Clinical utility of the left atrial strain analysis

Abstract

Abstract The importance of left atrial (LA) function is recognized, especially when left ventricular function fails or atrial fibrillation occurs and heart failure (HF) develops. A compensatory mechanism of LA function unremittingly operates to maintain cardiac performance and prevent the occurrence of HF. LA function consists of three components: booster pump, reservoir, and conduit function. Echocardiography enables assessment of these components of LA function by LA volumetric changes in one cardiac cycle. Currently, LA strain has emerged as a valuable diagnostic and prognostic tool in patients with various cardiovascular diseases. An aging society is confronted with an issue of public health due to an increased number of patients with heart failure with preserved ejection fraction (HFpEF). Because effective medical and interventional approaches for patients with HFpEF are limited, early diagnosis and prevention are important to avoid a transition from preclinical HF stage to clinically overt HFpEF. Echocardiography with LA strain analysis and exercise stress echocardiography have the potential to identify patients with undiagnosed HFpEF, thus facilitating several preventive and therapeutic interventions. In this review, the development, measurement, and clinical application of LA strain are summarized and future perspectives in preventive medicine, accurate diagnosis, and therapeutic guidance for patients with HF are discussed. Graphical abstract Clinical application of LA strain. A. Mitral inflow patterns and LA strain curves in LVDD. A cutoff value of LA reservoir strain of 35% can differentiate patients with LVDD grade 0 from those with LVDD grades 1–3. Similarly, an LA strain of 24% distinguishes patients with LVDD grades 0–1 from those with LVDD grades 2–3, while an LA strain of 19% serves as a threshold to differentiate LVDD grades 0–2 from grade 3. The percentage values on the LA strain curves represent the LA reservoir strain values corresponding to the white-dotted line. B. LA reservoir strain can be used to estimate LV filling pressure. A cutoff value < 18% for reservoir strain can be used to estimate an elevated LV filling pressure > 12 mmHg. C. LA reservoir strain at rest can be used to diagnose HFpEF. This case was a 75-year-old woman with a history of repeated catheter ablation for AF evaluated for progressive symptoms of exertional dyspnea despite maintaining a sinus rhythm. She had a normal LV ejection fraction of 65% with an enlarged left atrium (LA volume index 57 mL/m 2 ) and reduced LA reservoir strain of 13% (left panel). Right heart catheterization showed mildly elevated pulmonary capillary wedge pressure at rest (a-wave, 18 mmHg; v-wave, 24 mm Hg). However, the pulmonary capillary wedge pressure increased during exercise (a-wave, 34 mmHg) with large v-waves (47 mmHg), suggesting severely reduced LA compliance (right panel). D. LA reservoir strain at rest can be used to predict future HF events in patients with preserved LV ejection fraction. Patients with a low LA reservoir strain value ≤ 21% experienced more HF events than those with a high LA strain value > 21%. LA, left atrial; HF, heart failure; LV, left ventricular; DD, diastolic dysfunction; HFpEF, heart failure with preserved ejection fraction.

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