Hypertrophic cardiomyopathy (HCM), the most common inherited cardiomyopathy, is both phenotypically and clinically diverse. Sudden cardiac death is a devastating and feared complication of this disease but remains difficult to predict because of the vast heterogeneity seen in disease expression. The need to better identify individuals at risk of fatal arrhythmic events has led to the quest for more powerful and sensitive markers of risk. Myocardial fibrosis is one such marker and believed to be an important substrate capable of promoting fatal arrhythmic events. Studies have shown that myocardial fibrosis can be progressive; however, the clinical significance of progressive disease and underlying causal mechanisms remain unclear. This thesis sought to examine the underlying mechanisms and prognostic significance of fibrosis progression in HCM patients and draws insights from a set of studies that use advanced cardiac magnetic resonance techniques to probe deeper into disease pathophysiology.