Atrioventricular Coupling (AV-Coupling) refers to the functional coordination between atrial and ventricular systole and diastole in the heart. Currently, the primary method for evaluating AV-Coupling is through the left atrioventricular coupling index (LACI), measured using imaging techniques. A higher LACI indicates a greater mismatch between the volumes of left atrium and left ventricle at the end of ventricular diastole, reflecting a more significant impairment of left AV-Coupling. AV-Coupling plays a vital role in the pathophysiology and progression of cardiovascular diseases. Therefore, early and accurate assessment of AV-Coupling is essential for evaluating a patient’s condition, guiding clinical decisions, stratifying risk, and determining prognosis. This review aims to summarize the physiological mechanisms and evaluation methods of AV-Coupling, as well as its clinical significance in various cardiovascular diseases.

Right ventricular-pulmonary artery coupling (RV-PAC) serves as an indicator of the efficiency of energy transfer from the right ventricle to the pulmonary circulation. It plays a critical role in the diagnosis, clinical treatment, and prognosis of conditions such as pulmonary hypertension, heart valve disease, and heart failure. Various non-invasive evaluation methods have recently been proposed for assessing RV contractility and arterial afterload, based on the end-systolic elastance to arterial elastance ratio (Ees/Ea), which is derived from invasive pressure-volume loops. In this review, we summarize the fundamental concepts, physiological mechanisms, examination methods, influencing factors, and clinical significance of RV-PAC to provide a valuable reference for clinical practice.

The left ventricle (LV) and right ventricle (RV) are interdependent, as both structures are nestled within the pericardium, share a common septum, and are encircled by interconnected myocardial fibers. Interventricular interaction refers to the dynamic relationship between LV and RV, particularly how changes in one ventricle influence the geometry and function of the other. Imaging, particularly echocardiography, is vital for characterizing interventricular interactions by assessing geometric indices, septal motion, Doppler flow patterns, and changes in strain, remodeling, and diastolic filling associated with the loading conditions of the contralateral ventricle. In this review, we summarized the physiological and anatomical basis of ventricular interaction, echocardiographic imaging indices, and their clinical utilities and limitations. The goal is to systematically review the research advancements in echocardiographic assessment of LV-RV coupling and to provide guidance for clinical practice.

Left ventricular-arterial coupling (LVAC) represents a critical physiological mechanism that characterizes the interaction between left ventricular (LV) contractility and the arterial system's resistance and elasticity. The balance within LVAC is essential for efficient energy transfer from the heart, which underpins optimal cardiovascular function. In a healthy state, the balance between LV contractility and arterial elasticity and resistance allows the heart to maintain normal circulation with minimal energy expenditure. However, with the progression of age and diseases such as atherosclerosis and hypertension, arterial stiffness increases, LV function decreases, and the LVAC balance is disrupted, leading to a significantly increased risk of cardiovascular events. This imbalance is particularly significant in patients with heart failure (HF) and coronary artery disease (CAD), where LVAC imbalance is strongly associated with increased cardiac load and decreased energy efficiency. Thus, understanding and evaluating LVAC are crucial for elucidating cardiovascular physiology and guiding therapeutic strategies for diseases such as HF, hypertension, and CAD. Methods for assessing LVAC include invasive pressure-volume loops and cardiac catheterization, as well as non-invasive techniques such as echocardiography and arterial pulse wave analysis (PWA). Despite the higher accuracy of invasive methods, non-invasive methods are commonly used in clinical practice to assess LVAC because of their lower risk. With cardiac magnetic resonance imaging (CMR) and 3D/4D imaging techniques advancing, more precise structural and functional analysis of the heart and arterial system will be possible in the future. In this review, we describe the physiological mechanisms, assessment methods, influencing factors, and clinical significance of LVAC, as well as interdisciplinary studies with biomechanics and metabolism, which provide new ideas for personalized treatment of LVAC.

Right ventricular-pulmonary arterial coupling refers to the interaction and functional matching between the right ventricle and the pulmonary artery. When the coupling is disrupted, it can lead to a series of cardiovascular diseases, such as pulmonary hypertension, congenital heart disease, heart failure and so on. Therefore, it is important to evaluate cardiovascular structure and function. Cardiac magnetic resonance has the advantage of multi-parameter, multi-sequence, and high-resolution imaging, which can be used to comprehensively evaluate the cardiovascular system through cardiac magnetic resonance feature tracking technology, cardiac magnetic resonance cine imaging technology, T1 mapping, and T2 mapping imaging, and so on. This review summarizes the application and research progress of cardiac magnetic resonance technology in the assessment of the right ventricle and the pulmonary artery (RV-PA) coupling.