Cardiomyopathy in Babies
Medically reviewed by Dr. Michael Okonkwo, MD, FAAP · Board-Certified Neonatologist
Content reviewed against published AHA, AAP, NIH guidelines
Last reviewed:
If your baby has been diagnosed with or you suspect cardiomyopathy in babies, here is what the evidence says.
The short answer
Cardiomyopathy is a disease of the heart muscle that affects how well the heart can pump blood. In babies, the main types are dilated cardiomyopathy (the heart becomes enlarged and weakened), hypertrophic cardiomyopathy (the heart muscle becomes abnormally thick), and restrictive cardiomyopathy (the heart muscle becomes stiff). Signs in infants include rapid breathing, poor feeding, excessive sweating, poor weight gain, and a fast heartbeat. Cardiomyopathy in babies can be inherited, caused by infection, or have no identifiable cause. Early diagnosis and treatment by a pediatric cardiologist are essential.
Key takeaways
- Cardiomyopathy is a disease of the heart muscle that affects how well the heart can pump blood. In babies, the main types are dilated cardiomyopathy (the heart becomes enlarged and weakened), hypertrophic cardiomyopathy (the heart muscle becomes abnormally thick), and restrictive cardiomyopathy (the heart muscle becomes stiff). Signs in infants include rapid breathing, poor feeding, excessive sweating, poor weight gain, and a fast heartbeat. Cardiomyopathy in babies can be inherited, caused by infection, or have no identifiable cause. Early diagnosis and treatment by a pediatric cardiologist are essential.
- Usually normal when: Your baby feeds well, gains weight appropriately, and breathes comfortably at rest
- Call your doctor if: Your baby has rapid or labored breathing, poor feeding, excessive sweating, and appears pale or gray -- these signs suggest heart failure and require emergency evaluation
- Varies by age — see the age-by-age breakdown below
“Fever itself is not an illness — rather, it is a sign or symptom that the body is fighting an infection. Fever stimulates certain defenses, such as the white blood cells, which attack and destroy invading bacteria.”
Parents everywhere have the same worry. You are doing the right thing by looking into it.
What Parents Should Know
According to AHA, AAP, NIH guidelines, cardiomyopathy is a disease of the heart muscle that affects how well the heart can pump blood. In babies, the main types are dilated cardiomyopathy (the heart becomes enlarged and weakened), hypertrophic cardiomyopathy (the heart muscle becomes abnormally thick), and restrictive cardiomyopathy (the heart muscle becomes stiff). Signs in infants include rapid breathing, poor feeding, excessive sweating, poor weight gain, and a fast heartbeat. Cardiomyopathy in babies can be inherited, caused by infection, or have no identifiable cause. Early diagnosis and treatment by a pediatric cardiologist are essential. At 0-3 months, cardiomyopathy in newborns may be detected prenatally on ultrasound or shortly after birth. Hypertrophic cardiomyopathy is more common in infants of diabetic mothers. Dilated cardiomyopathy may present with signs of heart failure: rapid breathing, poor feeding, failure to gain weight, and excessive sweating. Some metabolic disorders can cause cardiomyopathy in the newborn period. Early diagnosis through echocardiography is critical, and genetic and metabolic testing may be recommended. It is generally considered normal when your baby feeds well, gains weight appropriately, and breathes comfortably at rest. However, you should contact your pediatrician promptly if your baby has rapid or labored breathing, poor feeding, excessive sweating, and appears pale or gray -- these signs suggest heart failure and require emergency evaluation.
Normal vs. Concerning
When to Seek Immediate Care
- Your baby has rapid or labored breathing, poor feeding, excessive sweating, and appears pale or gray -- these signs suggest heart failure and require emergency evaluation
- Your child faints during exercise or physical activity -- call 911 and have them evaluated for cardiomyopathy or other cardiac conditions
- Your baby or child has a sudden episode of unresponsiveness, chest pain with difficulty breathing, or an irregular rapid heartbeat
By Age
What to expect by age
0-3 months
Cardiomyopathy in newborns may be detected prenatally on ultrasound or shortly after birth. Hypertrophic cardiomyopathy is more common in infants of diabetic mothers. Dilated cardiomyopathy may present with signs of heart failure: rapid breathing, poor feeding, failure to gain weight, and excessive sweating. Some metabolic disorders can cause cardiomyopathy in the newborn period. Early diagnosis through echocardiography is critical, and genetic and metabolic testing may be recommended.
3-12 months
Infants with cardiomyopathy may show progressive signs of heart failure, including tiring quickly during feeds, sweating during feeding, rapid breathing, and poor weight gain. The liver may be enlarged. Some infants develop cardiomyopathy after a viral infection (post-myocarditis). Echocardiography is the primary diagnostic tool. Treatment may include medications to support heart function (diuretics, ACE inhibitors, beta-blockers) and close monitoring by a pediatric cardiologist.
1-3 years
Toddlers with cardiomyopathy may show decreased activity, tiring easily, poor appetite, abdominal discomfort (from liver congestion), and breathing difficulty. They may want to be carried more and become short of breath with walking or playing. Hypertrophic cardiomyopathy may be first detected when a murmur is heard at a well-child visit. Some forms of cardiomyopathy are progressive, while others stabilize or improve with treatment.
3+ years
Older children with cardiomyopathy may experience exercise intolerance, chest pain, dizziness, or fainting. Hypertrophic cardiomyopathy carries a risk of sudden cardiac arrest during vigorous exercise, and affected children typically need activity modifications. Dilated cardiomyopathy may require ongoing medication. In severe cases, children may be evaluated for heart transplant. Family screening with echocardiography and possibly genetic testing is recommended when a child is diagnosed.
Family screening
Because many forms of cardiomyopathy are inherited, first-degree relatives (parents, siblings) of a child diagnosed with cardiomyopathy should be screened with echocardiography and ECG. Genetic counseling may be offered. Screening allows early detection and treatment in other family members who may be affected.
What to Tell Your Pediatrician
- Describe when you first noticed cardiomyopathy in babies and how it has changed over time.
- Note your baby's current age and which age-specific patterns you are seeing.
- Mention if your baby seems to tire easily during feeds and takes longer than expected to finish a bottle or breastfeed.
- Mention if there is a family history of cardiomyopathy, heart failure, or unexplained sudden death at a young age.
- Let your doctor know if you have noticed any related concerns, such as changes in feeding, sleep, or movement patterns.
- Bring a list of any questions or observations you want to discuss at the appointment.
What Should You Do?
When to take action
- Your baby feeds well, gains weight appropriately, and breathes comfortably at rest
- Your child's echocardiogram shows normal heart size and function
- A pediatric cardiologist has evaluated your child and found no signs of cardiomyopathy
- Your child is active and keeps up with peers without unusual fatigue or breathing difficulty
- Your baby seems to tire easily during feeds and takes longer than expected to finish a bottle or breastfeed
- There is a family history of cardiomyopathy, heart failure, or unexplained sudden death at a young age
- Your child seems to have less energy than peers or tires more easily during physical activity
- Your baby's weight gain has slowed significantly without an obvious cause
- Your baby has rapid or labored breathing, poor feeding, excessive sweating, and appears pale or gray -- these signs suggest heart failure and require emergency evaluation
- Your child faints during exercise or physical activity -- call 911 and have them evaluated for cardiomyopathy or other cardiac conditions
- Your baby or child has a sudden episode of unresponsiveness, chest pain with difficulty breathing, or an irregular rapid heartbeat
What You Can Do at Home
- Keep track of when you notice cardiomyopathy in babies — noting the time of day, duration, and any triggers can help your pediatrician.
- Remember that your baby feeds well, gains weight appropriately, and breathes comfortably at rest — this is generally within the range of normal.
- At 0-3 months, focus on observation rather than intervention unless your pediatrician advises otherwise.
- Follow any care instructions from your pediatrician. Keep a written log of symptoms to bring to appointments.
- While monitoring at home, seek immediate care if your baby has rapid or labored breathing, poor feeding, excessive sweating, and appears pale or gray -- these signs suggest heart failure and require emergency evaluation.
Related Conditions
Congenital Heart Defect Signs in Babies
Congenital heart defects (CHDs) are the most common type of birth defect, affecting about 1 in 100 babies. They range from small holes in the heart that may close on their own to complex defects requiring multiple surgeries. Early detection through pulse oximetry screening and recognizing key signs — such as blue skin, rapid breathing, poor feeding, and failure to gain weight — is critical. Advances in surgery have dramatically improved survival and quality of life.
Signs of Failure to Thrive in Babies
Failure to thrive (now often called growth faltering) refers to a baby or child who is not gaining weight as expected. It is typically defined as weight falling below the 2nd percentile, or crossing down two or more major percentile lines on the growth chart. While it sounds alarming, most cases are related to feeding difficulties, inadequate calorie intake, or transient illness, and can be successfully treated. Early identification and intervention are important for optimal outcomes.
Baby Heart Murmur - Innocent vs Concerning
Heart murmurs are very common in children - up to 75% of children will have an audible murmur at some point. The vast majority are "innocent" or "functional" murmurs, meaning there is no structural heart problem. These murmurs are simply the sound of blood flowing normally through the heart and are more audible during fever, illness, or excitement. A smaller number of murmurs indicate a structural heart difference that may need monitoring or treatment. Your pediatrician can usually distinguish between the two and will refer for an echocardiogram if there is any concern.
Related Resources
Frequently asked questions
Is cardiomyopathy in babies normal?
When should I call the doctor about cardiomyopathy in babies?
When is cardiomyopathy in babies normal?
What causes cardiomyopathy in babies?
What should I mention to my pediatrician about cardiomyopathy in babies?
Is cardiomyopathy in babies normal at 0-3 months?
Is cardiomyopathy in babies normal at 3-12 months?
Should I go to the ER for cardiomyopathy in babies?
Does cardiomyopathy in babies go away on its own?
References
Doctor Visit Checklist
Bring this checklist to your next pediatrician visit to discuss Cardiomyopathy in Babies.
Things to mention
- Describe when you first noticed cardiomyopathy in babies and how it has changed over time.
- Note your baby's current age and which age-specific patterns you are seeing.
- Mention if your baby seems to tire easily during feeds and takes longer than expected to finish a bottle or breastfeed.
- Mention if there is a family history of cardiomyopathy, heart failure, or unexplained sudden death at a young age.
- Let your doctor know if you have noticed any related concerns, such as changes in feeding, sleep, or movement patterns.
- Bring a list of any questions or observations you want to discuss at the appointment.
Observations to share
- Your baby seems to tire easily during feeds and takes longer than expected to finish a bottle or breastfeed
- There is a family history of cardiomyopathy, heart failure, or unexplained sudden death at a young age
- Your child seems to have less energy than peers or tires more easily during physical activity
Urgent signs to report immediately
- Your baby has rapid or labored breathing, poor feeding, excessive sweating, and appears pale or gray -- these signs suggest heart failure and require emergency evaluation
- Your child faints during exercise or physical activity -- call 911 and have them evaluated for cardiomyopathy or other cardiac conditions
- Your baby or child has a sudden episode of unresponsiveness, chest pain with difficulty breathing, or an irregular rapid heartbeat
My notes
From ismybabyalright.com — free, evidence-based baby health guides
All content follows our editorial policy and is reviewed against published clinical guidelines.
2,705 evidence-based guides6 authoritative medical sources5 medical advisory board members
Related Resources
Bottom line
Most cases of cardiomyopathy in babies are normal. Talk to your pediatrician if your baby has rapid or labored breathing, poor feeding, excessive sweating, and appears pale or gray -- these signs suggest heart failure and require emergency evaluation.
Trust your instincts. If something feels wrong, reach out to your pediatrician. Worrying about your baby means you care — that is a good thing.
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Related Medical Concerns
Congenital Heart Defect Signs in Babies
Congenital heart defects (CHDs) are the most common type of birth defect, affecting about 1 in 100 babies. They range from small holes in the heart that may close on their own to complex defects requiring multiple surgeries. Early detection through pulse oximetry screening and recognizing key signs — such as blue skin, rapid breathing, poor feeding, and failure to gain weight — is critical. Advances in surgery have dramatically improved survival and quality of life.
Signs of Failure to Thrive in Babies
Failure to thrive (now often called growth faltering) refers to a baby or child who is not gaining weight as expected. It is typically defined as weight falling below the 2nd percentile, or crossing down two or more major percentile lines on the growth chart. While it sounds alarming, most cases are related to feeding difficulties, inadequate calorie intake, or transient illness, and can be successfully treated. Early identification and intervention are important for optimal outcomes.
Baby Heart Murmur - Innocent vs Concerning
Heart murmurs are very common in children - up to 75% of children will have an audible murmur at some point. The vast majority are "innocent" or "functional" murmurs, meaning there is no structural heart problem. These murmurs are simply the sound of blood flowing normally through the heart and are more audible during fever, illness, or excitement. A smaller number of murmurs indicate a structural heart difference that may need monitoring or treatment. Your pediatrician can usually distinguish between the two and will refer for an echocardiogram if there is any concern.
My Baby's Head Shape Looks Abnormal
Many babies develop temporary head shape irregularities that are completely normal. A cone-shaped head from vaginal delivery reshapes within days. Mild positional flattening (plagiocephaly) from sleeping on the back is very common and usually improves with repositioning and tummy time. However, head shape changes involving ridges, a persistently bulging fontanelle, or rapid head growth changes should be evaluated to rule out craniosynostosis.
Achondroplasia (Dwarfism) in Babies
Achondroplasia is the most common form of short-limbed dwarfism, affecting about 1 in 15,000 to 40,000 births. It is caused by a mutation in the FGFR3 gene and is usually apparent at birth with characteristic features including short limbs, a larger head, and a prominent forehead. Intelligence is normal. With monitoring for specific complications and supportive care, children with achondroplasia lead full, active, and independent lives.
Adenoid Hypertrophy and Breathing
Adenoids are lymphoid tissue located behind the nose that help fight infection in young children. When adenoids become enlarged (adenoid hypertrophy), they can block the nasal airway, causing chronic mouth breathing, snoring, nasal speech, and sleep-disordered breathing. Enlarged adenoids are most common between ages 2-7 and are a leading cause of obstructive sleep apnea in young children. Treatment ranges from watchful waiting and nasal steroids to surgical removal (adenoidectomy) if breathing or sleep is significantly affected.