Heart attacks, also known as myocardial infarctions, can occur in birds just like they do in humans and other animals. However, the causes and risk factors for heart attacks in birds can be quite different than what is typically seen in mammals.
What is a heart attack?
A heart attack, or myocardial infarction, occurs when blood flow to part of the heart muscle is severely reduced or stopped completely. This occurs when one or more of the coronary arteries, which supply oxygen-rich blood to the heart muscle, become blocked. The blockage is usually caused by a buildup of fat, cholesterol and other substances that form plaque on the inner walls of the arteries. This plaque can rupture, causing a blood clot to form and block the artery.
When blood flow to the heart muscle is reduced or stopped, that part of the heart is deprived of oxygen. Heart muscle cells that don’t receive oxygen start to die. This can cause lasting damage to the heart if blood flow is not restored quickly.
What causes heart attacks in birds?
In birds, just as in mammals, heart attacks are generally caused by a blockage in one or more coronary arteries. However, the underlying causes of the blockages can be different.
Some of the potential causes of heart attacks in birds include:
- Atherosclerosis – Buildup of fatty plaques in the arteries, like in humans
- Infection – Bacterial, viral, fungal or parasitic infections
- Trauma – Blunt force trauma to the chest
- Toxins – Heavy metal poisoning or toxin exposure
- Tumors – Cancerous growths in or around the heart
- Blood clots – Clots that travel to the heart and block arteries
- Congenital defects – Abnormal development of the heart or blood vessels
- Nutritional deficiencies – Lack of vitamins E and A
Let’s explore some of these causes in more detail:
Atherosclerosis
Like humans, some birds can develop atherosclerosis, which is the buildup of fats, cholesterol and other substances on the walls of arteries. This causes thick, hardened plaques that can obstruct blood flow. Atherosclerosis is most common in older birds and birds fed high-fat diets.
Birds that may be prone to atherosclerosis include:
- Chickens
- Turkeys
- Ducks
- Geese
- Pigeons
- Parrots
- Cockatoos
Infection
Bacterial, viral, fungal and parasitic infections can cause inflammation of the heart muscle or sac surrounding the heart (pericarditis). This can obstruct blood flow and lead to heart attacks. Birds with weakened immune systems are most at risk. Common culprits include:
- Chlamydia bacteria
- Aspergillosis fungus
- Pacheco’s disease herpesvirus
- Avian malaria parasites
Trauma
Blunt force trauma to a bird’s chest, as may occur during an accident or attack by a predator, can lead to bruising, rupture or dissection of coronary arteries. This can cause a heart attack.
Toxins
Heavy metal poisoning and toxins like pesticides, rodenticides, and toxic plants can damage a bird’s heart and arteries, increasing the risk for blockages and heart attacks. For example, copper toxicity can lead to inflammation and plaque formation.
Tumors
Cancerous growths in the heart or surrounding the heart can compress coronary arteries and block blood flow. Heart tumors are seen occasionally in older birds.
Blood clots
A blood clot that forms elsewhere in the body may travel through the bloodstream and lodge in one of the coronary arteries, blocking blood flow. This is less common than some of the other causes.
Congenital defects
Some birds are born with abnormal development of the coronary arteries or heart that increases their risk for a heart attack. This includes conditions like coronary artery atresia, where an artery is narrowed or missing.
Nutritional deficiencies
Birds with diets deficient in vitamins E and A are prone to atherosclerosis and damage to the heart and arteries. Ensuring birds receive balanced diets with these vitamins can help reduce risk.
Risk factors
Certain factors can increase a bird’s risk of having a heart attack. These include:
- Advanced age
- Obesity
- Diets high in fat, cholesterol, or calories
- Lack of exercise
- Egg-laying in females (places stress on the body)
- Diabetes
- High blood pressure
- Kidney disease
- Hypothyroidism
- Cigarette smoke or air pollution exposure
- Stress
Symptoms of heart attack
Some of the signs that a bird may be having a heart attack include:
- Sudden collapse or falling off perch
- Difficulty breathing; sudden respiratory distress
- Cyanosis (blue discoloration of skin)
- Loss of consciousness
- Fluid accumulation in the lungs
- Decreased appetite
- Lethargy, reluctance to move
- Weakness
- Labored or rapid breathing
- Straining to defecate
Diagnosis
If a heart attack is suspected based on symptoms, the bird will need to be examined by an avian veterinarian. Diagnostic tests may include:
- Physical exam – listening to the heart and lungs
- Blood tests – to look for cardiac enzyme elevations that indicate heart damage
- Radiographs (x-rays) – to check heart size and look for fluid in the lungs
- Electrocardiogram (ECG) – to look for abnormal heart rhythms
- Echocardiogram (ultrasound) – uses soundwaves to look at the heart’s structure and function
- Endoscopy – insert a small camera into the trachea to visualize the air sacs and lungs
These tests can help determine if a heart attack has occurred and assess the severity of the damage to the heart.
Treatment
Treatment for a heart attack in birds focuses on limiting further heart damage and managing complications. This may involve:
- Emergency oxygen therapy
- Administering fluids and electrolytes
- Medications:
- Anticoagulants/antiplatelets – to prevent clot formation
- Analgesics – to control pain
- Diuretics – to reduce fluid accumulation in the lungs
- Vasodilators – to open blood vessels and improve circulation
- Positive inotropes – strengthen the heart’s contractions
- Low-salt diet
- Cage rest
- Monitoring heart rhythm with ECG
- Emergency surgery may be needed to address cardiac rupture, hemorrhage or other complications
Even with treatment, heart attacks have high mortality rates in birds. However, those that survive the initial event often require long-term management of heart failure and arrhythmias.
Prevention
Some things that can be done to help prevent heart attacks in birds include:
- Feeding a healthy diet low in saturated fats
- Avoiding obesity
- Regular exercise
- Routine veterinary checkups to monitor for heart disease
- Early treatment of infections
- Minimizing stress
- Vitamin supplementation if needed
Prognosis
The prognosis for a bird that has had a heart attack depends on how much heart damage occurred and the cause. In general, smaller heart attacks have a better prognosis than massive ones. Factors that improve the outlook include:
- Rapid treatment
- Younger age
- Otherwise healthy bird
- Single, reversible cause like a blood clot
- No history of heart disease
- Mild, temporary damage on diagnostic imaging
With aggressive treatment in the initial period after a heart attack, some birds may recover fairly normal heart function. However, often there is permanent damage that requires long-term management of heart failure. Severe heart attacks or those due to irreversible causes like cancer tend to have poorer prognoses.
Key Points
- Heart attacks in birds occur when blood flow to part of the heart muscle is cut off, usually due to a blocked coronary artery.
- Causes include atherosclerosis, infection, trauma, toxins, tumors and congenital defects.
- Risk factors include age, obesity, unhealthy diets, lack of exercise, diabetes and stress.
- Symptoms can include collapse, breathing problems, weakness, and cyanosis.
- Diagnostic tests such as x-rays, ECG and blood tests are needed to confirm a heart attack.
- Treatment focuses on limiting further heart damage and managing complications.
- Prevention involves healthy diets, exercise, vitamin supplementation and routine checkups.
- Prognosis depends on the severity and particular circumstances but can be poor in many cases.
| Bird Type | Heart Attack Risk Factors |
|---|---|
| Chickens | Obesity, atherosclerosis |
| Ducks | High-fat diets, obesity |
| Geese | Obesity, sedentary lifestyle |
| Pigeons | Atherosclerosis, air pollution exposure |
| Parrots | Atherosclerosis, vitamin A deficiency, egg laying |
| Finches | Diets high in fat/cholesterol |
| Canaries | Egg binding in females, copper toxicity |
Conclusion
Heart attacks can be a serious concern for pet bird owners given that birds often hide symptoms until the disease has progressed. However, being aware of the common causes and risk factors in different bird species can help bird owners and avian vets monitor for problems. Catching issues early and addressing diet, exercise, potential toxins and other factors may allow interventions that help prevent devastating events like heart attacks.
