Good evening.

If i understood you correctly, check Windkessel Model (the systolic and diastolic phases of the cardiac cycle).

Best.

There is only mechanical model which exactly describes blood transfer propagation and circulation. Any other way of recording "electrical alterations" of any parameters such as potentials, conductivity, impedance are "secondary" derivations of electrolytes distribution in flow. E.g., ECG and photoplethysmography demonstrate exactly the same function which can be the the result of "math transformations" (differentiation / integration) of blood pressure.

In my opinion, if the cardiomyocyte dipole is to be interpolated to the "total heart's dipole", then the cell's action potential can be provisionally represented as an electrical model of mechanical cardiac contraction.The action potential in typical cardiomyocytes is composed of 5 phases (0-4), beginning and ending with phase 4. This model includes 3 electrophysiological phases (4, 0, 1 and terminal part of 3 phase) during diastole:

Phase 4: The resting phase

• The resting potential in a cardiomyocyte is −90 mV due to a constant outward leak of K+ through inward rectifier channels.
• Na+ and Ca2+ channels are closed at resting TMP.

Phase 0: Depolarization

• An action potential triggered in a neighbouring cardiomyocyte or pacemaker cell causes the TMP to rise above −90 mV.
• Fast Na+ channels start to open one by one and Na+ leaks into the cell, further raising the TMP.
• TMP approaches −70mV, the threshold potential in cardiomyocytes, i.e. the point at which enough fast Na+ channels have opened to generate a self-sustaining inward Na+ current.
• The large Na+ current rapidly depolarizes the TMP to 0 mV and slightly above 0 mV for a transient period of time called the overshoot; fast Na+ channels close (recall that fast Na+ channels are time-dependent).
• L-type (“long-opening”) Ca2+ channels open when the TMP is greater than −40 mV and cause a small but steady influx of Ca2+ down its concentration gradient.

Phase 1: Early repolarization

• TMP is now slightly positive.
• Some K+ channels open briefly and an outward flow of K+ returns the TMP to approximately 0 mV.

And the final part of the third phase when TMP back towards resting potential of −90 mV to prepare the cell for a new cycle of depolarization. Cells in this phase are particularly susceptible to arrhythmias when exposed to an inappropriately timed stimulus, which is why one must synchronize the electrical stimulus during cardioversion to prevent inducing ventricular fibrillation.

see also

4. Фазовая структура сердечного цикла at: http://docplayer.ru/55108439-4-fazovaya-struktura-serdechnogo-cikla.html

When we finally will be able to understand that electrical records are not related to any physiological processes (neuronal or muscle) activity then cardiology and physiology will actually able to build a right and practically useful model of either process or function.

Dear Dr. Vaikhanskaya.

I think Mr. Hyal mentioned PV loops, not electromechanical model of cardiac cell, or cell to system.

Best.