Thermal effects on cardiac alternans onset and development: A spatiotemporal correlation analysis

Alternans of cardiac action potential duration represent critical precursors for the development of lifethreateningarrhythmias and sudden cardiac death. The system’s thermal state affects these electrical disordersrequiring additional theoretical and experimental efforts to improve a patient-specific clinical understanding.In such a scenario, we generalize a recent work from Loppini et al. [Phys. Rev. E 100, 020201(R) (2019)]by performing an extended spatiotemporal correlation study. We consider high-resolution optical mappingrecordings of canine ventricular wedges’ electrical activity at different temperatures and pacing frequencies.We aim to recommend the extracted characteristic length as a potential predictive index of cardiac alternansonset and evolution within a wide range of system states. In particular, we show that a reduction of temperatureresults in a drop of the characteristic length, confirming the impact of thermal instabilities on cardiac dynamics.Moreover, we theoretically investigate the use of such an index to identify and predict different alternans regimes.Finally, we propose a constitutive phenomenological law linking conduction velocity, characteristic length, andtemperature in view of future numerical investigations.