GENERAL MEASURES :
β’ Therapy based on pathophysiology, namely interventions to reduce ventricular contractility or increase
ventricular volume, ventricular compliance, and outflow tract dimensions
β’ Digitalis glycosides are contraindicated except for atrial fibrillation with uncontrolled response
β’ Nitrates and sympathomimetic amines (e.g., isoproterenol) are contraindicated except with concomitant
coronary heart disease
β’ Diuretics are relatively contraindicated because of their effect on ventricular volume and left ventricular
myotomy
β’ Pacemaker therapy - AV sequential pacing is frequently helpful in symptomatic patients with an outflow obstruction who do not respond to medical therapy
SURGICAL MEASURES : Left ventricular myomectomy - done only in setting of severe symptoms refractory to medical therapy or sequential pacing in those patients with outfl ow gradient >50 mm Hg (<6.65 kPa), either at rest or with provocation. 95% successful in abolishing gradient with 70% of patients having a marked symptomatic improvement for at least 5 years.
ACTIVITY :
β’ Strenuous exercise, especially competitive sports, should not be undertaken because of high risk of sudden
death. Younger patients with little or no functional impairment have the greatest risk of sudden death.
β’ Sports participation by patients with IHSS is not permitted if any of the following are present: Marked left
ventricle hypertrophy, signifi cant outfl ow gradient, significant supraventricular and/or ventricular arrhythmias,
or history of sudden death in relatives with hypertrophic cardiomyopathy
DRUG(S) OF CHOICE :
. Beta blockers (propranolol, metoprolol, etc)
. May decrease outflow obstruction: Some evidence suggests that it may increase ventricular compliance.
No clear evidence that it reduces incidence of sudden death.
. 1/3 to 2/3 of patients experience symptomatic improvement
. May titrate up to 320 mg/day of propranolol equivalent to obtain clinical effect provided patient tolerates
dose
. Calcium channel blockers (primarily verapamil) :
. Alternative to therapy with propranolol
. May have better effect on exercise performance
. Decrease in outflow gradient due to depression of cardiac contractility
. Improves diastolic filling by improved diastolic relaxation
. Amiodarone (Cordarone) :
. Limited use in treating ventricular arrhythmias because of documented pro-arrhythmic effects in HCM
. Only to be used in patients with ventricular tachycardia associated with hemodynamic compromise. Use of drug is to be guided by initial and followup electrophysiological studies.
CONTRAINDICATIONS:
. Verapamil:
. Major side effects include depression of impulse formation and A-V block, negative inotropism, and
vasodilatation - all of which can result in hypotension, shock, pulmonary edema, and death
. Therefore, relatively contraindicated for use in patients with increased left ventricle end diastolic
pressure (LVEDP), paroxysmal nocturnal dyspnea (PND), orthopnea, and/or in patients with sinus node
disease and A-V block (unless there is an appropriate pacing device)
ALTERNATIVE DRUGS :
β’ Diltiazem
β’ Disopyramide
PATIENT MONITORING : Yearly when symptoms and pharmacologic regimens become stable
PREVENTION/AVOIDANCE :
β’ Avoid strenuous exercise, especially competitive sports
β’ Avoid rapid standing
β’ Avoid inotropic drugs and diuretics
β’ Use antitussives for infections that are accompanied by a cough
POSSIBLE COMPLICATIONS :
β’ Sudden death
β’ Congestive heart failure
β’ Arrhythmia
β’ Atrial fi brillation with mural thrombosis formation
β’ Infective mitral endocarditis
EXPECTED COURSE/PROGNOSIS :
β’ Annual mortality rate - 4% a year (sudden death most common reason)
β’ Chronic illness with restricted life-style