Download Sudden Cardiac Arrest - Bahman Arrhythmia Clinic

Sudden Cardiac Death
• Definition
– Death occurs within minutes
– Cardiac in nature
– Unwitnessed death
• Incidence
– 375,000 people suffer Sudden Cardiac
Death per year
– Approximately 43 people every hour
– 75,000 (20%) survive
Sudden Cardiac Arrest
Magnitude of SCA in the U.S.
Stroke3
167,366
Lung Cancer2
157,400
1
2
3
4
Breast Cancer2
40,600
AIDS1
42,156
SCA claims
more lives
each year
than these
other
diseases
combined
450,000
SCA4
#1 Killer in
the U.S.
U.S. Census Bureau, Statistical Abstract of the United States: 2001.
American Cancer Society, Inc., Surveillance Research, Cancer Facts and Figures 2001.
2002 Heart and Stroke Statistical Update, American Heart Association.
Zheng Z. Circulation. 2001;104:2158-2163.
Sudden Cardiac Arrest is one of the Leading
Causes of Death in the U.S.
300,000
250,000
200,000
150,000
100,000
50,000
0
AIDS
Breast Cancer
Lung Cancer
Stroke
Source: Statistical Abstract of the U.S. 1998, Hoover’s Business Press, 118 th Edition
SCA
Sudden Cardiac Death
• Causes
– 80-90% are tachyarrhythmias
– Only 10-20% are due to an acute
myocardial infarction or to
bradyarrhythmias
Underlying Arrhythmia of
Sudden Cardiac Arrest
Primary
VF
8% Torsades
de Pointes
13%
VT
62%
Adapted from Bayés de Luna A. Am Heart J. 1989;117:151-159.
Bradycardia
17%
Coronary Heart Disease
• An estimated 13 million people had CHD in the
U.S. in 2002. 1
• Sudden death was the first manifestation of
coronary heart disease in 50% of men and 63% of
women. 1
• CHD accounts for at least 80% of sudden cardiac
deaths in Western cultures.3
Etiology of Sudden Cardiac Death2,3
5% Other*
15%
Cardiomyopathy
1
American Heart Association. Heart Disease and Stroke Statistics—2003 Update. Dallas, Tex.:
American Heart Association; 2002.
2
Adapted from Heikki et al. N Engl J Med, Vol. 345, No. 20, 2001.
3
Myerberg RJ. Heart Disease, A Textbook of Cardiovascular Medicine. 6th ed. P. 895.
80%
Coronary
Heart
Disease
* ion-channel abnormalities,
valvular or
congenital heart disease, other causes
SCD
CAD Risk Factors
“Reduced left ventricular ejection
fraction (LVEF) remains
the single most important risk factor
for overall mortality
and sudden cardiac death.”1
Control Group Mortality at2 years
SCD Rates in Post-MI Patients with LV
Dysfunction
30
28
Total Mortality
Arrhythmic Mortality
28
21
20
20
18
16
19.8
16
14
12
10
10
9.4
7
0
TRACE
CAPRICORN
EMIAT
MADIT
MUSTT
Inducible
MUSTT
Registry
MADIT II*
Total Mortality ~20-30%; SCD accounts for ~50% of the total deaths.
References in slide notes. * MADIT-II mortality values at 20 months.
Treatments to Reduce SCD
Correcting Ischemia
– Revascularization
– Beta-blocker
Preventing Plaque Rupture
– Statin
– ACE inhibitor
– Aspirin
Stabilizing Autonomic
Balance
– Beta-blocker
– ACE inhibitor
Zipes DP. Circulation. 1998;98:2334-2351.
Pitt B. N Engl J Med. 2003;348:1309-1321.
Improving Pump Function
– ACE inhibitor
– Beta-blocker
Prevention of Arrhythmias
– Beta-blocker
– Amiodarone
Terminating Arrhythmias
– ICDs
– AEDs
Prevent Ventricular
Remodeling and Collagen
Formation
Ann Noninvasive Electrocardiol. 1999;4:83-91
MADIT II (1997-2002)
Multicenter Automatic Defibrillator Implantation Trial II
• Objective - To evaluate the role of ICD vs.
medical therapy in a group of patients
with left ventricular dysfunction and MI
• Inclusion - Post MI patients with EF < 30%.
No prior assessment of VT in the EP lab.
Requirement for freq. PVC’s was dropped
six months in to the study (only 23 pts
enrolled).
• Exclusion - Approved indication for an
ICD; Undergone coronary
revascularization within 3-months; An MI
within the past 1-month
MADIT II
Multicenter Automatic Defibrillator Implantation Trial II
• Patients - 1,232 randomized in a 3:2 ratio
to receive an ICD (752) or conventional
medical therapy (490)
• Results - Over a 4-yr period with an
average follow-up of 20-months, the ICD
group resulted in a 5.6% absolute and 31%
relative risk reduction in mortality over
conventional group - 14.2% vs. 19.8%
respectively
– Study terminated early due to this favorable
result
MADIT II
Multicenter Automatic Defibrillator Implantation Trial II
Probability of Survival
Moss, A. et. al. N Engl J Med 2002;877-83
Reductions in Mortality with ICDs
Compared to Antiarrhythmic Drugs
60%
% Mortality Reduction
60%
54%
50%
40%
37%
31%
30%
20%
20%
10%
0%
AVID1
CASH2
CIDS3
MADIT4
MUSTT5
3 years
2 years
3 years
2 years
5 years
3
1
The AVID Investigators. N Engl J Med. 1997;337:1576-1583.
2 Kuck K. ACC98 News Online. April, 1998. Press release.
Connolly S. ACC98 News Online. April, 1998. Press release.
AJ. N Engl J Med. 1996;335:1933-1940.
5 Buxton AE. N Engl J Med. 1999;341:1882-1890.
4 Moss
Incremental Cost-Effectiveness Results
($LYS)*
$200
$180
Expensive
$160
$LYS (X 1000)
Unattractive
$174,100
$140
$120
$100
$91,500
$80
Borderline Cost Effective
Cost Effective
$57,300
$60
$44,300
$40
$20
$18,200
$27,000
$28,400
Highly Cost Effective
$0
CABG
ICD
Chronic CAD
Mild Angina
3 VD1
Therapy2
*Versus Conventional Therapy
1 Kupersmith. Progress in Cardiovascular Disease. 1995.
2
Captopril
Post MI
EF < .401
Cardiac
Peritoneal
Transplant
CHF
Transplant
Candidate1
Dialysis3
Owens. Annals of Internal Medicine. 1997.
PTCA
Anticoag.
Chronic CAD
Mitral
Mild Angina
Stenosis
1 VD LAD1 NSR, Female
Age 351
3 Kupperman.
Circulation. 1990
GOAL OF ICD THERAPY
• 375,000 people suffer Sudden Death
each year
• Only 20% survive
• In 1985, the only indication for AICD
implantation was survival of 2 sudden
death episodes
• Today, we are attempting to identify
those patients who are at high risk and
treat them prior to SCD
EF Clinic Program Patient Screening Pathway
(The Ohio Heart & Vascular Center)
PATIENT
Does patient have
history of cardiac
arrest, VF, or
symptomatic VT?
YES
Consult EP for
possible ICD
Note: Pathway only begins
after optimal medical therapy
& coronary evaluation /
intervention as appropriate
NYHA Class
II or III CHF
NYHA Class I CHF
40 days post MI
with EF ≤ 30%
Is patient on
optimal medical
therapy?
NO
Optimize therapies or
consult HF specialist
Consult EP for
possible ICD
YES
Determine EF
EF ≤ 35%
EF > 35%
1. Consider referral
to HF Specialist or HF Program.
2. Repeat diagnostics
with change of symptoms.
Ischemic
Non-Ischemic
Class III or IV CHF
and QRS > 120 ms
40 days post MI
OR
3 months post
revascularization
3 months
post diagnosis
Consult EP for
possible CRT-D
Consult EP for
possible ICD
Consult EP for
possible ICD
This is a general protocol to assist in
the management of patients. This
protocol is not designed to replace
clinical judgment or individual patient
needs.
Indications for ICD
Class I
1. Cardiac Arrest
– Due to VT or VF
– Not due to transient or reversible cause
2. Spontaneous sustained VT
– Structural heart disease must be present
3. Syncope of undetermined origin with:
– Sustained VT that has clinical relevance and/or
hemodynamic significance
– VF induced during EP study when drug therapy to
sustained VT is not preferred
Indications for ICD
Class I
4. Nonsustained VT with:
–
–
–
–
Coronary disease
Prior MI
LV Dysfunction
Inducible VF or sustained VT
(Non-suppressible by antiarrhythmic drugs)
5. Spontaneous sustained VT
– Not amenable to other treatments
Indications for ICD
Class IIa
1. LVEF <30% at:
– 1 month post MI
– 3 months post coronary revascularization
Indications for ICD
Class IIb
1. Cardiac Arrest
– Assumed due to VF
– EP test precluded by other medical conditions
2. Symptomatic sustained VT while awaiting
cardiac transplant
3. Conditions with life-threatening risk
– Long QT Syndrome
– Hypertrophic cardiomyopathy
Indications for ICD
Class III
1. Syncope of undetermined origin
– Without structural heart disease
– No inducible VT or VF
2. Incessant VT or VF
3. VT or VF with an ablatable or surgically
treatable cause
– WPW, LVOT VT, ILVT, Fascicular VT
4. Transient or reversible VT
– Due to AMI, electrolyte imbalance, drugs
or trauma
Indications for ICD
Class III
5.Psychiatric illness that may:
– Be aggravated by device
implantation
– Preclude follow-up
6.Terminal illness
– <6 month life expectancy
ICD Evolution
Evolution of ICD Technology
ICD Evolution
THEN…
• Required major surgery
• Nonprogrammable
• High-energy shock only
• Indicated for 2X SCD
survivors only
• 1 ½ year longevity
• < 1,000 implants/year
ICD Evolution
…and NOW
• Transvenous, single incision
• Local anesthesia, conscious
sedation
• Programmable therapy
options
• Single, dual and triple
chamber
• Up to 9 years longevity
• > 100,000 implants/year
ICD Evolution
The ICD System
*
Animation
How it Works
The ICD System
How it Works
Atrium & Ventricle
Ventricle
•
•
•
•
VT prevention
Antitachycardia pacing
Cardioversion
Defibrillation
• Bradycardia sensing
• Bradycardia pacing
• Antitachycardia
pacing
ICD
Device Components
(Header)
(Used for Telemetry)
Question?
What is the function of an ICD?
•
•
•
•
Sense
Detect
Therapy
Pace
Question?
What is Sensing?
• The process of identifying cardiac
depolarizations from an intracardiac
electrogram
• It’s what the device sees
Sensing
• Sensing - what the device “sees”
• Electrical Activity - what the device is look
for
• Lead – contains the ‘eyeball’ of the device
The EGM Signal
Farfield
Morphology Comparison
SINUS RHYTHM
VT
EGM Source = Variable
Marker Channel™
ICD Function Annotations
•Therapy:
–TP = Anti-Tachycardia Pacing Initiated (ATP)
–CE = Charge End
–CD = Charge Delivered
* in Medtronic devices
Detection
Detection Rate
•Measured in:
– Beat-to-beat intervals (milliseconds), or
– Beats-per-minute (BPM)
•Classifies rhythm by detection zone:
–VT = Ventricular Tachycardia
–VF = Ventricular Fibrillation
•Programmable in ranges of rates
Example: VT = 162 bpm – 188 bpm
VF = 188 bpm and faster
Question?
Can you name some therapies delivered
by an ICD?
ICD Therapies
•
ICD Therapy
– Low Power (Pacing Therapies)
• Anti-tachycardia Pacing (ATP
• Bradyarrhythmia Pacing
– High Power (Shock Therapies)
• Cardioversion
• Defibrillation
ICD Therapies
•Tachyarrhythmia Therapy
–Anti-Tachycardia Pacing (ATP)
Low Power
•Pacing pulses delivered at a rate faster
than the rhythm detected
•Can successfully terminate re-entrant
tachycardias
Anti-Tachycardia Pacing
*
Animation
Click image to view animation
Anti-Tachycardia Pacing
Re-entry initiated
ATP delivered at a rate faster
than tachyarrhythmia.
Wavefronts collide.
Subsequent Pulses:
Wavefronts collide even
closer to re-entry circuit
Subsequent Pulse:
Wavefronts collide closer
to re-entry circuit
Arrhythmia
terminated
Cardioversion
• Delivers shock on an R-wave
• Aborts if synchronization cannot be
obtained due to arrhythmia termination
Defibrillation
*
Animation
Click image to view animation
ICD Therapy
Benefits of Tiered Therapy
VT
FVT
VF
Bradyarrhythmia Therapy
Pacing Modes
•Most ICDs offer:
– Single Chamber Pacing
•AAI(R), VVI(R) and VOO
– Dual Chamber Pacing
•DDD(R), DDI(R), DOO and ODO
•Mode Switch
– Separate post-shock pacing programming
•Ensures capture