“My heart is racing” is a common complaint of children and teenagers. This feeling may be a result of not drinking enough water, being scared or doing vigorous activity. There are conditions, however, where heart palpitations are related to a problem with the electrical system of your child’s heart.
The two most common conditions are supraventricular tachycardia and postural orthostatic tachycardia syndrome. Both conditions can affect all age groups and can lead to long-term problems if not diagnosed or treated appropriately.
Supraventricular tachycardia is the most common childhood heart rhythm abnormality. It can occur in children, whether or not they have a history of known heart problems. It is important to recognize SVT because if untreated, it can lead to heart failure or can increase your child’s risk for sudden death.
In a normal heartbeat, an electrical impulse begins in the top chambers (called the atria), and then takes a pathway down into the bottom chambers (the ventricles) and spreads, making the ventricles squeeze to send blood out to the body. In SVT, children have an extra “backdoor” pathway, in addition to the normal pathway, located between the atria and ventricles. The heart conducts a beat normally, but the extra pathway sends the beat back up to the atria. This sets off a circular event that causes the heart rate to increase substantially.
SVT can present in all age groups, including newborns. With SVT, a child’s heart rate is usually over 240 beats per minute (the normal heart rate is age dependent, but can range from 60 to 140 beats per minute) and there are characteristic changes on an electrocardiogram. There is usually no initiating event, and SVT can happen intermittently or be sustained. It can be asymptomatic in the beginning, but if it persists for more than 6 to 12 hours, an infant will start to show symptoms such as irritability, increased breathing rate, poor feeding and pale skin color.
Older children experiencing SVT may complain of chest pain or may tell you they feel their heart beating rapidly. If your child is diagnosed with SVT, a pediatric cardiologist will be involved in his or her care, and an electrocardiogram will confirm the diagnosis.
Treatments can include medical and surgical options. A doctor will first try to get your child to spontaneously switch back to a normal heart rhythm with maneuvers such as stimulating him or her to have a bowel movement, placing a bag of ice on his or her face for a short time or having your child attempt a headstand. If these maneuvers are not successful and your child is stable, a medication will be given through an IV that will convert the rhythm back to normal. If your child is unstable, electricity may be needed to slow down the heart. Once the heart rate normalizes, the cardiologist may advise your child to have an electrical study of the heart, which can be diagnostic and curative.
If your child is diagnosed with SVT as an infant, the cardiologist may choose observation only because many children outgrow this condition.
In comparison, postural orthostatic tachycardia syndrome is diagnosed mostly in teenage females and is due to the body responding slowly to postural changes. When a person with POTS goes from sitting to standing, the blood that is circulating in the legs does not immediately return to the heart; therefore, the heart increases its rate to help get the blood to return faster. Symptoms of this disorder include fatigue, exercise intolerance and repeated episodes of near fainting and palpitations. POTS is diagnosed by measuring heart rate and blood pressure in different positions; a positive test includes having symptoms when moved from a lying to a standing position, an increase in heart rate (tachycardia) by greater than 30 beats per minute, and a decrease in blood pressure (hypotension). This test can be done in your pediatrician’s office or by a pediatric cardiologist.
A pediatric cardiologist usually will be involved in your child’s care if POTS is diagnosed. There are many lifestyle modifications that can decrease symptoms, including drinking lots of water, eating salty foods and avoiding extreme heat. Your doctor also will go over all of your child’s medications and supplements to make sure they are not worsening their symptoms. Some children may require medication.
SVT and POTS can be effectively managed when diagnosed and treated early. If you think your child may have one of these conditions, it is very important to see your pediatrician for further evaluation.
Dr. Meghann McKane is a resident pediatrician at Carolinas Medical Center, and Dr. Erin Stubbs is a board-certified pediatrician at CMC Myers Park Pediatrics.