Human ventricular cardiac anatomy is extremely complex. Access to the ventricular chambers are often necessary for both mapping and treating ventricular arrhythmias. To date, electrophysiologists who perform these catheter ablations typically rely on fluoroscopy and the patient specific electroanatomical maps they generate so to begin to navigate through these complex functional anatomies. However, limited mapping resolutions do not provide often required insights relative to actual anatomical barriers. Hence, such discordances can lead to larger induced lesion sizes and ultimately, poorer patient outcomes. Here we describe both unique anatomic studies and the development of 3D computational models and assessment strategies for investigating human ventricular anatomies as they relate to arrhythmogenic mapping and therapies. A diverse range of fixed human anatomies were used to study and predict relative distances from an inter-chamber. placed balloon catheter to both true endocardial and epicardial surfaces. This work can be used to inform mapping and ablation catheter designs so to determine and optimize the placements of mapping electrodes to ensure both accurate electrical recording and applied ablations.