Hypertrophic cardiomyopathy affects approximately 1 in 500 people worldwide, causing the heart muscle to thicken abnormally and making it harder for the heart to pump blood effectively. Though many people with this genetic condition live without symptoms, others face serious complications that require careful medical management and, in some cases, advanced interventions.

Treatment Goals and Approaches for Heart Muscle Thickening

When someone receives a diagnosis of hypertrophic cardiomyopathy, which doctors often call HCM, the treatment plan focuses on several important goals. The main aim is to reduce symptoms such as shortness of breath, chest pain, and dizziness, while also preventing serious complications like dangerous heart rhythms or sudden cardiac arrest. Treatment success depends heavily on how much the thickened heart muscle blocks blood flow and how severely symptoms affect daily life.^[1]

The approach to managing HCM varies significantly from person to person. Some individuals may need only lifestyle changes and regular monitoring, while others require medications, surgical procedures, or implanted devices to protect against life-threatening heart rhythms. The disease can affect people at any age, though most receive their diagnosis around age 40, and treatment plans must be tailored to each person’s unique situation.^[4]

Medical societies have established guidelines to help doctors decide on the best treatment path. These recommendations take into account whether the condition is the obstructive type, where thickened muscle blocks blood flow from the heart, or the non-obstructive type, where thickening occurs but doesn’t create a blockage. About two-thirds of people with HCM have the obstructive form, which often requires more aggressive treatment approaches.^[4]

Beyond standard treatments that have been used for decades, researchers are actively investigating new therapies in clinical trials. These experimental approaches aim to target the underlying mechanisms that cause the heart muscle to thicken, offering hope for more effective treatments in the future. Early diagnosis and appropriate treatment have greatly improved survival rates for people with HCM over the past few decades.^[3]

Standard Medical Treatment for Hypertrophic Cardiomyopathy

The foundation of HCM treatment for most people involves medications that help the heart function more effectively despite the thickened muscle. Beta-blockers are typically the first line of treatment. These drugs slow the heart rate and reduce the force of heart contractions, which helps the heart fill with blood more completely between beats. This is particularly important because the thickened, stiff heart muscle has difficulty relaxing and filling properly.^[7]

When beta-blockers alone don’t adequately control symptoms, doctors may add or switch to calcium channel blockers, particularly verapamil or diltiazem. These medications work similarly to beta-blockers by helping the heart muscle relax and improving blood flow. However, calcium channel blockers must be used carefully in people with severe obstruction, as they can sometimes worsen symptoms by causing blood pressure to drop too low.^[13]

For patients with obstructive HCM who continue to have symptoms despite beta-blockers or calcium channel blockers, a medication called disopyramide may be added. This drug has a unique property of reducing the strength of heart contractions, which can decrease the obstruction in the heart’s outflow tract. Disopyramide is often used in combination with a beta-blocker to achieve the best symptom control.^[7]

The duration of medication therapy for HCM is typically lifelong, as the condition itself is chronic and progressive. Doctors regularly adjust medication doses based on how well symptoms are controlled and whether any side effects develop. Common side effects of beta-blockers include fatigue, cold hands and feet, and sometimes mild depression. Calcium channel blockers may cause ankle swelling, constipation, or dizziness, particularly when standing up quickly.^[8]

Many people with HCM also develop atrial fibrillation, an irregular heart rhythm that increases the risk of stroke. When this happens, doctors prescribe blood-thinning medications such as warfarin or newer anticoagulants to prevent blood clots from forming. The choice of blood thinner depends on individual factors including kidney function, other medical conditions, and patient preference regarding monitoring requirements.^[4]

For patients with non-obstructive HCM who develop heart failure symptoms, treatment focuses on managing what doctors call heart failure with preserved ejection fraction. This means the heart pumps strongly but can’t fill properly due to the stiff, thickened muscle. Treatment may include diuretics to remove excess fluid, along with careful blood pressure management to reduce strain on the heart.^[11]

Surgical and Interventional Procedures

When medications fail to adequately control symptoms in people with obstructive HCM, more invasive treatment options become necessary. Septal myectomy is a surgical procedure considered the gold standard for treating severe, drug-resistant obstructive HCM. During this operation, a cardiac surgeon removes a small portion of the thickened septum, the wall between the left and right sides of the heart. This creates more space for blood to flow out of the heart to the rest of the body.^[7]

Septal myectomy is a complex procedure that requires significant expertise and is best performed at specialized centers with extensive experience in treating HCM. The surgery involves opening the chest and temporarily stopping the heart while the surgeon carefully removes just enough muscle tissue to relieve the obstruction without weakening the heart. In many cases, surgeons also repair the mitral valve during the same operation if it’s not functioning properly.^[11]

An alternative to surgery is alcohol septal ablation, a less invasive procedure performed by interventional cardiologists in a cardiac catheterization laboratory. During this procedure, doctors inject a small amount of pure alcohol into one of the arteries that supplies blood to the thickened portion of the septum. The alcohol causes a controlled, small heart attack that destroys some of the thickened muscle tissue, gradually reducing the obstruction over several months.^[7]

The choice between septal myectomy and alcohol ablation depends on several factors, including the patient’s age, the specific anatomy of the heart, and the presence of other heart conditions that need correction. Generally, younger patients and those who need additional heart repairs are better candidates for surgery, while older patients or those who prefer to avoid open-heart surgery may choose alcohol ablation. Both procedures have been shown to significantly improve symptoms and quality of life in most patients.^[13]

Some patients with HCM may benefit from a permanent pacemaker, a small device implanted under the skin that sends electrical signals to control heart rhythm. In certain cases, specialized pacing patterns can help reduce the obstruction by changing how the heart muscle contracts. However, pacemakers are not as effective as surgery or ablation for most people with obstructive HCM.^[7]

For people at high risk of sudden cardiac death, an implantable cardioverter-defibrillator, or ICD, may be recommended. This device continuously monitors heart rhythm and can deliver an electrical shock to restore normal rhythm if a dangerous arrhythmia occurs. The decision to implant an ICD involves careful risk assessment based on factors including family history of sudden death, thickness of the heart muscle, unexplained fainting, and abnormal heart rhythm patterns detected during monitoring.^[4]

In rare cases where HCM leads to severe, end-stage heart failure that doesn’t respond to any other treatment, heart transplantation may be the only option. This is reserved for people whose hearts can no longer pump effectively enough to sustain life despite all available medical and surgical therapies. The transplant evaluation process is extensive and considers many factors to determine if a patient is an appropriate candidate.^[13]

Innovative Treatments Being Studied in Clinical Trials

One of the most exciting developments in HCM treatment is mavacamten, a medication that represents an entirely new class of therapy called cardiac myosin inhibitors. This drug works at the molecular level by reducing the number of myosin protein heads that can attach to actin, the proteins that cause heart muscle to contract. By decreasing the force of contraction, mavacamten helps reduce both symptoms and the obstruction in the heart’s outflow tract.^[13]

The U.S. Food and Drug Administration approved mavacamten for adults with symptomatic obstructive HCM based on results from the EXPLORER-HCM trial, a Phase III clinical study. In this multicenter trial involving 251 patients, those who received mavacamten showed significantly greater improvement in symptoms and exercise capacity compared to those who received placebo. At 30 weeks, patients taking mavacamten reported better quality of life and increased ability to perform daily activities.^[13]

Mavacamten works differently from traditional HCM medications because it directly targets the fundamental problem in the disease: excessive contraction of the heart muscle caused by too many myosin-actin cross-bridges forming. Traditional medications like beta-blockers simply slow the heart rate, but mavacamten addresses the underlying molecular abnormality that causes the thickening and obstruction in the first place.^[13]

Clinical trials for mavacamten are conducted in multiple phases to ensure safety and effectiveness. Phase I trials tested the drug’s safety in a small number of healthy volunteers and patients. Phase II trials evaluated optimal dosing and preliminary effectiveness in larger groups of HCM patients. Phase III trials, like EXPLORER-HCM, compared mavacamten directly against placebo in hundreds of patients to definitively prove its benefits and identify any significant side effects.^[13]

Researchers are also investigating whether mavacamten might benefit people with non-obstructive HCM, not just those with the obstructive form. Additional clinical trials are underway to study the drug’s long-term effects, its impact on the progression of heart muscle thickening, and whether it might prevent complications like atrial fibrillation or the development of heart failure.^[13]

Beyond mavacamten, researchers are exploring other molecular approaches to treating HCM. Some studies are investigating whether medications that affect calcium handling in heart cells might improve how the thickened muscle relaxes between beats. Other researchers are studying whether drugs that reduce inflammation or prevent scarring in the heart muscle might slow disease progression and prevent complications.^[12]

Gene therapy represents a potential future treatment approach for HCM, since the condition is caused by mutations in genes that control heart muscle proteins. Scientists are working to develop methods to either correct the defective genes or compensate for their effects. However, these approaches are still in very early research stages and are not yet being tested in human clinical trials.^[3]

Most common treatment methods

• Medication therapy
  • Beta-blockers as first-line treatment to slow heart rate and reduce contraction force
  • Calcium channel blockers, particularly verapamil, to help heart muscle relax
  • Disopyramide to reduce obstruction by decreasing contraction strength
  • Blood thinners for patients who develop atrial fibrillation
  • Diuretics to manage fluid retention in heart failure
  • Mavacamten, a cardiac myosin inhibitor, for symptomatic obstructive HCM
• Surgical procedures
  • Septal myectomy to remove thickened heart muscle and relieve obstruction
  • Mitral valve repair or replacement when the valve is damaged
  • Heart transplantation for end-stage heart failure unresponsive to other treatments
• Catheter-based interventions
  • Alcohol septal ablation to destroy small portions of thickened muscle
  • Mitral clip procedure in selected patients with valve problems
• Device therapy
  • Implantable cardioverter-defibrillator (ICD) for prevention of sudden cardiac death
  • Permanent pacemaker for specific cases to modify heart contraction patterns
• Lifestyle modifications
  • Light to moderate intensity exercise approved by physician
  • Avoidance of strenuous activities and competitive sports
  • Maintaining adequate hydration to support heart function
  • Stress management and monitoring for signs of infection