Key Points: AVNRT is a paroxysmal, regular, usually narrow-complex SVT caused by a reentry circuit within or adjacent to the AV node. Dual-pathway physiology is typical. Bedside hallmark is a…
Key Points Most Common Sustained Arrhythmia: Atrial Fibrillation (AFib) is the most frequently encountered sustained arrhythmia in clinical practice, particularly among the elderly population. Misdiagnosis Risk: AFib is commonly misdiagnosed…
Key Points Continuous-flow LVADs can mask shock: patients may talk through VT/VF because pump flow maintains some perfusion. Treat the rhythm, not the appearance. First steps in any unstable LVAD…
Key Points Rare, inherited ventricular arrhythmia triggered by adrenergic stress during exertion or emotion. Classically presents in children or adolescents with syncope or cardiac arrest despite a normal resting ECG…
Key Points Artifact is a common source of misdiagnosis for serious arrhythmias such as polymorphic ventricular tachycardia (PVT), torsades de pointes, or ventricular fibrillation (VF). Always correlate the ECG findings…
Key Points Monomorphic ventricular tachycardia (MMVT) is the most common sustained VT. It shows a single, uniform QRS morphology throughout. Classified as sustained if lasting > 30 seconds or associated…
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…
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…
Key Points Idiopathic monomorphic VT arising from the right ventricular outflow tract. Most patients have no structural heart disease; catecholamine and cAMP-mediated triggers are common. Classic ECG pattern: LBBB morphology…
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…
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…
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: Slow ventricular tachycardia is defined as a wide complex tachycardia with a ventricular rate between 100–120 bpm. Distinction: Typical sustained VT usually exceeds 120 bpm. When encountering…
Key Points Purpose: The Lewis Lead (modified S5 lead) is a bedside ECG modification designed to enhance visualization of atrial activity. It is particularly useful for differentiating VT from SVT…
Key Points Definition: Sinus pause/arrest is failure of the sinus node to generate an impulse, producing a transient absence of P waves. On ECG the pause does not equal an…
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…