• Cardiomyopathy dilated
• endomyocardial fibrosis
• heart failure
• heart failure with normal ejection fraction
• systolic heart failure

Hypertrophic cardiomyopathy (HCM) is the most common genetic heart disease, occurring in one in 500 of the general population. It is caused by different mutations of genes encoding proteins of the sarcomere, and increased mortality due to sudden cardiac death and high transition to symptomatic heart failure are the key clinical characteristics of these patients. Early research started in the late 1950s, and diagnosis of patients was based mostly on physical findings and ECG.1 Diagnosis is now usually established by echocardiography and genetic testing2 for the causative sarcomeric mutations. Cardiac MRI provides additional information, especially with regard to late gadolinium enhancement, and is therefore used increasingly. Late gadolinium enhancement represents a myocardial scar with fibrotic areas formed by an accumulation of cardiac collagen. These fibrotic areas seem to be important for outcome in HCM,3 but also in different cardiac diseases triggering sudden cardiac death most probably due to arrhythmias. Coupled with this, others have shown in patients with hypertrophic obstructive cardiomyopathy that the degree of fibrosis correlates with hypertrophy as well as diastolic dysfunction,4 known to be important for the symptomatology of patients with heart failure in general. Unfortunately, our understanding of why fibrosis occurs in these hypertrophied hearts is still limited.

The paper by Kuusisto et al5 increases our knowledge about the pathophysiology of profibrotic processes in HCM (see …