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…
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…
Key Point Narrow QRS bradycardias are often related to vagal tone or reversible causes, but not always benign. Certain AV blocks and conduction abnormalities may still carry significant risk, even…
Key Points: Treat the patient, not just the number or rhythm. Start with a 10-second stability check. If the rhythm explains hypotension, shock, ischemic chest pain, altered mentation, or severe…
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…
Key Points Definition: Multifocal Atrial Tachycardia (MAT) is a rare type of irregularly irregular supraventricular tachycardia (SVT) characterized by the presence of at least three or more different P wave…
Key Points Narrow therapeutic window: Small dosing errors or renal decline can push serum digoxin above the safe range. Excess automaticity + AV block: Toxicity increases atrial and ventricular irritability…
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…
Key Points Definition: Ashman phenomenon is an aberrant intraventricular conduction pattern triggered by cycle-length variation. It is most often seen in atrial fibrillation but can appear in any supraventricular rhythm….
Key Points: Definition: Atrial tachycardia is a supraventricular arrhythmia characterized by rapid atrial depolarizations from one or more ectopic foci outside the SA node. Atrial Rate: > 100 bpm, typically…
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,…
Key Points Common Offenders: Beta-blockers, calcium channel blockers, and digoxin often top the list of medication-induced bradycardia. High Vagal Tone or AV Block can arise from structural heart disease, ischemia,…
Key Points Definition: Ectopic atrial rhythms occur when atrial depolarization originates from a site other than the sinoatrial (SA) node, producing P waves with abnormal morphology and axis on ECG….
A 54-year-old man with no significant PMHx presents to the ED with palpitations. He is hemodynamically stable with a normal blood pressure. The following ECG is obtained prior to the…