Left Ventricular Phase Analysis and Outcomes of Cardiac Resynchronization Therapy

Background: Left ventricular dyssynchrony plays an important role in predicting response to Cardiac Resynchronization Therapy (CRT). Methods: Thirty patients underwent CRT implantation. Assessment of Left Ventricular (LV) dyssynchrony was done through Gated Spect LV phase analysis. Results: Thirty patients received CRT (mean age 58.7 ±9.0, 24 males). CRT implantation had a favorable prognosis on cardiac functions (LVEF pre-implantation: 26.8 ±4.7% versus 29.1±6.4% post-implantation; p=0.002). Reverse LV remodeling (≥ 15%) was documented in 19 patients. LV dyssynchrony parameters were correlated to LV reverse remodeling. Applying ROC curve for LV phase analysis showed that a cutoff 152o for histogram bandwidth had a sensitivity of 72.7% and specificity of 63.2% for predicting CRT non-response status. Also, a cutoff 54o for histogram standard deviation had a sensitivity of 81.8% and specificity of 63.2%. Conclusion: Responders of CRT showed improved LV dyssynchrony profiles. Utilizing Gated SPECT LV analysis could provide predictors for CRT non-response.