Rhythm
Results:
Ventricular Flutter (V-Flutter)
Key Points Definition: A malignant ventricular tachyarrhythmia with a regular, sine-wave–like waveform at ~250–350 bpm, no isoelectric baseline, and no discernible P/QRS/T distinction. Clinical importance: Rapidly degenerates into ventricular fibrillation…
Unstable Bradyarrhythmias
Key Points: Unstable bradyarrhythmias cause poor perfusion which can rapidly progress to shock, irreversible organ injury, or cardiac arrest. Priority: Do not treat the heart rate alone — treat clinical…
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: Basics
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 Rhythms: Basics
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 & Rhythm Interpretation
Key Points Treat the patient, not just the number or rhythm. If the strip explains hypotension, ischemic chest pain, shock, altered mentation, or hypoxia, manage instability (cardioversion/pacing) before granular analysis….
Sinus Arrhythmia
Key Points Definition: Phasic variation in sinus rate with respiration. P-P intervals shorten on inspiration and lengthen on expiration, producing a mild, patterned irregularity. Diagnostic threshold: Difference between the shortest…
Fusion Beats
Key Points Definition: A fusion beat occurs when two impulses — one from the normal conduction system (typically supraventricular) and one from an ectopic ventricular focus (e.g., during VT) —…
Escape-Capture Bigeminy
Key Points Escape-capture bigeminy is a unique rhythm characterized by alternating escape beats and normally conducted sinus beats, resulting in a bigeminal (paired) rhythm pattern. It typically occurs in patients…
Ventricular Escape Rhythms
Key Points Wide QRS Complex Rhythm: Ventricular escape rhythms (aka idioventricular rhythms) are characterized by a wide QRS duration (>120 ms), absent or dissociated P-waves, and a regular, slow ventricular…
Sinus Tachycardia
Key Points Definition: Sinus tachycardia is a regular rhythm originating from the sinoatrial (SA) node, defined by a heart rate >100 bpm in adults or above age-adjusted norms in children….
Sinus Bradycardia
Key Points Definition: Sinus bradycardia is a rhythm originating from the sinoatrial (SA) node with a rate < 60 bpm. Physiological Occurrence: Common in young, healthy adults, athletes, and during…
Sinus Node Dysfunction (Sick Sinus / Brady-Tachy Syndrome)
Key Points Spectrum, not one rhythm: Look for sinus brady, pauses, arrest, alternating atrial tachyarrhythmias (AF, flutter, ATach). Symptoms matter: Syncope, presyncope, fatigue usually come from cerebral/systemic hypoperfusion, especially after…
Slow Atrial Fibrillation
Key Points Definition: Atrial fibrillation with a slow ventricular response, usually < 60 bpm. ECG: Irregularly irregular rhythm, no discrete P waves, slow R-R intervals. Common causes: AV-nodal blockers (digoxin,…
Rhythm Interpretation: Sutton’s rule for the best lead to evaluate atrial activity
A patient presents to the emergency department with palpitations and is found to have an irregular rhythm. The following ECG is obtained:
Narrow Complex Tachycardia: the maximum achievable sinus heart rate
A 67-year-old woman is brought to the ED by EMS for palpitations. She is found to have a heart rate ~168. Vital signs are otherwise within normal limits aside from…
Recurrent syncope with a short PR interval
A 48-year-old man presents with an episode of palpitations and near-syncope. He has had many similar episodes in the past without previous evaluation. Currently having mild palpitations with no other…
Stepwise approach to ECG interpretation: systematic rhythm interpretation in a case of syncope
A 76-year-old male presents to the emergency department after an episode of syncope. He denies a prodrome and has no focal neurological complaints or findings. The following ECG was obtained:
ECG Tags
- A-Z
- ACS-OMI
- Annual ECG Competition
- Approach
- Arrest
- Arrhythmia
- Artifact
- Attending
- AV Block
- aVL
- aVR
- Axis
- Board Review
- Bradyarrhythmia
- Chest Pain
- Clumped Beats
- Conduction
- Core
- Curriculum
- DDx
- Devices
- Documentation
- ECG Interpretation
- ECG Variant
- Education/Teaching
- Electrolytes
- Emergencies
- Emergent Cath Lab Activation
- EMS
- Guidelines
- Hub
- Hypercalcemia
- Hyperkalemia
- Hypermagnesemia
- Hypocalcemia
- Hypokalemia
- Hyponatremia
- Hypothermia
- Index
- Intervals
- Irregular
- Ischemia
- J Waves
- LBBB
- Lead Placement
- Metabolic
- Mimics
- Narrow QRS
- Occlusion MI
- OMI Pattern
- Osborn Waves
- P Wave
- Paced Rhythms
- Pacemaker/ICD
- Paramedics
- Pauses
- PE
- Pediatrics
- Pericardial
- Pericarditis
- PGY-1
- PGY-2
- PGY-3
- PGY-4
- Post-Cardiac Arrest
- Posterior MI
- PR
- Preexcitation
- Prolonged QT
- Pulmonary Embolism
- PVCs
- Q Wave
- QRS
- QT
- R Waves
- RAD
- RBBB
- Regular
- Reperfusion
- Rhythm
- S Waves
- Segments
- Seizure
- Serial ECGs
- Shock
- ST
- ST Elevation
- STEMI
- STEMI Equivalent
- Stroke
- Structural
- Students
- Syncope
- T Waves
- Tachyarrhythmia
- Tachycardia
- Tamponade
- Toxicology
- TP
- U Waves
- Unstable
- Ventricular Rhythms
- Ventricular Tachycardia
- Voltage
- Waveforms
- Wide QRS
© 2026 ECG Weekly. All rights reserved. | Terms of Use | Privacy Policy
Powered by the member(dev) platform
Loading...