Abstracts

Rationale: Myoclonic status epilepticus has classically been associated with poor neurological outcome and in-hospital mortality after cardiac arrest CA(1). In this study, we have assessed the clinical value of observed myoclonus and correlated those outcomes with EEG findings. Methods: The EEGs of 34 patients who had cardiac arrest and developed clinical myoclonus were reviewed by three clinical neurophysiologists and ranked according to terminology of the American Clinical Neurophysiology Association (ACNS) as highly malignant (suppression, suppression with periodic discharges, burst-suppression) Figure 1, malignant (periodic or rhythmic patterns, pathological or nonreactive background), or benign EEG (absence of malignant features) (1). The outcome measure was determined using Glasgow Outcome Scale (GOS) on discharge from the hospital and the clinical exam. Results: Out of the 34 individuals reviewed, 3 patients had good outcomes and achieved a GOS of 3-4 while 31 patients had poor outcomes with a GOS of only 1-2. 24 patients developed early myoclonus within 4 hours of CA and 16 patients developed late myoclonus after 4 hours of CA. Some patients progressed continuously from early to late myoclonus. 24 patients had EEGs which were started at an average of 35 hours (2-130) after CA. 10 of these patients had highly malignant EEG patterns, 9 of them died, and one had a GOS of 3 upon discharge. 12 patients had malignant EEG patterns, 2 of which had good outcome. 1 patient had benign EEG pattern and had good outcome. Mean patients age was 61.2 years (within a range of 18-86 years) and average resuscitation time was 16.94 minutes (within a range of 0-60). 19 patients were males and 15 were females. 29 patients received therapeutic hypothermia. 28 patients had non-shockable rhythm while 3 patients had shockable rhythm and 3 had unknown rhythm. Three patients had good outcome (Table 1). Conclusions: The presence of clinical myoclonus is highly predictive of poor outcome after cardiopulmonary arrest in the presence of highly malignant EEG. However, in the three patients with good outcome, EEG showed malignant pattern in only two of the three patients which might indicate that early or late myoclonus by itself might not be enough to have a poor outcome but needs EEG correlation in addition. EEG is a good prognostic tool in patients with post-anoxic clinical myoclonus. Post cardiopulmonary arrest clinical myoclonus needs to be taken in the context of EEG patterns to develop a more accurate prognostic prediction. Funding: No support was received