A novel non-invasive electrical synchrony method to improve cardiac resynchronization therapy responders

Abstract

Abstract Introduction Cardiac resynchronization therapy (CRT) has emerged as an important treatment for patients with heart failure and reduced ejection fraction (EF) despite optimal pharmacological therapy. Some studies showed non-responders rate near 30%. Nowaday there is no gold standard method for selection, evaluation and follow up on this group of patients. Multiple techniques used and operator dependence made echocardiogram failed. Synchromax 2 is a device designed to evaluate non-invasive electrical synchrony. It is fast, reproducible and non-operator dependent. Synchromax was evaluated and correlated with other techniques in previous studies. Objective Evaluate CRT response rate guided by electrical synchrony during the device implantation and follow up. Material and methods 43 patients were evaluated in an institution in Buenos Aires. A ICD-CRT was implanted in all patients due dilated cardiomyopathy, low EF (less than 35%) and left bundle branch block (LBBB). Non-invasive electrical synchrony evaluation (Synchromax 2) was performed in all patients in baseline condition, during device implantation and the follow up. Synchrony index and curves were analyzed. Curve type 4 and index between 0,4 and 0,7 were considered synchronous. Curve type 6 and 10 and index more than 0.7 were considered disynchronous. Interventricular intervals were modified to achieve the best curve and synchrony index. Super responders were considered when EF increased >50%. Baseline and 6 month after implantation echocardiogram were performed. Results Mean age 64 years. 39% females. Non-coronary dilated cardiomyopathy was main aetiology (63,1%). EF baseline average was 27%. A baseline index more than 0,7 was in 73,3% of the patients. Curve 6 was the most frequent (55,2%). Follow up average EF was 39% (increased 12%), the super responders rate was 18,6% (8 patients). Type 4 curve and index between 0,4 and 0,7 were achieved in 28 cases (65,1%). EF increased from 23% (baseline) to 42% (follow up). Average 19%. Type 4 curve was not achieved in 15 patients (34,9%). In this group, EF increased from 29% (baseline) to 34% (follow up). Average 5%. Conclusion Electrical synchrony evaluation using Synchromax 2 during ICD-CRT device implantation improves responders rate. When synchronous type 4 curve is achieved EF improves significantly. If type 4 curve is not found results will be unsuccessfully. Synchromax is fast, simple and non-operator dependent. Funding Acknowledgement Type of funding source: None