Feasibility of non-invasive determination of the stability of propagation reserve in patients

This study investigates the feasibility of using surface ECG recordings to assess stability of cardiac propagation. Our novel method customizes a reaction-diffusion model of cardiac excitation using measurements of patient's repolarization dynamics. The customized model determines the stability-of-propagation reserve (SoPR) that measures the proximity of the patient's minimum level of refractoriness to the critical level associated with conduction instability. Using measurements from 15 patients, we compared SoPRs determined from the unipolar intracardiac electrograms and from the surface ECG leads. SoPRs computed from intracardiac and surface measurements correlated, and a formula was developed that estimated the intracardiac SoPR from surface measurements with 5% accuracy. Thus, this study may lead to new noninvasive tests for the risk of sudden cardiac death.