Introduction: Cardiac resynchronization therapy (CRT) is standard for heart failure patients with low left ventricular ejection fraction (LVEF ≤35%) and QRS duration ≥130ms despite optimal medical treatment (1).

Patients and Methods: This is a retrospective study that involved patients with implanted biventricular heart electrostimulators with (CRT-D) or without (CRT-P) defibrillator functions since 2011 to April 2018. The goal was to assess the CRT efficiency during check-ups after 6 months.

Results: Including 40 patients, 23 men and 17 women of an average age of 66.3 years. There were 4 (10%) patients with ischemic cardiomyopathy (IDCM), while 36 (90%) of the non-ischemic cardiomyopathy (NIDCM) had equal gender distribution. The average width of the QRS was 160 ms, and 75% of patients presented with typical Strauss left bundle branch block (LBBB). At the time of implantation, 6 (15%) patients had atrial fibrillation. The average LVEF value was 28%, and their NYHA status was III. CRT-D was implanted in all patients with IDCM. CRT-P was implanted in 19 and CRT-D in 17 patients with NIDCM. In 36 (85%) patients, there was an improvement of LVEF of which 11 (all with NIDCM, sinus rhythm and typical LBBB) achieved almost normal heart function (LVEF ≥50%) with regression of LV volume. There was no improvement in NYHA status with 5 (12.5%) patients, and with 6 (15%) there was deterioration or there was no improvement in LVEF. Four (10%) patients were hospitalized for acute heart failure. The average LVEF was 45.4% and the NYHA status was I/II. Sudden deaths or syncope in CRT-P patients were absent, while appropriate and necessary treatment of tachyarrhythmia occurred in 3 patients with CRT-D. Lethal outcomes were with 3 patients (one non-cardiac and two non-sudden cardiac deaths).

Conclusion: Targeted patient selection with proper left ventricular lead implantation and optimal device programming improves the response rate to resynchronization therapy.