Method and system for evaluating stability of cardic propagation reserve

Unmet Need

About 325,000 people in the United States die from sudden cardiac death (SCD) caused by ventricular tachyarrhythmias (VT) each year. When a patient experiences VT, the lower chamber of their heart beats faster than normal causing chest pain, dizziness, shortness of breath, and heart palpitations. This may lead to ventricular fibrillation, a condition in which the heart does not contract properly, so blood is not pumped effectively to the brain and body. Though VT often leads to SCD, there are no reliable and effective methods to identify individuals at risk for developing these arrhythmias. Current methods and risk stratification strategies are unclear, and most victims are not identified as high risk before experiencing SCD. There is a need for a novel risk assessment that more accurately and reliably identifies individuals at high risk for SCD.

Technology

Duke inventors have developed a novel risk assessment method to assess patients’ susceptibility to ventricular arrhythmias before cardiac disease can be detected using current clinical diagnostic tools. Specifically, the invention is a novel method to evaluate the stability-of-propagation reserve (SoPR) using a refraction-diffusion model, which measures the susceptibility to propagation instabilities and arrhythmias. This model utilizes two metrics: the reserve of refractoriness (RoR), the difference between the minimum level of medium refractoriness and the critical threshold for the stable solitary pulse, and the reserve of memory (RoM), the short-term cardiac memory. These metrics are combined to determine the SoPR and predict the likelihood of conduction block, more accurately capturing patients at risk. The feasibility of data collection in patients has been demonstrated for surface ECG measurements and for electrophysiological studies in the clinic.

Applications

• Large-scale population screenings in medical settings of all sizes
• Monitoring at-risk patient populations including those with Holter devices and implanted cardioverter defibrillators
• Assessing the impact of various treatments including ICD therapy, surgical procedures, and drug therapy on arrhythmia susceptibility

Advantages

• Captures a wider range of proarrhythmic states to more accurately identify patients at risk
• No specialized equipment required as it uses current commercial ECG exercise testing equipment
• Noninvasive medical assessment compared to the current standard catheterization procedure
• Patient remains comfortable and unstressed during the assessment