Implantable medical devices are active medical devices which are either partially or totally introduced surgically into the human body for treatment purposes. These biosensors are basically powered by Hybrid cathode Lithium batteries. Use of practical implantable cardiac pacemaker's dates back to 1950s powered by Zn/HgO batteries. Later Lithium batteries with hybrid cathodes of Ag2V4O11 and CF were developed. These hybrid batteries offer power density and energy density along with the stability and reliability required for implantable medical applications. Heart Failure (HF) is a chronic, degenerative condition which impairs the heart's ability to pump blood at normal filling pressures. The aim of this review is to high light the applications of implantable medical sensors such as Radiofrequency based Wireless Heart Failure Sensors (HFS); Swan-Ganz catheterization; Echocardiography (ECHO) in monitoring heart failure. In comparison the new HFS has more benefits in terms of simplicity of implantation procedure, safety profile, small size and accuracy when compared to SG catheters and ECHO.