Left atrial volume index and left atrial strain in the assessment of left atrial myopathy in heart failure with preserved ejection fraction

Abstract

Heart failure is a disease characterised by impaired heart function, leading to an increase in mortality. There are multiple heart failure subtypes based on the left ventricular ejection fraction, which is the fraction of blood pumped out of the left ventricle during systole. Patients with heart failure with a preserved ejection fraction (HFpEF) have an ejection fraction above 50%, which is normal. Patients with HFpEF often have a thicker left ventricle wall, making the left ventricle volume smaller. This impairs left ventricle filling and reduces the cardiac output. This causes heart failure symptoms, such as shortness of breath and fatigue.

In HFpEF, function of the left atrium is often impaired. This is called left atrial myopathy. With echocardiography, the extend of left atrial myopathy can be measured, using multiple parameters. These parameters can also be used to diagnose HFpEF. One of the parameters, left atrial size, is already used in diagnostic protocols for HFpEF. However, a new measure of left atrial myopathy, called left atrial strain, could also be used in the diagnosis of HFpEF. Left atrial strain, which is the amount of left atrial deformation, is lower in patients with HFpEF. Patients with decreased left atrial strain also have increased risk of death and heart failure hospitalization. In addition, diagnostic protocols for HFpEF would improve with addition of left atrial strain. Still, how to optimally include left atrial strain needs to be studied further.

A majority of HFpEF patients are women. Therefore, it is important to study if there are sex differences in left atrial size and strain. Men and women have similar left atrial sizes. However, there is evidence that left atrial volume is higher in women with HFpEF in the advanced stages of the disease. Left atrial strain, which naturally changes with age, is relatively similar in healthy men and women. However, in healthy women, the change in left atrial strain is more noticeable. It is not known if there are differences in left atrial strain in men and women with HFpEF. Currently, there is not enough evidence to advocate for different cutoff values for left atrial size and left atrial strain in the diagnosis of HFpEF.

Structural remodelling in the left atrium can cause atrial fibrillation in HFpEF patients. It is known that left atrial size and left atrial strain are worse in HFpEF patients with atrial fibrillation. However, it is not known if these parameters are different between men and women in HFpEF patients with atrial fibrillation.