Cardiomyopathy:
symptoms and when to suspect it

Article written and reviewed by Dr Luca Moretti

Cardiomyopathy can cause shortness of breath, fatigue, palpitations, dizziness or fainting, chest pain and swelling of the ankles or legs, but there is no single symptom that makes it possible to recognize it. Some people have obvious symptoms, others only have reduced exercise capacity, and still others have no symptoms for years.
Suspicion increases when these symptoms appear without a clear explanation, especially in a young or middle-aged person, or when the family includes cardiomyopathies, heart failure, serious arrhythmias or sudden cardiac deaths.

Signs that deserve greater attention include:

• shortness of breath during activities that were previously well tolerated or, in more advanced stages, even at rest;
• fatigue and reduced ability to walk, climb stairs or exercise;
• palpitations, a very fast or irregular heartbeat, or a heartbeat perceived as abnormal;
• significant dizziness, a feeling of impending fainting or actual fainting;
• chest pain or pressure, especially during exertion;
• swelling of the ankles, legs or abdomen and rapid weight gain from fluid retention;
• a family history of cardiomyopathy, heart transplantation or sudden death at a young age.

The term cardiomyopathies refers to a heterogeneous group of diseases of the heart muscle. This guide does not describe the classification and mechanisms of individual forms in detail, but helps explain which symptoms can raise suspicion and in which situations medical assessment is appropriate.

Shortness of breath, fatigue and swelling: when the heart struggles to work

One of the most common reasons cardiomyopathy becomes symptomatic is difficulty of the heart in filling or pumping blood adequately. The result may be reduced exercise tolerance: activities that were previously normal, such as walking quickly or climbing several flights of stairs, begin to cause disproportionate breathlessness or fatigue.
In cardiomyopathies with reduced pumping function, the symptom may resemble that of heart failure; in forms with very thick or stiff walls, by contrast, the ejection fraction may be preserved and the problem may depend mainly on ventricular filling. Therefore, having a normal ejection fraction does not by itself exclude cardiomyopathy.

When pressures inside the heart rise, shortness of breath while lying down, waking at night because of breathing difficulty and fluid retention may develop, with swelling especially of the ankles and legs. These symptoms are not specific: they can have many other cardiac, pulmonary, renal or metabolic causes. Their progressive appearance, however, warrants medical assessment, especially when associated with a clear decline in physical capacity.

Palpitations, dizziness and fainting: symptoms related to heart rhythm

Cardiomyopathies can promote atrial or ventricular arrhythmias. A person may feel palpitations, a very fast, irregular or suddenly unusual heartbeat; in other cases, the arrhythmia is not perceived and is identified on an electrocardiogram or Holter monitor.
Palpitations are also very common in people without heart disease, so on their own they do not indicate cardiomyopathy. They become more significant when prolonged, when they occur during exertion or when accompanied by chest pain, severe shortness of breath, dizziness or loss of consciousness.

Fainting deserves particular attention when it occurs during or immediately after exertion, when it is preceded by sudden palpitations or when it affects a person with known cardiomyopathy. Family history also matters: unexplained loss of consciousness in someone who has relatives with cardiomyopathy or sudden death should not automatically be dismissed as a simple drop in blood pressure.
This does not mean that every episode of syncope is cardiac: vasovagal reflexes, dehydration, medications and many other conditions are much more common. The clinical context determines how suspicious the symptom is.

Chest pain and symptoms during exertion

Chest pain can occur in some cardiomyopathies, particularly when the heart muscle is very thick, when there is obstruction to blood flow or when oxygen demand increases during physical activity. In hypertrophic cardiomyopathy, for example, pain, shortness of breath, palpitations or a feeling of impending fainting may be triggered by exertion.

Chest pain should not, however, automatically be attributed to cardiomyopathy. Possible causes include coronary artery disease, pulmonary disorders, gastroesophageal reflux and musculoskeletal problems. If the pain is sudden, persistent, severe or associated with marked shortness of breath, sweating, nausea, weakness or loss of consciousness, the priority is to rule out a cardiac emergency rather than trying to distinguish the cause independently.

Cardiomyopathy can also be present without symptoms

The absence of symptoms does not exclude the disease. Some cardiomyopathies are discovered incidentally after an abnormal electrocardiogram, a heart murmur, an echocardiogram performed for other reasons or during sports screening. Others are identified because a family member has been diagnosed and first-degree relatives undergo assessment.
Family history is therefore important even when someone feels completely well. Particularly relevant findings include a diagnosis of cardiomyopathy, heart failure without a clear cause, ventricular arrhythmias, implantation of a defibrillator, heart transplantation or sudden death occurring in the family at a relatively young age.

The different forms may also present differently. Dilated cardiomyopathy more often presents with reduced pumping capacity and symptoms of heart failure; arrhythmogenic cardiomyopathy may present with palpitations, arrhythmias or syncope; restrictive and infiltrative forms may mainly cause impaired filling and congestion. Symptoms therefore guide the diagnostic pathway but cannot identify the type of cardiomyopathy on their own.

When to seek assessment and when to call emergency services

A medical assessment should be arranged when shortness of breath, an unexplained decline in physical capacity, recurrent palpitations, swelling of the lower limbs or episodes of dizziness and near-fainting occur, especially if the symptoms are new or progressive. The threshold for further investigation should be lower when there is a family history of cardiomyopathy or sudden death.
In these cases, diagnosis is not based on symptoms but on integration of personal and family history, physical examination, electrocardiogram, echocardiogram and, when indicated, other tests such as Holter monitoring, cardiac magnetic resonance imaging and genetic testing.

Emergency services should instead be used when symptoms are acute and severe: severe breathing difficulty, persistent chest pain, loss of consciousness, prolonged palpitations associated with marked illness, or when a person is unresponsive and not breathing normally. In these situations, call 112 or 118 and follow the operator's instructions.

Frequently asked questions about cardiomyopathy symptoms

What are the most common symptoms of cardiomyopathy?
Shortness of breath, fatigue, reduced exercise tolerance, palpitations, dizziness or fainting, chest pain and swelling of the ankles or legs. None of these symptoms, however, is specific to cardiomyopathy.

Can someone have cardiomyopathy without symptoms?
Yes. The disease may be discovered by ECG, echocardiography, MRI or family screening even in an asymptomatic person.

Do palpitations mean I have cardiomyopathy?
No. They are very common and have many causes; they become more suspicious when associated with syncope, chest pain, severe shortness of breath or a significant cardiac family history.

When should fainting raise suspicion of a heart problem?
When it occurs during exertion, is preceded by palpitations, occurs in a person with known heart disease or occurs in a family with cardiomyopathy or sudden death.

When should you call 112 or 118?
For severe breathing difficulty, persistent chest pain, loss of consciousness, prolonged palpitations with marked illness or signs of cardiac arrest.