Protocol Number: 08-H-0210

Title:

Long Term Follow Up of Children and Adolescents Diagnosed with Hypertrophic Cardiomyopathy: Identification of Risk Factors that Predict Arrhythmia Events

Number:

08-H-0210

Summary:

Patients with HCM have an increased incidence of sudden death, particularly younger individuals. However, HCM has markedly variable clinical presentations, and the risk of sudden death and arrhythmia events (AE) differs significantly from one patient to another. Several risk factors for AE have been proposed. These risk factors have been defined in predominantly adult HCM populations. Little data is available defining risk factors for sudden death in a carefully defined HCM population composed of only children and adolescents. Those at highest risk may benefit from implantable defibrillator (ICD) therapy. However, the universal application of ICD therapy is not without significant morbidity and mortality.

Traditional risk factors for sudden death (SD) in adult HCM patients include a family history of SD, young age, non-sustained ventricular tachycardia (VT) on Holter monitoring, increased ventricular septal thickness (ST), abnormal blood pressure (BP) response to exercise and syncope.

The purpose of this study will be to 1) to determine whether risk factors for and mechanisms of AE in adults have predictive value in children, and 2) in particular, whether ventricular septal thickness and inducible ventricular tachycardia at electrophysiologic study (EPS) would identify a subgroup of children that might benefit most from ICD implantation.

Clinical features that will be examined as potential AE predictors included: age at presentation to the NIH; family history of SD; pre-syncope or syncope; exercise-induced hypotension; ventricular septal thickness; LV outflow obstruction; elevated LV end diastolic pressure; QRS duration; QT interval; VT on ambulatory electrocardiographic monitoring; myocardial ischemia on stress nuclear perfusion imaging; inducible VT; intra-cardiac conduction intervals; and ventricular refractory periods. Statistical significance for the time-to-event analyses will be assessed using the logrank statistic for dichotomous variables and Cox's score statistic for continuous variables.

We anticipate that this study will improve risk stratification in children and adolescents with HCM, enhance our ability to predict AE, and refine guidelines for ICD therapy in children.

Sponsoring Institute:

National Heart, Lung and Blood Institute (NHLBI)

Recruitment Detail

Type: Completed Study; data analyses ongoing

Gender: Male & Female

Referral Letter Required: Yes

Population Exclusion(s): None

Eligibility Criteria: This study is not currently recruiting new subjects. If you have questions about participating in a study, please contact the Patient Recruitment and Public Liaison Office, CC.

Special Instructions:

Currently Not Provided

Keyword(s):

Hypertrophic Cardiomyopathy

Children

Sudden Death

Arrhythmias

Electrophysiology Study

Recruitment Keyword(s):

None

Condition(s):

Hypertrophic Cardiomyopathy (HCM)

Investigational Drug(s):

None

Investigational Device(s):

None

Interventions:

None

Supporting Site:

National Heart, Lung, and Blood Institute

Contact(s):

This study is not currently recruiting new subjects. If you have questions about participating in a study, please contact the Patient Recruitment and Public Liaison Office, CC.

Citation(s):

Colan SD, Lipshultz SE, Lowe AM, Sleeper LA, Messere J, Cox GF, Lurie PR, Orav EJ, Towbin JA. Epidemiology and cause-specific outcome of hypertrophic cardiomyopathy in children: findings from the Pediatric Cardiomyopathy Registry. Circulation. 2007 Feb 13;115(6):773-81. Epub 2007 Jan 29.

Frenneaux MP. Assessing the risk of sudden cardiac death in a patient with hypertrophic cardiomyopathy. Heart. 2004 May;90(5):570-5. Review. No abstract available.

Maron BJ, Shen WK, Link MS, Epstein AE, Almquist AK, Daubert JP, Bardy GH, Favale S, Rea RF, Boriani G, Estes NA 3rd, Spirito P. Efficacy of implantable cardioverter-defibrillators for the prevention of sudden death in patients with hypertrophic cardiomyopathy. N Engl J Med. 2000 Feb 10;342(6):365-73.

• Questions about participating in a study, please contact the Patient Recruitment and Public Liaison Office, CC.
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