Angiology
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Sympathetic skin response (SSR) and R-R interval variation (RRIV) are noninvasive electrophysiological tests used in the assessment of sympathetic and parasympathetic nervous system function, respectively. Cardiac syndrome X (CSX) is usually diagnosed in the presence of typical angina pectoris, a positive response to exercise testing, and normal-appearing coronary angiograms without spasm induced by hyperventilation or ergonovine. Alterations of autonomic nervous system control of cardiac function have been described in CSX. ⋯ A linear correlation was found between SSR amplitude and D%/R% (r = 0.336, p = 0.036). The authors conclude that, among patients with CSX, there are alterations of autonomic nervous control of skin as well as of other organs (ie, heart). SSR and RRIV testing can be done easily in the neurophysiology laboratory to assess the sympathetic and parasympathetic system, respectively.