Myocardial fibrosis is a crucial marker of adverse cardiac remodeling. Research suggests a strong correlationbetween the extent of myocardial fibrosis and adverse myocardial remodeling that occurs after ischemic injury orduring the progression of cardiomyopathies and heart failure. Diffuse myocardial fibrosis is thought to provide a high-risk substrate for the development of atrial and ventricular arrhythmias. Therefore, early detection of myocardialfibrosis might be prognostic for the development of heart failure and increased risk of both atrial and ventricular heartrhythm disorders. In addition, a means to easily assess the development of myocardial fibrosis is expected to providea more effective way to monitor therapeutic efficacy of interventions intended to slow or halt the progression of thesecardiac disorders. Although present methods can detect "frank" fibrosis, new methods that target the early stages offibrogenesis are expected to be extremely useful as they may be more effective in guiding interventions that blockfurther development of fibrosis and prevent the onset of myocardial remodeling associated with heart failure andarrhythmias.