Basics & Fundamentals
Latest
Pacemaker Syndrome
Key Points Pacemaker syndrome is a hemodynamic problem caused by loss of proper atrioventricular (AV) synchrony. Most commonly occurs with ventricular pacing that produces retrograde atrial activation, but can also…
Pacemaker Basics
Key Points Pacemakers treat bradyarrhythmias by delivering timed atrial, ventricular, or dual-chamber pacing when intrinsic activity is slow or absent. Know the major device types encountered in the ED: single-chamber,…
Paced Rhythms
Key Points Ventricular pacing changes depolarization, so ST–T segments often look “abnormal.” Expect appropriate discordance: ST/T deflect opposite the main QRS polarity. RV pacing (most common) ≈ LBBB pattern: wide…
T Wave Alternans
Key Points Definition: Beat-to-beat alternation in T wave amplitude or morphology with stable P waves and QRS complexes. Significance: A visible marker of ventricular electrical instability. Strongly associated with torsades,…
Ventricular Tachycardia (VT): Core Overview
Key Points VT is a ventricular-origin rhythm: ≥3 consecutive ventricular beats, QRS >120 ms, rate usually 120–250 bpm. Types include monomorphic VT, polymorphic VT, torsades (PMVT with long QT), ventricular…
Premature Atrial Complexes (PACs)
Key Points PACs are early atrial depolarizations from an ectopic focus that create a premature P wave with a different morphology and axis than the sinus P wave, usually followed…
Atrial Fibrillation (AFib)
Key Points Prevalence: The most common sustained cardiac arrhythmia, particularly prevalent among elderly individuals, associated with increased stroke, heart failure, and mortality risks. Mechanism: Caused by chaotic, multiple reentry circuits…
Post-Cardiac Arrest ECGs
Key Points Early post-ROSC ECGs often mislead. Within the first 8–10 minutes, transient global ischemia and catecholamines can exaggerate ST changes. Plan a repeat at 10–15 minutes before making cath…
First-Degree AV Block
Key Points Defined by a PR interval >200 ms with consistent 1:1 AV conduction and no dropped QRS complexes. Conduction delay is most often at the AV node; His–Purkinje delay…
Premature Junctional Complexes (PJCs)
Key Points PJCs are premature impulses from ectopic foci in or near the AV junction. ECG hallmark is a narrow premature beat with an absent or retrograde P wave. Retrograde…
J Point Basics
Key Points The J point is the junction where QRS ends and the ST segment begins. It is a location, not a waveform. ST deviation is judged at the J…
Blocked Premature Atrial Complexes (PACs)
Key Points Definition: early ectopic atrial beats that do not conduct to the ventricles. You see a premature P wave with no following QRS and a pause that is usually…
J Wave Basics
Key Points Definitions: The J point is the QRS–ST junction (a location). A J wave is an added deflection at or just after that point (notch or slur). Why it…
Premature Complexes (PACs, PJCs, & PVCs) Overview
Key Points Premature complexes are early depolarizations arising from the atrium, AV junction, or ventricle which interrupt the expected sinus rhythm. Rapid classification by origin: look for a P wave…
Osborn (J) Wave
Key Points An Osborn wave is a notch or slur at the J point that becomes more prominent as core temperature falls. Most visible in inferolateral and precordial leads; can…
Premature Ventricular Complexes (PVCs)
Key Points PVCs are early ventricular depolarizations that produce a wide QRS with secondary ST-T changes and are usually followed by a full compensatory pause. No preceding P wave. A…
Spontaneous Coronary Artery Dissection (SCAD)
Key Points SCAD Definition: A spontaneous, non-atherosclerotic tear in the coronary artery wall, often affecting young, otherwise low-risk women (including peripartum patients). SCAD presents similarly to ACS and is an…
Non-Thrombotic Causes of Acute Coronary Syndrome (ACS)
Key Points ACS ≠ Always Thrombosis: While most ACS is due to plaque rupture with thrombus formation, several important non-thrombotic causes can produce identical ECG changes, troponin elevation, and symptoms….
ECG Lead Misplacement
Key Points Lead misplacement is common and can mimic ischemia, MI, conduction blocks, and arrhythmias. Always verify placement when ECG and clinical picture do not match. V1 and V2 placed…
Proper 12-Lead ECG Electrode Placement
Key Points A diagnostic 12‑lead ECG is only as good as your electrode placement. Misplacement can mimic MI, BBB, or poor R‑wave progression and trigger unnecessary workups. A standard 12‑lead…
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...