Reading File
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Finding Sources
Finding Sources
Reading File
I now have all the information needed for a thorough ECG interpretation. Here is a detailed analysis:
ECG Interpretation - Full Analysis
Technical Details
- Machine: GE MAC2000 | Date: 20.07.2025 | Time: 10:03
- Paper speed: 25 mm/s | Gain: 10 mm/mV
- Status: Unconfirmed (computer interpretation - requires physician review)
Measured Intervals
| Parameter | Value | Normal Range |
|---|---|---|
| Heart Rate | 109 bpm | 60-100 bpm |
| QRS Duration | 186 ms | <120 ms |
| PR Interval | 132 ms | 120-200 ms |
| QT / QTc (Bazett) | 438 / 589 ms | QTc <450 ms (M), <460 ms (F) |
| P Duration | 70 ms | <120 ms |
| P Axis | 34° | 0-75° |
| QRS Axis | -58° | -30° to +90° |
| T Axis | 99° | Variable |
Machine Interpretation (Unconfirmed)
The GE algorithm flagged:
- Sinus tachycardia
- Possible left atrial enlargement
- Left axis deviation
- Left bundle branch block (LBBB)
- Abnormal ECG
Clinical Analysis
1. Sinus Tachycardia (109 bpm)
The RR intervals are ~552 ms (109 bpm), and P waves are present with a consistent PR interval of 132 ms, confirming sinus rhythm with tachycardia. The cause of tachycardia should be sought clinically (pain, fever, anxiety, heart failure, anemia, thyrotoxicosis, hypovolemia).
2. Left Bundle Branch Block (LBBB) - CONFIRMED
The QRS duration is 186 ms (markedly prolonged, >120 ms = bundle branch block threshold). The pattern is consistent with LBBB:
- Broad, notched (M-shaped) QRS in lateral leads (I, aVL, V5-V6) - the classic "W" pattern
- Broad rS or QS complexes in V1-V3 (right precordial leads show deep S or QS)
- No septal Q waves in lateral leads
- Secondary ST-T wave changes: ST and T wave vectors opposite to the main QRS deflection (discordant)
The QRS axis of -58° (left axis deviation) is common with LBBB.
3. Markedly Prolonged QTc = 589 ms
This is critically elevated. Normal QTc is <450 ms in men, <460 ms in women. A QTc of 589 ms is significantly prolonged and raises concern for:
- Secondary QT prolongation due to LBBB itself (LBBB causes QT lengthening as an artifact of slow conduction - the "JTc" is a more reliable measure in LBBB)
- Drug-induced QT prolongation
- Electrolyte abnormalities (hypokalemia, hypomagnesemia, hypocalcemia)
- Structural cardiomyopathy
- Important note: In the setting of LBBB, the Bazett QTc formula overestimates true repolarization. The JT interval (QT minus QRS) should be assessed separately. JT = 438 - 186 = 252 ms, which is relatively preserved, suggesting much of the QT prolongation is from the wide QRS itself rather than true delayed repolarization.
4. Left Axis Deviation (-58°)
QRS axis of -58° places this in the left axis deviation range. In the context of LBBB, LAD can suggest left anterior fascicular block (LAFB) co-existing, or may simply reflect the LBBB conduction pattern.
5. Possible Left Atrial Enlargement
The machine has flagged this based on P wave duration/morphology (70 ms P duration alone is not diagnostic). Common causes include hypertension, mitral valve disease, and LV dysfunction.
Clinical Significance & Recommendations
LBBB is an important finding. According to cardiology references, LBBB can result from:
- Ischemia or myocardial infarction
- Left ventricular hypertrophy or dilation
- Fibrosis of the conduction system (age-related)
- Hypertension, cardiomyopathy
Key clinical priorities:
| Priority | Action |
|---|---|
| Is this new LBBB? | Compare with prior ECGs. New LBBB with chest pain = STEMI equivalent - treat as ACS until proven otherwise |
| Symptoms? | Chest pain, dyspnea, syncope, palpitations demand urgent evaluation |
| Structural assessment | Echocardiogram is indicated to assess LV size and function |
| Electrolytes | Check K+, Mg2+, Ca2+ given prolonged QTc |
| Medications | Review all QT-prolonging drugs |
| If cardiomyopathy found | Patient may be a candidate for cardiac resynchronization therapy (CRT/biventricular pacing), as LBBB with reduced EF responds well |
⚠️ If this patient has chest pain: A new LBBB with ischemic-type chest pain is treated as an ST-elevation MI equivalent and urgent reperfusion (PCI or thrombolysis) should be considered per Sgarbossa criteria.
⚠️ This ECG is marked "Unconfirmed" - all findings must be reviewed and signed by a physician.
Summary: This ECG shows sinus tachycardia at 109 bpm with a complete LBBB (QRS 186 ms), left axis deviation, and a machine-flagged concern for left atrial enlargement. The QTc is elevated but largely explained by the LBBB-related QRS widening. The patient requires urgent clinical correlation, comparison with prior ECGs, echocardiography, and assessment for underlying structural heart disease or acute coronary syndrome.
- Pfenninger and Fowler's Procedures for Primary Care - LBBB section
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