"The T-wave alternans test
is especially important, because it can identify who's at risk for sudden cardiac death," says Cleveland Clinic cardiologist Patrick Tchou, MD.
Microvolt T-wave alternans test done at baseline was abnormal in 66% of patients, and the two-year event rate was 15% and 2.5% in abnormal and normal groups, respectively (HR 6.5, 95% CI 2.4 to 18.1, p<0.001).
The T-wave alternans test emerges as a good predictor of ventricular malignant arrhythmias permitting the selection of low risk heart failure patients (independent of etiology: ischemic or idiopathic), who may not benefit of ICD implantation by standard criteria, due to high negative predictive values in most studies.
Consider the FDA's recent approval of a T-wave alternans test
. (25) This test can identify a substantial portion of individuals who should not be candidates for an ICD, though they meet current criteria.
About the Cambridge Heart Microvolt T-Wave Alternans Test
The Cambridge Heart Microvolt T-Wave Alternans Test measures extremely subtle beat-to-beat fluctuations in a person's heartbeat called T-wave alternans.
Taking the alternans test
is similar to getting the standard stress test except that a patient is hooked up to a few extra leads.
All but one had an abnormal T-wave alternans test. Among the entire study population, only one patient with an indeterminate or negative T-wave alternans test died.
Moreover, an abnormal T-wave alternans test was associated with a 7.4-fold increase in mortality, whereas a wide QRS carried only a 1.5-fold increased risk.
Of those, all but one had an abnormal T-wave alternans test. And among the entire study population, only one patient with an indeterminate or negative T-wave alternans test died.
Therefore, all eyes are now on two large, more definitive ongoing prospective randomized interventional ICD trials that incorporate the only Food and Drug Administration-approved T-wave alternans test, developed by Cambridge Heart Inc.
Interpretation and classification of microvolt T-wave alternans tests
. J Cardiovasc Electrophysiol 13(5):502-512.