Hypertrophic cardiomyopathy medical treatment
Editors-In-Chief: C. Michael Gibson, M.S., M.D. [1], Cafer Zorkun, M.D. [2], Caitlin J. Harrigan [3], Martin S. Maron, M.D., and Barry J. Maron, M.D.
Overview
In all patients with hypertrophic cardiomyopathy risk stratification is essential to attempt to ascertain which patients are at risk for sudden cardiac death [1] [2]. In those patients deemed to be at high risk the benefits and infrequent complications of defibrillator therapy are discussed; devices have been implanted in as many as 15% of patients at HOCM centers. Treatment symptoms of obstructive HOCM is directed towards decreasing the left ventricular outflow tract gradient and symptoms of dyspnea, chest pain and syncope.
Simple Supportive Measures
Avoid volume depletion
- These patients should avoid volume depletion and dehydration which reduces Left ventricular volume and thereby exacerbates left ventricular outflow tract obstruction.
Avoid strenuous Activity
- Strenuous activity has been associated with sudden cardiac death in these patients and for this reason these patients are counseled to avoid engaging in competitive sports.
Screening Relatives
- This autosomal dominant disease has a high degree of penetrance and first degree relatives should be screened.
Pharmacotherapy
Medical therapy is successful in the majority of patients. The first medication that is routinely used is beta-blockade (metoprolol, atenolol, bisoprolol, propranolol)[1]. If symptoms and gradient persist disopyramide may be added to the beta-blocker [3]. Alternately a calcium channel blocker such as verapamil may be substituted for beta-blockade. It should be stressed that most patient's symptoms may be managed medically without needing to resort to inteventions such as surgical septal myectomy, alcohol septal ablation or pacing. Severe symptoms in non-obstructive HCM may actually be more difficult to treat because there is no obvious target (obstruction) to treat. Medical therapy with verapamil, beta-blockade may improve symptoms. Diuretics should be avoided, as they reduce the intravascular volume of blood, decreasing the amount of blood available to distend the left ventricular outflow tract, leading to an increase in the obstruction to the outflow of blood in the left ventricle [4].
As a summary:
- The asymptomatic patient without risk factors for SCD (sudden cardiac death[) does not require therapy, even in the presence of NSVT. The symptomatic patient can be treated with negative inotropes such as calcium channel blockers and/or beta-blockers. Atrial fibrillation should be treated aggressively. Some use Disopyramide to maintain NSR (normal sinus rhythm) because of its negative inotropic effects. Amiodarone is the best medicine to maintain NSR and has been associated with symptomatic improvement in patients with HCM.
- These patients require endocarditis prophylaxis.
2011 AHA/ACC Guidelines in management of Atrial Fibrillation in Hypertrophic Cardiomyopathy[5]
Class I
Oral anticoagulation (INR 2.0 to 3.0) is recommended in patients with hypertrophic cardiomyopathy who develop atrial fibrillation, as for other patients at high risk of thromboembolism. (Level of Evidence: B)
Class IIa
Antiarrhythmic medications can be useful to prevent recurrent atrial fibrillation in patients with hypertrophic cardiomyopathy. Available data are insufficient to recommend one agent over another in this situation, but (a) disopyramide combined with a beta blocker or nondihydropyridine calcium channel antagonist or (b) amiodarone alone is generally preferred. (Level of Evidence: C)
References
- ↑ 1.0 1.1 Maron BJ (2002). "Hypertrophic cardiomyopathy: a systematic review". JAMA. 287 (10): 1308–20. PMID 11886323.
- ↑ Wigle ED, Rakowski H, Kimball BP, Williams WG (1995). "Hypertrophic cardiomyopathy. Clinical spectrum and treatment". Circulation. 92 (7): 1680–92. PMID 7671349.
- ↑ Sherrid MV, Barac I, McKenna WJ, Eliott M, Dickie S, Chojnowska L, Casey S, Maron BJ. Multicenter study of the efficacy and safety of disopyramide in obstructive hypertrophic cardiomyopathy. J Am College of Cardiol 2005; 45:1251–58
- ↑ Wynne J, Braunwald E. Hypertrophic cardiomyopathy. In: Braunwald E, ed. Heart disease: a textbook of cardiovascular medicine. 5th ed. Philadelphia: WB Saunders; 1997.
- ↑ Fuster V, Rydén LE, Cannom DS, Crijns HJ, Curtis AB, Ellenbogen KA; et al. (2011). "2011 ACCF/AHA/HRS focused updates incorporated into the ACC/AHA/ESC 2006 guidelines for the management of patients with atrial fibrillation: a report of the American College of Cardiology Foundation/American Heart Association Task Force on practice guidelines". Circulation. 123 (10): e269–367. doi:10.1161/CIR.0b013e318214876d. PMID 21382897.