Maritime Cardiac Emergency
STEMI at Sea
A heart attack at sea unfolds without a cath lab, without interventional cardiology, and often without reliable connectivity. Maritime clinicians must recognise STEMI early, make high-stakes thrombolysis decisions, and coordinate evacuation—all from a moving vessel.
Step 1
Recognising STEMI at Sea
A heart attack at sea presents the same way it does ashore—but with fewer diagnostic safety nets. Atypical presentations in elderly passengers and diabetic patients mean a high index of suspicion is essential.
- Central crushing chest pain radiating to the jaw, left arm, or back
- Diaphoresis, nausea, and a sense of impending doom
- Atypical features: epigastric pain, syncope, isolated dyspnoea, or acute confusion in elderly patients
- Immediate 12-lead ECG within 10 minutes of first medical contact
Clinical Principle
Time is myocardium—even at sea
Door-to-ECG targets still apply on a ship. The maritime environment delays definitive PCI, making early recognition the single most impactful intervention you control.
Step 2
ECG Interpretation at Sea
Interpreting a 12-lead ECG in a moving medical centre with limited cardiology backup requires systematic confidence. Ship motion artefact and electrical interference from vessel systems can obscure ST-segment changes.
- Look for ST-elevation in two or more contiguous leads (≥1mm limb leads, ≥2mm precordial)
- Identify the culprit territory: anterior (V1–V4), inferior (II, III, aVF), lateral (I, aVL, V5–V6)
- Check for reciprocal changes—these increase STEMI specificity at sea where confirmatory troponin may be unavailable
- Repeat the ECG at 15-minute intervals if the initial trace is equivocal
If point-of-care troponin is available, it supports but does not replace the ECG. Treatment decisions in maritime STEMI are driven by the ECG and clinical picture.
Step 3
Thrombolysis Decision-Making
When PCI is hours or days away, thrombolysis becomes the primary reperfusion strategy for maritime STEMI. This is a high-consequence decision made in isolation—and it must be made quickly.
- Consider thrombolysis when PCI cannot be achieved within 120 minutes of first medical contact
- Screen absolute contraindications: active bleeding, recent surgery, haemorrhagic stroke, aortic dissection
- Weigh relative contraindications against the cost of withholding treatment far from definitive care
- Document decision rationale, TMAS consultation, and time of administration
Maritime Context
The isolation amplifies the stakes
Ashore, a borderline case can be discussed with interventional cardiology in real time. At sea, you may be making this decision with a satellite phone delay and a patient deteriorating in front of you. Preparation and protocol familiarity are your only advantages.
Step 4
TMAS Consultation for Maritime STEMI
Telemedical Maritime Assistance Service (TMAS) is your remote specialist link. For a cardiac emergency at sea, early TMAS contact provides clinical validation and documentation support.
- Contact TMAS early—before you need permission, not after
- Transmit the 12-lead ECG digitally if your system supports it
- Use structured handover: patient demographics, symptom onset time, ECG findings, contraindication screen, and your proposed plan
- TMAS can advise on thrombolytic dosing, adjunctive therapy, and evacuation coordination
If satellite connectivity is unreliable, document your clinical reasoning thoroughly. You may need to proceed on clinical grounds alone.
Step 5
Bridge Communication
The bridge controls the ship. In a maritime STEMI, the bridge needs to know why your patient changes their operational plan. Speak in operational terms, not clinical jargon.
- Use SBAR-M: Situation, Background, Assessment, Recommendation, Maritime context
- State clearly: “This patient is having a heart attack. I need the nearest port with a cardiac catheterisation facility.”
- Provide a time-critical frame: how long the patient can safely remain aboard
- Request diversion, helicopter evacuation, or pilot boat transfer as appropriate
The bridge does not need to understand STEMI pathophysiology. They need to understand urgency, timeline, and what you need from them. See our Bridge Phrases guide.
Step 6
Medevac Considerations
Evacuating a STEMI patient from a vessel involves clinical, logistical, and operational variables that must align. The decision to evacuate is clinical; the execution is operational.
- Helicopter range is typically 150–200 nautical miles from the coast—beyond this, diversion may be faster
- Post-thrombolysis patients require monitoring during transfer; communicate anticoagulation status to the receiving team
- Prepare a complete handover: ECG copies, medication times, vital sign trends, and clinical trajectory
- Coordinate with the bridge on deck preparation, wind conditions, and approach vectors
For a complete medevac decision framework, see Medevac Decision-Making at Sea.
Step 7
Weather Limitations
Weather does not pause for a cardiac emergency. Sea state, wind speed, and visibility directly determine whether helicopter evacuation is possible and how long diversion will take.
- Helicopter operations are typically limited to sea state 5 or below and wind speeds under 50 knots
- Night winching adds complexity and may not be available from all coast guard services
- Heavy weather extends diversion time—factor this into your oxygen and medication endurance calculations
- If evacuation is delayed, your role shifts to sustained stabilisation: serial ECGs, rhythm monitoring, and complication management
When the weather closes in, the ship becomes the ICU. Plan for the worst-case evacuation timeline, not the best.
Why It Matters
Why STEMI at Sea Is Different
Every maritime cardiac emergency unfolds under constraints that land-based clinicians never face.
No Cath Lab
PCI is hours to days away
Limited Comms
Satellite delay, dropped calls
Weather-Dependent
Evacuation subject to sea state
Solo Clinician
Often one doctor, one nurse
Resources
Build Your Maritime STEMI Readiness
Preparation is the intervention you make before the emergency starts. These resources cover the clinical and operational skills needed to manage a heart attack at sea.
- Case Simulations — Practice maritime cardiac scenarios with structured decision points
- Clinical Tools — NEWS2 calculator, SBAR-M templates, and oxygen planning tools
- Emergency Protocols — Rapid-access protocols for shipboard cardiac arrest and STEMI
- Maritime Medicine Playbook — The full operational and clinical resource package
- STEMI at Sea Field Note — Detailed clinical walkthrough of maritime STEMI management
Educational and operational support only. Does not replace employer protocols, telemedical advice, company medical policy, flag-state requirements, local regulations, or clinical judgment. Do not enter patient-identifiable information into clinical tools.
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