Landmark Study Reveals
New Paradigm for Pediatric Cardiac Arrest
May 31, 2006
From: Darci Slaten,
520-626-7217
When we think of cardiac arrest -- the
abrupt loss of heart function that can quickly lead to death -- we typically
picture a middle-aged man dramatically clutching his chest before dropping to
the ground, unconscious.
The most common causes of cardiac arrest
leading to death occur from either ventricular tachycardia (VT -- when the electrical impulses in the
heart beat too rapidly -- or ventricular
fibrillation (VF), when the electrical impulses in the heart become
chaotic and abnormal. Other causes of cardiac arrest are due to
asystole/pulseless electrical activity arrests (e.g. loss of oxygen, shock,
septic shock, asphyxia).
Because cardiac arrest is generally
associated with heart disease, we don't typically think of cardiac arrest
affecting children. However, every year approximately 16,000 children suffer
from cardiac arrest.
In the largest study of its kind,
researchers at The University of Arizona's
Steele Children's Research Center, the Children's
Senior author of the study, Robert Berg, MD, professor in the
department of pediatrics at The University of Arizona, contends that these
findings represent a paradigm shift in our understanding of pediatric cardiac
arrest. "This study of in-hospital pediatric cardiac arrests has led to two
major paradigm shifts. First, abnormal rhythms (VF) were thought to be
relatively uncommon during pediatric cardiac arrests-less than 10 percent.
However, our study showed that they occurred during 27 percent of these
arrests," he explained. "And, our study showed that 89 percent of those who did
survive had good neurologic outcomes."
"Second," he continued, "the old paradigm
was that outcomes were much better after VF/VT cardiac arrests than cardiac
arrests due to asystole/pulseless electrical activity. But this study revealed
two kinds of VF: initial VF, a
sudden cardiac arrest due to a rhythm abnormality, and subsequent VF, an
abnormal rhythm occurring during the
resuscitation. We found that the outcomes from initial VF are very
good, but outcomes from subsequent VF are poor."
"Where we once thought that all ventricular
fibrillation in children was the same, there now appears to be two kinds,
associated with either a better outcome or a poorer outcome, depending on when
they occur during the cardiac arrest," said lead author of the study, Ricardo Samson, MD, associate professor in
the department of pediatrics at The University of Arizona.
Although the reasons for worse outcomes
after subsequent VF are currently unknown, Dr. Berg believes a few possibilities
may be true:
"We may be able to improve outcomes through
better recognition and treatment, or through better resuscitation regimens,"
said Dr. Berg. "Although we don't yet know why outcomes are so much worse for
those with subsequent ventricular fibrillation, the foundation is laid to
explore this question further," said Dr. Samson.
Co-authors of the
study, in addition to Drs. Berg and Samson, were Vinay M. Nadkarni, MD, and
Peter A. Meaney, MD, MPH, of the Children's Hospital of Philadelphia and the
University of Pennsylvania; Marc D. Berg, MD, of The University of Arizona; and
Scott M. Carey of Digital Innovations, Bel Air, Md. The Emergency Cardiovascular
Care Committee of the AHA and the Endowed Chair of Pediatric Critical Care at
The Children's Hospital of Philadelphia supported this
study.
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