A test to measure heartbeat fluctuations may improve the cost effectiveness of at least one type of heart therapy in patients at heightened risk for life-threatening cardiac events, Cambridge Heart has announced.

Results published recently in the online version of the Journal of the American College of Cardiology (JACC) evaluated the cost effectiveness of implantable cardioverter defibrillator (ICD) therapy for heart patients using the Microvolt T-Wave Alternans (MTWA) test -- a diagnostic tool that measures beat-to-beat changes in heart rhythm called "T-wave alternans."

Patients who test positive for T-wave alternans are at significantly greater risk for future cardiac events -- including sudden death -- than those who test negative, Cambridge Heart noted.

The study suggests that implanting ICDs in all at-risk patients yields a minimal benefit of an additional .24 quality-adjusted life years at a cost of $88,700 per year, the company said. By comparison, using the MTWA "risk stratification" strategy can help distinguish between patients who are likely to benefit from ICD therapy and those who are not, company sources explained.

Costs were evaluated from a societal perspective and included lost productivity and adverse events, Cambridge Heart said.