Revealing Risk of Sudden Cardiac Death
Causing over half a million deaths yearly in the U.S. alone, sudden cardiac death is the country’s leading killer. Over twelve million Americans are believed to be at enough risk of sudden cardiac death to be candidates for an implantable cardioverter defibrillator (ICD), a small device which detects heart-rhythm disturbances and corrects them with electrical shocks.
Yet only a small fraction of those people will get that ICD. And even among those who do, over 70% of implanted ICDs will never have an appropriate firing. In other words, patients will have been exposed to the discomfort, risk and expense of surgery for nothing.
What's worse, almost 80% of those who do die of sudden cardiac death — who may well have been saved by an ICD — don’t even meet the criteria for implantation. In this large, unfortunate second group, death is their first and only symptom. 95% will have died by the time they reach the hospital.
Clearly, current methods do not offer adequate guidance for selecting ICD candidates. It’s no wonder many cardiologists believe that sudden cardiac death risk-stratification — the science of determining who would benefit from an ICD — is in disarray.
Simple, Inexpensive Risk-Stratification…with Unprecedented Accuracy
Vicor Technologies’ PD2i CA™ test is poised to solve the problem of inaccurate identification of those needing ICDs. In about fifteen minutes, the PD2i CA™ may be able to identify patients who are at high risk of sudden cardiac death within the following six to twelve month period. In fact, in clinical trials to date, the PD2i CA™ has had virtually no false negatives — in other words, of those whom the test said would live, no one died.
In addition, the PD2i® nonlinear algorithm demonstrated very high specificity of 83%, which would dramatically reduce over-implantation compared with other triage methods and result in immense savings in healthcare costs. And unlike competing diagnostics, the PD2i CA™ test is inexpensive, non-invasive, requires no active patient participation, is not derailed by irregular or ectopic heartbeats and can be performed on patients taking beta blockers commonly prescribed for coronary artery disease. (These studies have not been reviewed by the Food and Drug Administration).
The PD2i CA™ at Work
The charts below provide a typical example of the ability of the PD2i CA™ to detect risk of sudden cardiac death. While both patients presented at the E.R. with the identical complaint of chest pains, the disparity between their PD2i charts, taken upon admission, suggested that these patients would have very different prognoses. This would indeed be the case:
PD2i traces from two typical E.R. patients
upon admission for chest pains.
Patient A (above left) was safely discharged from the hospital after 24 hours, and did not die of sudden cardiac death during the year of follow-up. Patient B (above right) died in-hospital, suffering sudden cardiac death less than 24 hours after admission.
In the PD2i trace of the arrhythmic death patient (above right), note that a sustained low-dimension occurs (red underline) followed by a transient low-dimensional excursion (red arrow.) The PD2i patterns indicated by the red graphics show PD2i values of ≤1.4 and are typical of what constitutes an abnormal PD2i test, possibly indicating high risk of sudden cardiac death.
What The PD2i CA™ Test Is Measuring
Research by Vicor Technologies’ scientists established that sudden cardiac death is caused by abnormal neurological communication between the brain and heart.
There are multiple neurologic centers that normally work in semi-coordination to control the heart rhythm. By analyzing fifteen minutes of EKG data, the PD2i CA™ can detect if these centers are being overly-coordinated. Excessive coordination of these control systems, reflected by a reduced PD2i value, appears to show a clear indication that the patient is at imminent risk of sudden cardiac death.
(For more in-depth explanations of PD2i technology, please see our PD2i® nonlinear algorithm and Clinician pages, or read the underlying research.)
PD2i CA™ Clinical Trials
The PD2i CA™ test is currently being employed by the University of Rochester and the Catalan Institute of Cardiovascular Sciences in Barcelona to retrospectively analyze the dataset from the Muerte Subita en Insuficiencia Cardiaca (MUSIC) trial, which investigated sudden cardiac death among people in heart failure. (Of the 651 patients who participated in the MUSIC trial, 52 actually died from SCD.)
FDA 510(k) Clearance Expected in 2010
Vicor believes that the data obtained from analysis of the MUSIC trial results will be sufficient to support FDA 510(k) approval for sudden cardiac death in the first half of 2010, with marketing to commence shortly thereafter.
