Key result
Microvolt T-wave alternans testing is not widely applicable in typical heart failure patients, as 49% were ineligible and 46% of completed tests yielded indeterminate results.
Observational (n=1,003)
Microvolt T-wave alternans testing is not widely applicable in typical heart failure patients due to high rates of ineligibility and indeterminate results, limiting its utility for sudden death risk stratification.
MTWA testing should not yet guide sudden death risk stratification in HF; leaves open whether refined protocols improve applicability in future studies.
AIMS: Observational studies in selected populations have suggested that microvolt T-wave alternans (MTWA) testing may identify patients with heart failure (HF) at risk of sudden cardiac death. The aims of this study were to investigate the utility of MTWA testing in an unselected population of patients with HF and to evaluate the clinical characteristics associated with the MTWA results. METHODS AND RESULTS: A total of 1003 patients hospitalized with decompensated HF were enrolled. MTWA testing was planned 1 month post-discharge; 648 patients returned for MTWA testing. Mean age was 70.8 ± 10.6 years and 58% were male. Of these patients who returned, 318 (49%) were ineligible for MTWA testing due to atrial fibrillation (AF), pacemaker dependency, or physical inability to undertake the test. Of the MTWA tests, 100 (30%) were positive, 78 (24%) were negative, and 152 (46%) were indeterminate; 112/152 indeterminate tests (74%) occurred because of failure to achieve target heart rate (HR) due to chronotropic incompetence or physical limitations. There were differences in patient characteristics according to MTWA result. Independent predictors of a negative result included younger age and higher left ventricular ejection fraction (LVEF). Independent predictors of a positive result included higher HR during MTWA testing and lower LVEF. Independent predictors of an indeterminate result included older age and history of previous/paroxysmal AF. CONCLUSIONS: Only half of patients with HF are eligible for MTWA testing and the most common result is an indeterminate test. Patients with positive and indeterminate tests have different clinical characteristics. MTWA treadmill testing is not widely applicable in typical HF patients and is unlikely to refine risk stratification for sudden death on a population level.
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Jackson et al. (2012) conducted an observational in Heart failure (n=1,003). Microvolt T-wave alternans (MTWA) testing was evaluated on MTWA test result (positive, negative, or indeterminate). Microvolt T-wave alternans testing is not widely applicable in typical heart failure patients, as 49% were ineligible and 46% of completed tests yielded indeterminate results.
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