Cardiac contractility modulation therapy in patients with implanted cardiac resynchronization therapy: results of the 2 year follow-up

Aim. Cardiac contractility modulation (CCM) is a device therapy for patients with heart failure with reduced ejection fraction (HFrEF), most of the data on its programming are concerned patients with narrow QRS and of limited follow up. Our aim was to propose programming approach for Optimizer device in setting of wide QRS complex and fragmented ventricular local activation. Methods. We enrolled 11 patients with HFrEF (median age, 8 males, median NYHA class 3) and LBBB-related wide QRS complex, who underwent Optimizer™ device implantation. Three patients got Optimizer™ IV system and eight patients were implanted Optimizer™ Smart. Ten patients were previously implanted with CRT-D due to HFrEF and LBBB; one patient received CRT-D after Optimizer™ implantation. Results. During the implantation procedure ventricular local sense (LS) channel signal fragmentation was detected in all patients. In five patients signal detection was optimized by lead relocation. In six patients LS signal sensitivity limitations were resolved by programming. At two-year follow-up survival 4 patients died of noncardiac causes (1 intracranial hemorrhage, 1 gastrointestinal bleeding and 2 - terminal kidney failure). At 12-month follow-up we observed a non-significant improvement in 6-minute walking distance (300 vs 305, p=0.093), NYHA class (2.75 vs 2, p=0.085), MLHF score (53 vs 42, p=0.109) and left ventricular ejection fraction (LVEF) (30 vs 33.5, p=0.212). Conclusion. CCM system implantation is feasible and safe in patients with HFrEF and LBBB-related wide QRS complex. Device programming maneuvers can resolve the challenges of ventricular local signal detection in these patients.