Normal passive viscoelasticity but abnormal myofibrillar force generation in human hypertrophic cardiomyopathy.

ABSTRACT: Hypertrophic cardiomyopathy (HCM) is characterized by left ventricular hypertrophy, increased ventricular stiffness and impaired diastolic filling. We investigated to what extent myocardial functional defects can be explained by alterations in the passive and active properties of human cardiac myofibrils. Skinned ventricular myocytes were prepared from patients with obstructive HCM (two patients with MYBPC3 mutations, one with a MYH7 mutation, and three with no mutation in either gene) and from four donors. Passive stiffness, viscous properties, and titin isoform expression were similar in HCM myocytes and donor myocytes. Maximal Ca(2+)-activated force was much lower in HCM myocytes (14 ± 1 kN/m(2)) than in donor myocytes (23 ± 3 kN/m(2); P<0.01), though cross-bridge kinetics (k(tr)) durin

SUBMITTER: Hoskins AC 

PROVIDER: S-EPMC2954357 | biostudies-literature | 2010 Nov

REPOSITORIES: biostudies-literature