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Adrenergic effects on force–frequency relationship: a pivotal role for the cardiac intrinsic systems

Aim:  The force–frequency relationship (F–FR) is an important intrinsic regulatory mechanism of cardiac contractility. The involvement of autonomic nervous system in this physiological aspect of cardiac control remains unclear. The aim of the study was to evaluate the role of extrinsic and intrinsic cardiac adrenergic innervations on the heart rate (HR)‐related positive inotropic response.