancy to childhood independent of the heart rate 9,10. In older people, LVET also becomes prolonged 11. In systolic heart failure, IVCT is prolonged and LVET shortens, but the SI does not change significantly 12. In a study on diabetic patients, autonomic neuropathy increased the ratio of SI to DI13. Theoretically, SI and change in the ratio of SI to DI may also apply to the right ventricle, and these parameters may also change in RV systolic dysfunction.
Evaluation of RV function is crucial in the management of cardiac diseases. As measuring tricuspid systolic excursion (TAPSE) is an essential part of evaluating RV systolic function. When TAPSE is measured, changes in SI, IVCT, or ET are not considered. We hypothesized that evaluating the rate of this systolic excursion may also be beneficial and should be considered. As mentioned above, two people with similar heart rates may have different systolic intervals. In equal systolic intervals, higher TAPSE-slope reflects better RV function. Still, in different systolic intervals, the rate of acceleration of RV free wall may give us better information regarding RV function.
As this was a new index, ”reliability analysis” for TAPSE-t measurements was also done, and Intra class correlation (ICC) between the three cardiologists was 0.886 (95% CI: 0.827-0.925). According to Cicchetti’s classification 14 values between 0.75-1.00 show excellent inter-rater agreement. In 2010 15 Pinedo et al. showed excellent inter-observer ICC for TAPSE measurements of about 0.79. They measured Intra and inter-observer variability of different indices of RV function in 30 patients with isolated mitral valvulopathy who were candidates for heart surgery. TAPSE-slope was not measured in this study.