Reverse cardiac remodeling in patients with dilated cardiomyopathy post Cardiac Resynchronization Therapy (CRT) and its clinical implication

Aim: To track the reverse cardiac remodeling in patients with dilated cardiomyopathy post cardiac resynchronization therapy (ON and OFF modes) and its implication on patients clinical condition emphasizing  the factors achieving  that remodeling. Patients and Methods: 30 patients indicated for the device were enrolled and studied before and three to six   months after device insertion by history taking, clinical examination, transthoracic echocardiogram, ECG and six minutes' walk test. Results: 30 patients (23 males and 7 females, mean age (54.50 ± 6.24years) with implanted CRT. All patients were in sinus rhythm, QRS duration ≥120 ms and LBBB with dilated cardiomyopathy (ischemic etiology was excluded by coronary angiography in patients having risk factors for IHD). There was clinical response to CRT as NYHA class improved p < 0.001 and 6 min walk test p < 0.001, electrocardiographically, there were significant differences in HR, PR interval, QRS duration ,axis and morphology between pre and post CRT measurements (P<0.001) and echocardiographic response as LV volume improved in 80%, EF in 76.6% and change (∆QRSD) significantly correlated with changes in NYHA, LVEDD, LVESD, and LVEF. s. Area under the curve was 0.824 for ∆QRSD (p=0.005), ∆QRSD of ≥-20 ms as a cutoff value had high specificity for predicting both clinical and Echocardiographic response. Coronary sinus lead selection and positioning had a major role in achieving that remodeling with best response was shown with the lateral veins (70 % of responders ) and worst response with mid vein ( 65 % of non- responders);Achieving that targeted  significant ∆QRSD of ≥-20 ms sometimes required a more than usual programmable VV delay up to 60 ms in some patients. Conclusion: Reverse cardiac remodeling post CRT in patients with DCM in both (CRT ON + OFF modes ) was associated with a significant improvement in patients clinical conditions with subsequent reduction of the incidence   of their  need to hospital admissions.