---

📋 Complete ECG Analysis & Diagnostic Report

---

STEP 1 — ECG Overview & Systematic Approach

---

STEP 2 — Rhythm

• Regular R-R intervals
• P waves are visible before each QRS → Normal sinus rhythm
• Rate approximately 60–75 bpm (regular intervals spanning roughly 4–5 large boxes)

---

STEP 3 — Heart Rate

• Each large box = 0.2 sec at 25 mm/sec
• R-R interval ≈ 4–5 large boxes → Rate ≈ 60–75 bpm → Normal

---

STEP 4 — PR Interval

• PR interval measured in Lead II ≈ 3–4 small boxes = 0.12–0.16 sec
• Normal (normal: 0.12–0.20 sec)
• No evidence of first, second, or third-degree AV block

---

STEP 5 — QRS Duration & Morphology

---

STEP 6 — ST Segments

---

STEP 7 — T Waves

• V1–V3: T waves upright (with negative QRS) → Expected
• V4–V6: T waves inverted (with positive QRS) → Expected
• No primary T-wave changes suggesting additional ischemia

---

STEP 8 — QT Interval

• QT interval is prolonged relative to baseline due to LBBB (wide QRS contributes to wide QT)
• Corrected QT (QTc) cannot be reliably calculated in the presence of LBBB

---

STEP 9 — P Waves

• P waves visible before each QRS in lead II
• Morphology: No notching or biphasic pattern suggesting atrial enlargement
• Normal P waves

---

STEP 10 — Axis

• Lead I: Upright QRS → Left-facing
• Lead II: Small/negative
• aVF: Negative or small

• This is expected in LBBB (vector directed leftward and posteriorly)

---

STEP 11 — Voltages / Ventricular Hypertrophy

• The broad, tall R waves in V5–V6, I, aVL raise the question of underlying Left Ventricular Hypertrophy (LVH)
• Per Harrison's: "Multiple voltage criteria for LVH have been proposed based on tall left precordial R waves and deep right precordial S waves (SV₁ + RV₅ or RV₆ > 35 mm)"
• LVH often progresses to incomplete or complete LBBB — this pattern is consistent
• LBBB itself makes independent LVH voltage criteria unreliable

---

STEP 12 — R-Wave Progression

• Right precordial leads (V1–V3): Small or absent R waves → Poor R-wave progression
• In LBBB this is expected because septal depolarization is reversed

---

STEP 13 — Abnormal Q Waves

• No pathological Q waves visible in inferior or lateral leads that are not explained by LBBB
• LBBB eliminates the normal septal Q waves in I, V5, V6

---

🔴 PRIMARY DIAGNOSIS

Complete Left Bundle Branch Block (LBBB)

New or Old — this is the critical clinical question

---

🩺 FULL DIAGNOSTIC Interpretation

Main Findings:

1. Sinus rhythm — ~60–75 bpm
2. Normal PR interval — AV conduction intact
3. Complete LBBB — QRS ≥ 120 ms, broad monophasic R in I/V5/V6, rS or QS in V1
4. Left axis deviation — secondary to LBBB
5. Discordant ST-T changes — secondary (expected) in LBBB
6. Possible underlying LVH — suggested by high lateral voltages, consistent with LBBB etiology

---

⚠️ Is This an STEMI Equivalent?

---

Differential Diagnosis for LBBB

---

📌 Clinical Action Points

---

Summary Table

---

• Harrison's Principles of Internal Medicine, 22nd Ed. — ECG Interpretation (Chapter 247)
• Tintinalli's Emergency Medicine — STEMI ECG Criteria, Table 49-4
• Sgarbossa EB et al. Electrocardiographic diagnosis of MI in LBBB. NEJM 1996

⚠️ Clinical Disclaimer: ECG interpretation must always be correlated with the patient's clinical presentation, symptoms, history, and serial troponins. A new LBBB in a symptomatic patient is a medical emergency until ruled out.

---

🫀 Hyperacute Myocardial Infarction — ECG Screening & Full Explanation

The correct term is "Hyperacute" MI — referring to the very first minutes to hours of a complete coronary artery occlusion, before classic STEMI changes fully develop. This is the most time-critical window for intervention.

---

🔬 What Is "Hyperacute" Phase MI?

"When the acute ischemia is transmural, the ST vector usually is shifted in the direction of the outer (epicardial) layers, producing ST elevations and sometimes, in the earliest stages of ischemia, tall, positive so-called hyperacute T waves over the ischemic zone."

---

⏱️ The 4 Stages of MI Evolution on ECG

---

🏆 Stage 1 — HYPERACUTE T WAVES (Key Finding to Screen For)

What They Look Like:

Real ECG Example from Rosen's Emergency Medicine:

This is why serial ECGs every 15–30 minutes are mandatory in high-suspicion chest pain — the hyperacute phase can be missed on a single ECG.

---

🩺 How to SCREEN for Hyperacute MI on ECG — Step by Step

Step 1: Look at T-Wave Proportionality

• Hyperacute T waves are taller than the R wave they follow, or at minimum strikingly disproportionate
• In anterior MI: check V2, V3, V4
• In inferior MI: check II, III, aVF

Step 2: Assess T-Wave Shape

• Hyperacute T waves are symmetric and broad-based
• Normal T waves are asymmetric (slow upstroke, steep downstroke)
• A "fat," "inflated," or "balloon-like" T wave = hyperacute until proven otherwise

Step 3: Look for Early ST Changes

• Straightening of the ST segment (loss of concavity before frank elevation)
• J-point elevation — even 0.5 mm elevation in the right leads matters
• The ST may still appear borderline while T waves are already hyperacute

Step 4: Check for Reciprocal Changes

• Inferior hyperacute MI (RCA/LCx occlusion): hyperacute T waves in II, III, aVF + reciprocal T-wave flattening/inversion in aVL
• Anterior MI (LAD occlusion): tall T in V1–V4 + possible ST depression in inferior leads

Step 5: ST/T Ratio (New Concept)

T-wave amplitude / R-wave amplitude > 1 in the same lead = highly suspicious for occlusion MI

---

🧭 ECG Localisation: Where to Look

---

⚡ The Current-of-Injury Mechanism (Why It Happens)

"Severe, acute ischemia lowers the resting membrane potential and shortens the duration of the action potential. Such changes cause a voltage gradient between normal and ischemic zones. These currents of injury are represented on the surface ECG by deviation of the ST segment."

• Subendocardial ischemia (NSTEMI): ST vector points inward → ST depression in overlying leads
• Transmural ischemia (STEMI/hyperacute): ST vector points outward → ST elevation + hyperacute T in overlying leads

---

⚠️ Stage 3 — Q Waves (Established Infarction)

"Necrosis of sufficient myocardial tissue may lead to decreased R-wave amplitude or abnormal Q waves in the anterior or inferior leads. Abnormal Q waves were once considered markers of transmural infarction..."

• Duration ≥ 0.04 sec (1 small box)
• Depth ≥ 25% of the R wave in the same lead
• Present in at least 2 contiguous leads

---

❌ Mimics to Exclude (False Positives)

---

🚨 Clinical Screening Protocol (What to Do)

Chest pain patient arrives
         ↓
ECG within 10 minutes
         ↓
Look for: hyperacute T waves (tall, broad, symmetric)
         ↓
Borderline? → Serial ECG every 15–30 min
         ↓
Dynamic change confirmed?
         ↓
ACTIVATE CATH LAB — don't wait for full STEMI criteria
         ↓
Troponin + Serial Troponin (0h, 1h, 2h, 6h)

---

📋 Quick Reference Summary

---

• Harrison's Principles of Internal Medicine, 22nd Ed. — Chapter 247, Myocardial Ischemia and Infarction
• Rosen's Emergency Medicine — Chapter 64, Electrocardiographic Abnormalities in Acute Coronary Syndromes (Fig. 64.1)
• ACC/AHA Guidelines — Hyperacute T waves as STEMI equivalent (2022)

Key takeaway: Hyperacute MI is screened by recognizing disproportionately tall, broad, symmetric T waves in ≥2 contiguous leads, often with early ST straightening and reciprocal changes — before frank ST elevation appears. Serial ECGs are essential because this phase lasts only minutes to 30 minutes.