Patients with ischemic heart disease (IHD) fall into 2 groups: stable angina secondary to ischemic heart disease (coronary artery disease) and acute coronary syndromes (ACS).

Acute coronary syndromes are further grouped into acute myocardial infarction (AMI) and unstable angina (UA)

Epidemiology

• Prevalence - >1.5 million cases of ACS in U.S. annually
• Age - peak onset >50 years
• Gender - M>F

Risk Factors

• Hypertension
• Hyperlipidemia
• Tobacco use
• Family history
• Obesity
• Diabetes mellitus
• Physical inactivity
• Increasing age

Pathophysiology

• Atherosclerosis
• Clot formation in the coronary arteries

Clinical Presentation

• Acute coronary syndrome
  • Substernal chest pain, dyspnea, gastric discomfort, diaphoresis, tachycardia or hypotension
  • May auscultate S3 or S4, new murmur, pericardial friction rub or bibasilar rales
  • It is sometimes difficult to distinguish the chest pain of AMI or UA from other diseases such as Gastroesophageal Reflux (GERD)

Treatment

• Early recognition of ACS is important to prevent complications

Prevention

• Aggressive management of risk factors

Diagnosis

• Clinical history and risk factor assessment
• Electrocardiogram (ECG)
• Cardiac markers, particularly cardiac troponins
  • Useful to distinguish AMI from UA
  • Preferred markers for the diagnosis of AMI
  • Obtain blood at presentation, 6 to 9 hours follow up
• The cardiac-specific troponins have amino acid sequences different from skeletal muscle forms and therefore are highly specific for cardiac injury
• Stress testing

Differential Diagnosis

• Cardiac contusion
• Congestive heart failure
• Aortic dissection
• Esophageal reflux
• Infiltrative cardiac disease
• Myocarditis
• Pulmonary embolism