A fractional-order approach to cardiac rhythm analysis

Abstract

• Our model provides further insights into the electrical activity of the heart. • Changes in fractional parameters allow comparison of electrocardiogram recordings. • Changes in delay times allow comparison of electrocardiogram recordings. • We analyzed signals from healthy, hypertensive and spider-fearful subjects. In this research, fractional dynamics has been incorporated into a nonlinear model of three coupled oscillators to capture cardiac behavior more closely. We observe that in the case of the rhythms associated with a normal heart, the fractional orders are close to 1. For the spider-fearful individuals, fractional dynamics were incorporated into each oscillator. It might be due to that fear is a motivational state induced by specific stimuli which give rise to escape or defensive behavior. Meanwhile, in the cardiac rhythms associated with hypertensive participants, only the first oscillator, sinoatrial node, has fractional dynamic. This may have physiological relevance if we consider that hypertension is, first at all a risk factor for cardiovascular diseases. Second at all, hyperkinetic circulation is orchestrated by the sinoatrial node, in interaction with the autonomic nervous system, which leads to cardiac muscle hypertrophy. Our results show that electrocardiogram (ECG waveforms) can be simulated when various physiological conditions occur in the human heart, which is why the proposed model may find applications in clinical practice.