The assessment of pulmonary artery pressure (PAP) and parameters describing right ventricular function stand in the focus of the diagnosis and clinical management of pulmonary hypertension (PH). Right heart catheterization (RHC) is the gold standard method to measure PAP and to provide hemodynamic information on right ventricular function. However, due to its invasive nature, RHC is not optimal for screening and for close monitoring of the disease. Therefore, the development of non-invasive methods providing reliable PAP measurements and right ventricular functional parameters would be of major benefit.

Today, the most often used comprehensive non-invasive method for these purposes is echocardiography. However, the method has limitations; in many cases PAP is significantly under- or overestimated - especially in subjects with co-existing pulmonary diseases. Regarding right ventricular function, although novel echocardiography parameters appear to be promising, they have not yet been evaluated in all forms of PH.

Another emerging non-invasive method is cardiac magnetic resonance imaging (MRI). MRI is considered to be as gold standard for the non-invasive assessment of right ventricular function. In addition, our group showed that with a special approach ("vortex method"), MRI enables the determination of PAP with physiologic accuracy, but the method has not yet been validated systematically in different forms of PH.

All patients undergoing right heart catheterization in our clinic are candidates for the study. Excluded will be patients not eligible for MRI or declining to take part in the study. MRI and Echocardiography will be performed within two weeks of the RHC.

Hypothesis:

1. MRI is superior to echocardiography to non-invasively determine mean PAP in a broad collective of patients with PH of diverse ethology.
2. MRI derived right ventricular functional parameters correlate better to invasive measurements and to established prognostic parameters than echocardiography derived right ventricular functional parameters.
3. Novel right ventricular tissue Doppler parameters add substantially to "classical" echocardiography parameters to describe right ventricular function.

Inclusion Criteria: patients undergoing right heart catheterization due to clinical reasons -

Exclusion Criteria: patients not eligible for MRI, patients not agreeing with investigation

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Patients undergoing right heart catheterization due to clinical reasons