Download Heart Rhythm Refresher Course 2014 Module 1: Epidemiology

Dr Yue Chiu Sun
Consultant and Head
Division of Cardiology
Dept of Medicine & Geriatrics
United Christian Hospital
6 Apr 2014
• Sudden cardiac death (SCD) is an unexpected death due to
cardiac causes that occurs in a short time period (generally
within 1 hour of symptom onset) in a person with known
or unknown cardiac disease
• SCD represents the first expression of cardiac disease in
many individuals who experience out-of-hospital cardiac
arrest
• ~80-90%: VT and VF
• survival rate for out of hospital arrest <5%.
Epidemiology of SCD
 It is estimated that more than 7 million lives per year
are lost to SCD worldwide, including ~325,000 in the
United States (incidence of ~0.1-0.2%/year in adult
population)
 In Hong Kong, more than one thousand people lose
their lives suddenly and unexpectedly every year.
 Many cases are due to ventricular fibrillation VF
causing sudden cardiac arrest
Sudden Death
 U.S.A. 100-200 / 100,000 / year
 Japan 68-104 / 100,000 / year
 Netherlands 100 / 100,000 / year
 Greece 90 / 100,000 / year
 Taiwan 58~73 / 100,000 / year
 Iceland 56 / 100,000 / year
 Finland 48 / 100,000 / year
 Israel 46 / 100,000 / year
 England 40 / 100,000 / year
Huang et al. Acta Cardiol Sin 2006
Epidemiology of sudden cardiac
death in Asia
 Sudden cardiac death (SCD) occurs in ~40 cases per 100,000 persons
annually in each country of Asia
 Most cases are caused by MI and VF in out-of-hospital cardiac arrest
cases, but the proportion of myocardial infarction is lower in Asia
than in Western countries
 The
primary
electrophysiological
disorders
related
to
channelopathies, such as long QT syndrome, short QT syndrome,
Brugada syndrome, early repolarization syndrome, and
catecholaminergic polymorphic ventricular tachycardia (CPVT) are
estimated to be responsible for 10% of SCDs
Circ J. 2013;77(10):2419-31
Incidence and Demographics of Sudden
Death in Hong Kong
 The first territory-wide survey on sudden death in
the Hong Kong SAR was conducted by the
Cardiology Division, Department of Medicine, HKU
 an incidence of 18 sudden deaths per 100,000
population in the year 1997
 Out of 1204 cases of out-of-hospital sudden deaths
reported to the coroner, the underlying causes were
-AMI in 31%, CAD in 26%, HT heart diseases in 14%,
ruptured aortic aneurysm in 6%, CMP in 5%,
other CV diseases in 7%, non-CV causes in 11%
Causes of SCD
 Causes of SCD depend on age, gender, ethnicity, and
genetics
 Age < 40 yrs: common causes include hypertrophic
cardiomyopathy (HCM), unexplained left
ventricular hypertrophy, myocarditis, congenital
heart disease and less commonly aortic dissection,
valvular heart disease and arrhythmogenic right
ventricular dysplasia/ cardiomyopathy (ARVD/C)
 Age > 40 yrs: atherosclerotic coronary heart disease is
the most common cause
Causes of SCD
 Under one year of age, SCD can be part of sudden
infant death syndrome (SIDS) which is often
associated with a negative postmortem
 Sudden death with a negative postmortem is
referred to as “autopsy-negative sudden
unexplained death (SUD)”, the cause of which is
most likely a primary arrhythmogenic event
Genetics of SCD
 The inherited structural cardiovascular diseases
causing SCD are most frequently HCM, ARVC and
dilated cardiomyopathy
 On the other hand, the most likely encountered
inherited arrhythmogenic disorders that may
cause SCD are congenital long QT syndrome
(LQTS), Brugada syndrome, catecholaminergic
polymorphic ventricular tachycardia (CPVT)
and short QT syndrome (SQTS)
Genetics of SCD
 Postmortem molecular diagnostic studies, referred to
as “molecular autopsy”, have identified pathogenic
mutations in LQTS, Brugada syndrome, CPVT and
SQTS-related genes in over one third of SCD victims
-> inherited arrhythmogenic disorders : ion channelopathies
Genetics of SCD- Brugada syndrome
 Brugada syndrome has been linked to mutations in the SCN5A gene that
encode the –subunit of the sodium channel and those in the CACNA and
CNCNB genes that encode the -and -subunits of the calcium channel
respectively and the gene that encodes glycerol-3-phosphate dehydrogenase
1-like enzyme GPD-L
 However, more than 70% of cases remain unaccounted for by the genotype
In Japan, the incidence of SCN5A mutations varies from 2% to 27%
(mean 12%) which is much lower than that reported in Europe (20%)
 Brugada phenotype is 8 to 10 times more prevalent in men than in women
 This gender distinction is attributed to the presence of a more prominent Ito
giving rise to a more prominent notch in the action
 potential of right ventricular epicardial cells in males versus females
Ethnicity of SCD
 Most studies demonstrate inconclusive data with
regard to racial differences as they relate to the
incidence of sudden death. Some studies suggest
that a greater proportion of coronary deaths were
"sudden" in blacks compared to whites
Gender difference
 Men have a higher incidence of SCD than women,
with a ratio of 3:1
 This ratio generally reflects the higher incidence of
obstructive coronary artery disease in men
 Recent evidence suggests that a major sex difference
may exist in the mechanism of myocardial infarction.
- men tend to have coronary plaque rupture
- women tend to have plaque erosion
Sudden death in Atheletes
The incidence of SCD among young athletes is estimated to be 1–3 per 100,000 person years,
is higher than in non-athletes
Br J Sports Med 2009;43:644–648
Causes of Sudden Death in young athletes
Hypertrophic cardiomyopathy HCM
Van Cam et al.（%）
Maron et al.（%）
51
36
Possible death due to HCM
5
10
Coronary artery anomalies
16
19
Myocarditis
7
3
Aortic valve stenosis
6
4
Dilated cardiomyopathy
5
3
Aortic rupture
2
5
Arrhythmogenic right ventricular cardiomyopathy ARVC
1
3
Atherosclerotic coronary artery disease
3
2
Others
4
15
100
100
Total
Athletes Recommendations
Class I
1. Pre-participation history and physical examination, including family history of
premature or sudden death and specific evidence of cardiovascular diseases such
as cardiomyopathies and ion channel abnormalities is recommended in athletes.
(Level of Evidence: C)
2. Athletes presenting with rhythm disorders, structural heart disease, or other
signs or symptoms suspicious for cardiovascular disorders, should be evaluated as
any other patient but with recognition of the potential uniqueness of their activity.
(Level of Evidence: C)
3. Athletes presenting with syncope should be care-fully evaluated to uncover
underlying cardiovascular disease or rhythm disorder. (Level of Evidence: B)
4. Athletes with serious symptoms should cease competition while cardiovascular
abnormalities are being fully evaluated. (Level of Evidence: C)
Class IIb
1. 12-lead ECG and possibly echocardiography may be considered as
preparticipation screening for heart disorders in athletes. (Level of Evidence: B)
ACC/AHA/ESC 2006 Guidelines
Prevention of SCD at Community Level
1. Recognition of risk factors for CV disease 2.
3.
4.
5.
appropriate treatment and control
Recognition of high risk population for SCD
Maintain healthy lifestyle
Public education
Pre-participation CV screening of athletes
1) Recognition of risk factors for CV disease treatment and control
 Smoking
 Dyslipidemia
 Hypertension
 Diabetes
 Obesity
 Family history of premature coronary artery disease
 Sedentary lifestyle
Treatment and Control
 Risk Factor Modification
 Healthy diet
 Regular exercise
 Weight reduction (IBW)
 Smoking cessation
 Medical Therapy
 Beta blockers
 ACE inhibitors / ARB
 Lipid-lowering therapy
 Medications for DM, HT
 Interventional Procedures
 Implantable cardioverter defibrillator (ICD)
 Revascularization therapy
 Ablative therapy
2) Recognition of high risk population for
SCD
 Survivors of sudden cardiac arrest
 Sustained VT
 Prior Myocardial Infarction with low LVEF, NSVT
and inducible VT/VF during EPS
 Heart Failure (Class III to IV)
 LV Ejection Fraction < 35 - 40%
 Family History of Sudden Cardiac Arrest
 Others: Recurrent unexplained syncope and significant
LV
dysfunction , HCM or ARVC who have risk factor(s) for SCD, longQT syndrome, Brugada syndrome with syncope or VT, CPVT
2012 ACCF / AHA / HRS Guidelines for Device-Based
Therapy of Cardiac Rhythm Abnormalities
ICD Therapy
Class I
1 ICD therapy is indicated in patients who are survivors of
cardiac arrest due to VF or hemodynamically unstable
sustained VT after evaluation to define the cause of the
event and to exclude any completely reversible causes.
(Level of Evidence: A)
2 ICD therapy is indicated in patients with structural heart
disease and spontaneous sustained VT, whether
hemodynamically stable or unstable. (Level of Evidence: B)
ICD therapy
Class I
3 ICD therapy is indicated in patients with syncope of undetermined
origin with clinically relevant, hemodynamically significant
sustained VT or VF induced at electrophysiological study. (Level of
Evidence: B)
4 ICD therapy is indicated in patients with LVEF less than 35% due to
prior MI who are at least 40 days post-MI and are in NYHA
functional Class II or III. (Level of Evidence: A) (1º prevention)
5 ICD therapy is indicated in patients with non-ischemic DCM who
have an LVEF less than or equal to 35% and who are in NYHA
functional Class II or III. (Level of Evidence: B) (1º prevention)
ICD therapy
Class I
6 ICD therapy is indicated in patients with LV
dysfunction due to prior MI who are at least 40 days postMI, have an LVEF less than 30%, and are in NYHA
functional Class I. (Level of Evidence: A) (1º prevention)
7 ICD therapy is indicated in patients with non-sustained
VT due to prior MI, LVEF less than 40%, and inducible VF
or sustained VT at electrophysiological study. (Level of
Evidence: B)
ICD therapy – Class IIa
1 ICD implantation is reasonable for patients with
unexplained syncope, significant LV dysfunction, and
non-ischemic DCM. (Level of Evidence: C)
2 ICD implantation is reasonable for patients with
sustained VT and normal or near-normal ventricular
function. (Level of Evidence: C)
3 ICD implantation is reasonable for patients with HCM
who have 1 or more major risk factors for SCD. (Level of
Evidence: C)
4 ICD implantation is reasonable for the prevention of
SCD in patients with ARVD/C who have 1 or more risk
factors for SCD. (Level of Evidence: C)
ICD therapy – Class IIa
5 ICD implantation is reasonable to reduce SCD in
patients with long-QT syndrome who are experiencing
syncope and/or VT while receiving beta blockers. (Level
of Evidence: B)
6 ICD implantation is reasonable for non hospitalized
patients awaiting transplantation. (Level of Evidence: C)
(from Class IIb)
7 ICD implantation is reasonable for patients with
Brugada syndrome who have had syncope. (Level of
Evidence: C) (from Class IIb)
ICD therapy – Class IIa
8 ICD implantation is reasonable for patients with
Brugada syndrome who have documented VT that has
not resulted in cardiac arrest. (Level of Evidence: C)
9 ICD implantation is reasonable for patients with
catecholaminergic polymorphic VT who have syncope
and/or documented sustained VT while receiving beta
blockers. (Level of Evidence: C)
10 ICD implantation is reasonable for patients with
cardiac sarcoidosis, giant cell myocarditis, or Chagas
disease. (Level of Evidence: C)
3. Maintain healthy lifestyle
4. Public education
i) Regular body check
ii) Bystander CPR
iii) AED (Automated External Defibrillator)
iv) HK-IN-PACE: Sudden Cardiac Death Public
Awareness Campaign
Bystander CPR
For adults with sudden out-of-hospital SCA,
compression-only bystander CPR (without rescue
breathing) appears to have equal or possibly greater
efficacy compared with standard bystander CPR
(compressions plus rescue breathing). The 2010
American Heart Association (AHA) Guidelines for
CPR recommended that bystanders perform
compression-only CPR to provide high-quality chest
compressions prior to the arrival of emergency
personnel
時間是復甦搶救成功的關鍵
100
發現心臟驟停



1 分鐘
急救車到達現場


1 分鐘
致電 999


1 分鐘
80
進行自行急救

6 分鐘
確認病者並進行電擊

成功率每分鐘下降 7-10%
90
2分鐘
總時間 11分鐘
% 復甦成功率

70
60
50
40
缺腦
氧細
，胞
損
傷
30
20
10
0
0
1
2
3
4
5
6
7
8
9
時間 (分鐘)
美國心臟協會建議, 在醫院以外發生心臟驟停後3-5分鐘內要進行除顫
10
自動體外除顫器 AED
(Automated External Defibrillator)
AED
11
2
3
HKCC AED program 2008
Aim: increase public awareness, promote layperson training in basic life
support skill, and coordinate AED installation in suitable locations
Hong Kong College of Cardiology (HKCC) donated the first public-access AED to
Lan Kwai Fong in 2007
Public-access AED has been proven in clinical trials that it saved 50% more lives from
out of-hospital cardiac arrest
5. Pre-participation Cardiovascular Screening
of Competitive Athletes
 Both the American Heart Association (AHA 2007)
and the European Society of Cardiology (ESC 2005)
have proposed guidelines for pre-participation
screening for young athletes planning to begin
competitive sports.
 The most significant difference between these two
proposals is that the AHA guidelines include a
preparticipation history and physical examination
without further routine testing, while the ESC
proposal includes a standard 12-lead ECG in all
patients.
Pre-participation Cardiovascular Screening of
Competitive Athletes
 the incidence of SCD among competitive athletes is
actually quite low, estimated to be between 1 per
50,000 athletes to 1 per 300,000 athletes over a 10 to
20 year period
 the incidence of SCD among marathon runners is
low (one death per 215,000 hours) but is higher than
that for other exercise, such as non-competitive
jogging (one death per 396,000 hours), cross-country
skiing (one death per 607,000 hours), or general, noncompetitive exercise (one death per 375,000 hours)
AHA Recommendations for Pre-participation
Cardiovascular Screening of Competitive Athletes 2007
Medical history:
1. Exertional chest pain/discomfort
2. Unexplained syncope/near-syncope†
3. Excessive exertional and unexplained dyspnea/fatigue, associated with exercise
4. Prior recognition of a heart murmur
5. Elevated systemic blood pressure
Family history:
6. Premature death (sudden and unexpected, or otherwise) before age 50 years due to heart disease, in
1 relative
7. Disability from heart disease in a close relative 50 years of age
8. Specific knowledge of certain cardiac conditions in family members: hypertrophic or dilated
cardiomyopathy, long-QT syndrome or other ion channelopathies, Marfan syndrome, or clinically
important arrhythmias
Physical examination:
9. Heart murmur‡
10. Femoral pulses to exclude aortic coarctation
11. Physical stigmata of Marfan syndrome
12. Brachial artery blood pressure (sitting position)
ESC 2005
Pre-participation Cardiovascular Screening of
Competitive Athletes
 Controversy has evolved over the most practical and effective strategy for
preparticipation cardiovascular screening of competitive athletes to detect
unsuspected cardiovascular disease and prevent sudden death on the athletic field

Athlete screening in the Veneto region of Italy is part of a national program (with 12lead ECG) that has reported the detection of previously undiagnosed hypertrophic
cardiomyopathy and a decrease in the cardiovascular death rate in young athletes. In
this study, over time periods of similar length, cardiovascular-related mortality rates
in Veneto athletes were compared with those of a demographically similar region of
the United States (Minnesota) in which screening is limited to history and physical
examination
 There were 55 sudden CV deaths reported in Veneto over 26 years (2.1/year),
compared with 22 deaths in 23 years (0.96/year) in Minnesota. Over the recent and
comparable 11-year period, 1993 to 2004, 12 deaths were reported in Veneto and 11 in
Minnesota. When analyzed as deaths per 100,000 person-years, Veneto exceeded
Minnesota for all years combined (1.87 for 1979 to 2004 vs 1.06 for 1985 to 2007,
respectively, p = 0.006), although the 2 regions did not differ significantly for 1993 to
2004 (0.87 vs 0.93, respectively, p = 0.88) or most recently for 2001 to 2004 (0.43 vs 0.90,
respectively, p =0.38)
Pre-participation Cardiovascular Screening of
Competitive Athletes
 In conclusion, sudden CV deaths in young competitive athletes
occurred at a low rate in both Veneto and Minnesota. Despite
different pre-participation screening strategies, athlete sudden death
rates in these demographically similar regions of the United States
and Italy have not differed significantly in recent years
 These data do not support a lower mortality rate associated with
pre-participation screening programs involving routine ECG and
examinations by specially trained personnel
Am J Cardiol. 2009 Jul 15;104(2):276-80
Recreational athletes
 In general, patients with known genetic disorders that predispose to SCD
(eg, hypertrophic cardiomyopathy, arrhythmogenic right ventricular
cardiomyopathy, Marfan syndrome, long QT syndrome) should avoid
recreational activities with the following characteristics:
-"Burst" exertion, involving rapid acceleration and deceleration, as is
common in sprints, basketball, tennis, and soccer. Activities with
stable energy expenditure, such as jogging, biking on level terrain,
and lap swimming are preferred.
- Extreme environmental conditions (temperature, humidity, and
altitude) that impact blood volume and electrolytes.
- Systematic and progressive training focused on achieving higher
levels
of conditioning and excellence.
 Patients with unusual or high-risk clinical features may require greater
restriction. These features include a history of syncope or presyncope, prior
cardiac surgery, prior arrhythmic episodes, or an implantable cardioverterdefibrillator (ICD).