What Affects Heart Contractility

An increase in sympathetic stimulation to the heart increases contractility and heart rate. An increase in contractility tends to increase stroke volume and thus a secondary increase in preload.

What factors affect contractility?

• Calcium concentration. Catecholamines and the autonomic nervous system. ATP availability (eg. ischaemia) Extracellular calcium.
• Temperature.

What controls the contractility of the heart?

Contractility is also determined by the prevailing conditions of pH, temperature, and redox state. Short-term control of contractility is fully expressed during exercise.