Dallas, TX - Children with attention-deficit/hyperactivity disorder (ADHD) should receive careful cardiac evaluation—including an ECG—before starting treatment with stimulant drugs, a new American Heart Association statement recommends [1].

The statement, published online April 21, 2008 in Circulation, notes that stimulant medications used to treat ADHD can increase heart rate and blood pressure, and although these side effects are insignificant for most children with ADHD, they are an important consideration for children who have certain forms of congenital heart disease or arrhythmias with a predisposition for sudden cardiac arrest. The statement says that these new recommendations "are not intended to limit the appropriate use of stimulants in children with ADHD, to label children with heart disease, or to limit their participation in athletic activities but to add clarity to who has or does not have heart disease and the extent of the risk."

It advises that after a diagnosis of ADHD has been made, but before therapy with a stimulant or other medication is initiated, a thorough evaluation should be performed, with special attention to symptoms that can indicate a cardiac condition, such as palpitations, near syncope, or syncope. All additional medications, including prescribed and over-the-counter medications, should be determined, and a complete family history should be obtained. Because "some of the cardiac conditions associated with sudden cardiac death might not be detected on a routine physical examination, we are suggesting that an ECG be added to increase the likelihood of identifying significant cardiac conditions that might place the child at risk," the authors write.

Head of the statement-writing committee, Dr Victoria Vetter (University of Pennsylvania School of Medicine, Philadelphia), commented to heartwire: "The FDA has issued medication guidelines for stimulant drugs used to treat ADHD that state that you should tell your doctor if you have any heart condition, but there are many children who have structural heart disease that could lead to sudden cardiac death who don't know they have it until a significant event occurs. It is possible that using a stimulant medication could be a trigger for such an event. While there are patients who have had sudden cardiac arrest and strokes on these drugs, there are no large studies that have proven that the drugs have caused these events. However, it is thought that if adrenergic stimulation is increased, something these drugs do, this could trigger sudden cardiac arrest in susceptible patients."

Vetter explained that the committee has therefore recommended that physicians consider ordering an ECG to aid them in deciding whether or not underlying heart disease is present before prescribing these drugs for ADHD and, if there is any indication of heart disease, the child should be referred to a pediatric cardiologist for a full examination, because ECGs can give false-positive results.

She added that children with underlying heart disease can still take drugs for ADHD if they are stable and under the care of a pediatric cardiologist. "Even if an underlying disorder is confirmed by the cardiologist, these children can still take stimulant drugs, but they should be monitored very carefully. We know that many children with structural heart disease have ADHD, and we still want them to take the drugs because ADHD has a huge emotional and social impact on children and affects the way they grow up and their ability to be successful. The drugs do work in helping this; we don't want to limit people from getting these medications. We just want them to be used as safely as possible," Vetter told heartwire.

She stressed that if a child does not have access to an ECG or to a pediatric cardiologist who can evaluate an ECG or perform a cardiology consultation, this does not mean that they should not receive treatment for ADHD. "This is a class 2a recommendation—we feel it is useful, helpful, and reasonable, but it is has not been proven to be of benefit. We recommend that doctors use family history, a physical exam, and an ECG to make a decision about possible heart disease in children before prescribing stimulant drugs and, although we feel that an ECG is reasonable and helpful as a tool in identifying children with cardiac conditions that can lead to sudden cardiac death, if, in the view of the physician, a child requires immediate treatment with stimulant medications, this recommendation is not meant to keep them from getting that treatment," she said.

The statement adds that once stimulant treatment begins, all children should have their heart health monitored periodically, with a blood-pressure check one to three months after starting medication and during routine follow-ups every six to 12 months thereafter. Because some heart conditions do not appear until adolescence, it is recommended that if the initial ECG was obtained when the child was younger than 12 years of age, a repeat ECG should be done when the child is older than 12 years.

In 2003, an estimated 2.5 million children in the US took medication for ADHD. Surveys indicate that ADHD affects an estimated 4% to 12% of all school-aged children in the US, and it appears more common in children with heart conditions. Studies report that, depending on the specific cardiac condition, 33% to 42% of pediatric cardiac patients have ADHD, Vetter said. The number of undiagnosed children with heart conditions is unknown because routine heart screening is not performed. However, Vetter said, in a recent pilot study, up to 2% of healthy school-aged children had potentially serious undiagnosed cardiac conditions identified by an ECG.