In the field of cardiovascular imaging, there have recently been a large number of reports concerning the usefulness of strain analysis for evaluating left atrial function and right ventricular function in addition to left ventricular function. The MESA trial includes a comparison of left atrial function between patients with heart failure and patients without heart failure as assessed using the Vitrea WMT software. The measured indices of left atrial function are shown in Figure 9. It has been reported that a reduction in global peak longitudinal atrial strain may be an independent contributory factor for heart failure, in addition to an increase in left atrial volume, which was identified as a contributory factor in previous studies.11
How is left atrial function related to heart failure? One report has described a possible pathophysiological mechanism. The relationship between the degree of left ventricular fibrosis and left atrial function, including left atrial strain, was investigated using T1 mapping / LGE.12
This report concluded that the Vitrea WMT software is useful for analyzing left atrial function and for visualizing anatomical structures, and a clear relationship was observed between the progression of left ventricular fibrosis and the deterioration of left atrial function.
Left atrial strain analysis is also useful in patients with arrhythmias such as atrial fibrillation. Inoue et al. described the relationship between cerebral infarction and left atrial function as assessed by strain analysis using CMR/WMT (Vitrea) in patients with atrial fibrillation.13
One of the most important findings of their study is that an increase in left atrial volume and a reduction in left atrial strain are associated with a higher risk of cerebral infarction, in addition to the CHA2DS2-VASc score, which has been widely employed to assess the risk of cerebral infarction in routine clinical practice.
A number of studies on right ventricular analysis are also currently ongoing. Various indices of right ventricular function, such as RVEF, RVEDV, RVESV, RVSV, and RVM, which are difficult to evaluate using echocardiography due to the structural characteristics of the right ventricle, can be accurately determined using CMR.