Analysis ecg and suggest diagnosis
Reading File
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Here is a full systematic ECG analysis based on all three images:
ECG Analysis
Technical Details (from the machine printout)
| Parameter | Value |
|---|---|
| Heart Rate | 96 BPM |
| QRS Duration | 85 ms |
| QT Interval | 342 ms |
| QTc | 432 ms |
| PR Interval | 132 ms |
| RR Interval | 625 ms |
| QT/RR | 54% |
| RV5/SV1 | 1.16/0.96 mV |
| P axis | 72° |
| QRS axis | 55° |
| T axis | 52° |
| Speed / Gain | 25 mm/s, 1.0 mm/mV |
| Filter | 0.5–20 Hz |
Systematic Analysis
1. Rhythm
- Regular rhythm, rate ~96 bpm — sinus tachycardia (upper end of normal, borderline)
- P waves present and upright in leads I, II, aVF → normal sinus origin
- PR interval 132 ms → normal (< 200 ms), no AV block
2. Axis
- QRS axis ~55° → Normal axis (0° to +90°)
- P axis 72°, T axis 52° → both normal
3. P Wave
- Visible and positive in leads I, II; inverted in aVR — normal morphology
- No bifid or broadened P waves suggesting atrial enlargement
4. QRS Complex
- Duration 85 ms → narrow, no bundle branch block
- RV5/SV1 = 1.16/0.96 mV → total 2.12 mV — below the Sokolow-Lyon criterion of 3.5 mV for LVH, though borderline
- Transition zone in precordials appears around V3–V4 (normal)
- No pathological Q waves visible in inferior (II, III, aVF) or lateral (I, aVL, V5–V6) leads
5. ST Segment
- No ST elevation or depression evident in any lead
- No STEMI pattern
6. T Waves
- Upright in I, II, aVF, and V4–V6
- V1 T-wave may be slightly flat/biphasic — within normal range for this lead
- No deep T inversions to suggest ischaemia
7. QT/QTc
- QTc 432 ms → upper limit of normal (normal < 440 ms men, < 460 ms women)
- Patient is male; QTc 432 ms is normal
Machine Interpretation
"Normal Sinus Rhythm ECG" — confirmed by the automated report
Diagnosis / Impression
Primary: Normal Sinus Rhythm with Heart Rate of 96 BPM
The machine automated interpretation and manual analysis are concordant. This is an essentially normal ECG with no acute ischaemic changes, no conduction abnormality, and no arrhythmia.
Points to Note / Subtle Findings
| Finding | Significance |
|---|---|
| HR 96 bpm | Borderline sinus tachycardia — consider anxiety, fever, pain, dehydration, anaemia, hyperthyroidism |
| QTc 432 ms | Normal, but monitor if QT-prolonging drugs are used |
| RV5/SV1 near 2.1 mV | Does not meet LVH criteria, but if the patient is hypertensive, correlate clinically |
| No ST/T changes | No evidence of acute coronary syndrome |
| No Q waves | No evidence of old MI |
Clinical Recommendation
- This ECG is reassuring and does not show any acute or dangerous abnormality.
- The slightly elevated heart rate (96 bpm) should be correlated with the clinical context (symptoms, temperature, hydration, thyroid status).
- If the patient has chest pain, breathlessness, or palpitations, further evaluation (echocardiogram, troponin, thyroid function) may be warranted despite the normal ECG.
⚠️ Disclaimer: This analysis is for educational purposes. Final clinical decisions must be made by a qualified physician after correlating with the patient's history and examination.
Search for ECG interpretation guidelines
Finding Sources
Searching PubMed
"electrocardiogram" AND "interpretation" AND "guidelines"
Searching the Web
ECG electrocardiogram interpretation guidelines 2024 AHA ACC
Reading File
Reading File
Here is a comprehensive guide to ECG interpretation, drawn from authoritative textbook sources and current guidelines:
ECG Interpretation Guidelines
Sources: Harrison's Principles of Internal Medicine 22E (2025), Tintinalli's Emergency Medicine, AHA/ACCF/HRS Scientific Statements
The 14-Step Systematic Approach
(Harrison's Principles of Internal Medicine, 22nd Ed, 2025)
Every ECG must be analysed in this order — errors of omission are the most common mistake:
| # | Parameter | What to Assess |
|---|---|---|
| 1 | Standardisation & Technical | Calibration (1 mV = 10 mm), paper speed (25 mm/s), lead placement, artefacts |
| 2 | Rhythm | Sinus vs non-sinus; regular vs irregular |
| 3 | Heart Rate | 60–100 bpm normal; calculate from RR interval |
| 4 | PR Interval / AV Conduction | Normal 120–200 ms; look for blocks |
| 5 | QRS Duration | Normal < 120 ms; widened in BBB, pacing |
| 6 | QT / QTc Interval | QTc < 440 ms (men), < 460 ms (women) |
| 7 | Mean QRS Electrical Axis | Normal −30° to +90°; LAD or RAD |
| 8 | P Waves | Morphology, duration, axis (normal upright in I, II) |
| 9 | QRS Voltages | LVH / RVH criteria |
| 10 | Precordial R-Wave Progression | Normal R grows V1→V5; poor progression suggests old anterior MI |
| 11 | Abnormal Q Waves | Pathological Q ≥ 40 ms wide or ≥ 25% of R height |
| 12 | ST Segments | Elevation, depression, morphology |
| 13 | T Waves | Inversion, peaking, symmetry |
| 14 | U Waves | Prominent U = hypokalaemia, bradycardia |
"Comparison with any previous ECGs is invaluable." — Harrison's, 22E
Normal Values Reference
| Parameter | Normal Range |
|---|---|
| HR | 60–100 bpm |
| PR interval | 120–200 ms |
| QRS duration | < 120 ms |
| QTc (men) | < 440 ms |
| QTc (women) | < 460 ms |
| QRS axis | −30° to +90° |
| R-wave progression | Transition V3–V4 |
Rhythm Interpretation
Sinus Rhythm criteria:
- P wave before every QRS
- P upright in I, II; inverted in aVR
- Constant PR interval
- Rate 60–100 bpm
Key Arrhythmias to Identify:
| Arrhythmia | Key Feature |
|---|---|
| Sinus tachycardia | Rate > 100, normal P waves |
| Sinus bradycardia | Rate < 60, normal P waves |
| AF | Absent P waves, irregularly irregular |
| AFL | Sawtooth flutter waves ~300/min, regular |
| SVT | Narrow QRS, rate 150–250, P waves hidden |
| VT | Wide QRS > 120 ms, rate > 100, AV dissociation |
| AV blocks | PR prolonged (1°), dropped beats (2°), no conduction (3°) |
| LBBB | Wide QRS, negative V1, broad notched R in I, V5–V6 |
| RBBB | Wide QRS, RSR' in V1 ("M" pattern), broad S in I, V6 |
ST-Segment & Ischaemia Patterns
STEMI Criteria (elevation in ≥2 contiguous leads):
- ≥ 1 mm in limb leads
- ≥ 2 mm in V1–V3 (men); ≥ 1.5 mm in V1–V3 (women)
- New LBBB with concordant ST changes
Localisation of MI:
| Territory | Leads | Artery |
|---|---|---|
| Inferior | II, III, aVF | RCA |
| Anterior | V1–V4 | LAD |
| Lateral | I, aVL, V5–V6 | LCx |
| Posterior | ST depression V1–V3 + tall R V1 | RCA / LCx |
| RV | ST elevation V1 + V4R | Proximal RCA |
Conditions Where ECG Interpretation is Difficult
(Tintinalli's Emergency Medicine)
Can Mimic ST Elevation (without AMI):
- Early repolarisation
- Left ventricular hypertrophy
- Pericarditis / Myocarditis
- LV aneurysm
- LBBB / Ventricular paced rhythm
- Takotsubo cardiomyopathy
- Hypothermia (Osborn J-waves)
- Hypertrophic cardiomyopathy
ST Depression WITHOUT Ischaemia:
- Hypokalaemia
- Digoxin effect
- Cor pulmonale / right heart strain
- Early repolarisation
T-Wave Inversions WITHOUT Ischaemia:
- Persistent juvenile pattern (V1–V3 in young women)
- Post-tachycardia T-wave inversion
- CNS haemorrhage / intracranial pathology
- Pulmonary embolism
- RBBB
- Myocardial contusion
LVH Voltage Criteria
| Criterion | Threshold |
|---|---|
| Sokolow-Lyon | SV1 + RV5 (or RV6) ≥ 3.5 mV |
| Cornell | RaVL + SV3 > 2.8 mV (men), > 2.0 mV (women) |
| Limb lead | R in aVL > 1.2 mV |
LVH with repolarisation changes ("strain pattern") = ST depression and T-wave inversion in lateral leads.
Special Patterns to Recognise
| Pattern | ECG Features | Significance |
|---|---|---|
| Wellens' Syndrome | Biphasic / deep T-wave inversion V2–V3, pain-free | Critical LAD stenosis |
| de Winter T-waves | Upsloping ST depression + tall peaked T V1–V6 | Proximal LAD occlusion, STEMI equivalent |
| Brugada Type 1 | Coved ST elevation ≥ 2 mm, T inversion V1–V2 | SCD risk |
| Long QT | QTc > 440 ms (men) / 460 ms (women) | Torsades de Pointes risk |
| Hyperkalaemia | Tall peaked T → wide QRS → sine wave | Life-threatening |
| Digoxin toxicity | Scooped ST "Salvador Dali" depression | Drug toxicity |
| PE | S1Q3T3, sinus tach, RBBB, T inversion V1–V4 | Pulmonary embolism |
Key Guideline References
- AHA/ACCF/HRS Scientific Statement — Standardization and Interpretation of the ECG (Parts I–VI) — the definitive reference
- International Recommendations for ECG in Athletes — Sharma S et al., Eur Heart J 39:1466, 2018 [PMID 29029207]
- 2024 ACC/AHA Perioperative Guideline — guidance on preoperative ECG use
- Goldberger's Clinical Electrocardiography, 10th Ed, 2024 — standard clinical reference text
- ECG Wave-Maven (Harvard) — free self-assessment tool at ecg.bidmc.harvard.edu
⚠️ Automated computerised ECG analyses have major limitations and should never be accepted without careful clinician review. — Harrison's, 22E
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