Extended head up tilt table test (HUTT) in unexplained recurrent loss of consciousness; a single centre prospective study.

Objectives: Recurrent loss of consciousness (rLOC) carries significant risk of injuries because of falls. On history and examination about 60% of them can be diagnosed as syncope. However history may be misleading because symptoms like head turning and jerky movement during LOC which are considered to support seizure could be associated with neurocardiogenic syncope (NCS). Material and methods: 83 patients of rLOC without triggering factors were prospectively recruited from March 2010 to December 2014 for HUTT and using Italian protocol of HUTT. Results: 63% of the patients with unexplained rLOC were positive on HUTT (pHUTT). Out of 15 patients with previous diagnosis of epilepsy 9(60%) turned out to have pHUTT. Tonic posturing was seen in 10 (12%) patients. The positive predictive value (PPV) of motor phenomenon for diagnosing seizure during rLOC was 40%.POTS was more common with younger age (? 30 years) group patients and these patients having more chance to develop NCS (p value 0.04). Severe hemodynamic compromised and LOC were significantly associated with SFS (slow flat slow) EEG pattern. Conclusion: During LOC various types of motor phenomenon were seen including tonic posturing in 12% of patients on HUTT. Patients with POTS did not show any EEG changes during tachycardia. 9.6% of the patients with unexplained rLOC have asystole of more than 3 seconds. All patients with syncope do not show ictal EEG changes and all patients with presyncope do not have normal ictal EEG.