Basics & Fundamentals
Latest
Isoelectric Segment of the ECG
Key Points The reference for ST-segment shift is the J point relative to an isoelectric baseline. The two candidates for that baseline are the TP segment and the PR segment….
Monomorphic Ventricular Tachycardia (MMVT)
Key Points MMVT is the most common sustained VT. It shows a single, uniform QRS morphology throughout. Classified as sustained if lasting > 30 seconds or associated with hemodynamic instability….
Inverted U waves
Key Points Definition: A negative deflection after the T wave (a true U wave) that is ≥0.5 mm deep in a lead where the T wave is upright. Why it…
Wide QRS Complex DDx
Key Points A QRS duration greater than 120 ms indicates abnormal ventricular depolarization. A wide QRS can signal conditions that range from benign to immediately life-threatening. Developing a focused differential…
VT vs SVT with Aberrancy
Key Points ECG alone cannot reliably distinguish VT from SVT-aberrancy in many cases. Use ECG features to rule in VT, not to exclude it. Default: treat regular WCT as VT…
Atrioventricular Blocks (AVB): Comprehensive Summary
Key Points AV block specifically reflects delayed or failed impulse conduction from atria to ventricles. Classification of blocks depend on the location of conduction delay or block within the cardiac…
Hypokalemia
Key Points: Hypokalemia slows ventricular repolarization and alters the T–U complex before it triggers arrhythmias. Progressive pattern: T-wave flattening → prominent U waves → T–U fusion with apparent QT prolongation;…
Understanding ECG Artifacts
Key Points Artifacts = non-cardiac signals that distort or obscure true ECG. They come from the patient, leads/equipment, or the environment. Clues to artifact: lacks a physiologic pattern, varies beat-to-beat…
Ischemia & Infarction
Key Points Why the ECG matters: Fastest way to detect acute occlusion and dynamic ischemia before troponin and often before classic symptoms. ACS is dynamic: Arteries occlude and reperfuse. Serial…
Fascicular Ventricular Tachycardia (Idiopathic Left Fascicular VT)
Key Points Idiopathic reentrant VT arising within the left Purkinje system, most often the left posterior fascicle. Patients are usually young and lack structural heart disease. Signature ECG: RBBB-like morphology…
Isorhythmic AV Dissociation
Key Points Definition: A type of AV dissociation in which sinus and escape rates are nearly identical, so P waves and QRS complexes appear to “track” each other while remaining unrelated….
Third-Degree AV Block (Complete Heart Block)
Key Points Definition: Third-degree AV block is complete failure of conduction from atria to ventricles, resulting in independent atrial and ventricular activity—known as AV dissociation. Hallmark Feature: No P waves…
High-Grade (Advanced) AV Block
Key Points Definition: A severe form of second-degree AV block with two or more consecutive non‑conducted P waves (for example 3:1, 4:1). Do not force a Mobitz label when multiple…
Atrial Septal Defect (ASD) & Crochetage Pattern
Key Points ASD Overview: Atrial septal defects are often detected and repaired in childhood, but uncorrected lesions may remain silent into early adulthood. Symptoms usually appear by age 30–40 and…
Irregularly Irregular Rhythms
Key Points Definition: An irregularly irregular rhythm occurs when the R-R intervals or P-P intervals vary with no consistent pattern, making the rhythm unpredictable and abnormal. Clinical Significance: Identifying an…
Regularly Irregular Rhythms
Key Points Definition: A regularly irregular rhythm occurs when the distance between R-R intervals or P-P intervals varies in a consistent, repeating pattern throughout the ECG tracing. Significance: Determining the…
Regular Rhythm
Key Points Rhythm Regularity: Regular rhythm is characterized by equal distances between consecutive P waves (P-P intervals) and QRS complexes (R-R intervals). Verify rhythms with calipers—don’t trust the machine interpretation…
Heart Rhythm Basics
Key Points Don’t trust the ECG machines automated interpretation. Confirm the rhythm yourself. Start with the ventricles (R–R pattern), then the atria (P waves), then the AV relationship (PR behavior/P:QRS)….
Heart Rate Basics
Key Points Never accept the machine’s rate blindly. Confirm it yourself as ECG computer interpretations are frequently inaccurate. Verify paper speed and gain first (default 25 mm/s, 10 mm/mV). Name…
Normal STAT ECG
Key Points Clinical Context: A single normal 12-lead ECG in the emergent setting does not exclude life-threatening conditions such as occlusion MI, PE, tamponade, tension pneumothorax, or aortic dissection. Serial…
Free Content
Jump on our email list for free tips and insights delivered to your inbox monthly. No spam - just quick pearls and ECG education.
Categories
- No categories
© 2025 ECG Weekly. All rights reserved. | Terms of Use | Privacy Policy
Powered by the member(dev) platform
Loading...