Hypertrophic cardiomyopathy (HCM) is a genetic heart condition characterized by abnormal thickening of the heart muscle, particularly the ventricles. This thickening can make it harder for the heart to pump blood effectively throughout the body. HCM affects approximately 1 in 500 people worldwide, making it one of the most common inherited cardiac disorders. While some individuals with HCM may never experience symptoms, others can develop serious complications including heart failure, arrhythmias, and sudden cardiac death.
Understanding the symptoms of hypertrophic cardiomyopathy is crucial for early detection and proper management of this condition. Many people with HCM live normal lives with appropriate medical care, but recognizing warning signs can be life-saving. The symptoms can vary significantly from person to person, ranging from mild to severe, and may develop at any age. In this comprehensive guide, we’ll explore the most common symptoms of HCM, helping you identify when medical attention is necessary.
1. Shortness of Breath (Dyspnea)
Shortness of breath is one of the most frequently reported symptoms in people with hypertrophic cardiomyopathy. This occurs because the thickened heart muscle reduces the heart’s ability to fill with blood properly, leading to decreased oxygen delivery to the body’s tissues.
Patients with HCM typically experience dyspnea during physical exertion, such as climbing stairs, exercising, or performing routine activities. However, as the condition progresses, shortness of breath may occur even during rest or while lying down flat (orthopnea). This happens because the stiffened heart muscle cannot relax adequately between beats, causing blood to back up into the lungs.
The severity of breathlessness can vary considerably. Some individuals may only notice mild difficulty breathing during intense exercise, while others may struggle with everyday tasks like walking short distances. If you experience persistent or worsening shortness of breath, especially if accompanied by other symptoms, it’s essential to consult a healthcare provider promptly.
2. Chest Pain or Discomfort (Angina)
Chest pain, medically known as angina, is a common and often alarming symptom of hypertrophic cardiomyopathy. This discomfort typically occurs because the thickened heart muscle requires more oxygen than the coronary arteries can supply, especially during physical activity or emotional stress.
The chest pain associated with HCM can manifest in various ways. Some people describe it as a squeezing, pressing, or heavy sensation in the center of the chest. Others may experience a burning feeling or sharp, stabbing pains. The pain may radiate to the shoulders, arms, neck, jaw, or back, similar to the pain experienced during a heart attack.
Unlike typical angina from coronary artery disease, HCM-related chest pain may not always be relieved by rest. It can occur during exercise, after meals, or even at rest. The pain episodes can last from a few minutes to several hours. Any chest pain should be evaluated by a medical professional to determine its cause and appropriate management, as it could indicate insufficient blood flow to the heart muscle or other serious complications.
3. Heart Palpitations
Palpitations, or the sensation of an irregular, rapid, or forceful heartbeat, are experienced by many individuals with hypertrophic cardiomyopathy. These sensations occur because HCM can disrupt the heart’s electrical system, leading to abnormal heart rhythms (arrhythmias).
People with HCM may describe palpitations in different ways: feeling like the heart is racing, pounding, fluttering, skipping beats, or flip-flopping in the chest. Some patients report feeling their heartbeat in their throat or neck. These sensations can be brief and intermittent, or they may persist for extended periods.
Palpitations in HCM can be triggered by various factors including exercise, caffeine consumption, stress, alcohol, or certain medications. While occasional palpitations may be harmless, frequent or sustained episodes warrant medical evaluation. Some arrhythmias associated with HCM, particularly atrial fibrillation and ventricular tachycardia, can be serious and require prompt treatment. If palpitations are accompanied by dizziness, chest pain, or fainting, immediate medical attention is necessary.
4. Dizziness and Lightheadedness
Dizziness and lightheadedness are common symptoms in people with hypertrophic cardiomyopathy, often resulting from the heart’s reduced ability to pump adequate blood to the brain and other organs. These sensations can range from mild unsteadiness to severe vertigo that affects daily functioning.
The dizziness in HCM typically occurs during or immediately after physical exertion when the body’s demand for oxygenated blood increases. The thickened heart muscle, particularly in obstructive HCM (HOCM), can partially block blood flow out of the heart, causing a sudden drop in blood pressure and reduced cerebral blood flow. This obstruction may worsen during exercise when the heart contracts more forcefully.
Some patients experience positional dizziness, particularly when standing up quickly from a sitting or lying position (orthostatic hypotension). Others may feel lightheaded after eating large meals, as blood is diverted to the digestive system. Dehydration can exacerbate these symptoms. Recurrent dizziness or lightheadedness should be reported to a healthcare provider, as it may indicate dangerous arrhythmias or severe outflow obstruction requiring medical intervention.
5. Fainting or Near-Fainting Episodes (Syncope)
Syncope, or fainting, is a particularly concerning symptom of hypertrophic cardiomyopathy that should never be ignored. Fainting occurs when blood flow to the brain becomes temporarily insufficient, causing a brief loss of consciousness. In HCM, this can result from arrhythmias, outflow obstruction, or abnormal blood pressure responses during exercise.
Fainting episodes in HCM patients often happen during or immediately after physical exertion, though they can also occur at rest. Before losing consciousness, individuals may experience warning signs such as tunnel vision, nausea, sweating, weakness, or a feeling that the room is spinning. The person typically falls or slumps over and regains consciousness within a few seconds to minutes.
Pre-syncope, or near-fainting, involves experiencing the warning symptoms without actually losing consciousness. Both syncope and pre-syncope are considered red flags in HCM because they may indicate life-threatening arrhythmias or severe obstruction. Anyone with HCM who experiences fainting or near-fainting should seek immediate medical evaluation, as these episodes are associated with increased risk of sudden cardiac death. Additional testing, including continuous heart monitoring and exercise stress testing, may be necessary to identify the underlying cause and guide appropriate treatment.
6. Fatigue and Reduced Exercise Tolerance
Chronic fatigue and diminished ability to exercise are hallmark symptoms of hypertrophic cardiomyopathy that significantly impact quality of life. Unlike normal tiredness that improves with rest, HCM-related fatigue is persistent and disproportionate to the level of activity performed.
The fatigue stems from the heart’s inability to pump sufficient oxygenated blood to meet the body’s metabolic demands. The stiffened, thickened heart muscle cannot fill adequately with blood between contractions, reducing cardiac output. As a result, muscles and organs don’t receive enough oxygen and nutrients, leading to feelings of exhaustion, weakness, and heaviness in the limbs.
Reduced exercise tolerance is often one of the earliest noticeable signs of HCM. Individuals may find they cannot maintain their previous level of physical activity or athletic performance. Activities that were once easy, such as climbing stairs, carrying groceries, or playing with children, may become exhausting. Some people notice they need to rest more frequently during activities or require longer recovery periods afterward. This progressive limitation in exercise capacity should prompt medical evaluation, as it may indicate worsening heart function or the development of heart failure. Monitoring exercise tolerance helps healthcare providers assess disease progression and adjust management strategies accordingly.
7. Swelling in the Lower Extremities (Edema)
Swelling in the legs, ankles, and feet, known medically as peripheral edema, can occur in people with hypertrophic cardiomyopathy, particularly when the condition leads to heart failure. This symptom develops when the heart’s pumping inefficiency causes fluid to accumulate in the body’s tissues.
In HCM, the thickened and stiffened heart muscle struggles to relax properly during the filling phase of the cardiac cycle (diastolic dysfunction). This leads to increased pressure in the heart chambers, which backs up into the veins returning blood from the body. The elevated pressure forces fluid out of the blood vessels and into surrounding tissues, especially in the lower extremities where gravity compounds the effect.
The swelling typically appears gradually and is usually more noticeable at the end of the day or after prolonged periods of standing or sitting. Pressing on the swollen area may leave a temporary indentation (pitting edema). In addition to the legs and ankles, fluid can accumulate in the abdomen (ascites) or around the lungs (pleural effusion), causing abdominal distension or worsening shortness of breath. Weight gain from fluid retention may also occur. While edema can have many causes, its presence in someone with known or suspected HCM requires medical assessment to evaluate heart function and determine appropriate management to prevent further fluid buildup.
8. Difficulty Breathing While Lying Down (Orthopnea)
Orthopnea is the medical term for shortness of breath that occurs or worsens when lying flat and improves when sitting up or standing. This symptom is particularly common in HCM patients who have developed heart failure or significant diastolic dysfunction.
When a person with HCM lies down, gravity no longer helps drain fluid from the lungs, and blood from the lower body returns more readily to the heart. The already-stiff heart muscle cannot accommodate this increased blood volume effectively, causing pressure to build up in the lungs’ blood vessels. Fluid then leaks into the air sacs (alveoli), interfering with oxygen exchange and making breathing difficult.
People with orthopnea often describe needing to sleep propped up on multiple pillows or even sleeping in a recliner to breathe comfortably. Some may wake up shortly after lying down, gasping for air, forcing them to sit up or stand to catch their breath. The number of pillows required to sleep comfortably can serve as a rough indicator of symptom severity. Orthopnea represents significant cardiac compromise and should be reported to a healthcare provider promptly. It may indicate the need for adjustments in medical management or further evaluation of heart function.
9. Sudden Awakening with Shortness of Breath (Paroxysmal Nocturnal Dyspnea)
Paroxysmal nocturnal dyspnea (PND) is a frightening symptom characterized by sudden episodes of severe shortness of breath that awaken a person from sleep, typically one to two hours after lying down. This symptom is closely related to orthopnea but is generally more acute and distressing.
PND occurs in HCM patients with advanced disease when fluid that has accumulated in the legs during the day redistributes to the bloodstream upon lying down. After several hours of sleep, this fluid overload overwhelms the compromised heart’s ability to pump effectively, and fluid backs up into the lungs rapidly. The person wakes up with sudden, intense breathlessness, often accompanied by coughing, wheezing, or a feeling of suffocation or drowning.
During a PND episode, the individual typically sits upright or rushes to an open window seeking fresh air. The symptoms usually improve gradually over 15 to 30 minutes in the upright position as fluid redistributes away from the lungs. Some people may cough up pink, frothy sputum, indicating pulmonary edema (fluid in the lungs). PND episodes are frightening and represent significant heart dysfunction. They should be reported to a healthcare provider immediately, as they indicate poorly controlled heart failure that requires prompt medical attention and possible adjustment of treatment strategies.
10. Heart Murmur
A heart murmur is an abnormal sound heard during a heartbeat when listening with a stethoscope. While not a symptom that patients feel themselves, heart murmurs are often the first clinical sign that leads to the diagnosis of hypertrophic cardiomyopathy during routine physical examinations.
In HCM, particularly in obstructive forms (HOCM), the heart murmur is caused by turbulent blood flow as blood is ejected from the left ventricle through a narrowed outflow tract. The thickened interventricular septum and abnormal positioning of the mitral valve create an obstruction that produces a characteristic systolic murmur (heard during the heart’s contraction phase).
What makes the HCM murmur distinctive is that it changes intensity with different maneuvers. It typically becomes louder when the person stands up quickly or performs a Valsalva maneuver (bearing down as if having a bowel movement), as these actions decrease the heart’s blood volume and worsen the obstruction. Conversely, the murmur becomes softer when squatting or gripping hands tightly, which increases blood volume. Healthcare providers use these characteristics to help distinguish HCM from other heart conditions. While patients cannot detect their own heart murmurs, anyone diagnosed with a murmur suggestive of HCM should undergo further cardiac evaluation, including echocardiography, to confirm the diagnosis and assess disease severity.
Main Causes of Hypertrophic Cardiomyopathy
Hypertrophic cardiomyopathy is primarily a genetic disorder with several underlying causes:
Genetic Mutations: The vast majority of HCM cases (approximately 60-70%) result from inherited mutations in genes that encode proteins of the cardiac sarcomere, the contractile unit of heart muscle cells. More than 1,400 mutations in at least 11 different genes have been identified, with the most commonly affected genes being MYH7 and MYBPC3. These mutations are inherited in an autosomal dominant pattern, meaning a child has a 50% chance of inheriting the mutation if one parent carries it.
Spontaneous (De Novo) Mutations: In some cases, HCM results from new genetic mutations that occur spontaneously in an individual without being inherited from either parent. These de novo mutations account for a smaller percentage of cases and can then be passed on to future generations.
Unknown Genetic Factors: Approximately 30-40% of HCM patients test negative for known sarcomeric gene mutations despite clear disease manifestation. Research continues to identify additional genetic variants and mechanisms that may contribute to HCM development in these cases.
Modifier Genes and Environmental Factors: Even among individuals with the same genetic mutation, disease severity and symptom onset can vary considerably. This variability suggests that other genetic factors (modifier genes) and environmental influences may affect how the disease manifests. Factors such as high blood pressure, intense athletic training, and other cardiac stressors may influence disease expression and progression.
Secondary Causes: While rare, some conditions can cause cardiac hypertrophy that mimics HCM, including certain metabolic disorders (such as Fabry disease, amyloidosis, or glycogen storage diseases), syndromic conditions (such as Noonan syndrome), and mitochondrial diseases. These are sometimes referred to as “phenocopies” of HCM and require different management approaches.
Prevention Strategies
While hypertrophic cardiomyopathy is primarily a genetic condition that cannot be prevented, there are several strategies to reduce the risk of complications and manage the disease effectively:
Genetic Counseling and Family Screening: Since HCM is inherited, first-degree relatives (parents, siblings, and children) of affected individuals should undergo cardiac screening with echocardiography and electrocardiogram (ECG). Genetic testing can identify at-risk family members before symptoms develop, allowing for early monitoring and intervention. Prospective parents with HCM should consider genetic counseling to understand inheritance risks.
Regular Cardiac Monitoring: Individuals diagnosed with HCM or those with known genetic mutations should have regular follow-up appointments with a cardiologist, typically annually or more frequently if symptoms develop. Serial echocardiograms help track disease progression, and periodic Holter monitoring can detect arrhythmias before they become problematic.
Activity Modifications: People with HCM should discuss appropriate exercise levels with their cardiologist. While moderate physical activity is generally encouraged for overall health, competitive sports and high-intensity exercise may increase the risk of sudden cardiac death in some HCM patients. Individualized exercise recommendations based on disease severity, symptoms, and risk factors are essential.
Lifestyle Management: Maintaining a heart-healthy lifestyle can help manage HCM symptoms and prevent complications. This includes staying well-hydrated (as dehydration can worsen outflow obstruction), avoiding excessive alcohol consumption, managing stress, maintaining a healthy weight, and controlling blood pressure. Patients should also avoid medications that can worsen symptoms unless specifically approved by their cardiologist.
Prompt Treatment of Symptoms: Addressing symptoms early can prevent progression and complications. Patients should report new or worsening symptoms to their healthcare provider promptly. Following prescribed treatment plans and attending regular follow-up appointments are crucial for optimal disease management.
Sudden Cardiac Death Risk Stratification: Patients should undergo comprehensive risk assessment for sudden cardiac death. Those at higher risk may be candidates for an implantable cardioverter-defibrillator (ICD), which can prevent fatal arrhythmias. Risk factors include family history of sudden cardiac death, unexplained syncope, extreme cardiac hypertrophy, abnormal blood pressure response to exercise, and certain arrhythmias.
Endocarditis Prevention: While not routinely recommended for all HCM patients, those with certain features may need antibiotics before dental or surgical procedures to prevent infective endocarditis. Discuss this with your cardiologist and dentist.
Frequently Asked Questions
What is the difference between HCM and obstructive HCM (HOCM)?
HCM refers to abnormal thickening of the heart muscle, while obstructive HCM (HOCM) is a subtype where the thickened muscle blocks blood flow out of the heart’s left ventricle. Approximately 70% of HCM patients have the obstructive form. HOCM typically causes more pronounced symptoms including chest pain, shortness of breath, and dizziness, especially during exercise.
Can you have HCM without symptoms?
Yes, many people with hypertrophic cardiomyopathy remain asymptomatic throughout their lives. Some individuals are diagnosed incidentally during screening for other reasons or through family screening after a relative is diagnosed. However, even asymptomatic patients require regular cardiac monitoring, as symptoms can develop over time.
Is HCM life-threatening?
HCM can be serious, but most people with the condition live normal lifespans with proper management. The most concerning risk is sudden cardiac death, particularly in younger patients and athletes, though this is relatively rare (approximately 1% per year). Regular monitoring, risk stratification, and appropriate interventions such as medications or implantable defibrillators significantly reduce this risk.
At what age do HCM symptoms typically appear?
HCM symptoms can appear at any age, but they most commonly develop during adolescence or young adulthood (teenage years to 30s) when the heart undergoes growth-related changes. However, some people develop symptoms in childhood, while others remain asymptomatic until middle age or later. The timing of symptom onset varies depending on the specific genetic mutation and individual factors.
Should people with HCM avoid exercise completely?
No, but exercise recommendations must be individualized. While competitive sports and high-intensity training are generally discouraged due to increased risk of sudden cardiac death, moderate recreational exercise is often safe and beneficial for overall health. Each patient should discuss appropriate activity levels with their cardiologist based on their specific disease severity, symptoms, and risk profile.
Can HCM be detected through a regular ECG?
An electrocardiogram (ECG) can show abnormalities suggestive of HCM in many cases, including signs of left ventricular hypertrophy, abnormal Q waves, and repolarization changes. However, a normal ECG does not rule out HCM. Echocardiography is the primary diagnostic tool, as it directly visualizes the heart muscle thickness and function. Some patients may also require cardiac MRI for comprehensive evaluation.
Is HCM the same as having an enlarged heart?
Not exactly. HCM specifically involves thickening (hypertrophy) of the heart muscle, particularly the wall between the ventricles (septum), while the heart’s overall size may not be significantly enlarged. An “enlarged heart” (cardiomegaly) is a broader term that can result from various conditions including high blood pressure, valve disease, or dilated cardiomyopathy. The pattern of muscle thickening in HCM is distinctive and differs from other causes of cardiac hypertrophy.
If I have HCM, will my children definitely have it?
Not necessarily. HCM follows an autosomal dominant inheritance pattern, meaning each child of an affected parent has a 50% chance of inheriting the genetic mutation. However, inheriting the mutation doesn’t guarantee symptoms will develop, as the disease shows variable penetrance and expression. Genetic testing and cardiac screening can identify at-risk family members before symptoms appear.
Can stress or anxiety worsen HCM symptoms?
Yes, emotional stress and anxiety can temporarily worsen HCM symptoms. Stress triggers the release of adrenaline and other hormones that increase heart rate and contractility, potentially worsening outflow obstruction and triggering palpitations, chest pain, or shortness of breath. Managing stress through relaxation techniques, counseling, or other strategies may help reduce symptom frequency and severity.
When should I seek emergency medical care for HCM symptoms?
Seek immediate emergency care if you experience severe chest pain that doesn’t resolve with rest, fainting or loss of consciousness, sudden severe shortness of breath, rapid or irregular heartbeat that doesn’t resolve, or any symptoms suggesting a heart attack or stroke. These could indicate serious complications requiring urgent treatment. Any new or significantly worsening symptoms should be reported to your cardiologist promptly, even if not requiring emergency attention.
References:
- Mayo Clinic – Hypertrophic Cardiomyopathy
- American Heart Association – Hypertrophic Cardiomyopathy
- National Heart, Lung, and Blood Institute – Cardiomyopathy
- Johns Hopkins Medicine – Hypertrophic Cardiomyopathy
- National Center for Biotechnology Information – Hypertrophic Cardiomyopathy
The information on this page is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making decisions related to your health.
Read the full Disclaimer here →