Cardiac Resynchronization Therapy May Avoid Dilated Rather Than Ischemic Cardiomyopathy Patients the Need for Primary Prevention Defibrillator Implantation

The influence of the aetiology of systolic heart failure (HF) on the potential benefit of cardiac resynchronization therapy (CRT) is still unclear. We aimed at comparing the response to CRT among patients with dilated (DCM) versus ischemic cardiomyopathy (ICM) and checking the possibility that CRT implantation may avoid some patients the need for defibrillator (ICD) implantation. Patients and Methods: This prospective observational study included patients with advanced systolic HF who had CRT implantation and were followed-up for at least 6 months. Results: The 1st group included 51 patients aged 51.94± 10.84 years who had DCM. The 2nd group included 17 patients aged 52.71±10.61 years who had ICM. During the follow-up period, 42 patients (82.4%) of group 1 showed good response to CRT vs. 4 patients (23.5%) of group 2 (p=0.00). About 69% of the responders showed improvement of EF to 35%; all belonged to group 1. They had wider QRS than other patients in group 1 (157.06±19.74 vs. 137.65±18.38; p=0.001). Sustained ventricular tachycardia and ICD shocks happened in 2 patients (4.1 %) of responders to CRT vs 6 patients (31.6%) of non responders (p=0.005), and occurred more among ICM (35.3%), p=0.002. Conclusion: Patients with DCM may benefit more than ICM patients from CRT implantation. The significant EF improvement after CRT implantation may avoid some patients with DCM the need for 1ry prevention ICD, specially patients with a significantly wide QRS before implantation. This may not be the case for ICM patients.