Wide QRS
Results:
Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT)
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…
Artifact vs Ventricular Rhythms: DDx
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…
VT vs SVT with Aberrancy: DDx
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…
RV Outflow Tract Tachycardia (RVOT 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…
Fascicular Ventricular Tachycardia (Idiopathic Left Fascicular VT)
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…
Heart Rate & Rhythm Interpretation
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…
Wide & Irregular Tachycardia: DDx
Key Points: Definition: QRS >120 ms with an irregular ventricular rate. Clinical Priority: Always first consider AF with accessory pathway (AF + WPW) and polymorphic VT (PMVT, including torsades) —…
Bundle Branch Blocks
Key Points: Bundle branch blocks widen the QRS, usually to 120 ms or more, because ventricular depolarization is delayed through one of the main bundle branches. The two classic patterns…
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) —…
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…
Left Bundle Branch Block (LBBB): DDx
Key Point Overview: Left bundle branch block (LBBB) is an intraventricular conduction delay that results from a block in the left bundle branch of the heart’s electrical conduction system. It…
Wide QRS Bradyarrhythmia: DDx
Key Point Wide QRS bradycardias usually reflect infranodal conduction disease (His–Purkinje or below), making them much more dangerous than narrow QRS bradycardias. These rhythms often lead to hemodynamic instability and…
Sodium Channel Blocker Toxicity
Key Points: Recognizing the Danger: Sodium channel blocker toxicity can present with a variety of ECG changes that are critical to recognize, especially in patients with altered mental status or…
Wide Complex Tachycardias: does response to Valsalva maneuvers or adenosine rule out ventricular tachycardia?
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…
Differential Diagnoses: must know causes of right axis deviation and wide QRS complexes
A 30-year-old man is pulled over by police for speeding. He begins feeling nauseous and has multiple episodes of vomiting. During transport to the emergency department by EMS he is…
Differential Diagnoses: important considerations in patients with new onset seizures or altered mental status, must know diagnoses in the emergency department
A 40-year-old man is brought into the ED after being found in the street and noted to have intermittent seizures. He is tachycardic, hypertensive, and febrile. The following ECG was…
Differential Diagnoses: wide QRS, right axis deviation, tall R wave in V1
A 76-year-old woman presents to the ED with dyspnea and a syncopal episode. History is limited because the patient is listless and confused. The following ECG was obtained:
Literature Review: Wolff-Parkinson-White syndrome with atrial fibrillation
A 50-year-old man is referred from clinic to the ED for chest tightness for the past 3 hours and a presumed new left bundle branch block. He is found to…
STAT ECG Diagnoses: must know ECG differentials in the evaluation of patients with altered mental status
A young woman presents to the ED unconscious with a GCS of 4. The following ECG was obtained during the initial evaluation:
ECG Basics & Fundamentals: a 5 step approach to ECG interpretation and how to think of differential diagnoses
HPI: A 70-year-old man presents with generalized malaise. He has a history of ESRD and has missed dialysis this week. The following ECG is obtained: Case ECG Before watching…
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