What does a widened QRS complex indicate?
A “wide QRS complex” refers to a QRS complex duration ≥120 ms. Widening of the QRS complex is related to slower spread of ventricular depolarization, either due to disease of the His-Purkinje network and/or reliance on slower, muscle-to-muscle spread of depolarization.
Is wide QRS an emergency?
Abstract. Wide QRS complex tachycardias (WCT) present significant diagnostic and therapeutic challenges to the emergency physician. WCT may represent a supraventricular tachycardia with aberrant ventricular conduction; alternatively, such a rhythm presentation may be caused by ventricular tachycardia.
What conditions are typically associated with wide QRS complexes?
Topic Outline
- Ventricular tachycardia.
- Supraventricular tachycardia. Aberrant conduction. Pre-excitation syndrome. Pacemakers.
- Artifact mimicking ventricular tachycardia.
What electrolyte imbalance causes widened QRS complex?
ECG in severe hyperkalemia (Potassium >7,5 mmol/L) The QRS complex becomes wider.
How do you treat a wide QRS complex?
Treatment / Management
- SVT will typically be managed with adenosine, Afib with WPWS will be treated with amiodarone, and Afib with aberrancy with either diltiazem or a beta-blocker.
- Typically, amiodarone will be the first-line drug of choice for all ventricular arrhythmias (VT, polymorphic VT, Vfib, etc.)
Why does hyperkalemia cause wide QRS?
As serum potassium levels increase to greater than 6.5 mEq/L, the rate of phase 0 of the action potential decreases, leading to a longer action potential and, in turn, a widened QRS complex and prolonged PR interval.
How does hyperkalemia affect PR interval?
As hyperkalemia progresses (6.5-7.5 mEq/L), the P-wave increases in duration and decreases in amplitude, and PR and QRS intervals widen. The QT-interval prolongs. Other changes include decreased amplitude of the R-wave with concomitant increased depth of the S-wave and ST-segment depression or elevation.
Which drugs cause wide QRS?
Permanent transvenous pacemaker results in wide QRS complexes. Tricyclic antidepressant (TCA) overdose causes a WCT due to the quinidine-like effects of these drugs. The class IA sodium channel blocking activity widens the QRS complex, with tachycardia being part of the toxidrome caused by these agents.
What medications cause wide QRS?
Certain antiarrhythmics can cause or exacerbate AFL, including the sodium channel–blocking drugs flecainide and propafenone, which slow atrial conduction, increase the flutter cycle length, and can result in 1:1 atrioventricular conduction with a wide QRS.
What does Brugada syndrome feel like?
Signs and symptoms that may be associated with Brugada syndrome include: Dizziness. Fainting. Gasping and labored breathing, particularly at night.
Why does hyperkalemia cause QRS widening?
As hyperkalemia worsens, the ECG first demonstrates peaked T waves resulting from global APD shortening causing more synchronous repolarization across the ventricular wall. Subsequently, the P wave broadens and decreases in amplitude, eventually disappearing, and the QRS widens because of CV slowing.
Why is QRS widened in hyperkalemia?