Friday, March 8, 2002
RICHMOND, Va. – Doctors at Virginia
Commonwealth University have implanted a pacemaker in a premature baby girl, one
of the youngest children ever to undergo the surgical procedure.
Using a small, newly designed pacemaker, Inder
Mehta, M.D., assistant professor of surgery in the VCU School of Medicine and
director of pediatric cardiac surgery at the Children’s Heart Center of the
VCU Health System’s MCV Hospitals, corrected a congenital condition known as a
heart block. In heart block, the upper and lower chambers fail to get an
electrical signal in rhythmic fashion.
"She should have good cardiac function
like a normal child," Mehta said about the baby girl, who remains on a
respirator but is gaining weight. "She will always need a pacemaker. We
will replace it as she grows, but we believe she will have a normal childhood
and a normal life."
A team of VCU physicians, including pediatric
cardiac surgeons, cardiologists, a obstetrician/gynecologist and a neonatologist,
made the decision to deliver the baby 11 weeks early – at 29 weeks of
gestational development -- and implant the pacemaker after a fetal
echocardiogram revealed a fluid collection around the heart. Doctors already
were concerned about the pregnancy going to full term of 40 weeks because the
fetal heart rate had fallen to 43 beats a minute, one-third the rate of a normal
fetal heart rate of 120 to 150 beats per minute.
At the time of surgery on Jan. 12, the baby
weighed only two pounds, 11 ounces.
"We originally had planned to try to wait
until 32 weeks to deliver the child, " said Mary T. Donofrio, M.D.,
associate professor of pediatrics in the School of Medicine and medical director
of the pediatric noninvasive cardiac lab and perinatal cardiology at the VCU
Children’s Heart Center.
"We attempted to improve fetal heart
function by giving medicine to the mother that crossed the placenta to the baby.
Initially this worked, and we were able to give additional medicine in the same
way to help mature fetal lungs," Donofrio said. "But when a follow up
fetal echocardiogram showed that the fluid buildup around the heart was worse,
we couldn’t wait any longer and decided to go ahead with the delivery."
The pacemaker used was the Microny II SR+
AutoCapture Pacing System, the world’s smallest pacemaker at 12.8 grams.
Roughly the size of two quarters stacked together, the unit is 40 percent
smaller than comparable single-chamber, rate-responsive pacemakers. It is
manufactured by St. Jude Medical, Inc., of St. Paul, MN, the world’s
second-largest maker of pacemakers.
The pacemaker is comprised of two components, a
generator that provides electrical impulses and wire leads that carry the
charges to the heart. Mehta made one incision in the chest to connect the lead
wires directly to muscle of the baby girl’s heart and a second incision in the
abdomen to place the miniature generator unit under the skin.
The generator works by sensing the patient’s
heart rhythm and heart rate and delivers an electrical stimulus to the heart to
maintain rhythm when appropriate. The device also has an archival feature that
retains data about the patient’s heart rate and heart rhythm. It also tracks
how the pacemaker has been pacing the patient for up to 10 years.
"If there were any irregularities, any
episodes, where the heart rate went up, or if there were any arrhythmia, when
the rhythm of the heart is not proper, it can all be stored in the
pacemaker," Mehta said. "And that data can be reproduced after years
and years of use."
Each year about 100 pediatric cardiac surgeries
are performed at the Children’s Heart Center of the VCU Health System’s MCV
Hospitals. Of those, about six involve pacemaker implants.
About the Children's Heart Center
Children’s Heart Center at the Virginia Commonwealth University Health System’s
MCV Hospitals brings together a unique team of doctors, nurses and medical staff
who specialize in the care of children with heart disease. The center treats
problems ranging from heart murmurs and chest pains to those requiring cardiac
surgery. The center’s Pediatric Noninvasive Cardiac Laboratory is a national
leader in identifying congenital heart disease. MCV Hospitals is the
second-oldest heart transplantation center in the country and has a long history
of innovation in pediatric cardiology. In 1985, a team of experts at MCV
Hospitals performed the first balloon dilation of a pulmonary valve in Virginia.
Five years later, physicians were credited with the first neonatal heart
transplantation in the state. And, in 1999, doctors performed Virginia's first
non-surgical closure of an atrial septal defect on a 4-year-old patient. For
more, see www.vcuhealth.org/childrensheartcenter.
About VCU and the VCU Medical Center
Virginia Commonwealth University is a major, urban public research university with national and international rankings in sponsored research. Located in downtown Richmond, VCU enrolls more than 31,000 students in 223 degree and certificate programs in the arts, sciences and humanities. Sixty-eight of the programs are unique in Virginia, many of them crossing the disciplines of VCU’s 13 schools and one college. MCV Hospitals and the health sciences schools of Virginia Commonwealth University comprise the VCU Medical Center, one of the nation’s leading academic medical centers. For more, see www.vcu.edu.