The Presentation
A 45-year-old man presents to the emergency department at 2 AM with chest pain that woke him from sleep. He describes the pain as a "pressure" in the center of his chest, rated 6/10, without radiation. He has no significant past medical history, takes no medications, and has no family history of premature coronary artery disease. He is a non-smoker who exercises regularly.
Vital signs: BP 138/82, HR 78, RR 16, SpO2 99% on room air, Temp 37.0°C.
Physical exam: Alert, mildly anxious. Cardiac exam reveals regular rate and rhythm, no murmurs, rubs, or gallops. Lungs are clear bilaterally. No peripheral edema. Abdomen is soft and non-tender.
Initial labs: Troponin I: <0.01 ng/mL (normal). CBC, BMP, and coagulation studies are within normal limits.
Before scrolling down, pause and consider: What's your initial differential? What do you expect the ECG to show?
The ECG
The 12-lead ECG is obtained. Instead of the expected normal sinus rhythm or ST changes suggesting ACS, the ECG reveals:
Sinus rhythm at 76 bpm with coved-type ST elevation in leads V1-V2, followed by a negative T wave. The ST segment has a characteristic "shark fin" morphology — rising from the S wave, peaking, and descending into an inverted T wave without returning to baseline.
This is not a STEMI pattern. There's no reciprocal ST depression. The morphology is wrong for acute MI. But it's definitely abnormal.
What's your diagnosis now?
The Diagnosis: Brugada Syndrome
The ECG pattern is classic for Type 1 Brugada pattern — the only pattern that is diagnostic of Brugada syndrome. The coved ST elevation ≥2 mm in one or more right precordial leads (V1-V2) followed by a negative T wave is pathognomonic.
Brugada syndrome is a genetic channelopathy affecting cardiac sodium channels (most commonly SCN5A mutations) that predisposes to ventricular fibrillation and sudden cardiac death. It's estimated to cause 4-12% of all sudden cardiac deaths and up to 20% of sudden deaths in patients with structurally normal hearts.
Why This Case Matters
This case illustrates several critical clinical reasoning principles:
1. Don't anchor on the obvious. Chest pain + middle-aged man = ACS is the reflexive diagnosis. But the negative troponin, atypical timing (waking from sleep), and absence of risk factors should prompt broader thinking.
2. The ECG tells you things you didn't ask. The team ordered the ECG looking for ST changes suggesting ACS. Instead, they found a completely different — and potentially more dangerous — diagnosis. Always read the entire ECG systematically, not just the parts you expect to be abnormal.
3. Incidental findings can be life-saving. This patient's chest pain may have been musculoskeletal or anxiety-related. But the ECG revealed a condition that carries a significant risk of sudden death. Without this ED visit, the diagnosis might have been made posthumously.
Management and Disposition
The patient was admitted to a telemetry unit and cardiology was consulted. Key management steps included:
Risk stratification: The presence of a spontaneous Type 1 pattern (not drug-induced) places this patient at higher risk. History of syncope, family history of sudden death, and inducibility on electrophysiology study further stratify risk.
ICD consideration: Current guidelines recommend an implantable cardioverter-defibrillator (ICD) for Brugada patients with spontaneous Type 1 pattern who have survived cardiac arrest or have documented sustained ventricular arrhythmias. For asymptomatic patients with spontaneous Type 1 pattern, the decision is individualized based on EP study results and risk factors.
Lifestyle counseling: Avoid drugs that can unmask or worsen Brugada pattern (see brugadadrugs.org). Treat fever aggressively (fever can provoke arrhythmias in Brugada). Avoid excessive alcohol and large meals (vagal stimulation).
Genetic counseling: First-degree relatives should be screened with ECG and potentially genetic testing.
Key Teaching Points
This case reinforces the importance of systematic ECG interpretation and maintaining a broad differential even when the presentation seems straightforward. The ECG Interpretation Guide covers Brugada pattern recognition alongside all major ECG findings. The ACS Clinical Decision Tool helps differentiate true ACS from mimics. And the Arrhythmia Management Tool covers the full spectrum of cardiac rhythm disorders including channelopathies.
Clinical reasoning is built one case at a time. Each unexpected finding, each diagnostic surprise, adds to your illness script library and makes you a better clinician.