Diastolic myofilament dysfunction in the failing human heart

Area of Science:

• Cardiology
• Molecular Biology
• Biochemistry

Background:

• Heart failure (HF) is increasingly recognized as involving impaired cardiac relaxation, not solely reduced contractility.
• Diastolic dysfunction is the primary deficit in over half of HF patients, characterized by preserved ejection fraction but elevated left ventricular end-diastolic pressure.
• Cellular changes in Ca(2+)-handling proteins, extracellular matrix, and myofilaments contribute to impaired myocardial relaxation.

Purpose of the Study:

• To review myofilament functional deficits in human heart failure.
• To identify underlying protein alterations responsible for impaired myofilament function.
• To discuss the impact of myofilament dysfunction on in vivo diastolic dysfunction, considering calcium handling.

Main Methods:

• Literature review of studies on human heart failure.
• Analysis of cellular and molecular changes in cardiac myofilaments.
• Integration of findings on Ca(2+) handling and diastolic function.

Main Results:

• Significant deficits in myofilament function are observed in human heart failure.
• Specific protein changes are implicated as causal factors in impaired myofilament relaxation.
• Altered myofilament properties contribute significantly to diastolic dysfunction in heart failure.

Conclusions:

• Myofilament dysfunction and associated protein alterations are key contributors to diastolic heart failure.
• Understanding these molecular changes is crucial for developing targeted therapies for diastolic dysfunction.
• Impaired myofilament relaxation plays a critical role in the pathophysiology of heart failure with preserved ejection fraction.