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Acute Medical Take · diagnostic library
ECG & Imaging
Pattern recognition is only the beginning. Read systematically, connect the trace or image to the physiology and escalate dangerous findings early.
♥⌁⌁╱╲⌁⌁TRACE → IMAGE → ACTION
ECG & IMAGING · SECTION 01
16 common ECG patterns
Real ECGs covering rhythm · conduction · ischaemia · inherited patterns · devices · metabolic and drug effects
This genuine clinical trace demonstrates organised flutter activity. AF is irregularly irregular with no consistent P waves; SVT is usually regular and narrow-complex.
Diagnostic trap
A regular rate near 150/min should trigger a deliberate search for flutter.
Specialist management
Unstable: synchronised cardioversion. Stable: rate/rhythm strategy, echocardiography and CHA₂DS₂-VASc-led anticoagulation; refer flutter for ablation assessment.
Monitoring & escalation
Continuous ECG when acute; reassess rate, BP and symptoms and document anticoagulation ownership.
Specialist medicines and adult doses
1Bisoprolol 1.25–5 mg orally daily is a common cautious rate-control start; avoid shock, marked block or acute decompensated HF.
2Diltiazem IR 60 mg orally three times daily is an alternative when LVEF is preserved; avoid HFrEF.
3Anticoagulant agent/dose requires renal, age, weight, valve and interaction checks.
This real 12-lead demonstrates AV dissociation. Separate sinus-node disease, AV block, bundle-branch block and escape rhythm; map every P wave to a QRS.
Diagnostic trap
Mobitz II, high-grade and complete block may deteriorate despite a temporarily acceptable blood pressure.
Specialist management
Adverse signs require bradycardia algorithm, pads and early transcutaneous then transvenous pacing; atropine is unreliable in broad-QRS high-grade block.
Monitoring & escalation
Continuous ECG/BP/perfusion and immediate cardiology ownership.
Specialist medicines and adult doses
1Atropine 500 micrograms IV, repeat every 3–5 min to total 3 mg when appropriate.
2If ineffective: adrenaline 2–10 micrograms/min or isoprenaline starting 5 micrograms/min while pacing is arranged.
This patient ECG shows sinus tachycardia and RBBB in pulmonary embolism. Right-axis deviation and anterior T inversion may also support RV strain.
Diagnostic trap
A normal ECG does not exclude PE; S1Q3T3 is neither sensitive nor specific.
Specialist management
Use clinical probability and definitive imaging. Shock requires immediate PE response/critical care and reperfusion decision; stable confirmed PE receives anticoagulation.
Monitoring & escalation
ECG, BP, SpO₂, perfusion/lactate and bleeding surveillance.
Specialist medicines and adult doses
1LMWH is weight- and renal-function based through the local PE protocol.
2DOAC loading/maintenance is agent-specific with renal and interaction checks.
3Thrombolysis is specialist-led for haemodynamic instability or arrest.
This genuine 12-lead ECG shows territorial anterior ST elevation with reciprocal change. Inspect contiguous leads and relate the pattern to symptoms and onset.
Diagnostic trap
Do not wait for troponin when the clinical picture and ECG show acute coronary occlusion; mimics can coexist with infarction.
Specialist management
Activate primary PCI immediately; do not await troponin. Use pathway-directed antiplatelet/anticoagulant treatment and transfer.
Monitoring & escalation
Defibrillator-ready telemetry, serial ECG, BP, electrolytes and complication surveillance.
Specialist medicines and adult doses
1Aspirin 300 mg orally once unless clearly allergic/contraindicated.
2GTN 400 micrograms sublingual if BP permits; avoid hypotension, RV infarction or recent PDE-5 inhibitor.
3P2Y12 inhibitor and anticoagulant are selected by the PCI pathway and bleeding/renal risk.
A genuine clinical ECG with high QRS voltage and lateral down-sloping ST depression/asymmetric T-wave inversion.
Diagnostic trap
Voltage criteria do not prove anatomical LVH, and LVH does not exclude acute ischaemia.
Specialist management
Confirm BP and end-organ injury, obtain echo and exclude ACS when ST–T changes are dynamic or disproportionate. Treat hypertensive emergency in monitored care.
Monitoring & escalation
Serial BP/organ markers, renal assessment and echo follow-up.
Specialist medicines and adult doses
1No drug for ECG voltage alone.
2Chronic therapy follows NICE hypertension guidance; IV labetalol or alternatives are titrated to organ-specific targets by senior teams.
A genuine ECG demonstrating ST depression, flattened/inverted T waves and prominent U waves with apparent QT/QU prolongation.
Diagnostic trap
Low magnesium and QT-prolonging medicines markedly amplify ventricular-arrhythmia risk.
Specialist management
Stop losses, correct magnesium and replace K orally when safe or IV for severe/symptomatic disease; concentrated/faster IV treatment needs monitored central access.
Monitoring & escalation
Continuous ECG when severe or IV rates are higher; repeat K/Mg and avoid overcorrection in renal impairment.
Specialist medicines and adult doses
1Potassium chloride 40 mmol orally is a common initial stable-patient dose.
2IV K commonly 20–40 mmol in 1 L at up to 10 mmol/h peripherally; higher rates require critical-care/local protocol.
3Magnesium sulfate 2 g IV may be used for significant concurrent deficit/arrhythmia risk.
Safety: Adult UK decision support—not automatic prescriptions. Verify the current BNF, RCUK/NICE/UKKA guidance, allergy, pregnancy, weight, renal/hepatic function, interactions and local cardiology protocols.
Do not let a picture overrule the patient.These are genuine de-identified clinical traces. Repeat the ECG during symptoms, obtain posterior/right-sided leads when indicated, compare previous traces and urgently escalate ongoing ischaemia, instability, high-grade block or malignant arrhythmia.
1. Orientate yourself on a real 12-lead ECG
First confirm the patient identifiers on the original, recording date/time, speed, gain and lead placement. Then read each lead and the rhythm strip systematically.
High QRS voltage plus a lateral “strain” pattern—down-sloping ST depression and asymmetric T-wave inversion. Voltage criteria are screening tools, not proof of anatomical LVH.
Keep it simple
Large left-sided voltage suggests increased LV muscle mass. Repolarisation then travels abnormally, producing ST–T changes that can resemble ischaemia.
Do not miss
LVH does not exclude acute coronary occlusion. Compare previous ECGs, look for disproportionate or dynamic change and correlate with echocardiography.
4. Electrolytes
Real patient traces: potassium disorders
1Tall narrow ‘tented’ T waves2Inspect P waves and PR3Watch QRS width
Severe hyperkalaemia (K 8.2 mmol/L)Agbayani & Gonzales, CC BY 4.0 · source and licence ↗
Hyperkalaemia can progress from peaked T waves to PR prolongation/P-wave loss, QRS widening and a sine-wave pattern. The sequence is unreliable: treat the patient and biochemical severity, not the picture alone.
1ST depression2Flattened / inverted T3Prominent U waves
Severe hypokalaemia (K 1.1 mmol/L)James Heilman MD, CC BY-SA 3.0 · source and licence ↗
Hypokalaemia produces ST depression, flattened/inverted T waves and prominent U waves, with apparent QT prolongation that is often a long QU interval. Arrhythmia risk increases with low magnesium or QT-prolonging medicines.
Calcium and magnesiumHypocalcaemia typically lengthens the QT (mainly ST); hypercalcaemia shortens it. Severe magnesium disturbance can alter PR/QRS/QT and provoke arrhythmia, but these appearances are nonspecific—confirm the blood result and clinical context.
5. Acute coronary syndromes
Real STEMI tracing and an NSTEMI reading approach
1Anterior ST elevation2Reciprocal ST depression3Assess contiguous leads
Anterior STEMI with reciprocal changeDisplaced, public domain · source and licence ↗
STEMI: look for ST elevation in anatomically contiguous leads with reciprocal change, hyperacute T waves and dynamic evolution. A convincing occlusion pattern requires immediate pathway activation—do not wait for troponin.
NSTEMI
The ECG may show ST depression, T-wave inversion, transient elevation—or be normal
Repeat ECGs during pain and after symptom change.
Compare with previous traces.
Look for new horizontal/down-sloping ST depression or dynamic symmetrical T inversion.
Diagnose NSTEMI from a troponin rise/fall plus clinical evidence of ischaemia—not from ECG alone.
Septal V1–V2Anterior V3–V4Lateral I, aVL, V5–V6Inferior II, III, aVFPosterior V7–V9 / reciprocal V1–V3Right ventricle V3R–V4R
6. STEMI mimics
Compare real clinical examples
A mimic can coexist with MI. Use symptoms, serial ECGs, troponin, echo and urgent expert review.
1Widespread concave ST elevation2Reciprocal depression in aVR3Look for PR depression
Coved ST elevation followed by T-wave inversion in the right precordial leads. Fever and medicines can unmask it; syncope or arrhythmia requires urgent specialist review.
1QRS ≥120 ms2Broad lateral R waves3Secondary discordant ST–T
Left bundle branch blockCardioNetworks/ECGpedia, CC BY-SA 3.0 · source and licence ↗
Wide QRS with secondary discordant ST–T change. Use validated occlusion criteria and clinical context; ongoing ischaemia still needs urgent review.
Large voltage with lateral ST depression/T inversion and sometimes discordant anterior elevation. Compare old traces; LVH does not rule out ACS.
Other mimics to remember: benign early repolarisation, ventricular aneurysm, hyperkalaemia, paced rhythm, takotsubo syndrome and myocarditis.
About these ECGs
All clinical traces are de-identified educational examples hosted by Wikimedia Commons. Labels are explanatory overlays added by Acute Medical Take; the original files remain unchanged. Attribution and licence links are shown beneath every image.
Educational examples—not a substitute for assessment of the original diagnostic-quality 12-lead ECG, clinical presentation, local ACS pathway and senior/cardiology interpretation.
Lung, pleura, DVT compression, aorta, bladder, biliary and renal assessment. Record the focused question, images and limitations.
ECHO
Focused echocardiography
LV → RV → valves → fluid
Global ventricular function, RV pressure/volume pattern, pericardial fluid/tamponade, severe valve disease and volume clues; comprehensive echo follows when needed.
CMR
Cardiac CT & MRI
Anatomy + function + tissue
Coronary anatomy, structural disease, myocarditis, infarction, infiltrative disease, cardiomyopathy, masses and viability using protocol-specific interpretation.
NM
Nuclear / PET imaging
Tracer → distribution → correlate
Perfusion SPECT/PET, infection/inflammation and oncology. Recognise physiological uptake, attenuation artefact and the need for CT/clinical correlation.
CONTRASTCheck allergy history, renal function, pregnancy possibility, metformin/local policy and the exact clinical question. Do not withhold a time-critical scan automatically—discuss risk versus delay with radiology.COMMUNICATEState modality, site, key positive and negative findings, severity, comparison, uncertainty and required action. Confirm that time-critical findings reached the responsible clinician.
Critical findings wall
! STEMI/occlusion or malignant arrhythmia! Complete/high-grade block or pacing failure! Tension pneumothorax or major airway/device problem! Intracranial haemorrhage, LVO or herniation! Aortic catastrophe, massive PE or active bleeding! Perforation, bowel ischaemia or infected obstruction! Tamponade, severe ventricular failure or acute valve catastrophe! Cord/cauda equina compression
New enhanced section
Interpretation of medical images
Chest X-ray • CT • MRI • PET/CT • ultrasound
Use a fixed system, compare prior imaging and read the radiologist’s report. These examples teach recognition; they do not replace diagnostic image review.
1ConfirmPatient, date/time, modality, body part, projection/sequence, contrast and clinical question.2QualityCoverage, rotation, inspiration/exposure, motion and artefact. Poor quality changes confidence.3SearchUse the modality-specific checklist below; inspect every region, not only the obvious lesion.4ConcludeDescribe finding, location, severity, complications, comparison and urgent action.
1Right upper-lobe airspace opacity2Compare both hila3Check pleural angles
Chest X-ray—right upper-lobe pneumonia
A real AP chest radiograph showing right upper-lobe shadowing. Consolidation is a pattern, not an organism.
Look for
RIPE quality, then A–E: airway, breathing/lungs/pleura, circulation/mediastinum, diaphragm, everything else. Seek air bronchograms, silhouette loss and complications.
Clinical next step
Correlate with physiology and infection syndrome. Follow-up imaging is indicated for selected patients according to local/NICE guidance.
1High FDG uptake2CT anatomical lesion3Review whole-body distribution
PET/CT—FDG-avid nodal metastasis
PET displays metabolism; CT supplies anatomy. Uptake is not synonymous with malignancy because inflammation and physiological activity also take up FDG.
Look for
Pattern and intensity of uptake, anatomical correlate, physiological sites, treatment timing, blood glucose and prior study.
Clinical next step
Use for the specific staging/response question and multidisciplinary interpretation; biopsy remains necessary when tissue diagnosis changes management.
RIPE quality → A–E review → compare prior. Never stop after the first abnormality.
CT
Confirm contrast phase and windows. Scroll systematically; one screenshot cannot exclude disease.
MRI
Know the sequence. Signal meaning changes between DWI/ADC, FLAIR, T1/T2 and susceptibility imaging.
PET/CT
Metabolic uptake needs anatomical and clinical correlation; infection/inflammation can be FDG-avid.
Ultrasound
Orientation, probe position, dynamic signs and Doppler matter; static images are incomplete.
Safety: If imaging and the patient conflict, reassess the patient, verify the study and contact radiology. Act immediately on time-critical findings such as tension pneumothorax, major haemorrhage, large-vessel occlusion, aortic catastrophe, massive PE, cord compression or perforation.
ESCALATE THE PATIENT—NOT JUST THE PICTURECall the appropriate senior, cardiology, radiology, stroke, surgical, critical-care or tertiary service immediately when an image or trace shows a time-critical abnormality or conflicts with a deteriorating patient.
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