Right Ventricular Hypertrophy

What is Right Ventricular Hypertrophy?

Right ventricular hypertrophy (RVH) is a condition where the muscle mass of the right side of your heart expands abnormally. This usually happens in response to long-term pressure overload and is often a result of a chronic, severe lung disease. Typically, the right side of your heart is smaller than the left, and its operations can be overshadowed by the more dominant left ventricle. But, when RVH occurs, changes like right axis deviation (RAD) and alteration of the normal R wave progression (an electrical pattern of your heart) take place. Pulmonary hypertension (high blood pressure in the lungs) and conditions affecting the tricuspid valve (a valve in the heart) like regurgitation (leakage), often lead to right ventricle impairment.

Understanding the structure of the right ventricle in the heart can be challenging due to its complex shape. Evaluating it fully requires different imaging techniques because of the many differences between the structures and functions of the right and left sides of the heart. These differences come from their separate origins during the development of an embryo. The right ventricle consists of various parts, including regions for blood inflow and outflow, valves and muscles, and boundaries defining the ventricle’s shape. Its inner surface is heavily ridged, and this, combined with other features, makes it distinct from the left ventricle when viewed on an ultrasound. The normal thickness of the right ventricle’s wall is smaller than that of the left side, contributing to its different functions and characteristics.

The function of the right ventricle can be affected by changes in preload (the volume of blood in the ventricle at the end of filling), afterload (the pressure the ventricle has to pump against), and its intrinsic ability to contract. The unique arrangement of muscle fibers in the right ventricle results in its symmetrical shrinking in various directions. The right ventricle also has certain distinctive characteristics compared to the left ventricle – it relies more on oxygen from the blood inside it than blood flowing through the coronary arteries, it has a shorter action potential duration (period of time for electrical activity), and it has more adrenergic and cholinergic receptors (receptors responding to nerve stimulation). The right ventricle mainly shrinks lengthwise, leading to its unique movement pattern. And because its wall is thinner, it’s more vulnerable to even small changes in the resistance of blood flow through the lungs. An ongoing pressure overload can lead to RVH and, if left untreated, to a failure of the right ventricle.

What Causes Right Ventricular Hypertrophy?

Right Ventricular Hypertrophy or RVH is a condition where the right side of your heart becomes thicker and larger because of an illness. There are a few different reasons that can cause this to happen.

One of these reasons is what we call Pulmonary Hypertension, which is essentially high blood pressure in the lungs. The World Health Organization has a system that classifies Pulmonary Hypertension into 5 groups:

1. Pulmonary arterial hypertension (PAH)
2. Pulmonary hypertension caused by a left heart disease,
3. Pulmonary hypertension caused by a lung disease,
4. Chronic thromboembolic pulmonary hypertension (CTEPH which is a fancy term to describe blood clot in the lungs), and
5. Pulmonary hypertension with unclear origins.

RVH can also occur due to some congenital heart diseases which are conditions you’re born with. These include:

1. Tetralogy of Fallot,
2. Isolated pulmonary stenosis,
3. Double-chambered right ventricle,
4. Post-atrial switch heart, and
5. Eisenmenger syndrome.

At times, it can be because of intrinsic myocardial disease, which means diseases that damage the muscles of your heart. Some conditions causing this could be:

1. Hypertrophic cardiomyopathy,
2. Cardiac fibrosis,
3. Athlete’s heart,
4. Cardiac amyloidosis,
5. Essential hypertension, and
6. Left heart failure.

Finally, RVH can be caused by a disease in the tricuspid valve. This is a condition where the valve between the two right heart chambers doesn’t close properly, allowing blood to flow back into the top chamber of the heart. This increases the workload of the right side of the heart, which can lead to RVH. This can be caused by the following:

1. Secondary tricuspid regurgitation mostly due to lung or heart disease, and
2. Primary tricuspid regurgitation caused by many things including damage from medical procedures, chest trauma, congenital disorders, bacterial infections, right heart blockages or heart attacks, connective tissue disorders, certain types of cancer, and drug reactions.

Risk Factors and Frequency for Right Ventricular Hypertrophy

While large-scale studies to determine the prevalence of Right Ventricular Hypertrophy (RVH) are scarce, some research offers some perspective on its occurrence across different conditions. For example, RVH was found in 33.6% of 330 patients with high blood pressure treated outside of a hospital setting in one study. In a different study, extreme RVH was noticed in 1.3% of 2413 people with a heart condition known as hypertrophic cardiomyopathy. The occurrence of RVH in athletes can vary based on the criteria used to identify it.

Understanding the prevalence of Pulmonary Hypertension (PH), which is often linked to RVH, can also provide insights. The prevalence of idiopathic and familial Pulmonary Arterial Hypertension (PAH) is estimated to be between 10 to 52 cases per million adults globally. However, the exact prevalence of PH caused by left heart failure is not clearly defined due to variations in study design, definition of pulmonary hypertension, and diagnostic methods. Nevertheless, most studies based on heart ultrasound suggest that diseases of the left heart cause 70% of PH cases.

• RVH was found in 33.6% of 330 high blood pressure patients in a study.
• In another study, 1.3% of 2413 people with hypertrophic cardiomyopathy had extreme RVH.
• RVH occurrence in athletes can vary based on the criteria used for identification.
• The estimated number of cases of idiopathic and familial Pulmonary Arterial Hypertension is between 10 to 52 per million adults worldwide.
• The exact prevalence of PH resulting from left heart failure is uncertain due to various factors.
• It’s estimated that left heart diseases cause 70% of PH cases based on ultrasound studies.

In older adults, a type of Pulmonary Hypertension known as ‘Group 3’ seems to be more common. A study showed that 14% of patients aged 65 and above had Group 3 Pulmonary Hypertension, while 28% had Group 2, and 17% had a combination of Group 2 and 3. The prevalence of Chronic Thromboembolic Pulmonary Hypertension (CTEPH) is not known, but it is thought to be between 1% and 5% among those who survive acute pulmonary embolism.

• Group 3 PH was found in 14% of patients aged 65 and above in a study.
• 28% of the same group had Group 2 PH, and 17% had a combination of Groups 2 and 3.
• The prevalence of CTEPH among survivors of acute pulmonary embolism is estimated to be between 1% and 5%.

Signs and Symptoms of Right Ventricular Hypertrophy

Right ventricular hypertrophy (RVH) is a condition that usually results from a long-term heart or lung problem, causing right-sided heart failure symptoms that gradually develop. People tend to seek medical attention when these symptoms suddenly worsen.

Common symptoms include:

• Chest pain during physical activities
• Sudden faintness or loss of consciousness during physical activity
• Rapid heart rate or palpitations
• Swelling of the arms and legs
• Loss of appetite and upper right stomach pain

Other less common symptoms could be a cough, spitting up blood, or a hoarse voice caused by nerve compression due to a widened main pulmonary artery. Patients may also present with a history of chronic lung or heart conditions, such as chronic obstructive pulmonary disease (COPD), and genetic heart or lung disorders in the family history. Severely affected patients may be unconscious and not breathing with no pulse, indicating a need for immediate resuscitation.

During a physical examination, someone with RVH might show signs such as:

• Weight loss, bluish discoloration of the skin or lips, and breathing difficulties
• Fast heart rate, with or without irregular heart rhythms
• Signs of low blood pressure, which could point to left heart failure or shock

An examination of the veins in the neck could show obvious, swollen veins – a sign of increased pressure in the right side of the heart. Some patients might also have noticeable outward movements in the chest, which can indicate a significant enlargement of the heart’s right ventricle. Various heart sounds may also be heard, possibly indicating other heart conditions. The severity of these findings can differ depending on the underlying cause of RVH.

In addition to these signs, swelling in the abdomen or legs, along with accumulation of fluid in the abdominal cavity, could suggest severe disease. An enlarged tender liver, which may be felt through the abdominal wall, could also be a sign of severe RVH.

Testing for Right Ventricular Hypertrophy

The process of checking for RVH, or Right Ventricular Hypertrophy which is when the muscle on the right side of the heart thickens, involves several steps. These steps can help the doctor to determine the underlying cause and any associated heart abnormalities.

A chest x-ray is one way a doctor checks for RVH. This can help the doctor to see if the right side of the heart is enlarged, a condition known as Right Ventricular Enlargement (RVE). The x-ray can also show other potential issues like fluid in the lungs or displacement of the diaphragm.

Another method doctors use is called an ECG, or electrocardiogram. This test measures the electrical activity of the heartbeat. With RVH, the pattern of the heart’s electrical activity can look different, which can help the doctor reach a diagnosis. The ECG may reveal tall R waves, which are a type of electrical pattern, in certain areas of the heart or deep S waves in others.

If the diagnosis is still unclear, a doctor might use a technique called echocardiography. This is a type of ultrasound for the heart, which helps to evaluate the chambers of the heart, the thickness of the heart muscle, how well the heart is pumping blood, and whether there’s blood flowing back into the heart because of a problem with one of the heart’s valves.

If the echocardiogram doesn’t provide a clear picture of the heart, a doctor might also use a technique called Cardiovascular Magnetic Resonance or CMR. This method is considered the best way to determine whether or not you have RVH. It helps the doctor to get a really detailed look at the heart. If needed, a procedure known as a cardiac catheterization could be performed, but this is usually not necessary as it’s more invasive.

Other tests can include pulmonary function tests or PFTs. These tests measure how well the lungs are working and may help to identify whether lung disease is contributing to RVH. Doctors might also do overnight oximetry, which checks oxygen levels in the blood while you sleep, or a sleep study called a polysomnography. An exercise test could also be done to see how well your lungs and heart work while you’re exercising.

Treatment Options for Right Ventricular Hypertrophy

Treatment for pulmonary hypertension, a condition causing high blood pressure in the lungs, aims to reduce the load on the right side of your heart by lowering resistance to blood flow in your lungs. Typically, doctors prefer to use a combination of medications rather than just one. These can include medicines like bosentan (which blocks certain substances in the blood vessels), sildenafil (which helps your lungs work better), and iloprost (which helps to widen your blood vessels). One study found that a combination of two specific drugs, ambrisentan and tadalafil, was more successful in reducing heart failure rates and improving exercise capacity than just one drug on its own.

People who have fluid buildup due to severe damage to the right side of their heart (right-sided heart failure) and associated issues may also use diuretics, which help to reduce excess fluid in the body. Aldosterone antagonists, which block actions of a hormone that can cause salt and fluid buildup, may provide extra help in certain cases, such as those experiencing an increase in aldosterone (a hormone affecting salt and water balance in the body) due to liver congestion.

If there is damage to the tricuspid valve in the heart, causing it to leak (tricuspid regurgitation), the treatment often targets the main cause of the problem. For instance, if heart failure is due to the left side of the heart not pumping properly, treatments could involve medication to reduce strain on the heart, such as β-blockers (which slow the heart rate), and treatments that inhibit the renin-angiotensin-aldosterone system, a body process that can affect blood pressure and fluid balance.

It’s crucial to treat the root cause of pulmonary hypertension. Depending on your condition, you may need additional treatments such as oxygen or blood thinners. Those who continue to struggle with pulmonary hypertension despite treatment should be evaluated by specialists for advanced therapies. The selection of the best therapy varies from person to person and can depend on a range of factors, including symptom severity, right ventricular function, and individual preference.

A procedure called balloon atrial septostomy, which can improve blood flow, could be an option for certain patients as a temporary measure before more definitive surgery, or as a way to relieve symptoms. In severe cases, lung transplantation could be needed, especially if symptoms persist after three months of a specific therapy called epoprostenol.

Regarding the treatment of severe tricuspid valve leakage, surgery could be a solution for those who are still struggling despite medical treatment. Repairing the valve is preferable to replacing it, if possible. Nonetheless, there is a recurring risk with repair procedures. Patients undergoing surgery for diseases affecting left-side valves might also benefit from simultaneous tricuspid valve repair. In severe cases, surgery may be necessary even if there are no symptoms. Choosing between different types of prosthetic tricuspid valves will depend on individual patient characteristics. Mechanical valves are durable but require blood thinners to minimise the risk of blood clots.

What else can Right Ventricular Hypertrophy be?

Diagnosing right ventricular hypertrophy (or RVH) involves differentiating it from other conditions that may appear similar based on signs, symptoms, and ECG results. Other conditions to consider can include:

• Left-sided heart failure: This can cause symptoms such as swelling due to fluid retention (peripheral edema), upper right abdominal pain from liver congestion, fainting (syncope) because of irregular heart rhythm or insufficient blood supply, and chest pain during exertion. Echocardiography or cardiac catheterization can help distinguish it from RVH.
• Coronary artery disease: This condition commonly causes symptoms like chest pain during exertion, fainting because of irregular heart rhythm, and symptoms similar to heart failure. It can be identified with stress tests or cardiac catheterization.
• Budd-Chiari syndrome: This condition results from blood clots in the liver’s veins and reduces the flow of blood from the liver, causing swelling due to fluid retention and upper right abdominal pain. Methods such as Doppler ultrasonography, CT scans, MRI, and venography can help identify this condition.
• Liver disease: These can be either acute or chronic and cause swelling because of fluid retention accompanied by upper right abdominal pain. Liver function tests and an ultrasound scan of the upper right abdomen can help identify liver diseases. A liver biopsy, while rarely necessary, is the most conclusive test for liver disease.

It’s also important to note that RVH has ECG characteristics similar to other conditions, including posterior-wall myocardial infarction, Wolff-Parkinson-White pattern, hypertrophic cardiomyopathy, early precordial transition and others. Interestingly, these ECG patterns can also appear in healthy people as normal variations or changes due to body position.

What to expect with Right Ventricular Hypertrophy

The outlook for someone with pulmonary hypertension – a type of high blood pressure that affects the arteries in the lungs and the right side of the heart – can greatly differ. It depends on the cause and how severe the symptoms are. In general, if severe pulmonary hypertension and right heart failure are not treated, the outlook isn’t good.

Evidence suggests that a condition known as RVH (Right Ventricular Hypertrophy) – the enlargement of the right side of the heart – plays a role in the survival of patients with pulmonary hypertension. Specifically, the measurement of the mass of the right side of the heart at the end of its resting phase is highly linked to survival. For every 10% increase in this measurement, there is a 12% rise in the risk of death. Therefore, measurements of the right ventricular mass could offer useful information about the outlook for patients with pulmonary hypertension, as RVH tends to occur before the right side of the heart becomes dilated (stretched) and fails in these patients.

Without treatment, individuals with Group 1 pulmonary hypertension typically have a worse outlook than those with Groups 2 to 5 pulmonary hypertension. However, with surgical treatment, patients with CTEPH (Chronic Thromboembolic Pulmonary Hypertension), a type of Group 1 pulmonary hypertension, usually have the best survival rate. People with chronic lung disease associated with pulmonary hypertension (Group 3) have a worse survival rate at one year (80% versus 88%), three years (52% versus 72%), and five years (38% versus 59%) than those with PAH (Pulmonary Arterial Hypertension), a form of Group 1 pulmonary hypertension. Meanwhile, those with Group 2 pulmonary hypertension typically have similar survival rates as those with PAH.

Possible Complications When Diagnosed with Right Ventricular Hypertrophy

Right ventricular hypertrophy (RVH), or an enlarged right side of the heart, can cause a disruption within the heart’s normal electrical conduction system. This disruption may lead to arrhythmias, which are abnormal heart rhythms. These can include both atrial and ventricular fibrillation. If these heart irregularities become severe and are not treated promptly, they can impair the heart’s ability to pump blood. This may result in fainting spells, heart palpitations, or even sudden cardiac death.

In some cases, RVH could eventually lead to right-sided heart failure. This happens when the enlarged right ventricle finds it hard to cope with increased pressure or volume, affecting its ability to effectively pump blood to the lungs. Such heart failure can cause congestion in the veins throughout your body, leading to potential symptoms like:

• Swelling in the legs and feet (peripheral edema)
• Buildup of fluid in the abdominal cavity (ascites)
• Liver dysfunction and swelling (hepatomegaly)

If left untreated, right-sided heart failure might also affect the left side, leading to biventricular failure with severe symptoms that can significantly reduce an individual’s quality of life and overall health prognosis. Therefore, it’s vital to promptly identify and treat RVH to prevent further deterioration of cardiac function.

However, it’s also important to note that the treatment for RVH can come with its own complications. These may include negative drug reactions, worsening of existing health conditions, or possible complications from surgical measures. Advanced therapies like implantable devices or transplantation also carry risks. Aggressive treatments can sometimes cause an imbalance in the body’s electrolytes, unstable blood pressure and heart rate, or damage to other organ systems. Constant monitoring and management are essential for managing these potential effects in individuals with RVH.

Preventing Right Ventricular Hypertrophy

The first step in preventing RVH, a condition where the right side of the heart has to work harder, involves identifying and managing risk factors. This includes treating conditions like lung disease, pulmonary hypertension, and congenital heart defects, as well as overall health issues. Regular exercise, staying fit, and avoiding smoking can greatly help prevent RVH. It’s also vital to catch and treat conditions connected to RVH early, such as sleep apnea, to stop it from getting worse.

If someone already has RVH, the focus shifts to managing the condition to halt further progression. This involves regular heart check-ups using diagnostic tests like echocardiography (an ultrasound of the heart) and ECG (a test that measures the electrical activity of the heart). They also need to assess symptoms and risk factors to monitor how the disease is progressing. Treatment might include medications to lower pulmonary hypertension, optimize the way the heart functions, and manage symptoms. In some instances, surgical procedures like replacing the pulmonary valve or fixing congenital heart defects might be necessary to reduce the pressure or volume overload on the right side of the heart. Patients also need to adapt their lifestyles and learn about their condition to better manage it and reduce the risk of complications.