Sudden Cardiac Death

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Sudden Cardiac Death
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Pathophysiology

• Clinical scenario where a person experiences a
  loss of consciousness, usually due to a
  ventricular tachyarrhythmia or severe bradycardia
  and asystole when a rhythm is not restored,
  results in death.
• Time and mode of death are unexpected.
• Occurs within minutes of onset of symptoms.

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SCD vs. Heart Attack

• Myocardial infarction (aka heart attack) refers
  to the death of heart tissue due to the lack of
  blood supply.
• Heart attack COULD lead to cardiac arrest and
  SCD.
• Cardiac arrest leads to SCD.

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Prevalence

• Who is at risk?
• Those who have had previous myocardial
  infarctions.
• Individuals with CAD.
• Considered a rare event but due to recent deaths
  in young athletes, sudden cardiac death (SCD) is
  drawing more attention in research.
• Very mysterious condition because there is no
  documented cause.

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Speculated Causes of SCD

• Most Common Factors
• Left ventricular hypertrophy
• Increased cardiac mass
• Aortic ruptures
• Myocarditis
• Aortic stenosis

• Rare Factors
• Dilated cardiomyopathy
• Atherosclerotic CAD
• Mitral Value prolapse
• Isolated arrhythmias
• Commotio cordis (Trauma to the chest wall common
  in young athletes)

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Left Ventricular Hypertrophy

• Most commonly found factor in people that have
  died from SCD
• Chronic elevation of myocardial stress (due to
  pressure overload) causes cardiac muscle to
  hypertrophy
• Leads to increase in myocardial thickness and
  impairment of systolic function and finally left
  ventricular failure

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Left Ventricular Hypertrophy

• Causes
• Hypertension
• Valvular heart disease
• Coronary Heart Disease
• There are no known symptoms of left ventricular
  hypertrophy.
• Strategies for controlling LVH
• Keep blood pressure low
• Manage weight
• Monitor blood glucose

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Signs SymptomsRelated to SCD

• Known left ventricular hypertrophy
• Syncope
• Non-sustained ventricular tachycardia
• Ventricular fibrillation
• Low ejection fraction (

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Prevention Management

• Treat and monitor diseases/conditions that can
  contribute to heart problems.
• Exercise
• Diet and weight control
• No smoking
• Control heart rhythms
• Implantable cardioverter defibrillators sense
  when the heart is beating too fast and send a
  jolt of energy directly to the heart and restored
  normal rhythm

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Treatment

• Direct treatment of SCD is unknown
• Typical treatment is based on existing conditions
• Pacemakers
• Automatic external defibrillator
• Medications for CAD

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Medications

• Taken to control heart rhythms or to treat other
  conditions that contribute to heart disease
• ACE inhibitors
• Beta-blockers
• Calcium channel blockers

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Effect on Exercise

• Death

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Effect of Exercise

• Acute, especially due vigorous exercise DEATH
• Chronic exercise decreases risk of CAD, which
  should decrease risk of SCD.
• Recommendations
• Aerobic vs. Resistance Exercise
• Which is safer if you are at risk?

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Precautions

• Individuals who should avoid vigorous exercise
• Diagnosed with CAD
• Positive family history of SCD
• Diagnosed left ventricular hypertrophy

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Recommendations

• Limited due to lack of knowledge of event
• Precautions should be taken when signs symptoms
  are evident.
• Diagnostic tests for heart disease
• ECG, sonogram, ultrasound
• Additional padding in contact sports to cover
  chest walls
• AEDs should be present at all sporting events or
  in all exercise facilities.
• Use of AED in combination with CPR has a high
  survival rate if used within 3 minutes of event.