Spinal cord stimulation affects T-wave alternans in patients with ischaemic cardiomyopathy: a pilot study

Aims An antiarrhythmic effect of spinal cord stimulation (SCS) has been recognized in an animal model. The actual mechanism is still mainly unknown. An adrenergic output reduction has been advocated as the main mechanism, although a modulation effect on the arrhythmic substrate has not yet been investigated. We studied T-wave alternans (TWA) modifications to test the hypothesis that SCS affects the arrhythmic substrate. Methods and results We performed TWA assessment in three high-risk patients who previously had undergone implantation of both implantable cardioverter defibrillator and SCS to treat refractory angina. The test was performed after switching off the SCS and after 2 and 24 h stimulation at the default amplitude. The protocol was executed 2 months apart in order to assess the reproducibility of the results, collecting a total of 18 TWA reports. In all the three patients, we observed a significant reduction of TWA amplitude after 2 h stimulation. All the tests were classified as negative after 24 h stimulation with the nominal parameters. Conclusion Spinal cord stimulation results in a decrease in the TWA magnitude, and thus it seems to positively affect the arrhythmic substrate in a time-dependent manner.