What Is Left Ventricular Non Compaction 

Overview

Left Ventricular Non-Compaction (LVNC) occurs when the left ventricle (the bottom left  chamber of the heart)  does not develop properly.¹ It is an extremely rare  congenital myopathy, a term that describes  any muscle disorder.  It  is usually genetic and  is often present at birth. Its  symptoms  include weakness and a lack of muscle tone (muscle tone  is what helps us to hold our bodies upright when sitting and standing). 

In LVNC the left  ventricle  can appear thick and spongy as opposed to being  smooth and firm. This  abnormality in the muscle of  the left ventricle means it cannot completely contract or   relax. This ultimately affects the heart’s ability to pump blood  efficiently and can also affect the electrical signalling of the heart which controls the speed at which the heart beats. 

Causes of left ventricular non compaction 

LVNC is  a congenital condition, so those who have LVNC are usually born with it. Mutations in several genes have been found to cause left ventricular non-compaction; specifically the MYH7 and MYBPC3 genes, which have been estimated to cause up to 30% of cases.  

Signs and symptoms of left ventricular non compaction 

LVNC is not always accompanied by symptoms and it varies  on the severity  and position of the non-compaction (the spongy muscle). 

Symptoms can occur because the non-compaction reduces how efficient the heart is, which can sometimes cause symptoms of heart failure, as not enough blood is pumped around the body. 

Symptoms can include: 

• Breathlessness 
• Fatigue (extreme tiredness)
• Feeling light-headed
• Fainting or passing out 
• Feeling abnormal palpitations (heart beats) 
• Swollen legs, ankles or feet  

Management and treatment for left ventricular non compaction 

The management and treatment of LVNC aims to control symptoms, prevent complications, and reduce the risk of heart failure and arrhythmias. Here are some common approaches:

1. Medications:
   • Heart failure management: Medications such as beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), or diuretics may be prescribed to manage symptoms of heart failure, including fatigue, shortness of breath, and fluid retention
   • Antiarrhythmic medications: If arrhythmias are present, antiarrhythmic drugs such as beta-blockers, sodium channel blockers, or other medications may be prescribed to control and prevent abnormal heart rhythms
2. Surgical interventions:
   • Left Ventricular Assist Device (LVAD): In severe cases of heart failure that does not respond to medication, a LVAD may be considered. This is a mechanical pump implanted in the chest that assists the heart in pumping blood
   • Heart transplantation: For individuals with end-stage heart failure or severe symptoms, heart transplantation may be an option
3. Lifestyle modifications:
   • Regular exercise: Engaging in regular physical activity  can help maintain cardiovascular fitness and overall health. However, it's important to consult with a healthcare professional before starting an exercise program
   • Heart-healthy diet: Adopting a balanced diet that is low in saturated fats, sodium, and cholesterol  and high in fruits, vegetables, whole grains, and lean proteins can promote heart health
   • Avoiding tobacco and alcohol: Smoking and excessive alcohol consumption can worsen heart function and should be avoided

It's important to note that  treatment  may vary based on the severity of symptoms, presence of complications, and on the individual . The management and treatment plan for LVNC should be tailored to each individual's specific needs and determined in collaboration with a cardiologist or a healthcare professional experienced in managing cardiomyopathies.

Diagnosis of left ventricular non compaction 

LVNC is typically diagnosed through a combination of medical history evaluation, physical examination, imaging studies, and cardiac function assessments. A few examples can include: 

1. Echocardiography: Transthoracic echocardiography (TTE) is the primary imaging technique  used to diagnose LVNC. It allows visualisation of the heart's structure and function using sound waves. LVNC is characterised by the presence of excessively trabeculated (irregular finger-like projections) and non-compacted segments (areas where the muscle appears spongey)  of the left ventricle
2. Cardiac magnetic resonance imaging (MRI): Cardiac MRI provides detailed images of the heart's structure and can help differentiate LVNC from other cardiomyopathies. It can also assess ventricular function, measure myocardial thickness, and evaluate blood flow patterns
3. Electrocardiogram (ECG): An ECG records the electrical activity of the heart. It may show abnormalities such as arrhythmias, conduction delays, or changes in the ventricular repolarization
4. Genetic testing: In some cases, genetic testing may be recommended to identify specific genetic mutations associated with LVNC. This can be valuable for identifying family members who may also be at risk

Risk factors & Complications 

Complications and risk factors associated with LVNC may include:²

1. Heart failure: LVNC can lead to impaired systolic function (the heart’s ability to contract and empty), resulting in heart failure. Symptoms may include fatigue, shortness of breath, fluid retention, and exercise intolerance
2. Arrhythmias: LVNC is associated with an increased risk of various arrhythmias, including ventricular arrhythmias, atrial fibrillation, and conduction abnormalities. These abnormal heart rhythms can increase the risk of sudden cardiac arrest or other life-threatening events
3. Thromboembolism: The trabeculated and non-compacted areas of the ventricle  provides the perfect environment  for blood clots to form. These clots can potentially dislodge and travel to other parts of the body, leading to stroke
4. Family history: LVNC  is a genetic condition , and a positive family history of LVNC or sudden cardiac death may increase the risk of developing the condition
5. Other cardiac abnormalities: LVNC can coexist with other congenital heart defects, such as ventricular septal defects, valvular abnormalities, or abnormalities in the coronary arteries

FAQs

How can I prevent left ventricular non compaction? 

Left ventricular non-compaction (LVNC) is a congenital condition, and currently, there are no known preventive measures to avoid its development. It is primarily caused by genetic factors and occurs during foetal  development. Lifestyle changes or interventions can help to control symptoms and prevent complications.

How common is left ventricular non compaction? 

LVNC is considered a relatively rare condition, and it is estimated to occur in approximately 0.05-0.24% of the general population.³ However, the true prevalence may be higher as some individuals with LVNC may remain undiagnosed or asymptomatic

When should I see a doctor?

If you suspect you may have LVNC or are experiencing symptoms associated with the condition, it is advised  to consult  a doctor. Other  situations when you should consider seeking medical attention include:

1. Symptoms: If you experience symptoms such as fatigue, shortness of breath, chest pain, lightheadedness, or palpitations, it is important to see a doctor for evaluation. These symptoms may indicate a potential heart condition, including LVNC
2. Family history: If you have a family history of LVNC or sudden cardiac death, it is recommended to consult with a doctor for further evaluation. Genetic factors can play a role in the development of LVNC, and screening may be recommended for at-risk family members
3. Abnormal test results: If imaging studies such as echocardiography or cardiac MRI reveal findings suggestive of LVNC, it is crucial to follow up with a doctor who specialises in cardiovascular medicine or genetic counselling for a comprehensive evaluation
4. Concerns or questions: If you have any concerns or questions about your heart health or the possibility of having LVNC, it is always appropriate to consult with a healthcare professional. They can evaluate your specific situation, provide appropriate guidance, and order further tests if necessary

Summary

Overall, left ventricular non-compaction (LVNC) is a rare congenital cardiomyopathy characterised by excessive and prominent trabeculations (finger-like projections) and non-compacted segments (where the muscle appears spongy ) within the left ventricle. This condition occurs during foetal development and is genetic in origin. 

Treatment aims to manage symptoms, prevent complications, and reduce the risk of heart failure and arrhythmias. Medications such as beta-blockers, ACE inhibitors, or ARBs may be prescribed. Device therapy, such as an implantable cardioverter defibrillator (ICD), may be recommended for individuals at high risk of arrhythmias or sudden cardiac death. In severe cases, a left ventricular assist device (LVAD) or heart transplantation may be considered. Regular follow-up with a healthcare professional is important for monitoring and adjusting the patient’s treatment plan.