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Abstract Right ventricular (RV) dysfunction is a major contributor to mortality in several cardiopulmonary diseases. However, the understanding of RV pathophysiology falls behind its left counterpart, limiting treatment options for conditions associated with discrete RV dysfunction and failure, such as pulmonary hypertension (PH). Accumulating evidence suggests that colchicine (COL) may have therapeutic benefits in multiple diseases, including PH. The mechanisms by which COL improves cardiovascular function are incompletely understood but may be associated with reductions in myocardial tissue viscoelasticity via microtubule depolymerization as demonstrated in prior ex vivo studies. The aim of this study is to investigate the impact of acute COL treatment on healthy and diseased RV organ function. Healthy and PH rats were anesthetized and catheterized for investigation of RV pressure-volume (PV) relationships before and after intramyocardial injections of COL. Marked RV failure was observed secondary to PH, characterized by elevated pulmonary vascular resistance (PVR), RV pressures, and end diastolic PV relation (EDPVR) with reduced RV compliance, preload and stroke volume. COL reversed pathological changes in parameters such as EDPVR, and improved RV preload, compliance, stroke volume and ejection fraction in PH rats. COL also reduced RV systolic pressure and heart rate in PH rats, which may be associated with broader effects of COL (improved PVR) in addition to myocardial viscoelastic reduction. In contrast, no significant effect on cardiopulmonary function was observed in healthy rats. These results highlight a potential contribution of RV viscoelasticity to ventricular dysfunction, implicating tissue viscoelasticity as a therapeutic target for RV failure patients.