Vicor’s PD2i® Nonlinear Algorithm — A Revolutionary New Vital Sign

Vicor’s point correlation dimension (PD2i®) nonlinear algorithm is at the heart of Vicor Technologies’ PD2i Analyzer™, which is sometimes referred to as the PD2i CA™ (Cardiac Analyzer), and PD2i VS™.

Decoding The Interaction of Brain and Heart

James Skinner, PhD., Jerry Anchin, PhD.We know intuitively that the brain influences the heart. Vicor has taken this understanding a step further. Through years of research and experimentation, Vicor Technologies’ Chief Scientist Dr. James Skinner was able to determine that while cardiac arrest occurs in the heart, it is initiated by the brain. Dr. Skinner developed the PD2i® nonlinear algorithm, which examines a sequence of heartbeats to detect the subtle tell-tale patterns that reveal whether the brain’s interaction with the heart is healthy or is putting the patient at high risk of cardiac death.

Conventional diagnostics, which only evaluate the heart, are of limited use in predicting cardiac death. Further, current guidelines for implantable cardioverter defibrillators (ICDs) are inadequate and lead to implantations in many people who don’t need them. Studies show that, at present, 20 ICDs must be implanted to save a single life. Of even greater concern, nearly 80 percent of those who do die from cardiac death would not even qualify for implantation under current criteria. Clearly, a more accurately predictive diagnostic is greatly needed.

Vicor’s PD2i® test may be that diagnostic.

A case in point: Both patients below meet current implantation guidelines. But which one will die without an ICD?

EKGs ability to predict SCD is limited

The ECG for Patient 032 (above left) is normal according to current interpretations. Conversely, the ECG for Patient 160 (above right) is grossly abnormal by current interpretations. Relying on the above tracings, a physician might well recommend “watchful waiting” for Patient 032 and an ICD for Patient 160.

In contrast, the PD2i® test is able to correctly indicate Patient 032′s imminent cardiac death and Patient 160′s lack of risk:

PD2i correctly predicts sudden cardiac death

Further, the PD2i® would predict that Patient 032 was in need of an ICD, and Patient 160 required no intervention.

In summary, the PD2i® nonlinear algorithm, as shown by these examples, should reduce both false positives and false negatives, indications for who does and who does not need an ICD.

Unprecedented Predictive Potential

Published clinical trial data shows the PD2i® nonlinear algorithm is a highly accurate predictor of cardiac death, with a sensitivity approaching 100 percent and a specificity of approximately 86 percent. All that is required to conduct the analysis is an ECG of a thousand heartbeats (requiring less than 20 minutes). The PD2i® typically uses recordings made at rest and does not require stress-testing or any active participation from the patient. The PD2i® test is relatively impervious to data non-stationarities and artifacts, setting it apart from other measures, and its sensitivity is unparalleled. (This study has not been reviewed by the Food and Drug Administration.)

Current Implementations of the PD2i® Nonlinear Algorithm

Vicor received FDA 510 (k) marketing clearance for the PD2i Analyzer™, on December 29, 2008. The PD2i Analyzer™ measures heart rate variability (HRV) in patients at rest, and in response to paced respiration and controlled exercise, and is expected to be capable of identifying autonomic nervous system (ANS) dysfunction earlier than conventional means.

During 2010, Vicor Technologies expects to launch two additional diagnostics:  the PD2i CA™, which identifies cardiovascular disease patients at risk of cardiac death resulting from arrhythmia or pump failure, and the PD2i VS™, which facilitates triage of seriously injured combat and civilian trauma victims.

An Advance Over Conventional Diagnostics

Vicor’s PD2i®-based diagnostics offer several potential advantages over other measures.  They:

  • are more predictive than competing tests
  • are non-invasive
  • may be performed by a nurse or technician
  • are done at rest
  • use inexpensive, non-proprietary ECG electrodes
  • provide results in less than 20 minutes
  • are easy to use
  • yield a simple binary result
  • are compact and portable
  • are forgiving of data issues plaguing other diagnostics and are not derailed by irregular or ectopic beats
  • may be performed on patients taking beta-blockers

Learn More About Vicor’s PD2i® Technology

To learn more about Vicor’s PD2i® technology, call Vicor at 877.528.PD2i (7324), or refer to our Contact page.