Understanding Cyanotic Heart Disease : Causes, Types, Symptoms & Diagnosis

Cyanotic heart disease is a group of congenital heart problems that occur at birth. It can lead to abnormally low oxygen levels in the blood causing the bluish color of skin and mucus membranes.

Congenital heart disease refers to the condition that occurs at birth including heart defects.

Cyanotic heart disease is a life-threatening condition and it is therefore important to have an understanding of it. It reduces the level of oxygen in the body which can lead to a range of complications including pulmonary hypertension, heart failure, and developmental delays in children.

According to the Centers for Disease Control and Prevention, congenital heart defects affect around 1% of birth in the United States.⁽¹⁾ Also, among the children with congenital heart disease, 25% have cyanotic heart disease.⁽²⁾

Understanding cyanotic heart disease can be helpful in recognizing its potential impact and taking appropriate steps to improve the overall health and quality of life of the people.

Cyanotic heart disease is caused by structural abnormalities of the heart and is associated with blood vessels that result in reduced oxygen flow to the body. These abnormalities can occur during fetal development and are present at birth.

Some of the potential causes of cyanotic heart disease include:

• Tetralogy of Fallot: It is a condition that is a combination of 4 structural defects in the heart, which include ventricular septal defect, pulmonary stenosis, overriding, and right ventricular hypertrophy.⁽³⁾
• Transposition of Arteries: It is a condition, in which the two main arteries (pulmonary artery and aorta) leaving the heart are switched resulting in blood poor in oxygen being circulated in the body.
• Truncus Arteriosus: It is a condition in which there is just a single artery leaving the heart instead of 2 separate arteries.
• Pulmonary Atresia: In this condition, there is a blockage in the pulmonary valve preventing the blood flowing from the heart to the lungs to be oxygenated.
• Total Anomalous Pulmonary Venous Connection: It is a condition in which the veins that carry oxygen-rich blood from the lungs to the heart are connected to the correct part of the heart.

Cyanotic heart disease is of three subtypes:

• Right Heart Obstructive Lesion: These lesions are caused due to the reduced flow of blood from the right side of the heart to the left. This reduces the blood flow between the heart and lungs.⁽²⁾ These lesions include pulmonary atresia and tricuspid atresia.
• Left Heart Obstructive Lesions: In these lesions, the flow of blood from the left to right of the heart is affected reducing the flow of the blood to the rest of the body. It includes hypoplastic left heart syndrome and critical aortic stenosis.
• Mixing Lesions: It involves conditions in which the flow of blood from the heart to the lungs and to the rest of the body is affected. It includes the transposition of the greater arteries and truncus arterioles.

Cyanotic heart disease leads to the spread of low-oxygen blood to the body. It may lead to the following symptoms:

• Bluish tint on the skin, lips, and nails
• Shortness of breath during exertion or physical activity
• Increased respiratory rate
• Fatigue and weakness during physical activity
• Poor growth of the child or difficulty in gaining weight
• Clubbing of fingers
• Pain in the chest

Some people with cyanotic heart disease may not experience any symptoms or may have mild symptoms. It is important to monitor the conditions and reach out for help if any of such symptoms are noted.

Before birth, cyanotic heart disease can be diagnosed with a fetal echocardiogram.

Other tests to diagnose the condition and determine the severity include:⁽⁶⁾

• Physical Examination: A doctor can thoroughly examine the person for the signs of a bluish tint on the skin, lips, eyes, and abnormal heart rhythm.
• Pulse Oximetry: This is monitoring the oxygen saturation in the body by attaching a sensor to the finger.
• Electrocardiogram: It records the electrical activity of the heart and helps in identifying the abnormality
• X-ray of the Chest: It provides the image of the heart and lungs and can reveal any abnormality or sign of heart failure
• Echocardiogram: It is a non-invasive test that creates images of the heart by using sound waves. It can also provide detailed information about the structure and function of the heart.
• Cardiac Catheterization: This test involves inserting a thin tube into the blood vessel and threading it up to the heart to measure pressure. It can also visualize the heart and blood vessels using contrast dye.
• Magnetic Resonance Imaging: It is an advanced imaging technique that provides details of the heart and blood vessels and can be helpful in diagnosing and monitoring cyanotic heart disease.

A group of specialists including a pediatrist can plan out what diagnostic test to go ahead with for the patient with cyanotic heart disease.

Certain medications such as diuretics can be helpful in eliminating excess fluid from the body and reducing the workload on the heart. Other medications include blood pressure medication.

Supplemental oxygen can be provided in some cases to increase the oxygen levels in the body and reduce the symptoms of cyanosis.

It is important to measure blood oxygen levels and electrolytes as they provide important information about the functioning of the heart and the overall health of the body. The blood oxygen level indicates the amount of oxygen being carried by the blood and being delivered to the body and it should be maintained well to maintain the function of the body.

Blood oxygen levels can be monitored by regular blood tests, pulse oximetry, and other diagnostic tests depending on the individual case.

Surgical interventions in cyanotic heart disease are important to correct the structural abnormalities and improve the blood flow in the individuals.⁽⁴⁾ The type of surgical intervention may depend on the type and severity of the defect.

Some of the surgical interventions for cyanotic heart disease include:

• Repairing or Replacing Heart Valve: Sometimes the heart valve may be malformed, reducing the blood flow or causing regurgitation of blood. Repairing the valve may improve the blood flow and improve the symptoms
• Closure of Septal Defect: Septal defects are the holes in the wall that separate the two chambers of the heart. These holes can cause the blood to move in the wrong direction reducing the efficiency of the heart.
• Creation of Shunt: A shunt is created to direct blood flow from one part of the heart to another. This can help increase the level of oxygen level in the blood and reduce the symptoms of deoxygenation.
• Heart Transplant: In some cases, a heart transplant may be needed. It can be done in the case of a severely damaged heart.

Lifestyle changes can play an important role in managing cyanotic heart disease. A few lifestyle changes include:⁽⁵⁾

• Avoid smoking as it worsens the symptoms. Secondhand smoke should also be avoided.
• Exercise regularly to improve heart health and increase oxygen levels in the blood.
• Eat a healthy and well-balanced diet as it can help in the management of the symptoms of cyanotic heart disease. A heart-healthy diet includes a diet low in saturated fat, cholesterol, and sodium.
• Keep the body hydrated as a dehydrated body worsens the symptoms of cyanotic heart disease.
• Stress worsens the symptoms of cyanotic heart disease. It is therefore important to manage stress with meditation, deep breathing exercises, or yoga.
• Avoid areas with high altitudes as the symptoms of cyanotic heart disease can worsen in these places.

Cyanotic heart disease leads to decreased oxygenated blood in the body. It can lead to the following potential complications including:

• Heart Failure: It is the inability of the heart to pump enough blood according to the body’s needs. In cyanotic heart disease, the heart needs to work harder to pump blood through the narrowed or obstructed blood vessels increasing the strain on the heart muscles. Over time the heart muscle weakens and gets less efficient. This may lead to heart failure.
• Pulmonary Hypertension: Pulmonary hypertension is a condition in which the blood vessels that supply the lungs have high blood pressure. In cyanotic heart disease, the arteries in the lung constrict increasing resistance to the blood flow and elevating blood pressure. This can further strain the heart and lead to shortness of breath, fatigue, and chest pain.

Other complications of cyanotic heart disease include arrhythmia, stroke, and bacterial endocarditis.

There are several factors that affect the outlook for cyanotic heart disease including early detection and treatment. It is a serious condition that needs immediate attention.

It is estimated that around 75% of babies with cyanotic heart disease survive their first years and 68% survive until the age of 18.⁽²⁾

Cyanotic heart disease is a condition that causes low oxygen levels in the blood. It can lead to potential complications. Treatment options depend on the type and severity of the defect and may include medication, surgical intervention, and lifestyle changes. Early diagnosis and treatment can be helpful in improving the outcome of the condition and also the quality of life of the people suffering from it.