It is expected that this method improves the response to CRT. The human and economic costs of CRT in non-responders are therefore expected to be reduced. If an excess increase in LVEF is achieved in this study, it will be possible to prevent and relieve invalidating symptoms and reduce mortality in selected heart failue patients in the future. The utility and potential benefits of participating in this study are expected to equalize the risks of exposure to ionizing radiation, possible side effects and inconvenience to the patient.