emergency medicine

1. SUDDEN CARDIAC DEATH
Etiology, Evaluation and Management

2. DEFINITIONS
Sudden Cardiac Arrest (SCA) -Abrupt cessation of cardiac
mechanical function (Reversible)
Sudden Cardiac Death (SCD) - Sudden Irreversible cessation of all
biological functions
Sudden Cardiovascular Collapse (SCVC) -Sudden loss of effective
blood flow .

3. Introduction
Sudden Cardiac Death (SCD)
Sudden Cardiac Death refers to an unexpected death due to
cardiac causes, occurring within1 hour of symptom onset in
witnessed cases, and within 24 hours of last being seen alive
when it is unwitnessed.

4. Why are we discussing it?
• 6-9 million people/year
• 1-2/1000 population
• 15-20% of all deaths
• 3-3.7 lakhs/year (USA)
• Mortality is more than 90%
7.9 % in USA
7.6 % in Europe,
6.8% in North
America,
3% in Asia,
9.7% in Australia

5. Phases of Sudden Cardiac Death
• Prodrome- chest pain, dyspnoea, diaphoresis
• Onset- Arrythmia , Increase in heart rate, respiratory
symptoms
• Cardiac arrest
• Biological Death

6. Risk Factors
Diabetes
Metabolic Syndrome
Obesity
Smoking
H/O structural heart disease
Channelopathies
Inherited cardiomyopathies

7. Common etiology of SCD/SCA
Coronary Heart Disease
70% In Western countries
25-50% in Japan
Cardiomyopathies
(NICM,HCM,ARVC,etc)
15% in Western countries
30-35% in Japan
Inherited Arrythmias
(LQTS,BS,CPVT,ERS)
1-2% in Western countries
10% in Japan
Valvular Heart Disease
1-5%
Others

8. Etiology
Adults
Coronary heart disease
Cardiomyopathy
Valvular heart disease
Disease of aorta
Electrolytes, Metabolic
Eisenmenger Syndrome
Massive PE
Pediatric
Congenital channelopathies
Myocarditis
Inherited cardiomyopathies
Congenital heart disease
Electrolytes, Metabolic
Pulmonary atresia
Drugs

9. Approach to Sudden cardiac
arrest/death
• History
• Symptoms
• Physical Examination
• Initial evaluation
• Post mortem evaluation

10. Symptoms
• Chest pain
• Diaphoresis
• Dyspnoea
• Palpitation
• Syncope/seizure
• Fatigue

11. Investigation
• 12 lead ECG
• Echocardiography
• Stress test (Provocation)
• Coronary Angiography
• Cardiac CT/MRI/Endomyocardial biopsy
• Electrophysiologic studies
• Genetic evaluation
CRP, IL-6,
Troponin
NT-Pro BNP
Lactate
pH & base
deficit

12. Predictors of SCD/SCA
Coronary artery disease/cardiomyopathy
• EF<30%
• QRS prolongation of > 120ms
• H/O cardiac failure/cardiac arrest
• >75% narrowing with >5mm length
• >10 PVC/hour
• MI < 6 months
Non-sustained VT
Inducible VT
QTc variability

13. HCM risk for SCD
• H/O aborted cardiac arrest/family history of SCD
• Recurrent syncope
• Sustained or repetitive non-sustained VT
• Severe cardiac hypertrophy (>30 mm)
• LVOT gradient >80 mm Hg
• Abnormal BP response to exercise

14. Risk of SCD in Brugada
• Symptomatic
• Inducible VT
• Ventricular refractory period <200ms
• STE in the recovery phase of exercise

15. Risk stratification
Long QT Syndrome
• QTc >500ms
• Female sex
• Drugs
• Structural heart
disease
• Metabolic causes
ARVD
• Dilated RV/RVOT
• Hypokinetic RV
• RVOT-VI
• Recurrent syncope
WPW Syndrome
• WPW with AF
• No AV Nodal blocking
agents
• DC shock
• Procainamide

16. Cardiac Arrest Score
Systolic blood pressure greater than 90 mm Hg = 1 point
ED SBP less than 90 mm Hg = 0 points
Time to ROSC < 25 minutes = 1 point
Time to ROSC > 25 minutes = 0 points
Neurologically responsive = 1 point
Comatose = 0 point
Patients with a score of 3
points can be expected
to have an 89% chance
of neurologic recovery
and an 82% chance of
survival to discharge

17. Management
• Bystander CPR and early defibrillation
• Adrenaline
• Standard ACLS
• Antiarrhythmic drugs
• Treat the specific etiology of SCA
Time to defibrillation from
11 minutes to 4,1 minutes
and improves
neurologically intact
survival to discharge from
14.3% to 49.6%

18. Management
 PCI/CABG/Thrombolytics
 Pacemaker
 RFA
 ICD
 CRTD
 VAD

20. Post Cardiac Arrest Care
Consider for the advance airway
Maintain saturation 94-98%
Do not hyperventilate (RR-10-12/min, lung protective strategy)
SBP 90 mmHg, MAP 65 mmHg
≥ ≥
? TTM (maintain normothermia)
Treat the reversible causes
Blood sugar 80-180 mg/dL

21. Predictors of Adverse outcome
 Before Arrest
 BP <100 mmHg
 Pneumonia
 BUN >50 mg/dL®
 Malignancy
 Bed/home bound
 During Arrest
 Arrest duration>15
mins
 Need for Intubation
 After ROSC
 Coma
 Need of pressors
 ROSC after 15
Mins

22. Neuro-prognostication
• Neurological exam
• Somatosensory evoked potential
• Electroencephalography
• CT Scan/MRI
• Four vessel angiography
• Biomarkers

23. Drug Therapy for prevention of SCD
• Beta-blocker
• Amiodarone
• Combination of Beta blocker and Amiodarone
• Anti aldosterone
• SGLT-2 Inhibitors
• ARB-Neprilysin inhibitors

24. Prevention of SCD
ICD is helpful in prevention of SCD
• EF<35%
• QRS >120ms
• H/O cardiac arrest
• Inducible VT
• Runs of non-sustained VT
• NYHA Class II-IV despite optimal MT
MADIT
MUSTT
MADIT-2
SCD-HF
DEFINITE
DINAMITT
IRIS
VEST

25. Cardiac Resynchronization
Therapy with defibrillation (CRT-D)
• Improves cardiac hemodynamics
• Prevents hospitalization
• Decrease death EF <35%
ORS >120 ms
NYHA Class JII-
IV

26. Take home message
• SCD is not always sudden
• Early CPR and defibrillation
• Early Adrenaline in Asystole and PEA
• Look for 5H and 5,T
• Good post cardiac arrest care
• Treat the precipitating cause of SCA