FIG. 1 is a perspective view of my new heart plasma lamp design shown in a position of use with a base; FIG. 2 is a front elevational view thereof; FIG. 3 is a left or right side view thereof; FIG. 4 is a front elevational view thereof shown with an attachment to a base; FIG. 5 is a top elevational view thereof; and, FIG. 6 is a bottom elevational view thereof. The broken line showing of a base or an attachment in FIGS. 1-6 is for illustrative purposes only and forms no part of the claimed design.