Exercise echocardiography

Abstract

Many tests have been proposed in combination with echocardiography, but only a few have a role in clinical practice. For the diagnosis of organic coronary artery disease, exercise remains the paradigm of all stress tests and the first which was combined with stress echocardiography. In the early 1970s, M-mode recordings of the left ventricle were used in normal subjects [1] and in patients with coronary artery disease [2]. Subsequently, two-dimensional (2D) echocardiography was used to document ischemic regional wall motion abnormality during exercise [3]. The technique was at that time so challenging [4] that with the introduction of dipyridamole [5] and dobutamine [6] as pharmacological stressors, many laboratories used pharmacological stress even in patients who were able to exercise. Large-scale, multicenter, effectiveness studies providing outcome data are available only with pharmacological [7, 8] not with exercise echocardiography, offering a more robust evidence-based platform for their use in clinical practice. Exercise echocardiography was only really applied as a clinical tool in the early 1990s [4], and it is now increasingly used for the diagnosis of coronary artery disease, the functional assessment of intermediate stenosis, and risk stratification. A series of successive improvements led to a progressively widespread acceptance: digital echocardiographic techniques, allowing capture and synchronized display of the same view at different stages [9], improved endocardial border detection by harmonic imaging [10], and ultrasound contrast agents that opacify the left ventricle [11]. In the USA, most laboratories use the post-treadmill approach with imaging at rest and as soon as possible during the recovery period [12, 13]. In Europe, a number of centers have implemented their stress echocardiography laboratory with a dedicated bed or table allowing bicycle exercise in a semisupine position and real-time continuous imaging throughout exercise [14, 15]. The diffusion of semisupine exercise imaging — much more user-friendly for the sonographer than the treadmill test — made image acquisition easier and interpretation faster [16 — 18]. Semisupine exercise gained its well-deserved role in the stress echocardiography laboratory for coronary artery disease diagnosis and, with growing frequency outside coronary artery disease, in the assessment of pulmonary hypertension, valve disease, cardiomyopathy, and heart failure [19, 20].