Basics & Fundamentals
Latest
RR Interval: Basics
Key Points: The RR interval is the time between consecutive R waves. It is the most practical way to assess rate and regularity. RR is the backbone of rhythm interpretation:…
Waveforms, Segments, & Intervals: Basics
Key Points: Every ECG tracing is built from waveforms (deflections), segments (baseline portions between waveforms), and intervals (time that include waveforms plus segments). Waveforms describe electrical events (depolarization or repolarization)….
Hypocalcemia
Key Points: Prolonged QTc is the hallmark ECG change in hypocalcemia, driven mainly by ST-segment prolongation with relatively normal T-wave shape. Hypocalcemia can increase arrhythmia risk, including TdP, but TdP…
Hypercalcemia
Key Points: Shortened QTc interval is the hallmark ECG clue in hypercalcemia, primarily due to a shortened ST segment duration. Hypercalcemia can mimic acute STEMI on ECG (pseudoinfarction pattern due…
ECG Findings of LV Aneurysm
Key Points: Definition: A true LV aneurysm is a chronic, post transmural MI complication from scarred myocardium with akinetic or dyskinetic (paradoxical) wall motion. ECG hallmark: Persistent ST elevation in…
Acute Pericarditis
Key Points: Acute pericarditis commonly mimics ACS clinically and on ECG, creating frequent diagnostic uncertainty in acute care. The first priority is excluding occlusion MI. Pericarditis should be considered only…
Hyperkalemia
Key Points: ECG as a Frontline Diagnostic Tool: Hyperkalemia often reveals itself on the ECG before lab confirmation. Early recognition of characteristic changes can be life-saving, especially in critically ill…
Hyperkalemia Emergencies
Key Points: Severe Hyperkalemia Mimics Several Life-Threatening Conditions: Severe hyperkalemia is one of the most dangerous ECG mimics in emergency medicine. It can resemble unstable bradyarrhythmias, VT, STEMI, and pacemaker…
Early Repolarization
Key Points: Historical View: Early repolarization (ER) was long considered a benign cause of ST elevation, often called benign early repolarization (BER). Modern View: Certain ER patterns, now termed malignant…
Post-Thrombolytic Reperfusion ECG Findings
Key Points Reperfusion after fibrinolysis is a bedside diagnosis using a bundle of findings: symptoms, ECG trend, and hemodynamic/electrical stability. Best ECG marker of successful fibrinolysis: at least 50% ST-segment…
ECG Evidence of Reperfusion After Occlusion
Key Points Reperfusion and re-occlusion can occur spontaneously or after therapy. The ECG often reflects these changes earlier than symptoms. Most useful bedside ECG marker of reperfusion is ST-segment resolution…
Early Reciprocal Changes: OMI Pattern
Key Points STEMI criteria alone miss some acute coronary occlusions, so look for subtle “occlusion clues,” not just traditional STEMI criteria cutoffs. Minor ST elevation under 1 mm paired with…
Acute Coronary Syndromes (ACS)
Key Points ACS is a clinical syndrome: classified by ischemic symptoms + ECG + troponin. ACS exists on a continuum of unstable angina, NSTEMI, STEMI, and patients can evolve between…
Hypomagnesemia
Key Points: Hypomagnesemia is an important arrhythmogenic electrolyte abnormality. It increases risk of atrial and ventricular ectopy, ventricular tachycardia, and torsades de pointes, especially when QT is prolonged. The most…
Pulse-Tapping Artifact
Key Points: Mechanical artifact caused by an ECG electrode sitting on top of a strong arterial pulse. Seen frequently in dialysis patients with AV fistulas. Can mimic serious pathology including…
Arrhythmogenic Cardiomyopathy (ACM)
Key Points: Definition & Terminology: Arrhythmogenic Cardiomyopathy (ACM), previously known as Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia (ARVC/D), is an inherited disorder characterized by progressive fibrofatty replacement of the ventricular myocardium, predominantly…
Atrial Parasystole
Key Points: Atrial parasystole is a rare atrial rhythm in which an ectopic atrial focus fires at its own intrinsic rate, relatively protected from sinus-node reset by entrance block. The…
de Winter T Waves: STEMI Equivalent Pattern
Key Points STEMI Equivalent: The de Winter ECG pattern is an uncommon STEMI equivalent indicative of an unstable proximal occlusion of the LAD (left anterior descending coronary artery). Treat the…
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…
Pacemakers: 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,…
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
© 2026 ECG Weekly. All rights reserved. | Terms of Use | Privacy Policy
Powered by the member(dev) platform
Loading...