Diagnosis in a heartbeat

Cardiologists at BC Children’s Hospital in Vancouver have developed a better way to view how well the hearts of their pediatric cardiac patients are performing, allowing them to detect problems that may have been missed before.

“Exercise echocardiography allows us to watch how a young patient’s heart performs from a resting stage through progressive exercise and then through recovery,” said Dr. Derek Human, head of the Children’s Heart Centre at BCÊChildren’s Hospital.

“It’s a vast improvement over putting a patient on an exercise bike and then having them lie down, which only allowed us to capture the resting and recovery stages. We’ve also learned that tests using medications to stress the heart show a different result than an actual exercise test.*”

Developed by BC Children’s cardiologist Dr. George Sandor and exercise physiologist Dr. Jim Potts, the exercise echocardiography test is the first of its kind. The equipment used for the exercise study consists of a semi-recumbent cycle ergometer and a standard echocardiography machine.

“Our echo techs love it because we have our patients on a recumbent bike, which gives the techs relatively good access to the chest to capture images,” said Dr. Sandor. “Having the ability to watch a child’s heart muscle working allows us to measure cardiac output and function in real time, making even the more subtle abnormalities of function more evident.”

Exercise echocardiography also allows BCÊChildren’s cardiologists to detect abnormalities of valve function such as narrowing of the aortic valve. “You can have a valve that looks okay at rest, but you want to know if the patient’s heart is adapting in a healthy or unhealthy way when you put it through its paces,” said Dr. Human.

“We also have the ability to detect wall motion abnormalities, an indication of the overall ventricular function in our pediatric transplant patients,” said Dr. Potts. “Our latest improvements allow us to also measure respiratory gas exchange to assess cardiopulmonary function.”

Patients who come to the BC Children’s Heart Centre for exercise echocardiography include children who received chemotherapy for the treatment of leukemia and other cancers, which can weaken the heart muscle. “They make up our largest group of test patients, and early detection of heart damage allows us to start treatment before that damage is even clinically obvious at rest,” said Dr. Human.

Other patients include the approximately 20 current pediatric transplant recipients in B.C. and those who had reconstruction of their venous return to check for obstructions. The adult cardiology program at St. Paul’s also sends patients with complex post-operative cardiac lesions or possible obstruction to their venous system for assessment.

“We’re expanding the exercise echocardiography program to look at eating disorder patients to see if the loss of protein associated with anorexia affects heart function now that activity is becoming a part of the treatment program for these patients,” said Dr. Human.

Dr. Potts said, “Any hospital can do what we’re doing – the equipment we’ve assembled is literally off the shelf. It’s how we’ve put all the pieces together and how and when we do our measurements that makes our test one of a kind.”

The BC Children’s Heart Centre would be happy to help any cardiac team develop a similar test for their patients. Contact Dr. Potts at jpotts@cw.bc.ca or call (604) 875-2120.

BC Children’s Hospital, an agency of the Provincial Health Services Authority, provides expert care for the province’s most seriously ill or injured children, including newborns and adolescents. For more information please visit www.cw.bc.ca.