Background: Spinal cord stimulation (SCS) may be a useful additional therapy for pain in patients with therapeutically refractory angina pectoris. But doubts remain about whether it also relieves ischaemia.
Methods: Indices of ischaemia were studied with and without SCS in 10 patients with otherwise intractable angina and evidence of myocardial ischaemia on 48 h ambulatory electrocardiographic (ECG) recording. Primary end points assessed by 48 h ECG recordings were total ischaemic burden, number of ischaemic episodes, and duration of ischaemic episodes. In addition, symptoms were assessed by a diary of glyceryl trinitrate intake and angina attacks.
Results: During SCS the total ischaemic burden of the entire group was significantly reduced from a median of 27.9 (1.9-278.2) before SCS to 0 (0-70.2) mm x min with SCS (p < 0.03). In six out of the 10 patients there was no myocardial ischaemia during 48 h ambulatory ECG monitoring with SCS. The number of ischaemic episodes was reduced from a median of 3 (1-15) before SCS to 0 (0-9) with SCS (p < 0.04). The duration of ischaemic episodes decreased from a median of 20.6 (1.7-155.4) min before SCS to 0 (0-48.3) min with SCS (p < 0.03). This was accompanied by a significant improvement in symptoms with a reduction in daily glyceryl trinitrate intake from a median of 3.0 (0-10) before SCS to 0.3 (0-10) tablets per 48 h (p < 0.02) and a decrease in the frequency of anginal attacks from a median of 5.5 (2-14) before SCS to 1.0 (0-10) per 48 h with SCS (p < 0.03).
Conclusions: SCS not only reduced symptoms but also myocardial ischaemia. Therefore, SCS appears to be both a safe and an effective therapy for patients with refractory angina.