Last week in San Francisco, study results of Harbinger Medical’s Harbinger ICD Patient (HIP) trial showed Wedensky Modulation’s positive predictive value (PPV) of near-term lethal arrhythmia risk in heart attack patients implanted with an ICD, according to three abstracts presented at the 2008 Heart Rhythm Society (HRS) meeting.
Three abstracts, including an oral presentation by the study’s primary investigator, Peter Brady, MD, FRCP, from the Mayo Clinic in Rochester, Minn., showed that a Wedensky Modulation Index (WMI RT) predicted more than 80 percent of all life-threatening arrhythmic events that occurred in the study population (PPV = 0.825).
The HIP study culminated years of research into Wedensky Modulation, a spectral analysis of sub-threshold stimulation to alternating cardiac cycles, according Eden Prairie, Minn.-based Harbinger.
Harbinger said that Wedensky Modulation describes cardiac tissue response to sub-threshold stimulation. The Wedensky Modulation Indices (WMI) are derived from the spectral analysis of Wedensky Modulation by applying sub-threshold electrical stimulation to alternating cardiac cycles and comparing the stimulated and non-stimulated beats. Specific segments of the cardiac cycle may be analyzed. WMI R, WMI T and WMI RT are indices derived from the R-wave, T-wave and the combined R- and T-waves respectively.
The company said that the HIP study enrolled 329 MI patients with recently implanted ICDs, separated into two groups based on their WMIRT. The 161 patients in the WMI RT -High group (WMI RT > 0.5) were 64 percent more likely to experience a life-threatening arrhythmia compared to the 106 patients in the WMI RT -Low group (WMI RT ≤ 0.5).
The HIP study was stopped at 12 months upon reaching its primary end-point based on WMIR with 268 patients completing at least six months of follow-up, according to Brady. Each patient’s WMI R, WMI T, and WMI RT were measured using data from Harbinger Medical’s MI-1000 system.
“WMI may be used to help physicians identify patients who are at higher near-term risk for SCA [sudden cardiac arrest],” said Brady. “This information may also help reluctant high-risk patients understand the importance of considering ICD therapy.”