Acute Coronary Syndrome Overview

Acute Coronary Disease/Syndrome

• Acute Coronary Syndrome (ACS) is a critical diagnosis needing immediate evaluation in patients presenting with acute chest pain.
• ACS results from sudden reduced coronary blood flow, leading to cardiac ischemia.
• Types of ACS include:
  • ST-Elevation Myocardial Infarction (STEMI): Complete blockage of a coronary artery, resulting in transmural infarct.
  • Non-ST-Elevation Myocardial Infarction (NSTEMI): Imbalance between myocardial oxygen supply and demand, causing non-transmural (subendocardial) infarct.
  • Unstable Angina: Imbalance between myocardial oxygen supply and demand, leading to myocardial ischemia but not infarction.

Pathophysiology of ACS

• ACS is often associated with atherosclerosis, a condition where fatty deposits (plaques) accumulate in the coronary arteries.
• Plaque rupture can lead to blood clot formation, partially or completely obstructing blood flow to the heart muscle.
• Insufficient oxygen supply to heart muscle cells can cause cell death and damage to muscle tissue, leading to a heart attack.

Potentiating Factors of ACS

• Modifiable: Hypertension, high cholesterol (hyperlipidemia), smoking, diabetes, obesity, physical inactivity, and excessive alcohol consumption.
• Non-modifiable: Age, family history, and gender.

Clinical Manifestations of ACS

• Chest pain
• Shortness of breath
• Sweating
• Nausea and vomiting
• Fatigue and weakness
• Palpitations

Laboratory and Diagnostic Tests for ACS

• 12-lead ECG: Records the heart's electrical activity to identify ischemic chest discomfort.
• Troponin I or T test: Measures heart muscle damage.
• Complete blood count (CBC) and coagulation studies: Assess risk of bleeding with antithrombotic therapy.
• Serum Creatinine (SCr) and Creatinine clearance (CrCl): Assess kidney function, important for medication dosage adjustments.
• Echocardiogram : Assess heart function and ejection fraction (EF).
• Stress test: Evaluates heart function during physical exertion.
• CT scan: Examines coronary arteries for blockages.
• Myocardial perfusion imaging: Assesses blood flow through the heart muscle.

Treatment and Management of ACS

• General Approach: Hospital admission, oxygen administration, continuous ST-segment monitoring, frequent vital sign checks, and pain relief.
• Pharmacologic Therapy:
  • Nitrates (NTG): Promote vasodilation.
  • Aspirin: Inhibits platelet aggregation.
  • Platelet P2Y12 Inhibitors (clopidogrel, prasugrel, ticagrelor): Prevent platelet aggregation.
  • Beta Blockers (metoprolol, propranolol, atenolol): Lower heart rate and oxygen demand.
  • ACE inhibitors (lisinopril, benazepril): Improve blood flow.
  • Statins (lovastatin, simvastatin): Lower cholesterol.
  • Thrombolytics (anistreplase, reteplase, streptokinase): Dissolve clots in emergencies.
• Non-pharmacologic Therapy: Maintaining a healthy weight, stress management, controlling blood pressure and cholesterol, and maintaining a heart-healthy diet.

Therapeutic Outcomes of ACS Treatment

• Restoration of blood flow to the infarct-related artery.
• Prevention of death and other complications.
• Prevention of coronary artery reocclusion.
• Relief of ischemic chest discomfort.
• Resolution of ST-segment and T-wave changes on the ECG.
• Relieve pain and distress
• Enhanced quality of life

Arrhythmia

• Arrhythmias are irregular heartbeats caused by problems with the heart's electrical system.
• Arrhythmias are classified by heart rate: Tachycardia when heart rate is greater than 100 bpm and Bradycardia when heart rate is less than 60 bpm.
• Pathophysiology of Arrhythmias:
• Abnormal impulse initiation: Problems with the heart's natural pacemaker (SA node) can result in slow or fast heart rates.
• Abnormal impulse conduction: Problems with the electrical pathways of the heart can lead to problems delivering impulses and improper electrical conduction.
• Types of Arrhythmias:
• Supraventricular arrhythmias
• Ventricular arrhythmias.
• Clinical manifestations of Arrhythmias include palpitations, dizziness, fainting, fatigue, shortness of breath, chest pain, anxiety and sudden cardiac arrest.
• Additional clinical manifestations may be needed for proper diagnosis.
• Diagnosis of Arrhythmias:
• Electrocardiogram (ECG): Records electrical activity of the heart.
• Electrophysiology study (EPS): Measures electrical activity of the heart in detail.
• Blood tests: Check electrolytes, thyroid levels, and other relevant values.
• Imaging tests like CT and MRI
• Treatment of Arrhythmias:
• Pharmacologic and Non-Pharmacologic Treatment.
• Note: Detailed information on medications and specific arrhythmia types will vary from those listed above.

Cardiopulmonary Arrest

• Cardiac arrest is a sudden, complete cessation of the heart's electrical activity and mechanical pumping ability.

• This results in lack of blood circulation and the immediate cessation of delivering oxygen to the body.

• Pathophysiology of Cardiac Arrest includes:

• Primary: fully oxygenated blood

• Secondary: lack of ventilation resulting in hypoxemia, hypotension and cardiac arrest.

• Clinical manifestations include : Loss of consciousness, Sudden Collapse, Anxiety, Shortness of breath, chest pain and nausea.

• Diagnosis of Cardiac Arrest:

• Electrocardiogram (ECG): records heart electrical activity.

• Electrolyte imbalances may need checking.

• Cardiac enzymes and imaging may be used for certain diagnostic needs.

• Treatment of Cardiac Arrest:

• Immediate Recognition

• Early CPR

• Rapid Defibrillation

• Advanced Cardiac life support (ACLS).

• Pharmacologic treatment such as epinephrine, vasopressin, amiodarone, lidocaine and magnesium may be used in appropriate circumstances.

• Non-pharmacologic therapy includes CPR, defibrillation, ventilation, placement of IV, and intraosseous access.

• Post-resuscitative care including airway support and oxygenation and hypothermia if indicated.