Does manual T-wave window adjustment affect microvolt T-wave alternans results in patients with structural heart disease?

•Spectral MTWA methodology can miss part of the T-wave window.•We evaluated T-wave window adjustment in patients with structural heart disease.•After manual review, 43% of patients required T-wave window adjustment.•Window adjustment changed the clinical MTWA result in 1.8% of the patients.•MTWA analysis without manual T-wave window adjustment remains an effective tool.