ECGs Flashcards
which are discordant/concordant and what is normal or suggestive of AMI?
discordant/concordant, normal or AMI?
A. discordant ST segment depression: normal
B. discordant ST segment elevation: normal
C. concordant ST elevation (suggestive of AMI)
D. concordant ST depression (suggestive of AMI)
E. excessive >5mm discordant ST segment elevation (weakly suggestive of AMI)
Diagnosis of Inferior STEMI
ST elevation in II, III, aVF; reciprocal ST depression in I, aVL.
Activate cath lab immediately.
Diagnosis of Anterior STEMI
ST elevation in V1-V3
>1mm STdepression 2,3,aVF
left anterior descending (LAD) occlusion
Likely LAD occlusion; urgent PCI required.
Diagnosis of Lateral STEMI
ST elevation in I, aVL, V5-V6; reciprocal changes in II, III, aVF.
Cath lab activation.
Posterior MI
ST depression in V1-V3; tall R waves and upright T waves in V2-V3
Often with inferior STEMI; check posterior leads (V7-V9).
Diagnosis of Right Ventricular MI: makes up 40% of inferior STEMIs
ST elevation in V1,
St elevation in lead 3 > lead 2
V4R with inferior STEMI
preload sensitive! treat with fluid loading and nitrates contraindicated.
Avoid nitrates; fluid bolus if hypotensive.
Wellens’ Syndrome: type A pattern.
biphasic T waves in V2-V3.
hx of chest pain, now resolved. highly specific for critical stenosis of LAD artery.
Critical LAD stenosis; urgent cardiology consult.
Winter’s T Waves
Upsloping ST depression in precordial leads (>1mm at J point)
peaked T waves in V1-V4
subtle ST elevation in aVR >0.5mm
STEMI equivalent; immediate cath lab.
how do you diagnose Sgarbossa Criteria and when?
With LBBB or ventricular paced rhythm infarct can be difficult. - –Concordant ST elevation > 1mm in leads with a positive QRS complex (score 5)
Concordant ST depression > 1 mm in V1-V3 (score 3)
Excessively discordant ST elevation > 5 mm in leads with a -ve QRS complex (score 2)
Treat as STEMI.
Diagnosis of Hyperacute T Waves
Tall, symmetric T waves in V1-V4.
seen in early stages of STEMI and preceed ST elevation and Q waves.
Early MI sign; monitor for ST elevation.
ST elevation in aVR and widespread ST depression.
This ECG pattern simply tells us there is an oxygen supply/demand mismatch causing subendocardial ischaemia. In a clinical context, this can be due to:
Hypotension
Hypoxia
Fixed stenosis limiting flow
Consider demand ischaemia or NSTEMI.
Acute Pericarditis Mimicking STEMI
Widespread concave ST elevation and PR depression is present throughout the precordial (V2-6) and limb leads (I, II, aVL, aVF).
There is reciprocal ST depression and PR elevation in aVR.
NSAID treatment; not cath lab.
Left Main Occlusion
ST elevation in aVR and V1 of similar magnitude
Widespread ST depression (V3-6, I, II, III, aVF)
Critical; immediate PCI.
Spiked Helmet
SignST elevation mimicking STEMI but with upsloping baseline.
major critical illness and high risk of death.
Seen in critical illness (e.g., sepsis); not MI.
Diagnosis of Ventricular Tachycardia (Monomorphic)
Wide QRS (>120 ms), regular, rapid rate; AV dissociation.
Defibrillate if unstable; amiodarone if stable.
Diagnosis of Ventricular Fibrillation
Chaotic, irregular waveforms; no discernible QRS.
Immediate defibrillation and CPR.
Diagnosis of Torsades de Pointes
Polymorphic VT with twisting QRS axis; prolonged QT precedes.
Magnesium IV stat.
Diagnosis of Supraventricular Tachycardia (SVT)
Narrow QRS, regular, rate >150 bpm; P waves absent or retrograde.
Vagal maneuvers, then adenosine.
Diagnosis of Atrial Fibrillation (New Onset)
Irregularly irregular rhythm; no distinct P waves, fibrillatory waves.
Rate control; anticoagulation if >48h.
Diagnosis of Atrial Flutter
Sawtooth flutter waves in II, III, aVF; regular atrial rate ~300 bpm.
Rate control or cardioversion.
Diagnosis of Multifocal Atrial Tachycardia
Irregular rhythm; ≥3 distinct P wave morphologies.
Treat underlying cause (e.g., COPD).
Diagnosis of Junctional Rhythm
Narrow QRS; absent or retrograde P waves; rate 40-60 bpm.
Usually benign; check reversible causes.
Diagnosis of Ventricular Bigeminy
Alternating normal QRS and PVCs.
Assess electrolytes; benign unless frequent.
Diagnosis of Complete Heart Block (3rd Degree)
No AV conduction; independent P waves and QRS; wide QRS if ventricular escape.
Pacing if symptomatic.
Diagnosis of Accelerated Idioventricular Rhythm (AIVR)
Wide QRS, regular, rate 50-100 bpm.
Post-reperfusion; observe unless unstable.
Diagnosis of Atrial Tachycardia
Narrow QRS, regular, abnormal P waves before QRS.
Adenosine ineffective; rate control.
Diagnosis of Premature Atrial Contractions (PACs)
Early P waves with variable morphology.
Benign; frequent PACs may precede AF.
Diagnosis of Premature Ventricular Contractions (PVCs)
Wide, bizarre QRS not preceded by P wave.
Assess frequency and cause.
Diagnosis of Sinus Tachycardia
Normal P-QRS-T, rate >100 bpm.
Treat underlying cause (e.g., pain, hypoxia).
Diagnosis of Sinus Bradycardia
Normal P-QRS-T, rate <60 bpm.
Symptomatic requires atropine or pacing.
Diagnosis of Wandering Atrial Pacemaker
Variable P wave morphology; rate <100 bpm.
Benign; seen in young or lung disease.
Diagnosis of Asystole
Flat line; no electrical activity.
Confirm in two leads; start CPR.
Diagnosis of Pulseless Electrical Activity (PEA)
Organized rhythm without pulse.
Treat reversible causes (H’s and T’s).
Diagnosis of Atrial Fibrillation with Rapid Ventricular Response
Irregularly irregular, rate >100 bpm.
Rate control urgent if unstable.
Diagnosis of Left Bundle Branch Block (LBBB)
Wide QRS (>120 ms); broad R waves in I, V5-V6; no Q in V5-V6.
New LBBB + chest pain = MI until proven otherwise.
Diagnosis of Right Bundle Branch Block (RBBB)
Wide QRS; rSR’ in V1-V2; wide S in I, V5-V6.
Assess for acute cause if new.
Diagnosis of First-Degree AV Block
PR interval >200 ms; all P waves conducted.
Usually benign; monitor in acute setting.
Diagnosis of Mobitz I (2nd Degree AV Block)
Progressive PR lengthening until a P wave is dropped.
Often vagal; observe unless symptomatic.
Diagnosis of Mobitz II (2nd Degree AV Block)
Fixed PR interval with intermittent dropped QRS.
High risk; prepare for pacing.
Diagnosis of Left Anterior Fascicular Block (LAFB)
Left axis deviation; qR in I, aVL; rS in II, III, aVF.
Common in elderly; check for MI.
Diagnosis of Left Posterior Fascicular Block (LPFB)
Right axis deviation; rS in I, aVL; qR in III, aVF.
Rare; consider structural heart disease.
Diagnosis of Bifascicular Block
RBBB + LAFB or LPFB; wide QRS and axis deviation.
Risk of progression to complete block; monitor.
Diagnosis of Trifascicular Block
Bifascicular block + 1st-degree AV block.
High risk for complete block; pacing may be needed.
Diagnosis of Brugada Pattern
RBBB-like morphology; ST elevation in V1-V3 (coved-type).
Risk of sudden death; cardiology referral.
Diagnosis of RBBB with ST Elevation
RBBB with ST elevation in V1-V3.
Consider acute RV strain or Brugada mimic.
Diagnosis of LBBB with Hyperkalaemia
Wide QRS with peaked T waves.
Treat potassium urgently.
Diagnosis of Intraventricular Conduction Delay (IVCD)
Wide QRS, non-specific pattern.
Assess for toxins or ischaemia.
Diagnosis of Sinoatrial Exit Block
Intermittent absent P waves; normal QRS follows.
Benign unless symptomatic.
Diagnosis of AV Dissociation (Non-VT)
Independent P and QRS; narrow QRS.
Seen in junctional rhythm; assess cause.
Diagnosis: Hyperkalaemia (Severe)
Description: Peaked T waves, wide QRS, absent P waves, sine wave.
Calcium gluconate stat; treat urgently.
Diagnosis: Hypokalaemia
Description: Flattened T waves, prominent U waves, ST depression.
Replace potassium; monitor for arrhythmias.
Diagnosis: Hypercalcaemia
Description: Shortened QT interval; normal T waves.
Check calcium levels; treat underlying cause.
Diagnosis: Hypocalcaemia
Description: Prolonged QT interval; normal T wave morphology.
Replace calcium; assess for tetany.
Diagnosis: Digoxin Toxicity
Description: Scooped ST depression (reverse tick sign); atrial tachycardia with block.
Stop digoxin; consider Digibind if severe.
Diagnosis: Hyperkalaemia (Mild)
Description: Peaked T waves only.
Early sign; check K+ level urgently.
Diagnosis: Hypomagnesaemia
Description: Prolonged QT; may mimic torsades risk.
Replace magnesium; common with hypokalaemia.
Diagnosis: Tricyclic Antidepressant Toxicity
Description: Wide QRS, right axis deviation, prominent R in aVR.
Sodium bicarbonate; urgent if unstable.
Diagnosis: Hypothyroidism
Description: Sinus bradycardia, low voltage QRS, flattened T waves.
Check TSH; treat underlying cause.
Diagnosis: Hyperthyroidism
Description: Sinus tachycardia or atrial fibrillation; normal QRS.
Beta-blockers for rate control; check thyroid function.
Diagnosis: Sodium Channel Blocker Toxicity
Description: Wide QRS, prolonged QT, rightward axis.
Sodium bicarbonate; consider tox history.
Diagnosis: Metabolic Acidosis (Compensated)
Description: Sinus tachycardia; normal QRS/T waves.
Non-specific; check ABG and cause (e.g., DKA).
Diagnosis: Hypoglycaemia Mimic
Description: Sinus tachycardia or non-specific ST-T changes.
Check glucose; treat if low.
Diagnosis: U Wave Prominence
Description: Distinct U waves after T waves; normal QRS.
Seen in hypokalaemia or bradycardia; assess electrolytes.
Diagnosis: Digoxin Effect (Non-Toxic)
Description: Scooped ST depression without arrhythmia.
Expected with therapeutic levels; monitor.
Diagnosis: Pulmonary Embolism (S1Q3T3)
Description: S wave in I, Q wave and inverted T in III; sinus tachycardia.
Non-specific; urgent CTPA if suspected.
Diagnosis: Pericarditis
Description: Diffuse concave ST elevation; PR depression in multiple leads.
NSAID treatment; echo for effusion.
Diagnosis: Cardiac Tamponade
Description: Low-voltage QRS; electrical alternans (QRS amplitude variation).
Urgent echo; pericardiocentesis if unstable.
Diagnosis: Tension Pneumothorax (Mimic)
Description: Sinus tachycardia; low voltage or axis shift.
Clinical diagnosis; decompress, not ECG-specific.
Diagnosis: COPD Exacerbation
Description: Right axis deviation; poor R wave progression; multifocal atrial tachycardia.
Treat hypoxia; avoid over-sedation.
Diagnosis: Acute Right Heart Strain
Description: RBBB, right axis deviation, ST-T changes in V1-V3.
Seen in massive PE; urgent imaging.
Diagnosis: Pneumonia (Non-Specific)
Description: Sinus tachycardia; no specific QRS changes.
Treat infection; ECG not diagnostic.
Diagnosis: Pulmonary Oedema (LVF)
Description: Sinus tachycardia; LVH or ST-T changes.
Diuretics and nitrates; urgent CXR.
Diagnosis: Chronic Pulmonary Hypertension
Description: Right axis deviation; tall R in V1; RVH pattern.
Echo confirmation; not acute management.
Diagnosis: Hypoxia (Non-Specific)
Description: Sinus tachycardia or atrial arrhythmias.
Oxygen therapy; check SpO2.
Diagnosis: Pericardial Effusion (Subtle)
Description: Low voltage QRS without alternans.
Echo to confirm; monitor for tamponade.
Diagnosis: Asthma Exacerbation (Mimic)
Description: Sinus tachycardia; no specific QRS changes.
Clinical diagnosis; bronchodilators.
Diagnosis: Massive PE (Sinus Tachycardia)
Description: Sinus tachycardia only; no S1Q3T3.
Most common PE finding; urgent imaging.
Diagnosis: Cor Pulmonale
Description: Right axis deviation; P pulmonale; RVH.
Chronic finding; manage underlying lung disease.
Diagnosis: Acute Respiratory Distress Syndrome (ARDS)
Description: Sinus tachycardia; non-specific ST-T changes.
Supportive care; ECG not diagnostic.
Diagnosis: Takotsubo Cardiomyopathy
Description: ST elevation in V1-V4; later deep T wave inversion.
Supportive care; echo confirmation.
Diagnosis: Myocarditis
Description: Diffuse ST elevation or T wave inversion; sinus tachycardia.
Supportive care; echo and troponin.
Diagnosis: Hypothermia
Description: Osborn (J) waves; prolonged PR, QRS, QT; bradycardia.
Warm patient; avoid aggressive rewarming if unstable.
Diagnosis: Wolff-Parkinson-White (WPW)
Description: Short PR; delta wave; wide QRS.
Avoid AV nodal blockers in AF; cardiovert if unstable.
Diagnosis: Prolonged QT Syndrome
Description: QTc >480 ms.
Remove QT-prolonging drugs; magnesium if torsades.
Diagnosis: Paced Rhythm
Description: Pacing spikes before QRS; wide QRS; LBBB-like morphology.
Check pacemaker function if new symptoms.
Diagnosis: Left Ventricular Hypertrophy (LVH)
Description: High voltage R waves in V5-V6; ST depression/T inversion.
Common in hypertension; assess for strain.
Diagnosis: Right Ventricular Hypertrophy (RVH)
Description: Tall R in V1; right axis deviation; ST-T changes.
Consider pulmonary hypertension.
Diagnosis: Aneurysmal SAH (Cerebral T Waves)
Description: Deep, wide T wave inversion; prolonged QT.
Neurogenic; treat underlying bleed.
Diagnosis: Artifact (e.g., Tremor)
Description: Irregular baseline mimicking VF; normal rhythm underneath.
Check leads; reassure if clinical mismatch.
Diagnosis: Left Ventricular Aneurysm
Description: Persistent ST elevation in V1-V4; Q waves present.
Post-MI; no acute intervention unless symptomatic.
Diagnosis: Cardiac Contusion
Description: Non-specific ST-T changes or RBBB.
Trauma-related; monitor troponin and echo.
Diagnosis: Hypertrophic Cardiomyopathy (HCM)
Description: Deep Q waves in inferior/lateral leads; LVH pattern.
Risk of sudden death; echo confirmation.
Diagnosis: Amyloidosis (Cardiac)
Description: Low voltage QRS; pseudo-infarct Q waves.
Rare; echo and biopsy for diagnosis.
Diagnosis: Dextrocardia
Description: Reversed R wave progression; right axis deviation.
Confirm with CXR; adjust lead placement.
Diagnosis: Ebstein’s Anomaly
Description: Tall P waves; RBBB; right axis deviation.
Congenital; echo confirmation.
Diagnosis: Athlete’s Heart
Description: Sinus bradycardia; early repolarization ST elevation.
Benign; history distinguishes from pathology.
Diagnosis: Early Repolarization
Description: J-point elevation with notched T waves in V3-V6.
Benign; common in young males.
Diagnosis: Lead Misplacement
Description: Inverted P waves in I or bizarre axis.
Recheck leads; repeat ECG.
Diagnosis: Normal Variant (Juvenile T Waves)
Description: T wave inversion in V1-V3; normal QRS.
Benign in young patients; no intervention.
outline ECG territories
Normal sinus rhythm in a healthy 18-year old male:
Regular rhythm at 84 bpm.
Normal P wave morphology and axis (upright in I and II, inverted in aVR)
Narrow QRS complexes (< 100 ms wide)
Each P wave is followed by a QRS complex
The PR interval is constant
Wellen’s Syndrome: type B pattern.
There are deep, symmetrical T wave inversions throughout the anterolateral leads (V1-6, I, aVL)
Positive Sgarbossa criteria in a patient with a ventricular paced rhythm:
There is concordant ST depression in V2-5 (= Sgarbossa positive).
The morphology in V2-5 is reminiscent of posterior STEMI, with horizontal ST depression and prominent upright T waves.
This patient had a confirmed posterior infarction, requiring PCI to a completely occluded posterolateral branch of the RCA.
Tall, narrow, symmetrically peaked T-waves are characteristically seen in hyperkalaemia
Hyperacute T waves (HATW)
Broad, asymmetrically peaked or ‘hyperacute’ T-waves (HATW) are seen in the early stages of ST-elevation MI (STEMI), and often precede the appearance of ST elevation and Q waves. Particular attention should be paid to their size in relation to the preceding QRS complex
Inverted T-waves in the right precordial leads (V1-3) are a normal finding in children, representing the dominance of right ventricular forces
Anterior T wave inversion with Q waves due to recent MI
Inverted T waves are seen in the following conditions:
Normal finding in children
Persistent juvenile T wave pattern
Myocardial ischaemia and infarction (including Wellens Syndrome)
Bundle branch block
Ventricular hypertrophy (‘strain’ patterns)
Pulmonary embolism
Hypertrophic cardiomyopathy
Raised intracranial pressure
ST elevation seen > 2 weeks following an acute myocardial infarction
ECG Features of Left Ventricular Aneurysm
Most commonly seen in the precordial leads
May exhibit concave or convex morphology
Usually associated with well-formed Q- or QS waves
T-waves have a relatively small amplitude in comparison to the QRS complex (unlike the hyperacute T-waves of acute STEMI)
rate of SA node spontaneous deplorisation?
60-100bpm
rate of Atria node spontaneous deplorisation?
<60bpm
rate of AV node spontaneous deplorisation?
40-60bpm
rate of ventricular spontaneous deplorisation?
20-40bpm
Sinus arrest with a ventricular escape rhythm
Sinus pause / arrest (there is a single P wave visible on the 6-second rhythm strip).
Broad complex escape rhythm with a LBBB morphology at a rate of 25 bpm.
The LBBB morphology (dominant S wave in V1) suggests a ventricular escape rhythm arising from the right bundle branch.
Fusion beats due to VT – the first of the narrower complexes is a fusion beat (the next two are capture beats)
Apical hypertrophic cardiomyopathy (AHC)
- giant T-wave inversion in the precordial leads.
- Inverted T waves are also commonly observed in the inferior and lateral leads
Atrial Flutter with 2:1 Block
This is the classic appearance of anticlockwise flutter:
Inverted flutter waves in II, III + aVF at a rate of 300 bpm (one per big square)
Upright flutter waves in V1 simulating P waves
2:1 AV block resulting in a ventricular rate of 150 bpm
Note the occasional irregularity, with a 3:1 cycle seen in V1-3
