INTRODUCTION
Right ventricular (RV) dysfunction was established to be an important
outcome predictor in both arterial pulmonary hypertension (PH) [1]
and left heart disease [2]. Beyond RV systolic performance, the
mechanical efficiency of the ventriculo-vascular interplay also has
prognostic implications [3-4]. The right ventricular-pulmonary
artery coupling (RVPAC) reflects the interaction between the right heart
and the pulmonary circulation unit, which is optimal when all the
mechanical energy of the RV is transferred to the vascular bed [5],
providing an adequate cardiac output with minimal energy consumption
[6].
RVPAC is defined as the ratio between end-systolic RV elastance (EES)
and pulmonary arterial elastance (Ea), which is calculated using
pressure-volume loops derived from right heart catheterization (RHC).
Due to its technical complexity, the assessment of RVPAC is not
routinely performed. However, non-invasive estimation of RVPAC can be
done using cardiac magnetic resonance (CMR) [7] or transthoracic
echocardiography [8], and non-invasive parameters showed good
correlation with catheterisation-derived measurements [7-10].
Three-dimensional (3D) echocardiography overcomes the pitfalls of
conventional RV functional assessment [11] and has been validated
against CMR [12]. A 3D echocardiographic estimation of RVPAC has
been proposed, as the ratio between RV stroke volume (SV) and RV
end-systolic volume (ESV), which was found to have good correlation with
catheterisation-derived RVPAC [13].
We hypothesized that right ventriculo-vascular decoupling plays a role
in the occurrence of heart failure (HF) symptoms in patients with
dilated cardiomyopathy (DCM). Consequently, our aim was to evaluate the
RVPAC using 3D echocardiography in patients with DCM and to assess its
relationship with the severity of HF symptoms in this setting.