ELECTROCARDIOGRAPHIC PREDICTORS OF RESPONSE TO CARDIAC RESYNCHRONIZATION THERAPY AT PATIENTS WITH NON-ISCHAEMIC DILATED CARDIOMYOPATHY
Aims: prediction of response to cardiac resynchronization therapy (CRT) in pts with nonischaemic dilated cardiomyopathy (DCM) with LBBB.
Methods: 53 pts with DCM (75,5% male; 44,3±9,4 years; NYHA class 3,09±0,3; QRS 164±31ms; LVEF 24,9±4,7%) had CRT implanted. Pts were classified as responder if they were experienced 10% increase LVEF and 15% decrease LV end-systolic volume with improvement NYHA class 1point at 6 months after CRT. Clinical, laboratory and echocardiographic and surface ECG parameters assessment (by 3 independent doctors) was performed in all pts at baseline and 6 months follow-up.
Results: 35pts (66%) were identified as CRT-responders and 18pts (34%) were classified as non-responders. At baseline there were no significant differences in age, gender, NYHA, 6-MWT, peakVO2, LVEF, LVvolume end-diastolic and end-systolic and therapies. Univariate analysis revealed that CRT-responders had at baseline greater width QRS max lead and RS duration in V1 lead (p=0,0001), greater post-implantation RS shortening in V1 lead (p=0,000) and increase R wave in V1 lead (p<0,001). By multivariate regression analysis, pre-implantation predictors: baseline width RS in lead V1 (S: 0,94, 95% CI: 0,814-1,00; p=0,0001) and BNP (S: 0,92, 95% CI: 0,797-1,00; p = 0,001), and two post-implantation predictors: reduction width QRS - QRS (S: 0,80, 95% CI: 0,586-1,00; p=0,01) and RS V1 (S: 0,87, 95% CI: 0,72-1,00; p = 0.002) after CRT implantation were emerged as independent predictors of response to CRT. Receiver Operating Characteristic curve analysis identified a baseline RS V1 > 116 ms and post-implantation QRS> -25 ms and RS> -23 ms to predict responders.
Conclusion: Positive response to CRT was observed in 66% of the pts DCM. Width RS V1 lead can be used as an independent criteria for predicting CRT-response DCM with indications for resynchronization; intraoperatively assessment cut-off QRS, RS with correction positioning electrodes will increase the effectiveness of CRT.