Absolutely not!

Of course, there was initial concern that spinal cord stimulation would mask angina secondary to a myocardial ischemic event, and could prevent a patient from responding to an early warning signal. An elegant study showed that patients with spinal cord stimulators developed and recognized symptoms of angina from a new heart attack (although these were fairly infrequent). Further studies have shown that there is no increase in mortality in patients with spinal cord stimulator compared to those who did not have one.

Thus, spinal cord stimulation can safely be used for the treatment of refractory angina pectoris without masking the pain associated with a real myocardial ischemic event.

Reference

Mannheimer C, Eliasson T, Anderson B, et al. Effects of spinal cord stimulation in angina pectoris induced by pacing and possible mechanisms of action. BMJ 1993;307:477-80.