Reply to the editorial comment from Van der Wall concerning ‘The right ventricle: always normal in normal subjects?’

Right ventricular (RV) structure and function serve as important indicators of a wide spectrum of heart diseases such as congenital heart disease, pulmonary hypertension, hypertro-phic cardiomyopathy and arrhythmogenic right ventricular cardiomyopathy/disease (ARVC/D) [1–3]. Over the past years cardiac magnetic resonance imaging (CMR) has proven itself as the preferred imaging modality of choice to evaluate RV anatomy, structure, texture, motion and function [4–9]. In the study by Quick et al. [10], published in the current issue of the Netherlands Heart Journal, a quantitative analysis of normal variations in RV wall motion was evaluated in healthy subjects using CMR. The study population consisted of 65 consecutive patients referred for the evaluation of cardiac function by 3 Tesla-CMR. All subjects were shown to be free of heart disease based on the currently available guidelines for CMR. Balanced steady-state free-precession images were obtained and regional RV wall motion was evaluated and classified based on a standardised segmental model for the right ventri-cle. In 59 out of 65 subjects (>90 %) wall motion abnormalities of the right ventricle were observed. Wall motion abnormalities were predominantly seen in the apico-lateral segments (72 %) when compared with the medio-lateral (24 %) and infero-lateral segments (4 %). Dyskinesia was the most frequent wall motion disorder (62 %), followed by hypokinesia (21 %) and bulging (17 %). The authors concluded that RV wall motion abnormalities are common in subjects supposed to be normal, indicating that one should be aware of the notion that non-pathological wall motion disorders can easily be mistaken for a pathological regional wall motion abnormality, particularly in patients with ARVC where – according to the authors-to date, clear wall motion criteria are lacking. The study is certainly very interesting in the sense that the right ventricle in normal subjects does not always appear normal when visualised by CMR. Especially, regional wall motion abnormalities are predominantly seen in the apico-lateral segments. However, the study warrants the following three comments. First, also acknowledged by the authors, the study was based on a small patient population. As a result, the description of normal variations in RV morphology as observed by CMR are not necessarily absolute and should only be regarded as hypothesis-generating for studying larger patient samples. Second, according to the authors, there is supposedly no in-depth knowledge on RV motion in healthy subjects. This is an obvious understatement as already in 2004 Pennell's group (London, UK) showed that …