Wide QRS
Results:
The Lewis Lead (Unmasking Atrial Activity)
Key Points: Purpose: The Lewis lead (modified S5 lead) is a modified ECG lead configuration designed to amplify atrial electrical activity, making P waves, flutter waves, and the relationship between…
Monomorphic Ventricular Tachycardia (MMVT)
Key Points Definition: Monomorphic ventricular tachycardia is a ventricular rhythm with a wide QRS and a single, uniform QRS morphology throughout the run. Sustained VT: VT is sustained when it…
UMMC Cases Part III: When T Waves Help Tell the Story
A 23-year-old woman presents with palpitations and lightheadedness after a spontaneous episode of regular wide complex tachycardia. Her post-conversion ECG shows anterior T wave inversions with a subtle abnormality hiding…
UMMC Cases Part II: Grouped Beats, Slow VT, and Diffuse ST Elevation
A 63-year-old man presents with shortness of breath. His ECG shows an unusual rhythm with repetitive groups of two beats separated by pauses.
Slow Ventricular Tachycardia (VT)
Key Points: Definition: Slow VT refers to ventricular tachycardia occurring at an unusually low ventricular rate, often near or even below the conventional tachycardia threshold. There is no universally accepted…
Ventricular Tachycardia (VT) Mimics
Key Points: Default assumption: A regular wide-complex tachycardia should be considered VT until another diagnosis is more likely. Rate modifies the differential, not the diagnosis. Typical monomorphic VT is often…
Three High Risk ECGs and the Right Next Move
A 34 year old man presents with acute chest pain radiating to the left arm associated with diaphoresis. He has hyperlipidemia and a family history of early coronary disease. The…
Occlusion MI in Left Bundle Branch Block (LBBB): STEMI Equivalent Pattern
Key Points: LBBB does not exclude acute coronary occlusion. LBBBs produce abnormal depolarization and expected secondary ST-T changes, which can mask or mimic ischemia. Acute occlusion MI can still be…
A Post-Arrest ECG With a Dangerous New Bundle Branch Block
A 72-year-old man is brought to the ED after a witnessed out-of-hospital cardiac arrest. Bystander CPR is started quickly, EMS finds a non-shockable rhythm, and ROSC is achieved after one…
UMEM Cases, Part 4: When the Computer Misses the Rhythm and Flutter Fakes a STEMI
A 44-year-old man with severe cardiomyopathy, an LVAD, chronic amiodarone therapy, and an AICD presents with palpitations. His ECG shows a regular wide-complex tachycardia, but the rate is only 135….
Right Bundle Branch Block (RBBB)
Key Points: RBBB delays right ventricular activation. The left ventricle depolarizes normally through the left bundle, while the right ventricle is activated late by slow myocardial spread. ECG hallmark: QRS…
Left Bundle Branch Block (LBBB)
Key Points: LBBB delays left ventricular activation. The RV activates first through the intact right bundle, then the impulse spreads slowly from right to left across the septum and LV…
New RBBB + LAFB (Bifascicular Block) in ACS: OMI Pattern
Key Points: In a patient with ischemic symptoms, new RBBB + LAFB should raise concern for proximal LAD or septal ischemia until proven otherwise, especially if the patient has ongoing…
Wide QRS Complex: DDx
Key Points: A QRS duration greater than 120 ms reflects delayed or abnormal ventricular depolarization. A wide QRS may be chronic and benign in context, or it may be the…
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 instability….
Polymorphic Ventricular Tachycardia (PMVT)
Key Points: Definition: Polymorphic ventricular tachycardia is VT with beat-to-beat variation in QRS morphology, axis, and amplitude. Clinical significance: PMVT is electrically unstable and can rapidly deteriorate into ventricular fibrillation…
Nonsustained Ventricular Tachycardia (NSVT)
Key Points: Definition: Nonsustained ventricular tachycardia is 3 or more consecutive ventricular beats lasting less than 30 seconds and terminating spontaneously. Rate: VT is usually faster than 120 bpm, but…
STEMI vs Wide QRS (BBBs & Paced Rhythms): DDx
Key Points: Wide QRS rhythms distort repolarization. Bundle branch block and ventricular pacing create secondary ST-T changes even without occlusion MI. Appropriate discordance is expected. ST segments and T waves…
Occlusion MI in Ventricular Paced Rhythms: STEMI Equivalent Pattern
Key Points: Ventricular paced rhythms can mask acute coronary occlusion. Pacing alters depolarization and produces expected secondary ST-T abnormalities, so standard STEMI criteria are unreliable. Appropriate discordance is expected in…
Ventricular Paced Rhythms
Key Points: Ventricular pacing changes depolarization and repolarization, so ST-T segments often look abnormal. In most paced rhythms, some discordant ST deviation is expected and should not be mistaken for…
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