Abstract 181: Possible Favorable Marker of Positive Head-up Tilt and Negative T-Wave Alternans During Test in Patients with Suspected High-Risk Reflex Syncope
T-wave alternans (TWA) is the noninvasive index for predicting lethal arrhythmias and sudden cardiac death. Since the syncope is the important warning sign for sudden cardiac, the measures of TWA in high risk patients with syncope give us useful information in the clinical settings. Thus, we measured TWA during head-up tilt testing (HUT) by ambulatory ECG monitoring (AECG) in either exercise-induced syncope (EX-Group) or HUT-induced prolonged asystole (asystole>30 sec) previously named “malignant vasovagal syncope” (MLVVS-Group). Both of them have been considered as high risk patients. Among consecutive 302 syncope patients who underwent HUT and measured TWA during test, followings were selected as study populations: 12 patients belong to EX-Group (22±5 years); 6 patients to MLVVS-Group (22±11 years) and another age and sex matched 18 patients with suspected reflex syncope who underwent HUT with positive results (C-Group; 22±8 years, as control). Patients in C-Group have similar clinical characteristics to EX-Group or MLVVS-Group. None of these three groups had structural heart disease. Patients in C-Group have similar clinical characteristics to either EX-Group or MLVVS-Group. Although maximum T-wave alternans μV obtained by AECG in MLVVS-Group and EX-Group tended to be larger than that of C-Group (28±13, 24±5 vs. 21±7 μV), their differences were not significant. In addition, none of them showed reported abnormal TWA value of >75 μV. Long-term follow-up period for mean of 15 years (15.5±1.6 years) revealed that no lethal events occurred in any groups including EX-Group and LVVS-Group.
Conclusions: Even if considerable high risk factors exit in the syncope patients, the favorable outcome would be expected if they present symptoms of reflex features with positive HUT results accompanying negative TWA (< 75 μV).
Author Disclosures: B. Takase: None.
- © 2014 by American Heart Association, Inc.