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(Circulation. 2007;116:2662-2665.)
© 2007 American Heart Association, Inc.

Editorial

Quantifying Diastolic Function in Hypertrophic Cardiomyopathy

The Ongoing Search for the Holy Grail

Harry Rakowski, MD; Shemy Carasso, MD

From the University Health Network, Toronto General Hospital, Toronto, Ontario Canada.

Correspondence to Harry Rakowski, MD, University Health Network, Toronto General Hospital, 200 Elizabeth St, 4 North, Room 504, Toronto, Ontario, Canada M5G 2C4. E-mail harry.rakowski@uhn.on.ca

Key Words: Editorials • cardiomyopathy • diastole • echocardiography

An extract of the first 250 words of the full text is provided, because this article has no abstract.

	Introduction

 
Hypertrophic cardiomyopathy (HCM) is a primary autosomal-dominant disorder of the myocardium caused by mutations in sarcomeric contractile proteins. Histopathologically, it is associated with myocardial hypertrophy, fiber disarray, increased loose connective tissue, and fibrosis, which are all thought to interfere with myocardial force generation and relaxation.^1–3 There is tremendous heterogeneity in the phenotypic expression of HCM, which is generally unrelated to genotype. This is shown by the variability of the age of onset of clinical disease, degree and location of hypertrophy, and presence and site of intraventricular dynamic pressure gradients. Despite this heterogeneity, almost all patients with HCM have some degree of diastolic dysfunction. The presence of subtle changes in LV filling may even identify patients with preclinical disease without LV hypertrophy. Interventions such as medical therapy, septal alcohol ablation, and surgical myectomy improve symptoms by both reducing the left ventricular (LV) outflow tract gradients and improving diastolic function.

Article p 2702

The origin of diastolic dysfunction in HCM is both multifactorial and complex, with changes at the molecular, myocardial tissue, and global LV levels. More than 400 mutations have been described in HCM, which result in the production of abnormal myocardial sarcomeric proteins that have altered contraction and relaxation characteristics. These include changes in the affinity between the various contractile proteins, in the sensitivity to Ca⁺², and in the efficiency of energy use (from ATP) and its expenditure.^3,4 These abnormalities may vary with the sarcomeric protein affected and the site and effect of the mutation. Myocardial ischemia also has . . . [Full Text of this Article]