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Myocardial contractility

How strongly cardiac muscle contracts for a given filling state.

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What it is

Myocardial contractility describes how strongly the heart muscle contracts for a given filling state.[1,2]

Why it matters

Contractility changes how much blood the ventricle ejects from the blood it has already received.[1]

Root causes of abnormal values

  • Squeeze relation: Stronger myocardial contraction ejects more blood from the same filling volume; weaker contraction leaves more blood behind and lowers stroke volume and cardiac output.[1,2]
    Stroke volumeCardiac output

What it affects

  • It links myocardial function, stroke volume, cardiac output, perfusion, and heart-failure context.[1]

Interpretation traps

  • Contractility cannot be judged from how strong a pulse feels without clinical context.[1]

Related conditions

Heart failure and pump reserve