Acute Coronary Syndrome

• Chest pain is a common presentation in general practices
  • Primary care data estimate that 1–4% of chest pain presentations to general practitioners (GPs) are secondary to the effects of ACS
  • In addition, 15% of patients diagnosed with ACS have had an initial review with their primary care physician

Differential Diagnosis

• Life‑threatening diagnoses
  • Acute coronary syndrome (acute myocardial infarction, unstable angina pectoris) 
  • Pulmonary embolism
  • Aortic dissection
  • Spontaneous pneumothorax 
• Chronic conditions requiring urgent evaluation
  • Angina pectoris due to stable coronary artery disease
  • Aortic stenosis 
  • Aortic aneurysm
  • Lung cancer 
• Other acute conditions
  • Acute pericarditis
  • Pneumonia or pleurisy 
  • Herpes zoster
  • Peptic ulcer disease /Gastro-oesophageal reflux
  • Acute cholecystitis 
• Other diagnoses
  • Neuromusculoskeletal causes
  • Psychological

PAIN Onset: 

• Sudden Onset:
  • Angina
  • Myocardial Infarction
  • Aortic Dissection
  • Pulmonary Embolus
  • Esophageal Rupture
  • Spontaneous Pneumomediastinum
  • Spontaneous Pneumothorax
• Gradual or Variable Onset:
  • Pericarditis
  • Musculoskeletal Chest Pain
  • Costochondritis
  • Epidemic Pleurodynia
  • Mitral Valve Prolapse

PAIN Characteristic

• Pressure Sensation:  Angina, Myocardial Infarction, Esophageal Spasm
• Tearing Sensation:  Aortic Dissection
• Sharp or Stabbing Sensation: Pericarditis. Pulmonary Embolus, Musculoskeletal Chest Pain, Epidemic Pleurodynia , Mitral Valve Prolapse, Spontaneous Pneumothorax, Esophageal Spasm

Provocative Factors

• Exertion or stress: Angina, Myocardial Infarction
• Hypertension: Aortic Dissection
• Pleuritic (Deep breath or cough): Pulmonary Embolus, Pericarditis, Spontaneous Pneumomediastinum, Musculoskeletal Chest Pain, Cough fracture
• Swallowing or Vomiting: Esophageal Rupture, Spontaneous Pneumomediastinum
• Supine Position: Pericarditis, Spontaneous Pneumomediastinum
• Movement: Musculoskeletal Chest Pain, Cough fracture

definitions

• STEMI (S-T Segment Elevation Myocardial Infarction)
  • presentation with clinical symptoms consistent with an acute coronary syndrome together with S-T segment elevation on ECG
  • New LBBB may be included in this sub-heading as the treatment approach is similar to STEMI
• Non-STEMI (Non S-T Segment Elevation Myocardial Infarction)
  • By definition this will be shown by an elevation of serum troponin levels in the absence of S-T segment elevation
• Unstable Angina
  • A small but still significant proportion (< 4 %) of patients presenting with possible cardiac chest pain in whom biomarkers and ECGs are normal will have unstable angina due to underlying coronary artery disease
  • Note that “unstable angina” is measured against a patient’s usual pattern of “stable angina” which is most commonly classified according to the New York Heart Association’s Functional Classification of Angina
  • New onset angina should be considered unstable in the first instance

NEW YORK HEART ASSOCIATION FUNCTIONAL CLASSIFICATION OF ANGINA

Class 1	Patients with cardiac disease but without resulting limitation of physical activity.Ordinary physical activity does not cause undue fatigue, palpitation, dyspnea, or anginal pain.
Class II	Patients with cardiac disease resulting in slight limitation of physical activity.They are comfortable at rest. Ordinary physical activity results in fatigue, palpitation, dyspnea, or anginal pain.
Class III	Patients with cardiac disease resulting in marked limitation of physical activity.They are comfortable at rest. Less than ordinary activity causes fatigue, palpitation, dyspnea, or anginal pain.
Class IV	Patients with cardiac disease resulting in inability to carry on any physical activity without discomfort.Symptoms of heart failure or the anginal syndrome may be present even at rest. If any physical activity is undertaken, discomfort is increased.

Risk factors (these are of little diagnostic use in the acute setting):

• diabetes mellitus
• hypertension
• lipids
• family history
• male
• obesity
• previous MI
• hormone replacement for menopause
• inactivity

Risk classification for possible cardiac causes of chest pain (National Heart Foundation of Australia & Cardiac Society of Australia and New Zealand)

High risk

• Ongoing or recurrent chest discomfort despite initial treatment
• Elevated cardiac troponin level
• New ischaemic changes on electrocardiogram (ECG), such as persistent or dynamic ECG changes of ST segment depression ≥0.5 mm; transient ST segment elevation (≥0.5 mm) or new T wave inversion ≥2 mm in more than two contiguous leads; or ECG criteria consistent with Wellens syndrome
• Diaphoresis
• Haemodynamic compromise — systolic blood pressure <90 mmHg, cool peripheries, Killip Class >I and/or new-onset mitral regurgitation
• Sustained ventricular tachycardia
• Syncope
• Known left ventricular systolic dysfunction (left ventricular ejection fraction <40%)
• Prior acute myocardial infarction, percutaneous coronary intervention or coronary artery bypass grafting

Intermediate risk

• Neither high-risk nor low-risk criteria

Low risk

• Age <40 years
• Symptoms atypical for angina
• Remain symptom free
• Absence of known coronary artery disease, Normal troponin level, Normal ECG