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Factors Contributing to Increased Left Ventricle Size in Patients With Abnormally Enlarged Hearts

This study has been completed.
Information provided by:
National Institutes of Health Clinical Center (CC) Identifier:
First received: November 3, 1999
Last updated: March 3, 2008
Last verified: August 2002

The human heart is divided into four chambers. One of the four chambers, the left ventricle, is the chamber mainly responsible for pumping blood out of the heart into the circulation. There is an inherited condition affecting the heart, passed on through genetics, hypertrophic cardiomyopathy (HCM). HCM causes the left ventricle to become abnormally enlarged (left ventricular hypertrophy LVH).

Some patients with the abnormal genes that may cause HCM do not have the characteristic LVH. Approximately 20 - 40% of patients with the genetic abnormality (missense mutation of genes encoding for sarcomeric protein) actually have an enlarged left ventricle. Because of this, researchers believe there may be other factors, along with the genetic abnormality that contribute to the development of HCM. Researchers are interested in learning more about several factors they suspect may play a role in the development of HCM.

Specifically, researchers plan to study levels of a hormone and the protein it attaches to, which may contribute to the development of an abnormally enlarged heart. Insulin-like growth factor (IGF-1) and insulin-like growth factor binding protein (IGFBP) work together with growth hormone (GH) in the development and maturation of many organ systems. Previous studies have suggested that these hormones affect the development and function of the heart.

Patients participating in this study will undergo a variety of tests including collection of blood samples, echocardiogram of the heart, treadmill exercise test, and continuous electrical monitoring of heart activity (Holter monitor).

Hypertrophic Cardiomyopathy
Left Ventricular Hypertrophy

Study Type: Observational
Official Title: Contribution of Insulin-Like Growth Factor-I (IGF-I) and Its Binding Protein (IGFBP3) to Increased Left Ventricular Mass in Familial Hypertrophic Cardiomyopathy Caused by Distinct Sarcomeric Mutations

Resource links provided by NLM:

Further study details as provided by National Institutes of Health Clinical Center (CC):

Estimated Enrollment: 175
Study Start Date: February 1999
Estimated Study Completion Date: August 2002
Detailed Description:
Hypertrophic cardiomyopathy (HCM) is a genetic disease with an autosomal dominant pattern of inheritance which is characterized by left ventricular hypertrophy (LVH). HCM is often caused by missense mutations of genes that encode for sarcomeric proteins. The LVH varies markedly in patients with identical sarcomeric gene mutations, and notably, 20 to 40% of subjects with disease mutation do not have LVH as assessed by echocardiography. These findings suggest that other factors affect LV wall thickness in HCM. We wish (1) to investigate the potential role of IGF-I and its binding protein, IGFBP3, in determining increased LV mass in HCM caused by sarcomeric mutations; and (2) to assess myocardial ultrasound backscatter, exercise tolerance, and propensity to arrhythmias, in subjects who have inherited sarcomeric mutations but who do not have LVH.

Ages Eligible for Study:   Child, Adult, Senior
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No


HCM subjects 5 years or older, with distinct sarcomeric gene mutations and LV wall thickness greater than 15 mm in subjects older than 18 years, and greater than 2 SDs in subjects 18 years of age or younger, as assessed by MRI.

Age- and gender-matched blood relatives with sarcomeric gene mutations but without LVH.

Age- and gender-matched blood relatives without sarcomeric gene mutations.


History of hypertension (basal systolic and diastolic pressures above 170 mm Hg and 95 mm Hg, respectively) or another systemic or cardiac disease that may cause cardiac hypertrophy.

History of recent acute illness or other chronic illness that might affect plasma levels of IGF-I and IGFBP3.

History of thyrotoxicosis, diabetes mellitus or abnormally elevated fasting blood sugar.

Any conditions which would exclude patients from undergoing MRI scan.

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Please refer to this study by its identifier: NCT00001878

United States, Maryland
National Heart, Lung and Blood Institute (NHLBI)
Bethesda, Maryland, United States, 20892
Sponsors and Collaborators
National Heart, Lung, and Blood Institute (NHLBI)
  More Information

Publications: Identifier: NCT00001878     History of Changes
Other Study ID Numbers: 990058
Study First Received: November 3, 1999
Last Updated: March 3, 2008

Keywords provided by National Institutes of Health Clinical Center (CC):
Growth Hormone
Cardiac Hypertrophy
Hypertrophic Cardiomyopathy
Sarcomeric Gene Mutations

Additional relevant MeSH terms:
Cardiomyopathy, Hypertrophic
Hypertrophy, Left Ventricular
Cardiomyopathy, Hypertrophic, Familial
Heart Diseases
Cardiovascular Diseases
Pathological Conditions, Anatomical
Aortic Stenosis, Subvalvular
Aortic Valve Stenosis
Heart Valve Diseases
Genetic Diseases, Inborn processed this record on April 24, 2017