Syncope is predicted by neuromonitoring in patients with ICDs.

Decisions regarding ability of ICD patients to function in the work environment or at home are based primarily on subjective judgement. We have described noninvasive neuromonitoring techniques that are capable of characterizing cerebral blood flow 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 posture. 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 venous oxygen saturation (CVOS) determined noninvasively by applying a cutaneous patch with two infrared sensors from which a weighted venous percent oxygenated hemoglobin is continuously measured using INVOS 3100 (Somanetics). VT was induced via the implanted ICD and automatically terminated by ATP or cardioversion by the ICD, using the best treatment algorithm. HUT accentuated changes in cerebral blood flow and oxygen saturation and helped identify patients likely to experience syncope, whereas supine testing did not. These results suggest that HUT testing with noninvasive neuromonitoring is useful to predict ICD patients who are likely to remain conscious during VT.