Myocarditis in hypertrophic cardiomyopathy

We read with considerable interest the paper by Frustaci et al. We only wish to point out to the readership that these authors have reported a group of patients with hypertrophic cardiomyopathy (HCM) who differ distinctly in clinical profile from all other cohorts of patients with this disease reported anywhere in the world, including Italy—a country with an intense interest in HCM over many years. We refer specifically to the fact that Frustaci et al. have described 119 patients they regard as having HCM in whom fully 35% required emergency admission to the hospital for acute and profound heart failure (average age, 39; due to myocarditis in two-thirds of the cases based on endomyocardial biopsies), and also 20% who experienced sustained episodes of ventricular tachycardia. Both these disease expressions, so common in the experience of Frustaci et al., are in fact so rare within the broad HCM disease spectrum as to be virtually unheard of by most investigators.1,2 Also, the occurrence of the end-stage of HCM at 20% is fully 10 times greater than that reported by other investigators.3 It is particularly interesting that after almost 50 years of intense study, and reports consisting of literally thousands of HCM patients from around the world, a dramatic subset such as this would suddenly emerge at this time in a confined geographical area. It would be of interest if the authors would explain how and why this circumstance may have come about. For these reasons, we must sound a note of skepticism regarding the identity of the disease that Frustaci et al. have reported, so tightly linked with acute myocarditis.