What is the diagnosis for a patient with acute severe chest pain at rest, followed by brief and mild recurrence, with a recent history of asymptomatic strenuous activity?

Diagnosis: Unstable Angina

This clinical presentation is most consistent with unstable angina (option c), characterized by acute severe chest pain at rest followed by recurrent symptoms in a patient with recent normal functional capacity.

Clinical Reasoning

Key Diagnostic Features Present

The patient demonstrates the classic triad defining unstable angina 1:

• Prolonged chest pain at rest (>20 minutes): The acute severe chest pain at 2 a.m. lasting long enough to be considered "severe" meets this criterion 1
• Recent onset of severe symptoms: One week ago the patient was completely asymptomatic with excellent functional capacity (climbing 5 flights of stairs), indicating new-onset CCS Class III or IV severity angina 1
• Recurrent symptoms: The brief recurrence the morning of the visit demonstrates the unstable, fluctuating nature of the syndrome 1

Why Not the Other Options

Stable angina (option a) is excluded because:

• Stable angina requires symptoms that are predictable, relieved by rest, and without recent change in frequency or pattern 1
• This patient has pain occurring at rest and represents new-onset severe symptoms, which are defining features of instability 1

Acute myocardial infarction (option b) is less likely because:

• While prolonged rest pain can indicate MI, the brief and mild recurrence suggests ongoing ischemia without completed infarction 1
• The clinical scenario emphasizes the pattern of symptoms rather than suggesting biomarker elevation or ECG changes diagnostic of MI 1

Cardiac arrhythmias (option d) are not suggested because:

• The description focuses on anginal chest pain characteristics rather than palpitations, syncope, or other arrhythmia symptoms 1
• The temporal pattern and severity are classic for acute coronary syndrome, not rhythm disturbances 1

Clinical Context

This presentation represents high-risk unstable angina based on 1:

• Prolonged rest pain (>20 minutes) places the patient in the high-risk category
• The accelerating tempo with symptoms developing over 48 hours further increases risk 1

Critical Next Steps

The patient requires immediate evaluation including 1:

• ECG within 10 minutes to assess for STEMI
• Cardiac troponin measurement as soon as possible to differentiate unstable angina from NSTEMI
• Urgent transfer to emergency department if not already there 1

The distinction between unstable angina and NSTEMI will ultimately depend on troponin results, but both fall under the acute coronary syndrome spectrum and require identical initial management 1.