Evaluation of Response to Cardiac Resynchronization Therapy in Patients with Non-Ischemic Cardiomyopathy Based on Echocardiographic Features Including Sphericity Index and Global Longitudinal Strain

Background:
In patients with Non-Ischemic Cardiomyopathy (NICM), Cardiac Resynchronization Therapy (CRT) has been shown to improve Left Ventricular Ejection Fraction (LVEF) and NYHA functional class. However, in some patients who received CRT, the results were not satisfying.
Objectives:
This study aimed to evaluate echocardiographic features as a predictor of positive response to CRT in patients with NICM.
Methods:
This case series study was conducted on 11 consecutive patients with NICM who were eligible for CRT at Imam Khomeini Hospital Complex. The patients’ basic demographic and echocardiographic data including Septal Flash (SF), Sphericity Index (SI), and Global Longitudinal Strain (GLS) were recorded and followed for six months. Data analysis was done using the SPSS software, and paired t-test was used for comparison of the study variables.
Results:
The results revealed an improvement in the median NYHA functional class from 3 (interquartile range: 2 - 4) to 1 (interquartile range: 1 - 2) (P < 0.001) at the follow-up. Assessment of LVEF through the Simpson method also showed a significant improvement from 28.25% to 39.31% (P < 0.001). Moreover, GLS improved and SI and SF decreased post CRT implantation.
Conclusions:
The results demonstrated that a GLS of less than -10.48 before device implantation, but not SI or SF, might be a predictor of a positive response to CRT in patients with NICM. In these patients, higher GLS at baseline might add data to the existing criteria for selecting suitable patients for CRT implantation.