ISSN:
1540-8183
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
Implantable cardioverter defibrillator (ICD) programming is usually based on results of supine electrophysiological (EP) testing. However, EP testing does not provide any information about tolerance to ICD therapy in the upright posture. We hypothesized that in addition to the arrhythmia duration and ventricular tachycardia (VT) cycle length, cerebral perfusion may play a role in determining tolerance to tiered ICD therapy. Transcranial Doppler (TCD) and cerebral venous oxygen saturation (rCVOS) are relatively new noninvasive techniques that may be used to assess dynamic changes in cerebral blood flow and metabolism during VT. Sixteen patients with pace-terminable VT and ICDs underwent supine (S) and upright tilt (HUT) ICD testing in conjunction with TCD and rCVOS monitoring. ICDs were programmed to deliver antitachycardia pacing, cardioversion, and defibrillation for VT, in the ascending order of aggressivity. Despite no significant differences in the induced VT cycle length (320 ± 100 msec, S, vs 330 ± 90 msec, HUT) and VT duration (14.6 ± 6.7 sec, S, vs 17 ± 9.2 sec, HUT), cerebral perfusion was more significantly impared during HUT (21 ± 10 [S] vs 29 ± 7% decrease from baseline [HUT], P 〈 0.001), and rCVOS decreased from baseline (5 ± 6 [S] vs 10 ± 6 [HUT] %, P 〈 0.001). Five of 16 patients experienced syncope during HUT and none during supine testing. At 1-year follow-up five patients who experienced syncope during HUT experienced at least one episode of syncope, whereas none not so identified did. We conclude that: (1) Supine ICD testing is insufficient to predict individual patient tolerance to ICD therapy; (2) HUT testing predicts tolerance to ICD therapy; and (3) noninvasive neuromonitoring techniques are useful for assessment of cerebral blood flow and metabolism during ICD testing.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1540-8183.1998.tb00120.x
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