Reference values for a novel ambulatory-based frequency domain T-wave alternans in subjects without structural heart disease.

Abstract Background Conventional frequency domain T wave alternans (FD-TWA) is a noninvasive risk stratification marker for identifying arrhythmic sudden cardiac death, but the conventional FD-TWA device that was considered the gold standard device has been discontinued commercially. Recently, a newly developed ambulatory electrocardiogram (AECG) device that can detect FD-TWA continuously for 24 h has become available in clinical settings. However, information on the normal values using the novel AECG-based frequency domain TWA (FD-TWA) is lacking. Methods FD-TWA for AECG was examined in 312 subjects without heart disease (Sb-wHD) (range 20–89 years, 146 men) and 30 heart disease patients (HD-P) (mean age 17 ± 17 years, 24 men). The maximum FD-TWA amplitude over 24 h was measured with manual editing. The upper limit of local noise levels for measurement of FD-TWA was set to both Results The reference values (95th percentiles) of FD-TWA in Sb-wHD were 19.9 μV for the acceptable noise level Conclusions In the present study, the reference values for a novel FD-TWA in Sb-wHD and the distribution of TWA values in HD-P were established. In future research, the cut-off values of FD-TWA in HD-P will need to be examined.