Background: T-Wave Alternans (TWA) is a potential risk marker for selecting implantable cardioverter defibrillator (ICD) recipients. However, a large percentage of ICD candidates is ineligble for testing. We aimed to evaluate the risk of mortality and ventricular arrhythmia in patients ineligible for TWA testing.
Methods and Results: 269 Patients with ischemic or non-ischemic left ventricular dysfunction and who received an ICD between September 2007 and March 2010 were included in the analysis. TWA was assessed during treadmill testing and classified as non-negative or negative. TWA was technically not feasible in patients with atrial fibrillation (AF), pacemaker dependency or poor clinical state.
In 66 patients (24.5%), TWA testing was not possible. These patients were more frequently male (p=0.01), older (p<0.01), more frequent known with AF (p<0.001) and lower function class (p<0.001). Compared to non-negative and negative tested patients, both mortality (p=0.01) and appropriate shock therapy (p=0.01) was significantly higher in these ineligible patients.
Conclusions: TWA testing is not feasible in a large percentage of patients. These ineligible patients experience the highest risk for mortality.