Abstract
Background
In approximately 30-40% of cases, the left ventricular systolic function does not improve following cardiac resynchronization therapy (CRT; non-responders). Currently, the role of right ventricular (RV) systolic function is not yet completely clear in the background. Our aim was to assess the RV systolic function with 3D echocardiography in CRT patients.
Methods
We selected 19 patients who received CRT in our department between May and June 2017, and whose 1-year follow-up data were available. We characterized several 2D parameters of RV systolic function, such as RV free wall strain (RV GLSFW), annular s’ wave velocity (TDI s), tricuspid annulus plane systolic excursion (TAPSE), RV fractional area change (RV FAC). A number of 3D parameters were also assessed, such as RV ejection fraction (EF), end-diastolic (EDV) and end-systolic (ESV) volumes, using a dedicated RV analysis software. Moreover, we measured the LV EF and considered the patients "responder", when the LV EF improved with at least 10% after CRT implantation.
Results
From 19 patients, 12 was identified as responders (R) and 7 as non-responders (NR). No significant difference was seen in the mean age of patients in the two groups (NR: 68 ± 6 year; R: 67 ± 9 year, p = 0.76), however, the proportion of male individuals was higher in the NR group (8/12 vs. 1/7). The RV EF was higher in the R group (41 ± 8% vs.29 ± 10%; p = 0.012), while the EDV or ESV did not differ between the two groups. The RV GLSFW (–21.2 ± 7% vs.–13.9 ± 7%, p = 0.045) and the TAPSE (16.8 ± 5 mm vs.11.4 ± 3 mm, P = 0.03) values were significantly different between the two groups. Based on logistic regression analysis, the RV EF was an independent predictor of non-respondence.
Conclusions
The lower RV EF indicates non-respondence to CRT, however, it is not associated with RV dilation, i.e.adverse remodelling. These results suggest mechanical abnormality of RV function in the background of impaired EF.
Right ventricular systolic function and cardiac resynchronization therapy
