Syncope is predicted by neuromonitoring in patients with ICDs

Decisions regarding ability of ICD patients to function in the work environ ment or at home are based primarily on subjective judgement. We have descri bed noninvasive neuromonitoring techniques that are capable of characterizi ng cerebral bloodflow and cerebral oxygen saturation in conscious patients during ventricular tachycardia (VT). Upright tilt testing (HUT) was used to predict the hemodynamic response to VT in the upright and recumbent postur e. Sixteen patients (66 +/- 8 years) with pace-terminable VT and implanted ICD were tested during HUT with continuous measurement of arterial pressure , transcranial Doppler of the middle cerebral artery (TCD), and cerebral ve nous oxygen saturation (CVOS) determined noninvasively by applying a cutane ous patch with two infrared sensors from which a weighted venous percent ox ygenated hemoglobin is continuously measured using INVOS 3100 (Somanetics). VT was induced via the implanted ICD and automatically terminated by ATP o r cardioversion by the ICD, using the best treatment algorithm. HUT accentu ated changes in cerebral blood flow and oxygen saturation and helped identi fy patients likely to experience syncope, whereas supine testing did not. T hese results suggest that HUT testing with noninvasive neuromonitoring is u seful to predict ICD patients who are likely to remain conscious during VT.