[Myocardial viability and contractile reserve with echocardiography]. / Viabilidad miocárdica y reserva contráctil con ecocardiografía.

The recovery of the mechanical function of the myocardium is the best parameter of viability. Therefore, it is necessary that tissue perfusion and metabolic interchange at myocardiac fiber level be sufficient in both amount and quality, and also that the channels by which the nutrients arrive (microcirculation) are adequate, and the substratum (myocardium), still has the response capacity, meaning that it has its contractile reserve.