From the Guidelines
Normal left ventricular (LV) fractional shortening typically ranges from 25% to 45% in healthy adults. Fractional shortening is a measure of the heart's contractile function, calculated as the percentage change in the left ventricular internal diameter between diastole and systole. It is determined by the formula: [(LVIDd - LVIDs) / LVIDd] × 100, where LVIDd is the left ventricular internal diameter at end-diastole and LVIDs is the left ventricular internal diameter at end-systole. This measurement is commonly obtained during an echocardiogram and serves as a simple indicator of left ventricular systolic function.
Key Considerations
- Values below 25% may suggest impaired contractility and systolic dysfunction, while values above 45% might indicate hyperdynamic cardiac function.
- Fractional shortening has some limitations as it only measures contraction in one dimension and may not accurately reflect overall cardiac function in patients with regional wall motion abnormalities or geometric changes in the left ventricle.
- As noted in a study published in the European Heart Journal 1, defining normality in diagnostic imaging can be challenging, and the concept of "normal" can be influenced by various factors such as age, physiological variables, and risk factors.
Clinical Implications
- The measurement of LV fractional shortening is an important aspect of assessing cardiac function and can help identify patients with systolic dysfunction or other cardiac abnormalities.
- However, it is essential to consider the limitations of this measurement and interpret the results in the context of the individual patient's clinical presentation and other diagnostic findings.
- The study published in the European Heart Journal 1 highlights the importance of selecting diagnostic cut points with a sound statistical basis, which can help improve the accuracy of cardiac function assessments.
From the Research
Normal LV Fractional Shortening
- The normal range for left ventricular (LV) midwall fractional shortening (FSmw) has been suggested to be around 18.2±1.5% for males and 19.4±2.5% for females, although the differences between genders were not statistically significant 2.
- LV-FSmw was found to be unaffected by changes in age, with no significant correlation observed between LV-FSmw and age 2.
- In patients with chronic heart failure, LV fractional shortening was significantly increased after 6 months of treatment with a beta-blocker, in addition to an angiotensin-converting enzyme inhibitor (ACEI) 3.
- In hypertensive patients, LV fractional shortening was unchanged after 6 months of treatment with either a beta-blocker or an ACE inhibitor, despite significant reductions in left ventricular mass index 4.
Factors Affecting LV Fractional Shortening
- Reduction of left ventricular hypertrophy (LVH) has been associated with significant improvements in midwall fractional shortening, even in the presence of high blood pressure values 5.
- Changes in relative wall thickness, end-diastolic dimensions, and left ventricular mass index have been independently associated with changes in midwall fractional shortening 5.
- Beta-blocker therapy has been shown to improve left ventricular function, including fractional shortening, in patients with chronic heart failure 3 and acute coronary syndrome 6.