Shedding new light on the fascinating right heart

The only real voyage of discovery consists not in seeking new landscapes but in having new eyes. The glory of great men should always be measured by the means they have used to acquire it Since the discovery of the pulmonary circulation by the Arabian physician Ibn al-Nafis in 1242,1 the right side of the heart has been mainly considered the afterthought of left ventricular pathology, and its role in determining patients’ functional status and prognosis has been largely neglected for centuries. Several experimental studies performed in the mid of the 20th century transmitted the message that the right ventricle (RV) was mainly a conduit with minimal pumping capability.2–4 This perception of the limited functional role of the right heart in the circulatory system has found further support by the development of surgical interventions which excluded the right heart from the circulatory system to correct congenital heart diseases (e.g. the Fontan procedure),5 and by the belief that secondary tricuspid regurgitation (STR) was only an epiphenomenon of diseases affecting the left heart and should be ignored when surgically fixing the left-sided valves because it was supposed to resolve spontaneously.6 Along with the listed erroneous pathophysiological concepts, both the position of the right heart structures in the anterior mediastinum (just behind the sternum) and the complex geometry of the RV and the tricuspid valve, made the right heart structures difficult to be properly assessed by imaging techniques like M-mode, two-dimensional echocardiography, and angiography. The advent of newer cardiac imaging modalities, such as three-dimensional echocardiography (3DE), cardiac magnetic resonance (CMR), and cardiac computerized tomography (CT), able to provide the volumes of the right chambers independent of geometric assumptions and to assess the morphology and function of the tricuspid valve, has renovated the interest about the right heart by the cardiologists (Figure 1).7–10 In addition, both the understanding that STR is an independent determinant of patient morbidity11 and mortality and the development of transcatheter percutaneous procedures to repair the regurgitant tricuspid valve has further fuelled the interest of both clinicians and interventionists about the pathophysiology of right heart failure.12