Download Sudden Cardiac Death (SCD): Facts, Guidelines and Beyond

Sudden Cardiac Death (SCD):
Facts, Guidelines and Beyond
It is tough to make predictions,
especially about the future
Mandeep Bhargava
Cleveland Clinic
Intensive Review of Cardiology
SUDDEN CARDIAC DEATH
• SCD:
– Death from unexpected circulatory arrest
within an hour of onset of symptoms
• SCA:
– Death from unexpected circulatory arrest
within an hour of onset of symptoms, where
medical intervention reverses the event
Intensive Review of Cardiology
QUESTION
• A 30 year old male presents with palpitations
and Class II shortness of breath for a year. He
has no syncope or family history of SCD. He has
also noticed some occasional swelling in the feet.
• Physical examination shows mild pedal edema
and minimally elevated JVP. He has an
irregularly irregular pulse and a short systolic
murmur at the apex. Chest is clear. An EKG is
shown below and a 24 hour telemetry shows
consistency of this pattern most of the time
• Echocardiogram show a dilated LV with global
hypokinesia and an LVEF of 27% with moderate
MR.
Intensive Review of Cardiology
EKG
Intensive Review of Cardiology
Which of the following is the most
appropriate next step in his management:
1.
2.
3.
4.
5.
DC cardioversion
Flecainide 100 mg twice daily
Mapping and ablation of the arrhythmia
Single chamber ICD implantation
Admit for Amiodarone loading
Intensive Review of Cardiology
Which of the following is the most
appropriate next step in his management:
1.
2.
3.
4.
5.
DC cardioversion
Flecainide 100 mg twice daily
Mapping and ablation of the arrhythmia
Single chamber ICD implantation
Admit for Amiodarone loading
Intensive Review of Cardiology
SUDDEN CARDIAC DEATH
• The single most important prognostic
determinant is the underlying heart
– Ejection Fraction
– Scars
– Electrical homogeneity
Intensive Review of Cardiology
Reduced Left Ventricular Ejection Fraction (LVEF)
Remains the Single Most Important Risk Factor for
Overall mortality and Sudden Cardiac Arrest
1.00
1.00
0.98
p log-rank 0.002
0.96
Survival
Survival
0.96
0.98
0.94
No PVCs
0.92
1-10 PVCs/hr
0.90
0.94
0.92
p log-rank 0.0001
0.90
> 10 PVCs/hr
0.88
0.88
A
0.86
0.86
0
30
60
90
120
150
180
Days
Patients without LV Dysfunction
(LVEF >35%)
0
30
60
90
120
150
Days
Patients with LV Dysfunction
(LVEF ≤ 35%)
Maggioni AP. Circulation. 1993;87:312-322.
Intensive Review of Cardiology
CAUSES OF SCD
12%
Other Cardiac Cause
88%
Arrhythmic
Cause
Albert CM. Circulation. 2003;107:2096-2101.
Intensive Review of Cardiology
SCD: UNDERLYING ARRHYTHMIAS
Torsades de Pointes
13%
VT
62%
Bradycardia
17%
Primary VF
8%
B Adapted from Bayes de Luna A. Am Heart J. 1989;117:151-159.
ayés de Luna A. Am Heart J. 1989;117:151-159.
Intensive Review of Cardiology
Witnessed Arrhythmia during SCD as
a function of time
%
Time to tracing (minutes)
Hallstrom et al, Emergency health
services Q 1:41-47, 1983 (modified)
Survival as a function of
FIRST WITNESSED RHYTHM
Initial Rhythm of Cardiac Arresst Victims :
Unknown time
VF
Asystole
EMD
VT
Asystole
40%
Survival: 25%
VF
40%
Survival: 1%
EMD
19%
Survival: 6%
VT
1%
Weaver et al,.N Engl J Med 319:661-666, 1988
SCA Survival = Early Defibrillation
• Only effective treatment for SCA is an
electrical shock delivered by:
- Automated external defibrillator (AED)
- Implantable cardioverter-defibrillator (ICD)
• Time is critical: Each minute of delay
reduces survival by 10%
Intensive Review of Cardiology
IMPORTANT PARADOXES
• 65% of SCDs occur in patients with LVEF > 35%
• In 50% patients with SCD, it may be the first
manifestation of heart disease
• Up to 50% of SCDs may be non arrhythmic in
autopsy studies
• Reducing PVCs/NSVT does not improve
mortality
• The proportions of PEA is noted to be on the rise
THE MYERBURG PARADOX
How can we
effectively identify
patients at-risk?
SCD-HeFT,
MADIT II
AVID, CASH
MADIT I, MUSTT
Myerburg RJ, et al. Circulation. 1998. 97:1514-1521.
Intensive Review of Cardiology
PREVENTION OF SCD
• The key to SCD prevention is to identify
high risk patients
– Low left ventricular ejection fraction
• Coronary artery disease, previous MI
• Dilated cardiomyopathy and heart failure
– Inherited cardiac syndromes
• Survivor of sudden cardiac death
• Family history of sudden cardiac death
– Idiopathic VF
Intensive Review of Cardiology
VT/VF AFTER ACUTE MI
Long Term Management
• Late Sustained VT/VF
– Concerning if sustained VT/VF after 48 hours
– ICD for “secondary” prophylaxis if no
reversible factor
• If reversible factors present
– Beta-blockers and ACE inhibitors
– Reassess LVEF at 6 weeks/3 months
depending on revascularization
Intensive Review of Cardiology
ICM: Secondary prophylaxis
• 3 large trials have shown a benefit with ICD
therapy
Total mortality
• AVID Trial
• CASH Study
• CIDS Trial
25% less
12% less
20% less
Arrhythmic deaths
3% vs 7.4%
1.5% vs 5.1%
3% vs 4.5%
Conolly S, EHJ 2000
ICM: Secondary prophylaxis
Meta-analysis
P<0.05
P<0.05
•Meta-analysis of these 3 trials: 28% reduction
Conolly S, EHJ 2000
ICM: Secondary prophylaxis
Meta-analysis
P<0.05
P<0.05
•Main benefit in patients with an LVEF < 35%
Conolly S, EHJ 2000
ICM: Secondary Prevention
• Survivors of known sudden cardiac
death without any reversible cause are
Class I indications for an ICD
• Patients with unexplained syncope,
scars and inducible VT are also
indications for an ICD
ICM: Primary Prevention
TRIAL
DISEASE
EPS
ICD
BENEFIT
MADIT 1
CAD; EF <35%
+
+
MUSTT
CAD; EF <40%
+
+
MADIT 2
CAD; EF < 30%
-
+
SCD HFT
CAD & NICM;
EF<35%
-
+
ICM: Primary Prevention Trials
Mortality
No AA Tx
Medical Tx
ICD
Absolute Reduction
Relative Reduction
MADIT 1
MUSTT*
MADIT 2
32%
10%
22%
54%
48% (28%)
55% (33%)
18% (10%)
31% (23%)
60%
19.8%
14.2%
5.6%
31%
5 YR (2YR) *MUSTT
ICM and NICM: Primary Prevention
SCD-HeFT
(@ 2.5 years)
DEFINITE
(@ 2 years)
MADIT 2
@ 2 years
COMPANION
@ 1 year
Total
ICD
Medical RX
9.0%
13.0%
8.1%
13.8%
19.8%
14.2%
19.0%
12.0%
Absolute
Reduction
4.0%
(7.2%@5yrs)
5.7%
5.6%
6.0%
Relative
Reduction
(27%@ 5yrs)
34%
31%
36%
ICM: Primary Prevention Trials
TRIAL
DISEASE
EPS
ICD
BENEFIT
MADIT 1
CAD; EF <35%
+
+
AllMUSTT
the trials
showed
of+ICD
CAD;
EF <40% superiority
+
compared to best medical therapy
MADIT 2
CAD; EF < 30%
-
+
SCD HFT
CAD & NICM;
EF<35%
-
+
ICM: Primary Prophylaxis
Early intervention after MI/revascularization*
• CABG Patch Trial: ICD with revascularization
No benefit with ICD in the immediate
• IRIS: Early post MI intervention
post MI or post revascularization period
• DINAMIT: Early post MI intervention
*Optimize medical therapy presumed
ICM: CONCLUSION
• ICD therapy is useful in patients with ischemic
cardiomyopathy with severe LV dysfunction
(LVEF<35%) beyond 42 days of MI or 90 days or
revascularization
• ICD therapy is useful in patients with an EF of 3540% if they have NSVT and inducible VT
• ICD therapy has no proven benefit within 6 weeks
of an MI or 90 days of revascularization
• ICD therapy has no proven benefits in the very sick
NYHA Class IV patients*
*Beware of the need of CRT
Nonischemic Cardiomyopathy
• Two major trials have included substantial
number of patients with NICM
– DEFINITE
– ScD HeFT
• Inclusion
– Patients with an LVEF of 30-35%
– NYHA II-III
– Optimal medical therapy for 3-9 months
– CHF for at least 3 months
DEFINITE TRIAL
P>0.05*
P<0.05
NEJM 2004; 350:21
SCD HeFT Trial
23% reduction in mortality
P<0.05
P<0.05
NNT higher in NICM vs ICM
NEJM 2004; 352:225
Syncope and NICM
Time to first shock was shorter in the syncope group of patients
50% of patients with syncope had appropriate ICD shocks
Recurrent syncope was associated with arrhythmias
Should be treated with an ICD
Knight B, et al. JACC 1999
ROLE OF EPS IN NICM
• Minimal Utility
• “AT BEST” only in patients with
documented scars or concerns for
BBRT
• Specificity only for induced VT and
not VF
EP Study and Sarcoidosis
Mehta et al:
•Study of 76 patients with biopsy proven sarcoid
•11% inducibility
•Mean EF 36% in inducible group vs 55% in non inducible group
Circ Arrhythm Electrophysiol; 2011;4:43
NICM: CONCLUSION
• Patients benefit from an ICD if they have NICM,
LVEF <35% beyond 3 months of optimally treated
heart failure, NYHA II-III symptoms
• Unexplained syncope in the setting of NICM
portends poor prognosis and merits an ICD
• EP study has no role in risk stratification unless
there is significant documented scarring as in
cardiac sarcoid
• MRI and genetics may be newer tools
HYPERTROPHIC CMP
• Risk for SCD
– Prior VT/VF/cardiac arrest
– Syncope of “unclear” cause
– Family history of sudden cardiac death
– Severe septal thickness (> 3 cm septum)
– Other minor criteria:
• NSVT
• Failure of BP to rise on exercise stress
• Extensive scar on the MRI; absence is a good sign
Intensive Review of Cardiology
50 year old male has a syncopal episode. On EMS
arrival, ventricular fibrillation is shocked to SR. In the
ED he is alert and oriented. ECG is shown below.
•
What is best approach for his long term survival?
– A. Administer thrombolytic therapy
– B. Emergent percutaneous intervention to the LAD
– C. ICD implantation
– D. EP study and ablation of accessory pathway
Intensive Review of Cardiology
50 year old male has a syncopal episode. On EMS
arrival, ventricular fibrillation is shocked to SR. In the
ED he is alert and oriented. ECG is shown below.
•
What is best approach for his long term survival?
– A. Administer thrombolytic therapy
– B. Emergent percutaneous intervention to the LAD
– C. ICD implantation
– D. EP study and ablation of accessory pathway
Intensive Review of Cardiology
BRUGADA SYNDROME
•Genetic channelopathy causing loss or dysfunction of sodium channels
•About 5 in 10000 have such a pattern
•Responsible for about 12-20% of “Idiopathic VF” in “normal” heart
BRUGADA SYNDROME
• ICD implantation should be considered in
–
–
–
–
Survivors of sudden cardiac death
Unexplained syncope
Fever induced Brugada pattern
? Inducibility of “VF” on EP study
Males have a higher risk; mainly nocturnal deaths
Family history helps in “DIAGNOSIS” and not
“PROGNOSIS”/risk stratification
Quinidine (Ito blocker) and catheter ablation may
be used to treat ICD storms.
ARRHYTHMOGENIC RV CMP
• Predominant RV cardiomyopathy
– Progressive fibrofatty replacement of the RV
– Hypokinetic and thinned areas (Echo/MRI)
– May involve the LV
• Strong familial transmission (>50% of patients)
• Presentation with syncope, VT or sudden death
– VTs generally with multiple LBBB morphologies,
often precipitated by exercise
Intensive Review of Cardiology
ARVC
ECG Characteristics
•Anterior precordial T wave abnormalities
•Epsilon waves
From: McRae et al, CCJM 68:459-67, 2001
Intensive Review of Cardiology
ARVC Therapy
• ICD: Primary/Secondary prevention
– Cardiac arrest or spontaneous VT
– Inducible VT with Scars (EP Study)
– Depressed LV function/LV involvement
– Unexplained syncope
– Family history of sudden cardiac death
• Drug therapy and catheter ablation
– Adjunctive
Intensive Review of Cardiology
ION CHANNELS AND LONG QT
1
2
0
LQT3
LQT2
3
LQT1
Phase 0 – inward fast Na+ (Gain in LQT3)
Phase 1 – outward current – Ito
Phase 2 – plateau – inward currents
mainly Ca++, Na+
Phase 3 – outward current
IKur – ultra rapid delayed rectifier
IKr – rapid delayed rectifier (Loss in LQT2)
IKs – slow delayed rectifier (Loss in LQT1)
Intensive Review of Cardiology
4
LONG QT SYNDROME
• How long is Long QT: 440/450 or 470/480
• Risk stratification:
– Type of long QT (QT3>QT2>QT1)
– Duration of QT interval (>500 ms)
– History of syncope
• Triggers:
– LQT1: Exercise, swimming
– LQT2: Alarms, loud noises
Intensive Review of Cardiology
THERAPY FOR LQTS
• Treatment:
– Remove triggers and start beta blockers
– Consider left cardiac sympathectomy
• Indications
– Documented cardiac arrest
– Symptoms on beta blockers
– Very long QT
» LQT2 and LQT3 > 500 ms
» LQT1 > 550 ms
FAMILY HISTORY AND EP STUDY ARE NOT PROGNOSTIC
OTHER SUDDEN DEATH
SYNDROMES
• CPVT: Catecholaminergic Polymorphic Ventricular
tachycardia
– Defect in calcium handling
– Predisposes to exercise induced/bidirectional VT
– Beta blockers/Flecainide
– ICD for syncope/SCD despite beta blockers
For Boards also think Digoxin toxicity.
OTHER SUDDEN DEATH
SYNDROMES
• Short QT syndrome
– 340 ms or less
– 360 ms or less with syncope
– ICD for patients with SCA
• Early repolarization syndromes
– ICD for survivors of SCA
NEWER TOOLS: MRI
• MRI
• GENETIC TESTING
MRI in ICM/HCM
Al Jaroudi et al, JACC Cardiovasc Imag 2013
MRI in MYOCARDITIS
Al Jaroudi et al, JACC Cardiovasc Imag 2013
Al Jaroudi et al, JACC Cardiovasc Imag 2013
NEWER TOOLS: GENETIC TESTING
•
•
•
•
•
•
Long QT Syndrome
Brugada Syndrome
Hypertrophic cardiomyopathy
Short QT syndrome
Catecholaminergic Polymorphic VT
LV non compaction
IDIOPATHIC VF
TAKE HOME PEARLS
• Ruling out structural heart disease should be the
first step for high risk patients for sudden death
• Inherited diseases and channelopathies are rare
but dangerous and need a close eye
• EP studies have a role in only specific patients
and has poor negative predictive value
• ICD implantation should be considered only on
basis of objective data for each specific disease
• MRI and genetic tests may become important
newer risk stratification tools
Intensive Review of Cardiology
TAKE HOME PEARLS
• Normal Heart VT: treat only if symptomatic,
sustained or causing LV dysfunction
• Avoid ICD in normal heart VT; ablation often
curative
• For any sustained VT/VF, first remove reversible
factors
• If no reversible factors, ICD treatment of choice
for primary and secondary prophylaxis
Intensive Review of Cardiology
PEARLS: AADs and ABLATION
• Adjunctive treatment to prevent symptoms or ICD
shocks
• No survival benefit shown
• Class IC drugs only for normal hearts
• With structural heart disease, Amiodarone is the
most effective
• Ablation curative for normal heart VT
Intensive Review of Cardiology
THANK YOU
Intensive Review of Cardiology
The syndrome of “borderline” QT
How Long is LONG QT
• Mean QTc in Mayo series is 482 ms
• Range is 365 ms to 800 ms
• 40% of genetically proven LQT is <460
ms
• A lot more normal people have
borderline QT (10-20%)
• Pretest probability and clinical context
mean everything
• Understand that genetic test can miss
(20-25%) or over-read (2-5%) LQTS
How Long is LONG QT
TAKE HOME PEARLS FOR BOARDS
• For primary prophylaxis, ICD indicated only if
– Persistent, severe LV dysfunction (<35%) after adequate
therapy
– High risk inheritable syndromes
• Antiarrhythmics are adjunct and do not improve
survival
• Catheter ablation
– Drug refractory VT
– Drug intolerance or patient preference
– Primary therapy in normal heart VT
Intensive Review of Cardiology
TAKE HOME PEARLS FOR BOARDS
• Wide QRS tachycardia in structural heart disease
is mostly VT
• Concordant QRS, Discordant axis, AV dissociation,
scarred atypical patterns suggest VT
• Acute management for hemodynamic instability
or SCA is electric shock
• Amiodarone is the most effective drug in acute
settings except in Long QT
Intensive Review of Cardiology
FASCICULAR VT
Intensive Review of Cardiology
RBBB TACHYCARDIA
Vs > As
Intensive Review of Cardiology
BUNDLE BRANCH REENTRY
Intensive Review of Cardiology
LBBB TACHYCARDIA
Intensive Review of Cardiology
Long QT Syndrome
LQTS Risk Factors for “Cardiac
Events” in LQT1, LQT2, LQT3
Syncope, Cardiac Arrest, Sudden Death
• High Risk (50%)
– QTc  500 ms: LQT1, LQT2
and
Males with LQT3
• Intermediate Risk (30-49%)
– QTc 500 ms: Female LQT3
– QTc <500 ms: LQT3, female
LQT2
• Low Risk (<30%)
– QTc <500 ms: LQT1, Male
LQT2
Priori NEJM 348:1866, 2003
Which of the following patients is an
appropriate candidate for an ICD
• A 28 year old male with hypertrophic
cardiomyopathy with syncope and NSVT
• A 32 year old male with incessant VT with LBBB
pattern and inferior axis, EF 38%
• A 78 year old male with prior AWMI, EF 20%, Class
IV symptoms on Milrinone
• A 65 year old male with dilated CMP, EF 25% with
metastatic lung carcinoma
Intensive Review of Cardiology
KNOW WHEN NOT TO PUT AN ICD
• A 28 year old male with hypertrophic
cardiomyopathy with syncope and NSVT
• A 32 year old male with incessant VT with LBBB
pattern and inferior axis, EF 38%
• A 78 year old male with prior AWMI, EF 20%, Class
IV symptoms on Milrinone
• A 65 year old male with dilated CMP, EF 25% with
metastatic lung carcinoma
Intensive Review of Cardiology
VT IN NORMAL HEARTS
(IDIOPATHIC)
• Outflow Tract VT/PVCs
• Fascicular VT
• Papillary muscle VT/PVCs
Intensive Review of Cardiology
VT IN NORMAL HEARTS
Outflow Tract VT
• Repetitive monomorphic sustained VT
or PVCs
• Asymptomatic or symptomatic
• May have “PVC induced
cardiomyopathy”
• Treatment
– -blockers, CaCB, I or III AADs
– Catheter ablation – success rate ~90%+
Intensive Review of Cardiology
RV OUTFLOW TRACT VT
30 y/o M with frequent PVCs since age 10,
DCM progressive since age 13 -> LVEF 35%
Post ablation: LVEF 55% 3 months and 3 yrs afterwards
Intensive Review of Cardiology
VT IN NORMAL HEARTS
Fascicular VT
• Reentry involving calcium dependent
Purkinje/fascicular fibers
• Most common: Right Bundle/Left Superior Axis
• Terminated or suppressed by verapamil or
diltiazem
• Idiopathic VT: High success rates with ablation
and do not usually need an ICD
Intensive Review of Cardiology
ISCHEMIC VT AFTER ACUTE MI
• Asymptomatic PVCs, NSVT
– May be associated with increased
mortality
– Usually no need for acute therapy
• AIVR
– May have relation with coronary
reperfusion
– Generally no need for acute therapy
Intensive Review of Cardiology
VT/VF EARLY AFTER ACUTE MI
– Sustained VT/VF: First 48 hours
• Increased in-hospital mortality
• May not signify worse long-term
prognosis among survivors
• Acute therapy
– Defibrillation
– Antiarrhythmic drugs
Intensive Review of Cardiology
ISCHEMIC CARDIOMYOPATHY
• ICD for secondary prophylaxis
– Sustained VT/VF
• ICD for primary prophylaxis
– LVEF < 35% 6 weeks post MI or 90 days post
revascularization
– LVEF 35-40% with NSVT: ICD if inducible VT
by EP study
• Adjunctive treatment
– Antiarrhythmic drugs for symptoms/shocks
– Catheter ablation
Intensive Review of Cardiology
NON-ISCHEMIC CARDIOMYOPATHY
• VT/VF estimated to be cause of death in 8-50%
• Risk Assessment: Echo/?MRI
• Secondary prevention:
Known survivor of SCD
Syncope of unknown origin
• Primary prevention:
ICD for persistent severe LVEF < 35% after
3 months of CHF symptoms
• AADs/Ablation
Lower threshold for Bundle Branch Reentry
Intensive Review of Cardiology
POLYMORPHIC VT
• Torsades de Pointes
– Associated with Long QT
• Polymorphic VT not associated with long QT
– May be associated with ischemia or electrolyte
abnormalities or drugs
• Treatment
– Magnesium and reversal of the cause
– Defibrillation if degeneration to VF
Intensive Review of Cardiology
TORSADES: TWISTING OF QRS
AROUND THE BASELINE
Intensive Review of Cardiology
BRUGADA SYNDROME
• Presents with syncope or sudden death (VF) often
at night
– Cause of SCD in young healthy males
• RV conduction delay and mid precordial ST
elevation
– “RBBB-like pattern” with J point elevation V1-V3
– Worsened, unmasked by Na+ channel blockers (e.g.
ajmaline, flecainide, procainamide)
• Loss of function of Na channel due to SCN5A
mutation
Intensive Review of Cardiology
BRUGADA SYNDROME
• Risk stratification
– High risk:
• Aborted SCD
• Syncope
• Fever induced Brugada/Males
– Low risk:
• Asymptomatic patients with diagnostic ECG
only after provocative challenge (Type 2 and 3)
Intensive Review of Cardiology
ANTIARRHYTHMIC DRUGS
Class I: Sodium channel blockers
IA: Quinidine, Procainamide (Quinidine-Brugada
storms)
IB: Lidocaine, Mexiletine; Do not prolong QT
IC: Flecainide, Propafenone - Normal heart only
Class II: Beta Blockers
Reduce cardiac mortality and SCD
Class III: Potassium Channel Blockers
Sotalol, Amiodarone
Class IV: Calcium Channel Blockers
Fascicular VT
Intensive Review of Cardiology
MUSTT: Relation of LVEF and EPS to
Arrhythmic Death or Cardiac Arrest
(Buxton, et al, Circulation 2002;106:2466-2472)
HYPERTROPHIC CARDIOMYOPATHY
•
•
•
•
•
Family history of sudden cardiac death
Septal thickness > 3 cm
Syncope of unclear cause <45 years of age
NSVT at a rate of >130 bpm
Abnormal BP response of failure to augment >25
mmHg or fall with exercise*
Importance of one risk factor
?Role of MRI
Role of genetic testing
NO role of EP study
*Not studied as single risk factor
What is the role of Syncope
and EP Study in Non ischemic
Cardiomyopathy
ARVC
• Higher risk features
– Documented VT/VF/cardiac arrest
– Large areas of involvement/LV involvement
– Unexplained syncope
– Inducible VT on programmed stimulation
– Family member with ARVC or sudden death
MRI in ICM
Al Jaroudi et al, JACC Cardiovasc Imag 2013
MRI in HCM
Al Jaroudi et al, JACC Cardiovasc Imag 2013
MRI in NICM
Al Jaroudi et al, JACC Cardiovasc Imag 2013
ARVC
EKGs: Incomplete RBBB pattern, Epsilon waves, T inversion
Presentation with syncope, PVCs, SMVT or PMVT