Transcript Commotio cordis (7 Jan 2009)

Chest trauma
Case Presentation
Case presentation
• A paramedic call is received in the
emergency department (ED) reporting a
10-min estimated time of arrival for a 13year-old male who was found in cardiac
arrest following a blow to the chest.
Case presentation
• Prehospital personnel reveals a history of
witnesses reporting that the patient, a center
outfielder for a local baseball team, was trying to
catch a baseball when one of his teammates
accidentally ran into him, elbowing him in the
middle of his chest.
• The patient immediately dropped to the ground
and was unresponsive. Cardiopulmonary
resuscitation (CPR) was initiated by his coach
after no pulses were palpated.
Case presentation
• The paramedics arrived 5 minutes later
and, found the patient to be in ventricular
fibrillation.
• The patient returned to spontaneus
circulation with one 200 joule defibrilation.
• A normal sinus rhythm was noted and the
patient was noted to regain
consciousness.
• Upon arrival at the ED, the patient reports only
mild anterior chest wall pain and denies any
substernal chest pain, shortness of breath,
palpitations, weakness, or confusion.
• He states that he has never before fainted. The
patient and his mother deny any significant past
medical or family history, including any
arrhythmias, unexplained sudden deaths, or
cardiac structural diseases.
• He denies having a lower exercise tolerance
than his teammates and also denies any
smoking, drinking, use of medications, illicit
substance abuse, or doping practices.
• The primary survey of his airway, breathing, and
circulation is unremarkable.
• Vitals : Blood pressure of 130/71 mm Hg ,heart
rate of 106 bpm, with a normal rhythm. The
respirations are 28-30 breaths/min. The initial
oxygen saturation is 83% while the patient is
breathing room air, but it corrects to 98% on a
non-rebreather mask and, subsequently, to 99%
on 2 L nasal cannula.
• His mentation is intact and he remains alert, with
a Glasgow Coma Scale rating of 15. The skin
examination reveals mild ecchymosis just
anterior to his sternum.
• The rest of examination is normal. They noted
not Marfanoid in appearance.
The ECG
Further investigations
• ECG : sinus tachycardia at a rate of 110 bpm,
with mild right-axis deviation.
• The QRS complex, QT interval, ST/T waves, and
P waves are all noted to be normal.
• A portable, upright chest radiograph shows
somewhat underaerated lungs but no signs of
fractures, widening of the mediastinum,
cardiomegaly, or hemopneumothorax.
The Xray
Blood work
• FBC is normal, except for a mildly elevated white blood
cell (WBC) count of 13.6 ×103/µL (13.6 ×109/L).
• A metabolic panel is normal, including normal potassium
and magnesium findings.
• The initial troponin I is 0.04 ng/mL (0.04 µg/L; normal
range, 0.02-0.04 ng/mL; indeterminate 0.05-0.30 ng/mL).
• A urine drug screen is negative.
• Computed tomography (CT) scanning of the chest is
remarkable only for mild pulmonary and periportal
edema.
• The patient is admitted to the pediatric intensive care
unit (PICU) for continuous cardiac monitoring and
cardiology consultation. An echocardiogram is ordered in
the ED, to be done in the PICU.
Diagnosis please
•
What is the likely pathophysiology that led to
this patient's cardiac arrest?
•
Hint: The mechanism of injury and the
occurrence of ventricular fibrillation are linked.
Hypertrophic cardiomyopathy
Myocardial infarction
Commotio cordis
Long QT syndrome
1.
2.
3.
4.
Commotio Cordis
• Commotio cordis (which is Latin for "disturbance of the
heart") is, in essence, a concussion of the heart.
• Initially described as early as 1857, it is defined as an
instantaneous cardiac arrest produced by a witnessed,
nonpenetrating blow to the chest, in the absence of
preexisting heart disease or identifiable morphologic
injury to the sternum, ribs, chest wall, or heart.
• Commotio cordis is a diagnosis of exclusion in that other
causes, such as substance abuse, myocardial infarction,
electrolyte abnormality, prolonged QT syndrome, and
hypertrophic obstructive cardiomyopathy (HOCM), must
first be ruled out with examinations such as urine drug
screens, serial assessment of cardiac biomarkers and
EKGs, electrolyte level testing, and echocardiography.
• Second most common cause of sudden cardiac arrest in
young athletes (behind HOCM).
• The United States Commotio Cordis Registry (USCCR), in
Minneapolis, Minnesota, reported that as of September 2001,
only 180 cases had been documented. Up to 62% of these
cases involved engagement in organized, competitive sports,
with two-thirds of the patients being younger than 16 years of
age and 80% being male.
• The oldest reported case was that of a 20-year-old man struck
in the chest by a baseball, and the youngest case was that of
a 7-week-old crying infant struck in the chest by his frustrated
father.
• Eighty-one percent of cases involved a blunt, precordial blow
from a projectile object propelled against a stationary chest
wall, resulting in a relatively localized area of contact. It is
notable that those who are most susceptible to commotio
cordis are young athletic males.
• This is probably the result of the fact that there is less
protection of the heart by subcutaneous fat, muscle bulk, and
fully ossified ribs, all of which become more common in
adulthood
• Not all impacts to the anterior chest will lead
to the ventricular fibrillation observed in
commotio cordis.
• The impact must be delivered 10-30
milliseconds before the peak of the T
wave in the cardiac cycle in order to induce
ventricular fibrillation.
• If impact occurs during other portions of the
cardiac cycle, different conduction
disturbances, such as heart block, bundle
branch block, or transient ST segment
elevation, may be induced.
• Induction is likely secondary to the
activation of potassium-carrying ion
channels via mechanoelectric
coupling.
• The activation of these ion channels
generates an inward current, thus
locally augmenting repolarization
and resulting in premature
ventricular depolarization and the
initiation of unstable ventricular
arrhythmias.
A few key points
1. Cardiovascular collapse in the absence
of cardiac disease.
2. Associated ventricular fibrillation.
3. Impact by a projectile at speeds less
than 50mph
4. Instantaneous cardiac arrest
5. No significant laboratory abnormalities
The bottom line
• Regardless of etiology, if a young athlete
goes into sudden cardiac arrest, CPR
should be implemented immediately. Of
sports-related cases of commotio cordis
documented in the USCCR, 15% of
patients survived. In cases in which CPR
was instituted within 3 minutes of the
impact, 68% of patients survived; however,
if CPR was delayed by more than 3
minutes, only 3% of patients survived.