Treating congenital heart defects in babies still in the womb

Mar 30 2007

Treating congenital heart defects in babies still in the womb is a high-risk procedure, but one that can improve babies' outcomes after birth.

Researchers at Children's Hospital Boston and Brigham and Women's Hospital reviewed the cases of 80 fetuses who had prenatal cardiac interventions during a six-year period (most often to avert hypoplastic left heart syndrome, a life-threatening condition in which most of the structures on the left side of the heart are small and underdeveloped). The intervention was successful in 79 percent of fetuses. Although 43 percent developed unstable cardiac function during the procedure, all regained normal heart rate and ventricular function within about half an hour, and the cardiac procedure had to be halted in only six of these 34 fetuses. There were six fetal deaths within 72 hours, of whom four had developed unstable cardiac function during the procedure. Further follow-up of the babies with successful interventions will be crucial, say the researchers. Efforts are ongoing to further improve the safety of these minimally invasive but high-risk procedures.

Not only can most children with a heart transplant exercise safely, but new research suggests that the transplanted heart's response to exercise gradually improves. Researchers at Children's Hospital Boston analyzed 182 maximal treadmill exercise tests performed serially (usually annually) in 51 children who had received a heart transplant. The tests showed a steady improvement in peak heart rate; 2, 4, 6 and 8 years after transplant, peak heart rates were 75, 78, 81 and 84 percent of predicted heart rate, respectively. More importantly, over time, heart rates recovered more quickly from peak exercise. "These data suggest that there is a spontaneous re-growth of nerves into a substantial proportion of transplanted hearts, allowing patients to reach higher heart rates with exercise and to cool down more quickly," says T. P. Singh, MD, a cardiologist in the Heart Failure/Transplant Service at Children's and the study's lead author.

In a pediatric cardiac intensive care unit, children often must be resuscitated, but these "code blues" are technically complex and require close teamwork. Through its Simulator Program, Children's Hospital Boston provides specialized training using a mannequin with realistic heartbeats, pulses and other vital signs to rehearse high-stakes clinical situations. Each scenario is videotaped and followed by an extensive debriefing, focusing on technical issues and, equally important, team communication and organization. After training, participants felt more confident in participating in a resuscitation and were significantly more likely to voice concerns about a patient's management to the team leader.