Priority Topic: Chest Pain & Priority Topic: Ischemic Heart Disease

Chest Pain

Key Feature 1: Given a patient with undefined chest pain, take an adequate history to make a specific diagnosis (ex: determine risk factors, whether the pain is pleuritic or sharp, pressure, etc.).
Skill: Clinical Reasoning
Phase: History

Key Feature 2: Given a clinical scenario suggestive of life-threatening conditions (ex: pulmonary embolism, tamponade, dissection, pneumothorax), begin timely treatment (before the diagnosis is confirmed, while doing an appropriate work-up).
Skill: Selectivity
Phase: Diagnosis, Treatment

Key Feature 5a: Given a suspected diagnosis of pulmonary embolism: Do not rule out the diagnosis solely on the basis of a test with low sensitivity and specificity.
Skill: Clinical Reasoning 
Phase: Hypothesis generation, Diagnosis

Key Feature 5b: Given a suspected diagnosis of pulmonary embolism: Begin appropriate treatment immediately.
Skill: Selectivity
Phase: Treatment

Ischemic Heart Disease

Key Feature 1: Given a specific clinical scenario in the office or emergency setting, diagnose presentations of ischemic heart disease (IHD) that are:

1. Classic
2. Atypical (ex: in women, those with diabetes, the young, those at no risk)

Skill: Clinical Reasoning, Selectivity
Phase: Hypothesis generation, Diagnosis

When a patient presents with chest pain, first consider the ABCs. If the patient appears stable, the priority is then to risk stratify the likelihood of a life-threatening etiology of the chest pain, which are as follows:

1. ​Acute coronary syndrome (ACS)
2. Acute aortic dissection
3. Pulmonary embolism
4. Tension pneumothorax
5. Pericardial tamponade
6. Esophageal rupture

If you have obtain any information via history or physical exam that raises your suspicion for any of the above, it is critical to take steps immediately to further investigate +/- intervene immediately. Information that should raise your suspicion for the above etiologies includes:

1. ACS: Symptoms associated with the highest relative risk of myocardial infarction (MI) include radiation to an upper extremity, particularly when there is radiation to both arms, and pain associated with diaphoresis or with nausea and vomiting. Immediate investigations and intervention include obtaining a 12-lead ECG, attaching a cardiac monitor, obtaining IV access and  obtaining bloodwork including a troponin level, supplemental oxygen if indicated, and giving ASA 325 mg chewed +/- sublingual or intravenous nitroglycerin (contraindicated if systolic blood pressure <90 mmHg or ≥30 mmHg below baseline, marked bradycardia or tachycardia, known or suspected right ventricular infarction, phosphodiesterase inhibitor use within the last 24 to 48 hours, hypertrophic cardiomyopathy, or severe aortic stenosis).
2. Acute aortic dissection: Acute aortic dissection typically presents with an abrupt onset of thoracic or abdominal pain with a sharp, tearing, and/or ripping character, with or without syncope, symptoms of stroke, heart failure, or other clinical signs of end-organ ischemia (splanchnic ischemia, renal insufficiency, extremity ischemia, spinal cord ischemia). Physical examination may reveal a pulse or blood pressure discrepancy. If suspicious of a dissection, obtain a CT chest (beside ultrasound instead if the patient is unstable).
3. Pulmonary embolism (PE): The most common presenting symptom is dyspnea followed by chest pain and cough. Well's Criteria can hep risk stratify. Obtain a CTPA (computed tomography pulmonary angiography) if the patient is high risk. The mainstay of therapy for patients with confirmed PE is anticoagulation, depending upon the risk of bleeding (consider calculating HAS-BLED score). Alternative treatments include thrombolysis, inferior vena cava filters, and embolectomy.
4. Tension pneumothorax: Suspect a tension pneumothorax in the patient with hypotension, dyspnea, and ipsilateral decreased breath sounds. If suspected, obtain a chest xray. Immediate intervention with needle thoracocentesis is indicated if there is a high degree of clinical suspicion, even prior to obtaining confirmatory imaging.
5. Pericardial tamponade: Patients with acute cardiac tamponade typically have chest pain, dyspnea, and/or tachypnea associated with trauma or a cardiac procedure. Findings on physical examination may include sinus tachycardia, elevated jugular venous pressure, hypotension, and an exaggerated inspiratory decrease in systolic blood pressure (pulsus paradoxus). Bedside ultrasound is useful for both the diagnosis and treatment with pericardiocentesis. 
6. Esophageal rupture: This diagnosis should be suspected in patients with severe chest, neck, or upper abdominal pain after an episode of severe retching and vomiting or other causes of increased intrathoracic pressure and the presence of subcutaneous emphysema (crepitus) on physical exam. If there is a high index of suspicion, obtain a CT scan.

Otherwise the differential diagnosis for chest pain is broad, and includes multiple cardiac, pulmonary, gastrointestinal, musculoskeletal, psychiatric, and other causes. It is important to take a thorough history and perform a thorough physical examination of the relevant systems to narrow down the list of most likely possibilities to perform an appropriate workup. 

My DDx for common causes of chest pain is as follows (I keep this in the back of my mind to guide my history and physical assessment):

1. Cardiovascular
   1. Ischemic 
      1. Acute coronary syndromes 
      2. Stable ischemic heart disease 
   2. Non-ischemic 
      1. Aortic aneurysm 
      2. Pericarditis 
2. Pulmonary or mediastinal 
   1. Pulmonary embolus or pulmonary infarct 
   2. Pleuritis 
   3. Pneumothorax 
   4. Malignancy 
3. Gastro-intestinal 
   1. Esophageal spasm or esophagitis 
   2. Peptic ulcer disease 
   3. Mallory-Weiss syndrome 
   4. Biliary disease or pancreatitis 
4. Chest wall pain (ex: costochondritis) 
5. Anxiety disorders 

As you ran through the above list, you may have been thinking, "Oh, but what about this disease, and this other one, and this other one." There are a TON of possible reasons for chest pain, and the above list is simply a sample of causes for which patient may present with chest pain as their main concern. So, for example, a patient with a pneumonia may very well have chest pain as a symptom, but they are also more likely to present with shortness of breath. Hence the importance of starting with a complete history in the stable patient. Apart from the characterization of the chest pain using your go to history-taking mnemonic, it is also important to consider a patient's risk factors for cardiac other disease processes. Significant cardiac risk factors include:

1. Demographics: Male, age >55 yrs
2. Past medical history: Diabetes mellitus, dyslipidemia, hypertension
3. Tobacco, cocaine/amphetamine use
4. Family history of CAD

When it comes to chest pain, sometimes the diagnosis is apparent based on history alone. However, more often, the history simply narrows the differential, without having the capacity to point to a specific culprit by itself. As UpToDate states, "Thoracic organs share afferent nervous system pathways. This creates significant overlap in the symptoms patients experience when thoracic organs develop disease, and makes it difficult to distinguish which organ system is involved purely on the basis of history. Patient descriptions of their symptoms can be helpful in some instances, but (...) clinicians must guard against premature diagnostic closure based upon history. Several studies demonstrate that so-called "atypical" presentations occur more often than was previously thought and misinterpretation of such presentations increases the risk for misdiagnosis and adverse outcomes." So while history is a very important component of the evaluation of the patient presenting with chest pain, keeping an initially broad differential and narrowing this down as indicated is the safest strategy. This is particularly important when it comes to the diagnosis of ischemic heart disease, be it in the emergency department or outpatient clinic setting. Myocardial infarction is a huge burden on mortality and morbidity in the population, and intervening during an acute myocardial infarction or addressing symptoms of ischemic heart disease that portend a future MI can make a huge difference on the patient's quality of life (see my next post for symptoms of stable ischemic heart disease). Unless you feel confident the patient is presenting with symptoms attributable to separate disease processes only, investigate for ischemic heart disease always. And remember, this is relevant for the atypical presentations too, in which ischemic heart disease my present as simply dyspnea, weakness, fatigue, or epigastric pain. These atypical presentations of ischemic heart disease may be more common in women, those at the extremes of age (young or elderly), patients with diabetes, and those who may have no cardiac risk factors whatsoever. 

Below is an approach to chest pain from UpToDate. In any patient with new ongoing chest pain, they warrant an ECG to rule out cardiac ischemia (as well as to look for clues of other etiologies that may present with ECG findings), unless the chest pain is obviously from another etiology.