Top 15 most common ecg cases explained in detail alongside ecg strips
Top 15 Most Common ECG Cases
- Normal Sinus Rhythm (baseline reference)
- Sinus Tachycardia
- Sinus Bradycardia
Quick Overview
Which group of ECG cases should I explain in detail first (with strips)?
Top 15 Most Common ECG Cases
- Normal Sinus Rhythm (baseline reference)
- Sinus Tachycardia
- Sinus Bradycardia
Quick Overview
You are researching ECG (electrocardiogram) cases for a medical education answer. Your assignment covers these 9 cases: 1. Normal Sinus Rhythm 2. Sinus Tachycardia 3. Sinus Bradycardia 4. Atrial Fibrillation 5. Atrial Flutter 6. Paroxysmal Supraventricular Tachycardia (AVNRT/AVRT) 7. Premature Ventricular Contractions (PVCs) 8. Ventricular Tachycardia 9. Ventricular Fibrillation For EACH of the 9 cases, do the following: A) Consult the medical textbook library: read /skills/readonly/medical-library/SKILL.md first (offset 0, limit 700), then use query_library_db (headings_fts and paragraphs_fts) to find authoritative textbook content on the ECG criteria, mechanism, and clinical significance of that rhythm. Note book title and page/section for citation. B) Use the search_image tool with a natural-language query describing the ECG strip for that rhythm (e.g. "ECG strip atrial fibrillation irregularly irregular no P waves") to find a real ECG image. Record the best image_url and its caption. C) Compile a structured writeup for each case containing: - Definition/mechanism (brief, 1-2 sentences) - ECG diagnostic criteria: rate, rhythm, P waves, PR interval, QRS width/morphology, any other distinguishing features - Key clinical significance / what to do - Citation to the textbook (Book Title, p. XXX or section heading) - The image_url found (if any) with a short caption Return your FINAL answer as a single structured report with one section per case (use the case name as a heading), including all the above fields. Include the raw image URLs exactly as returned so they can be embedded in markdown later. Do not omit any of the 9 cases. Be thorough but concise per case (roughly 100-150 words of prose per case plus the criteria list).
You are researching ECG (electrocardiogram) cases for a medical education answer. Your assignment covers these 6 cases: 1. First-Degree AV Block 2. Second-Degree AV Block (Mobitz I and Mobitz II) 3. Third-Degree (Complete) AV Block 4. Bundle Branch Blocks (LBBB and RBBB) and Wolff-Parkinson-White (WPW) pattern 5. ST-Elevation Myocardial Infarction (STEMI) 6. NSTEMI / Ischemia (ST depression, T-wave inversion) and Acute Pericarditis ECG changes For EACH of the 6 cases (note case 2 covers Mobitz I AND II as distinct sub-entries, and case 4 covers LBBB, RBBB, and WPW as distinct sub-entries, and case 6 covers NSTEMI/ischemia AND pericarditis as distinct sub-entries — so effectively ~11 distinct ECG patterns total), do the following: A) Consult the medical textbook library: read /skills/readonly/medical-library/SKILL.md first (offset 0, limit 700), then use query_library_db (headings_fts and paragraphs_fts) to find authoritative textbook content on the ECG criteria, mechanism, and clinical significance of each pattern. Note book title and page/section for citation. B) Use the search_image tool with a natural-language query describing the ECG strip for each pattern (e.g. "ECG strip complete heart block AV dissociation", "ECG STEMI ST elevation anterior leads", "ECG right bundle branch block RSR' V1") to find a real ECG image. Record the best image_url and its caption for each pattern. C) Compile a structured writeup for each distinct pattern containing: - Definition/mechanism (brief, 1-2 sentences) - ECG diagnostic criteria: rate, rhythm, P waves/PR interval behavior, QRS width/morphology, ST/T changes, any other distinguishing features - Key clinical significance / what to do (e.g. pacemaker need, reperfusion urgency) - Citation to the textbook (Book Title, p. XXX or section heading) - The image_url found (if any) with a short caption Return your FINAL answer as a single structured report with one section per distinct ECG pattern (use the pattern name as heading), including all the above fields. Include raw image URLs exactly as returned so they can be embedded in markdown later. Be thorough but concise per pattern (roughly 100-150 words of prose plus the criteria list).
Quick answer
Top 15 Most Common ECG Cases
Sinus Rhythms
- Rate 60-100 bpm, regular rhythm
- P wave upright in lead II, one P before every QRS, normal PR interval (0.12-0.20s), narrow QRS (<0.12s)
- Strip: evenly spaced complexes, consistent P-QRS-T morphology throughout
- Rate >100 bpm, otherwise looks like NSR (upright P before every QRS)
- Strip: same morphology as NSR but complexes are closer together; P waves can be harder to see if they merge into the preceding T wave at very high rates
- Causes: fever, pain, anxiety, hypovolemia, hyperthyroidism, PE
- Rate <60 bpm, normal P-QRS-T sequence maintained
- Strip: widely spaced but regular complexes
- Causes: high vagal tone, beta-blockers, hypothyroidism, sick sinus syndrome, athletes
Atrial Arrhythmias
- Irregularly irregular rhythm, no discrete P waves - replaced by chaotic fibrillatory baseline
- Rate variable (often 100-180 if uncontrolled)
- Strip: no clear P waves, undulating baseline, R-R intervals vary unpredictably
- Risk: stroke (needs anticoagulation based on CHA2DS2-VASc)
- Atrial rate ~300 bpm with "sawtooth" flutter waves, classically 2:1 AV conduction giving ventricular rate ~150
- Strip: regular sawtooth pattern best seen in II, III, aVF
- Rhythm often regular (fixed conduction ratio) but can be variable
- Rate 150-250 bpm, regular narrow-complex tachycardia, abrupt onset/termination
- P waves often hidden in QRS or retrograde (inverted, right after QRS - "pseudo-R' " in V1 for AVNRT)
- Strip: sudden run of narrow regular complexes, no clear P before each QRS
Ventricular Arrhythmias
- Wide, bizarre QRS (>0.12s) occurring early, not preceded by a P wave, followed by a compensatory pause
- Strip: normal sinus beats interrupted by an occasional wide beat with discordant T wave
- Patterns: bigeminy, trigeminy, couplets
- 3+ consecutive PVCs, rate >100 bpm, wide QRS, regular or near-regular
- Strip: sustained wide-complex tachycardia, AV dissociation, capture/fusion beats support diagnosis
- Monomorphic (uniform QRS shape) vs polymorphic (varying, e.g. Torsades de Pointes with twisting axis around baseline)
- Chaotic, disorganized electrical activity, no identifiable P, QRS, or T waves
- Strip: irregular undulating waveform of varying amplitude, no organized complexes
- This is a cardiac arrest rhythm requiring immediate defibrillation
Conduction Blocks & Pre-excitation
- PR interval prolonged (>0.20s) but constant, every P still conducts to a QRS
- Strip: consistently long PR interval, otherwise normal-looking rhythm
- Mobitz I (Wenckebach): progressively lengthening PR intervals until a beat is dropped, then the cycle resets. Strip shows "grouped beating" with a gradually widening PR before a missed QRS.
- Mobitz II: PR interval constant, but QRS complexes are intermittently dropped without warning. Strip shows sudden dropped beats with unchanged PR - more dangerous, often needs pacing.
- Complete dissociation between P waves and QRS complexes - atria and ventricles beat independently
- Strip: P waves march out at their own regular rate, QRS complexes march out at a slower, independent regular rate, no fixed PR relationship
- Usually requires pacemaker
- RBBB: QRS >0.12s, "rabbit ear" (RSR') pattern in V1, wide slurred S wave in lateral leads (I, V6)
- LBBB: QRS >0.12s, broad monophasic R wave in V6/I, deep S in V1, absent normal septal q waves laterally
- WPW: short PR interval, delta wave (slurred upstroke of QRS) from an accessory pathway (Bundle of Kent) pre-exciting the ventricle; predisposes to AVRT and rapid AFib
Ischemia & Infarction
- ST elevation ≥1mm in 2+ contiguous leads (≥2mm in V2-V3 per some criteria), often with reciprocal ST depression in opposite leads
- Strip: convex ("tombstone") ST elevation, hyperacute T waves early, later Q waves as infarct evolves
- Location determined by lead group: II/III/aVF = inferior, V1-V4 = anterior, I/aVL/V5-V6 = lateral
- NSTEMI/ischemia: horizontal or downsloping ST depression ≥0.5mm, T wave inversion, without ST elevation
- Pericarditis: diffuse concave ("saddle-shaped") ST elevation across most leads plus PR depression, distinguishing it from a focal STEMI
Which ECG pattern would you like me to research in depth first?
Which ECG case(s) would you like a full deep-dive writeup on first (textbook citations + ECG image + criteria)?