Heart failure is a disease characterized by cardiac remodeling or progressive dilation of left ventricle and a consequent reduction in contraction. Ventricular remodeling has been shown to be a negative prognostic factor alone, and therefore the most beneficial drugs are those that prevent or reduce left ventricular dilation. The pharmacological therapy of heart failure, although maximal, has proven to be not fully effective. The aim of our research was to evaluate resynchronization therapy in a lot of patients, monitoring their cardiac performance before and after cardiac resynchronization therapy.