Myocardial mechanics
Introduction
Myocardial mechanics is the study of how the heart muscle contracts, deforms, and relaxes to pump blood effectively. It focuses on key parameters like strain and deformation, which provide detailed insights into the heart’s performance beyond traditional measures like ejection fraction. Techniques such as speckle tracking echocardiography (STE) allow precise assessment of global and regional heart function, making myocardial mechanics an essential tool for diagnosing, monitoring, and managing a range of cardiac conditions. This page explores the fundamental concepts, measurement techniques, and clinical applications of myocardial mechanics, highlighting its growing importance in modern cardiology.
What are myocardial mechanics?
Myocardial mechanics refer to the physical processes by which the heart muscle (myocardium) contracts, deforms, and relaxes to pump blood throughout the body. These mechanics are essential for maintaining efficient cardiac function and involve complex, coordinated movements of myocardial fibres during the cardiac cycle.
The heart’s muscular fibres are arranged in a helical pattern, enabling it to perform three key types of motion:
- Longitudinal Shortening: The muscle fibres shorten along the long axis of the heart, pulling the base of the heart closer to the apex during contraction.
- Radial Thickening: The myocardial walls thicken as the muscle fibres contract inwardly, ejecting blood from the ventricles.
- Torsion (Twisting Motion): The heart twists in opposite directions at the base and apex, storing and releasing mechanical energy for efficient contraction and relaxation.
These deformations are quantified using parameters such as strain (percentage change in length of myocardial fibres) and strain rate (rate of deformation over time). These metrics provide a detailed view of both global (overall heart function) and regional (specific segments of the heart) performance.
Understanding myocardial mechanics has become crucial in modern cardiology, as it allows clinicians to detect subtle changes in cardiac function that may not be apparent with traditional measures, such as ejection fraction. This is particularly valuable for early diagnosis and management of conditions like heart failure, cardiomyopathies, and ischaemic heart disease.
Use this section to create a graphic on different myocardial fibres – what they are and why they are important. ChatGPT gave a good example – use