The document discusses out of hospital sudden cardiac death (SCD) and whether rates are declining or escalating. Key points include: 1. Over 400,000 SCDs occur annually out of hospital or upon arrival to the emergency room. 2. Pre-hospital delay times in the U.S. have not declined in recent decades and impede treatment of SCD, which remains a major public health challenge. 3. Improving early recognition of heart attack symptoms and rapid intervention through public health initiatives could help reduce SCD rates and save more lives.

1. Out of Hospital SuddenOut of Hospital Sudden
Cardiac Death (SCD):Cardiac Death (SCD):
Declining or Escalating?Declining or Escalating?
Alireza Zarrabi, M.D.Alireza Zarrabi, M.D.
Center for Vulnerable Plaque ResearchCenter for Vulnerable Plaque Research
The University of Texas Health Science Center at HoustonThe University of Texas Health Science Center at Houston
and, Texas Heart Institute, U.S.A.and, Texas Heart Institute, U.S.A.
March 2002March 2002

2.  Every 29 seconds, one American suffersEvery 29 seconds, one American suffers
from an unexpected heart attack. Sadly,from an unexpected heart attack. Sadly,
one will die nearly every minute.one will die nearly every minute.
 Every year 225,000 people die of heartEvery year 225,000 people die of heart
attack before reaching the hospital.attack before reaching the hospital.

3.  The single most important cause of death in theThe single most important cause of death in the
adult population of the industialized world isadult population of the industialized world is
sudden cardiac death (SCD) due to coronarysudden cardiac death (SCD) due to coronary
disease.disease. 11
 SCD is defined as follows: " Natural death due toSCD is defined as follows: " Natural death due to
cardiac causes, heralded by abrupt loss ofcardiac causes, heralded by abrupt loss of
consciousness within one hour of the onset ofconsciousness within one hour of the onset of
acute symptoms; preexisting heart disease mayacute symptoms; preexisting heart disease may
have been known to be present, but the time andhave been known to be present, but the time and
mode of death are unexpected.mode of death are unexpected. 22

4.  50% of victims of sudden out-of-hospital50% of victims of sudden out-of-hospital
cardiac death have no prior diagnosis ofcardiac death have no prior diagnosis of
heart disease (asymptomatic).heart disease (asymptomatic). 33
 More than 60% of cardiac death continuesMore than 60% of cardiac death continues
to remain sudden. In 1998, there wereto remain sudden. In 1998, there were
719 456 cardiac disease deaths among US719 456 cardiac disease deaths among US
residents aged >=35 years, of whichresidents aged >=35 years, of which
456,076 (63.3%) were defined as SCD.456,076 (63.3%) were defined as SCD. 44

5.  The number of adolescents and youngThe number of adolescents and young
adults dying each year from suddenadults dying each year from sudden
cardiac arrest rose by about 10% betweencardiac arrest rose by about 10% between
1989 and 1996, the first study of1989 and 1996, the first study of
nationwide trends in the United States hasnationwide trends in the United States has
shown.shown. 77
 The number of sudden cardiac deaths inThe number of sudden cardiac deaths in
the 15-34 age group went up from 2,724the 15-34 age group went up from 2,724
in 1989 to 3,000 in 1996, an increase ofin 1989 to 3,000 in 1996, an increase of
10%. Of all the young people who died10%. Of all the young people who died
over the eight year period, 71% were menover the eight year period, 71% were men
and 29% women.and 29% women. 77

6. Age-adjusted death rates (per 100
000 US population) for sudden
cardiac death among men aged 35
years and older by race in the US
from 1989 to 1990.
Adapted from:Adapted from: Zhi-Jie Zheng, George A. Mensah, et al.; Sudden Cardiac Death in the UnitedZhi-Jie Zheng, George A. Mensah, et al.; Sudden Cardiac Death in the United
States, 1989 to 1998 .Circulation. 2001;104:2158States, 1989 to 1998 .Circulation. 2001;104:2158

7. Age-adjusted death rates (per 100 000
US population) for sudden cardiac
death among women aged 35 years
and older by race in the US from 1989
to 1990.
Adapted from:Adapted from: Zhi-Jie Zheng, George A. Mensah, et al.; Sudden Cardiac Death in the UnitedZhi-Jie Zheng, George A. Mensah, et al.; Sudden Cardiac Death in the United
States, 1989 to 1998 .Circulation. 2001;104:2158States, 1989 to 1998 .Circulation. 2001;104:2158

8.  400,000 to 450,000 SCD per year from400,000 to 450,000 SCD per year from
1989 to 1998 occurred out of hospital, in1989 to 1998 occurred out of hospital, in
the emergency room, or as "dead onthe emergency room, or as "dead on
arrival."arrival." 66
 The automated external defibrillatorsThe automated external defibrillators
(AEDs) represents an efficient method of(AEDs) represents an efficient method of
delivering defibrillation to personsdelivering defibrillation to persons
experiencing out-of-hospital cardiac arrestexperiencing out-of-hospital cardiac arrest
and its use appears to be safe andand its use appears to be safe and
effective.effective. 88

9. Survival to 1 month relative to delay time from cardiac arrest toSurvival to 1 month relative to delay time from cardiac arrest to
first defibrillation for bystander-witnessed patients withfirst defibrillation for bystander-witnessed patients with
ventricular tachycardia/ventricular fibrillation on firstventricular tachycardia/ventricular fibrillation on first
electrocardiogram (n = 2,748).electrocardiogram (n = 2,748). ArrowArrow indicates median delayindicates median delay
time (13 minutes).time (13 minutes).
Adapted from: Holmberg M, Holmberg S, Herlitz J.; The problem of out-of-hospital cardiac-arrest
prevalence of sudden death in Europe today. Am J Cardiol. 1999 Mar 11;83(5B):88D-90D.
(Minutes)

10.  There is evidence of a slight decline inThere is evidence of a slight decline in
average delay times in patientsaverage delay times in patients
hospitalized in 1997 (5.5 hours) comparedhospitalized in 1997 (5.5 hours) compared
with those hospitalized in 1994 (5.7with those hospitalized in 1994 (5.7
hours).hours).
 Approximately 20% of patients presentedApproximately 20% of patients presented
to the hospital within 1 hour of acuteto the hospital within 1 hour of acute
symptom onset, and slightly more thansymptom onset, and slightly more than
two thirds presented within 4 hours.two thirds presented within 4 hours.

11.  Delay times are shorter in patients withDelay times are shorter in patients with
cardiogenic shock than less severely illcardiogenic shock than less severely ill
patients.patients.
 Patients with previous acute MI or thosePatients with previous acute MI or those
with history of coronary angioplastywith history of coronary angioplasty
presented to hospital with shorter delaypresented to hospital with shorter delay
times.times.

12.  Poor knowledge of warning symptoms ofPoor knowledge of warning symptoms of
heart attack and lack of a convenientheart attack and lack of a convenient
method for out-of-hospital screening ofmethod for out-of-hospital screening of
patients with chest discomfort are amongpatients with chest discomfort are among
major factors contributing to themajor factors contributing to the
overwhelming burden of out-of-hospitaloverwhelming burden of out-of-hospital
SCD.SCD.

13. ConclusionConclusion
“Epidemiology”“Epidemiology”
I.I. Women increasingly die with SCD out-Women increasingly die with SCD out-
of-hospital.of-hospital.
II.II. The increased death rates for SCDThe increased death rates for SCD
among younger women warrantsamong younger women warrants
additional investigation of their potentialadditional investigation of their potential
risk factors.risk factors.

14. ConclusionConclusion
“Pathology”“Pathology”
I.I. Coronary thrombosisCoronary thrombosis (a product of(a product of
vulnerable plaque and vulnerable blood)vulnerable plaque and vulnerable blood)
does not exist in 43-51% of SCD cases.does not exist in 43-51% of SCD cases.
In other words, about half of SCDs areIn other words, about half of SCDs are
not caused by plaque rupture ornot caused by plaque rupture or
coronary thrombosis.coronary thrombosis.
II.II. This reiterates the fact that SCD is aThis reiterates the fact that SCD is a
product ofproduct of vulnerable plaque +vulnerable plaque +
vulnerable blood + vulnerablevulnerable blood + vulnerable
myocardiummyocardium..

15. ConclusionConclusion
“Public Health”“Public Health”
I.I. Pre-hospital delay in the US has notPre-hospital delay in the US has not
declined in the past few decades anddeclined in the past few decades and
holds as a major bottle neck in ourholds as a major bottle neck in our
challenge against SCD.challenge against SCD.

16. ConclusionConclusion
“Public Health”“Public Health”
II.II. The encouraging declines in the proportionThe encouraging declines in the proportion
of cardiac deaths occurring in the hospitalof cardiac deaths occurring in the hospital
or the emergency room may reflect theor the emergency room may reflect the
improvements in emergency services andimprovements in emergency services and
more timely and appropriate treatment inmore timely and appropriate treatment in
hospital.hospital.
However, the increased trend in SCDHowever, the increased trend in SCD
outside of the hospital reiterates the needoutside of the hospital reiterates the need
for public health initiatives to improve thefor public health initiatives to improve the
early recognition of heart attack symptomsearly recognition of heart attack symptoms
and signs with rapid intervention.and signs with rapid intervention.

17.  For saving more lives from SCD which oneFor saving more lives from SCD which one
of the following should be our firstof the following should be our first
impression:impression:
A.A. Detection and treatment of vulnerableDetection and treatment of vulnerable
plaque?plaque?
B. Detection and treatment of vulnerable heart?B. Detection and treatment of vulnerable heart?
C. Rapid out-of-hospital screening, detection,C. Rapid out-of-hospital screening, detection,
and treatment of patients with cardiac chestand treatment of patients with cardiac chest
discomfort?discomfort?

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