cardiovascular disorders
Hypertrophic Cardiomyopathy
Treatment of Hypertrophic Cardiomyopathy
Beta-blockers Rate-limiting and negative inotropic calcium channel blockers Mavacamten Avoidance of nitrates, diuretics, and angiotensin-converting enzyme (ACE) inhibitors Possibly antiarrhythmics (eg,disopyramide,amiodarone) Possibly implantable cardioverter-defibrillator and sometimes surgery or ablative procedures Treatment of hypertrophic cardiomyopathy is based on the phenotype. Patients without obstruction generally have a stable clinical course without significant symptoms, although some experience heart failure symptoms due to diastolic dysfunction. Beta-blockers and heart rate-limiting calcium channel blockers with a lower arterial dilation capacity (usuallyverapamil), alone or combined, are the mainstays. By slowing the heart rate, they prolong the diastolic filling period, which may increase left ventricular filling in patients with diastolic dysfunction. Long-term efficacy of such therapy, however, has not been proven. In patients with the obstructive phenotype, in addition to attempts at improving diastolic function, treatment is directed at reducing the outflow tract gradient. Non-dihydropyridine calcium channel blockers (eg,verapamil,diltiazem), beta-blockers, anddisopyramidereduce the outflow tract gradient through their negative inotropic effects.Disopyramideappears to be most effective for patients with a resting gradient whereas beta-blockers are best at blunting the gradient that occurs during exercise. Beta-blockers are generally considered first-line treatment for patients with the obstructive phenotype;disopyramidehelps relieve symptoms for patients in whom first-line therapy with beta-blockers,verapamil, ordiltiazemhas failed. Patients who continue to experience symptoms related to significant outflow tract gradients (≥ 50 mm Hg) despite medical therapy are candidates for invasive treatment. When done at an experienced center, surgical myectomy has a low operative mortality with excellent outcomes, making it the preferred therapy in such patients. Percutaneous catheteralcoholseptal ablation is an alternative to surgery in older patients and others who are at high surgical risk. , an oral cardiac myosin inhibitor that reduces actin-myosin cross-bridge formation, relieves symptoms, reduces left ventricular outflow tract (LVOT) obstruction, and increases exercise tolerance in patients with hypertrophic cardiomyopathy ( Treatment references ). If syncope or sudden cardiac arrest has occurred or if sustained ventricular arrhythmia is confirmed by ECG or 24-hour ambulatory monitoring, an Device therapy (ICD) should usually be placed. Controversy exists regarding the need to place a defibrillator in patients without syncope, sudden cardiac arrest, or ventricular arrhythmias. It is generally believed that ICD insertion should be considered in patients with high-risk features ( A family history of premature sudden cardiac arrest Left ventricular wall thickness > 3 cm Delayed enhancement on cardiac MRI Unexplained syncope Survival after a cardiac arrest due to ventricular arrhythmia Multiple burst of nonsustained ventricular tachycardia (NSVT) Left ventricular ejection fraction (LVEF) < 50% (end-stage disease) Left ventricular aneurysm ablation have been used to decrease outflow obstruction and relive symptoms. There is no proven difference on mortality between these interventions, but myomectomy is more effective for relieving obstruction and decreasing the need for repeat interventions ( Treatment references ). Avoidance of competitive sports was previously recommended because sudden deaths can occur during increased exertion. Current guidelines recommend that athletes with HCM undergo comprehensive evaluation and shared discussion of potential risk with an expert HCM specialist. Treatment of the dilated congestive phase of hypertrophic cardiomyopathy is the same as that of Treatment with predominant systolic dysfunction. Genetic counseling is appropriate for patients with asymmetric septal hypertrophy. 1.Olivotto I, Oreziak A, Barriales-Villa R, et al:Mavacamtenfor treatment of symptomatic obstructive hypertrophic cardiomyopathy (EXPLORER-HCM): a randomised, double-blind, placebo-controlled, phase 3 trial.Lancet396:759–769, 2020. doi: 10.1016/S0140-6736(20)31792-X 2.Spertus JA, Fine JT, Elliott P, et al:Mavacamtenfor treatment of symptomatic obstructive hypertrophic cardiomyopathy (EXPLORER-HCM): health status analysis of a randomized, double-blind, placebo-controlled, phase 3 trial.Lancet397:2467–2475, 2012. doi: 10.1016/S0140-6736(21)00763-7 3.Maron MS, Rowin EJ, Wessler BS, et al: Enhanced American College of Cardiology/American Heart Association Strategy for Prevention of Sudden Cardiac Death in High-Risk Patients With Hypertrophic Cardiomyopathy.JAMA Cardiol4(7):644–657, 2019. doi:10.1001/jamacardio.2019.1391 4.Nguyen A, Schaff HV, Hang D, et al: Surgical myectomy versus alcohol septal ablation for obstructive hypertrophic cardiomyopathy: A propensity score-matched cohort.J Thorac Cardiovasc Surg157(1):306–315.e3, 2019. doi:10.1016/j.jtcvs.2018.08.062 