Which diagnostic study is most appropriate for establishing a diagnosis in a patient experiencing acute episodes of rapid heart beating that can be relieved with Valsalva?

The most appropriate diagnostic study for a patient experiencing acute episodes of rapid heart beating that can be relieved with the Valsalva maneuver is an electrophysiology study. This test is specifically designed to assess the electrical activity of the heart and identify abnormal pathways that may be causing arrhythmias. Given that the Valsalva maneuver is often used to terminate certain types of fast heart rhythms, an electrophysiology study can help simulate these conditions while monitoring the heart's electrical function, providing crucial information for diagnosis and treatment planning.

The other options are less suitable for this specific clinical scenario. Cardiac catheterization is more focused on evaluating coronary artery disease and may not provide direct insight into the mechanisms of arrhythmias. Cardiac MRI is primarily used for assessing structural heart disease, myocardial viability, and some specific cardiomyopathies, rather than diagnosing arrhythmias. A chest CT scan is generally utilized for assessing lung pathology or evaluating vascular structures and does not focus on cardiac electrical activity or arrhythmias.