Left ventricular non-compaction (LVNC): what it means for the heart

The inner surface of the heart's left ventricle normally has a network of small muscle ridges called trabeculations. Cardiomyopathy UK explains that trabeculations are a normal finding, but some people have an excess amount, which has been referred to as non-compaction or hypertrabeculation. In these hearts the muscular wall looks spongy or non-compacted, and the term LVNC or LV hypertrabeculation is used.

It can occur on its own or together with thickening (hypertrophy), enlargement (dilation) or reduced pumping ability of the heart. The NHS describes cardiomyopathy more generally as diseases of the heart muscle, where the walls of the heart chambers become stretched, thickened or stiff, affecting the heart's ability to pump blood.

It is important to separate the appearance from a diagnosis of disease. Cardiomyopathy UK states that you will only be diagnosed with cardiomyopathy if your heart function is impacted, and that hypertrabeculation can be a transient finding that does not always develop into a cardiomyopathy. This is why scans that show prominent trabeculation do not always lead to treatment.

Cardiomyopathy UK says you are likely only to have symptoms if you have hypertrabeculation together with cardiomyopathy. Not everyone has symptoms, and some never do. Where symptoms occur they are specific to the type of cardiomyopathy.

• Breathlessness.

• Fatigue or extreme tiredness.

• Feeling dizzy or light-headed.

• Palpitations.

• Loss of consciousness.

LVNC can come to light when heart imaging is done for another reason, or because a relative has cardiomyopathy. Cardiomyopathy UK says someone with a family member with cardiomyopathy, or symptoms that suggest a heart condition, may be referred for tests including those below.

• A medical history and family tree, to look at symptoms and whether other family members have the condition, which can be genetic.

• A physical examination.

• An electrocardiogram (ECG), to look at the electrical activity of the heart and see whether abnormal rhythms are happening.

• An echocardiogram, to look at the function of the heart and the movement of blood through it.

• An MRI scan, which provides more detail on the structure and function of the heart muscle.

Cardiomyopathy UK says treatment is guided by the results of diagnostic tests and the symptoms, alongside the diagnosis of a specific type of cardiomyopathy such as hypertrophic, dilated or arrhythmogenic. Treatment is therefore individualised, and may include medication, implantable devices, surgery and lifestyle management.

Because hypertrabeculation does not always affect heart function, the plan depends on the individual findings and is agreed with the cardiology team. Where pumping function is reduced, the NHS notes in its description of dilated cardiomyopathy that there is a greater risk of heart failure, which typically causes shortness of breath, extreme tiredness and ankle swelling, and that regular appointments are needed to monitor the condition.

The NHS says most types of cardiomyopathy are inherited, though it can also be caused by other conditions or risk factors, and for some people the cause is unknown. Cardiomyopathy UK includes taking a family tree among the investigations because the condition can be genetic.

Cardiology and inherited cardiac conditions services may offer checks to close relatives, and Cardiomyopathy UK runs a genetic advice helpline and a nurse helpline for families.

Fainting or loss of consciousness, especially during or soon after exercise, new palpitations with dizziness, or worsening breathlessness or swelling should be assessed promptly by a doctor. Call 999 for collapse or loss of consciousness. People known to have LVNC should also discuss with their cardiologist what level of exercise is suitable and whether any sports restrictions apply.