Pediatric Hypertrophic Cardiomyopathy Treatment & Management

Updated: Apr 11, 2017
  • Author: Christina Y Miyake, MD; Chief Editor: Syamasundar Rao Patnana, MD  more...
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Treatment

Approach Considerations

Medical management of hypertrophic cardiomyopathy (HCM) in children should focus on the following:

  • Ruling out secondary causes

  • Following for progression of disease and identifying those with obstruction

  • Controlling symptoms and restricting activity (with avoidance of volume depletion)

  • Identifying those at risk for sudden cardiac death

  • Screening family members

Evaluation of the patient with HCM can usually be conducted on an outpatient basis. Inpatient studies and treatment may be necessary as well. Admit patients with HCM for testing, electrophysiology procedures, and/or surgical intervention. 

Consultations may be indicated with the following specialists:

  • Cardiologist

  • Cardiothoracic surgeon

  • Cardiac electrophysiologist

  • Geneticist

Ruling out secondary causes

Evaluation, especially in children, should be performed to rule out the following secondary causes of cardiac hypertrophy:

  • Athlete’s heart: Long-term athletic conditioning can result in ventricular hypertrophy but typically causes a concentric hypertrophy with an associated increase in left ventricular diastolic dimension, unlike primary HCM. When this differentiation is difficult, the following criteria favor HCM: unusual patterns of left ventricular hypertrophy, left ventricular cavity size smaller than 45 mm (in adults and older adolescents), left atrial enlargement, bizarre electrocardiographic (ECG) patterns, abnormal left ventricular filling, family history of HCM, and decreased left ventricular wall thickness after deconditioning.

  • Inborn errors of metabolism

  • Mitochondrial disorders

  • Neuromuscular disorders

Following for disease progression

Children with HCM are at particular risk for development or progression of outflow tract obstruction and should be followed yearly with serial echocardiography during puberty.

Controlling symptoms and restricting activity

Medical and surgical therapy are used to reduce ventricular contractility or increase ventricular volume, to increase ventricular compliance and outflow tract dimensions, and, in obstructive HCM, to reduce the pressure gradient across the left ventricular outflow tract.

Patients with symptoms or evidence of outflow tract obstruction are generally started on calcium channel blocker or beta-blocker therapy. Disopyramide has been used in adults, but has potential proarrhythmic effects and is not typically used in children. Carefully monitor medication dose and adverse effects.

Patients with severe outflow tract obstruction may be candidates for surgical myectomy. Alternative therapies, such as alcohol septal ablation, coil occlusion of septal perforators supplying the hypertrophied ventricular septum, [19] or pacemaker insertion, are less commonly performed in children.

Patients should be advised not to participate in competitive sports or strenuous activity.

Asymptomatic patients

The 2011 joint American College of Cardiology Foundation (ACCF)/American Heart Association (AHA) recommendations for asymptomatic patients with HCM include the following [15] :

  • Treat any comorbid conditions that may contribute to cardiovascular disease (eg, hypertension, hyperlipidemia, obesity, diabetes) (class I; level of evidence [LOE]: C)
  • Low-intensity aerobic exercise is reasonable as part of a healthy lifestyle (class IIa; LOE: C)
  • No well-established evidence exists for the use of beta blockade and calcium channel blockers in effectively affecting clinical outcomes in this population (class IIb; LOE: C)
  • Avoid performing septal reduction therapy for asymptomatic children and adults in the presence of normal effort tolerance regardless of the obstruction severity (class III; LOE: C)
  • Avoid pure vasodilators and high-dose diuretics, regardless of symptom status, in patients with resting or provocable outflow tract obstruction (class III; LOE: C)

Identifying risk factors for sudden death

Reduction of the risk of sudden death is paramount to any therapy for HCM. Although no strict guidelines are available, suggested risk factors for sudden cardiac death include a history of previous arrest, unexplained syncope, ventricular arrhythmias, a family history of sudden cardiac death, abnormal blood pressure response during exercise stress testing, and a markedly enlarged septum (>3 cm in adult studies). The degree of left ventricular outflow obstruction has not been shown to be a risk factor for sudden death.

Screening family members

All first-degree family members of the patient must be informed and screened for HCM. This entails a detailed history, physical examination, electrocardiography (ECG), and echocardiography. If a genetic defect is known, asymptomatic family members should be gene tested.

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Pharmacologic Therapy

Subacute bacterial endocarditis prophylaxis is not required. Beta-blockers and calcium channel blockers (eg, verapamil or diltiazem) are used to treat children with hypertrophic cardiomyopathy (HCM). In individuals with significant tachyarrhythmias, amiodarone and other class III-type antiarrhythmic agents have also been used.

Avoid administration of the following agents:

  • Inotropic drugs
  • Nitrates and sympathomimetic amines, except in patients with HCM and concomitant coronary artery disease
  • Digitalis, because glycosides are contraindicated, except in patients with uncontrolled atrial fibrillation
  • Diuretics, because of their effect on left ventricular volume

2011 ACCF/AHA guidelines

The 2011 joint American College of Cardiology Foundation (ACCF)/American Heart Association (AHA) recommendations for symptomatic patients with HCM are outlined below. [15]

Class I recommendations (all level of evidence [LOE]: B) [15]

Use beta-blockers to manage angina or dyspnea in adults with HCM (obstructive or nonobstructive). Take extra care when using these agents in the presence of sinus bradycardia or severe conduction disease.

For symptomatic HCM (angina or dyspnea) refractory to low doses of beta-blockers: Titrate the dose to a resting heart rate below 60-65 bpm (up to a maximum dose based on the recommended dosing of these agents).

For symptomatic (angina or dyspnea) HCM (obstructive or nonobstructive) refractory to beta-blockers or in patients intolerant of, or with contraindications to, beta-blockers: Initiate low-verapamil therapy and titrate up to 480 mg/day. Closely monitor patients with high gradients, advanced heart failure, or sinus bradycardia who are taking verapamil.

For acute hypotension in obstructive HCM that is refractory to fluid administration: Intravenous (IV) phenylephrine or another pure vasoconstrictor is recommended.

Class IIa recommendations [15]

For symptomatic, obstructive HCM (angina or dyspnea) refractory to beta-blockers or verapamil alone: Disopyramide in combination with a beta-blocker or verapamil is reasonable (LOE: B).

For persistent dyspnea in nonobstructive HCM refractory to beta-blockers, verapamil, or the two combined: The addition of oral diuretics is reasonable (LOE: C).

Class IIb recommendations (all LOE: C) [15]

For symptomatic (angina or dyspnea) pediatric HCM patients on beta-blockers: Monitor for adverse effects (eg, depression, fatigue, impaired academic performance).

For persistent congestive symptoms in obstructive HCM refractory to beta-blockers, verapamil, or the two combined: The addition of oral diuretics is reasonable.

In the presence of resting or provocable left ventricular outflow tract obstruction but preserved systolic function, proceed with caution if considering the use of angiotensin-converting enzyme (ACE) inhibitors or angiotensin-receptor blockers (ARBs). The efficacy of these agents is not well established for symptomatic (angina or dyspnea) HCM in this setting.

For HCM patients intolerant of, or with contraindications to, verapamil, consider diltiazem.

Class III recommendations: Harm

For symptomatic (angina or dyspnea) HCM in the setting of resting or provocable left ventricular outflow tract obstruction: Potentially harmful medications include nifedipine or other dihydropyridine calcium channel blockers (LOE: C).

For obstructive HCM in the setting of systemic hypotension or severe dyspnea at rest: Verapamil is potentially harmful (LOE: C).

For dyspnea in HCM the absence of atrial fibrillation: Digitalis is potentially harmful (LOE: B).

For symptomatic (angina or dyspnea) HCM in the setting of atrial fibrillation: Monotherapy with disopyramide without beta-blockers or verapamil is potentially harmful (potential enhancement of AV conduction and increased ventricular rate during episodes of atrial fibrillation) (LOE: B).

In the setting of obstructive HCM and acute hypotension: Potentially harmful medications include dopamine, dobutamine, norepinephrine, and other IV inotropic agents (LOE: B).

The 2014 European Society of Cardiology (ESC) recommendations are similar to those of the 2011 ACCF/AHA guidelines. [20]

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Left Ventricular Myectomy

Left ventricular myectomy is sometimes performed in patients with hypertrophic cardiomyopathy (HCM) who have severe symptoms refractory to therapy and an outflow gradient above 50 mm Hg either with provocation or at rest.

The procedure is typically successful in abolishing the outflow gradient; most patients have symptomatic improvement for at least 5 years. However, the reduction in left ventricular outflow gradient may not correlate with a reduction in the risk of sudden death or overall mortality. Furthermore, the outflow gradient may gradually increase over time and return to the same level as before, necessitating a repeat myectomy or additional medical therapy.

2011 ACCF/AHA guidelines recommendations

Class I recommendations (level of evidence [LOE]: C) [15]

Only experienced operators in the setting of a comprehensive HCM program should perform septal reduction therapy, and only in eligible patients with severe drug-refractory symptoms and left ventricular outflow tract obstruction.

Class IIa recommendations [15]

When considering management options for eligible patients with severe drug-refractory symptoms and left ventricular outflow tract obstruction, it is reasonable to consult with institutions experienced in surgical septal myectomy and alcohol septal ablation (LOE: C).

For most eligible patients with severe drug-refractory symptoms and left ventricular outflow tract obstruction, surgical septal myectomy can be beneficial and is first-line therapy when performed in experienced centers (LOE: B).

For symptomatic children with HCM in the setting of severe resting obstruction (>50 mm Hg) whose condition is refractory to standard medical therapy, surgical septal myectomy can be beneficial when performed in experienced centers (LOE: C).

For eligible adult patients with HCM with left ventricular outflow tract obstruction and severe drug-refractory symptoms (eg, New York Heart Association [NYHA] class III/IV) but who are not surgical candidates, alcohol septal ablation in experienced centers can be beneficial (LOE: B). (See Catheter Septal Ablation.)

Class III recommendations: Harm (all LOE: C)

Septal reduction therapy is not recommended in patients with HCM and the following [15] :

  • No symptoms with normal exercise tolerance or symptoms controlled/minimized with optimal medical therapy
  • Unless performed as part of a program dedicated to the longitudinal and multidisciplinary care of HCM patients

In addition, for HCM in the setting of left ventricular outflow tract obstruction for which septal reduction therapy is feasible for relief, mitral valve replacement is not recommended. [15]

2014 ESC guidelines recommendations

The 2014 European Society of Cardiology (ESC) recommendations are similar to those of the 2011 ACCF/AHA guidelines. [20]  However, the ESC guidelines indicate mitral valve repair should or may be considered, respectively, in the following settings [20] :

  • Symptomatic HCM with a resting or provocable left ventricular outflow tract obstruction (≥50 mm Hg) and moderate-to-severe mitral regurgitation not solely caused by systolic anterior motion of the mitral valve (class IIa; LOE: C)
  • Resting or provocable left ventricular outflow tract obstruction (≥50 mm Hg) and a maximum septal hypertrophy up to 16 mm at the point of the mitral leaflet–septal contact or in the presence of moderate-to-severe mitral regurgitation following isolated myectomy (class IIb; LOE: C)
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Pacemaker Implantation

Transvenous dual-chamber pacing has been used for patients with hypertrophic cardiomyopathy (HCM), although this is not current clinical practice. The right ventricular septal preexcitation induced by right ventricular apical pacing leads to a “pulling away” of the septum from the outflow region, allowing for an increase in flow with a decrease in left ventricular outflow tract obstruction.

Many patients with HCM and pacemaker implantation feel that their symptoms improve, allowing a reduction in prescribed medication. However, a reduction in left ventricular outflow tract gradient does not necessarily mean a reduction in vulnerability to ventricular arrhythmias and sudden death.

Some investigators have used permanent pacing in selected HCM patients as adjunctive rather than primary treatment. The reported results vary considerably, with a significant placebo effect and a wide range of patient outcomes. ICDs have essentially replaced pacemakers as cardiac rhythm management devices for HCM (see Implantable Cardioverter Defibrillator). [21, 22, 23, 24]

2008 ACC/AHA/HRS and 2011 ACCF/AHA guidelines recommendations

The 2008 American College of Cardiology (ACC), American Heart Association (AHA), and Hearth Rhythm Society (HRS) recommendations for permanent pacing in patients with HCM include the following indications [25] :

  • Sinus node dysfunction or atrioventricular block (class I; level of evidence [LOE]: C)
  • Medically refractory symptomatic HCM with significant resting or provoked left ventricular outflow tract obstruction (class IIb; LOE: A); consider implantation with a DDD implantable cardioverter defibrillator (ICD) for patients with class I indications in the presence of sudden cardiac death risk factors

The 2011 joint ACC Foundation (ACCF)/AHA recommendations for pacing in patients with HCM include the following [15] :

  • For individuals with a dual-chamber device that was implanted for non-HCM indications, a trial of dual-chamber atrial ventricular pacing from the right ventricular apex is a reasonable consideration for symptomatic relief from left ventricular outflow obstruction (class IIa; LOE: B)
  • For medically refractory symptomatic patients with obstructive HCM who are suboptimal surgical candidates for septal reduction, consider permanent pacing (class IIb; LOE: B)

Both the 2008 ACC/AHA/HRS and the 2011 ACCF/AHA guidelines state that permanent pacemaker implantation is not indicated for patients who are asymptomatic or whose symptoms are medically controlled, nor is it indicated for symptomatic patients in the absence of evidence of left ventricular tract outflow obstruction (both class III: harm ; LOE: C [2008 guidelines], and LOE: C and B, respectively [2011 guidelines]). [25, 15]

2014 ESC guidelines recommendations

The 2014 European Society of Cardiology (ESC) guidelines recommendations on indications for cardiac pacing in HCM patients with resting or provocable left ventricular outflow tract obstruction (≥50 mm Hg), sinus rhythm, and drug-refractory symptoms include the following to reduce the left ventricular outflow tract gradient or to facilitate beta-blocker and/or verapamil therapy (all class IIb; LOE: C) [20] :

  • Sequential atrioventricular pacing, with optimal AV interval, in those who are not candidates for septal myectomy or septal alcohol ablation, or who are at high risk of developing heart block following these procedures
  • Consideration of implanting a dual-chamber ICD in individuals with an indication for an ICD
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Catheter Septal Ablation

Transvenous catheter ablation of the septal region has been performed by using selective arterial ethanol infusion to destroy myocardial tissue in patients with hypertrophic cardiomyopathy (HCM). The procedure is analogous to a surgical myectomy, in that it attempts to decrease the amount of septal ventricular myocardium, thereby reducing the left ventricular outflow tract gradient.

The main drawbacks include the risk of inadvertent atrioventricular (AV) block and extension of the alcohol-induced infarct, leading to myocardial dysfunction or iatrogenic ventricular septal defects. Studies have demonstrated a higher rate of complications for alcohol septal ablation than for surgical myectomy. [26]  Coil occlusion of septal perforators supplying the hypertrophied ventricular septum has similar limitations. [19]

2011 American College of Cardiology Foundation (ACCF)/American Heart Association (AHA) guidelines

Class IIa recommendations (level of evidence [LOE]: B) [15]

Alcohol septal ablation in experienced centers can be beneficial in eligible adults with HCM with left ventricular outflow tract obstruction and severe drug-refractory symptoms (eg, New York Heart Association [NYHA] class III/IV) who are not surgical candidates. 

Class IIb recommendations [15]

For eligible adults with HCM with left ventricular outflow tract obstruction and severe drug-refractory symptoms who prefer septal ablation following a detailed discussion, alcohol septal ablation in experienced centers may be considered an alternative to surgical myectomy (LOE: B).

However, alcohol septal ablation is not recommended in the setting of HCM with marked (ie, >30 mm) septal hypertrophy as its efficacy is unclear in this scenario (LOE: C).

Class III recommendations: Harm (all LOE: C)

Alcohol septal ablation is not recommended in patients with HCM and the following [15] :

  • Concomitant disease that independently warrants surgical correction (eg, coronary artery bypass grafting for coronary artery disease, mitral valve repair for ruptured chordae) when surgical myectomy can be performed as part of the procedure
  • Children younger than 21 years or adults younger than 40 years if myectomy is a viable option
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Implantable Cardioverter Defibrillator

The implantable cardioverter defibrillator (ICD) has been used for prevention of sudden arrhythmic death. Transvenous placement is similar in technique to permanent pacemaker implantation. An ICD automatically detects, recognizes, and treats tachyarrhythmias and bradyarrhythmias using tiered therapy (ie, bradycardia pacing, overdrive tachycardia pacing, low-energy cardioversion, and high-energy shock defibrillation).

ICD therapy has been demonstrated to be lifesaving in children with hypertrophic cardiomyopathy (HCM) who receive appropriate shocks for ventricular tachycardia and ventricular fibrillation, even among those on appropriate antiarrhythmic drug therapy.

Smaller studies in children, as well as personal and anecdotal experience, appear to strongly favor using the ICD in HCM patients who have arrhythmias, aborted sudden death, malignant genotype or family history, and other factors that may increase mortality, particularly sudden arrhythmic death risk. [21, 22, 23, 24]

Clearly, in patients who have had an aborted sudden death event or documented sustained ventricular tachyarrhythmias, the ICD is indicated as secondary prevention.

In adults, teenagers, and children, primary prevention is also employed for patients with HCM but without a documented ventricular tachyarrhythmia or aborted sudden death event. Although this is a reasonable indication, the appropriate shock rate is significantly lower in these primary prevention patients.

Additional markers of higher risk (eg, left ventricular wall thickness, nonsustained ventricular tachycardia, abnormal exercise blood pressure response, malignant family history, and other stratifying tests) are useful in identifying patients who have greater ventricular arrhythmia vulnerability.

The main drawbacks to implanting an ICD include the relatively high rate of inappropriate shocks (for sinus tachycardia, supraventricular tachycardia, or lead problems) and a high lead fracture rate, particularly in younger patients.

ICDs last approximately 4-5 years; device failure is usually the result of either battery depletion or lead failure. Young patients require multiple ICD device replacements and lead extraction procedures, which carry additional surgical risks.

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Diet and Activity

No special diet is required in individuals with hypertrophic cardiomyopathy (HCM); however, patients should be instructed to avoid volume depletion, as this can increase pressure gradients across the left ventricular outflow tract. They should also be advised to avoid excessive weight gain.

Strenuous and anaerobic exercise should be avoided. [7] Competitive-level sports are not advised if any of the following are present:

  • Significant outflow gradient

  • Significant ventricular or supraventricular arrhythmia

  • Marked left ventricular hypertrophy

  • History of sudden death in relatives with HCM

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