In this paper, we present the details of the mechanical design for a haptic device intended to be used during minimally invasive cardiac surgeries. In addition, we develop the kinematics and dynamics equation of motion of the end effector of the device using the Euler-Lagrange equations. The viability of the design is demonstrated by integrating a virtual representation of the left ventricle to define unilateral constraints and finding a safe corridor for haptic guidance and control of the surgical robot.