What causes wide QRS tachycardia?
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.
What does a widened QRS complex indicate?
A wider QRS may indicate that the bottom of the heart is contracting a little later than it should. Wide QRS is noted on ECG when there is a delay, or widening, in the part of the ECG called the QRS complex.
What does wide complex tachycardia mean?
A wide complex tachycardia (WCT) is simple enough to define: a cardiac rhythm with a rate >100 beats per minute and a QRS width >120 milliseconds (ms).
Which arrhythmias have wide QRS?
Wide QRS complex tachycardia can be originated by 3 main mechanisms1:
- Ventricular tachycardia (VT).
- Supraventricular tachycardia (SVT) with an aberrant conduction attributable to a preexisting bundle-branch block or functional bundle-branch block induced by the fast heart rate.
Is wide QRS tachycardia normal?
A normal QRS should be less than 0.12 seconds (120 milliseconds), therefore a wide QRS will be greater than or equal to 0.12 seconds. To put it all together, a WCT is considered a cardiac dysrhythmia that is > 100 beats per minute, wide QRS (> 0.12 seconds), and can have either a regular or irregular rhythm.
What conditions are typically associated with wide QRS complexes?
Wide, bizarre QRS complexes of supraventricular origin are often the result of intraventricular conduction defect which usually occurs due to right or left bundle branch block. Wide QRS complexes may be seen in aberrant conduction, ventricular preexcitation and with a cardiac pacemaker.
Is wide complex tachycardia serious?
Despite hemodynamic stability in some patients with ventricular tachycardia, incorrect or untimely diagnosis can be dangerous, if not fatal.
What drugs should be avoided in patients with irregular wide complex tachycardia?
It is so very critical to choose the right kind of medication once the decision is made to treat a patient with wide complex tachycardia. Calcium channel blockers (Diltiazem and verapamil) are strongly advised not to be used for fear of hemodynamic collapse, hypotension and cardiac arrest [4].
What is the cause of wide QRS tachycardia?
Wide QRS tachycardia may be due to ventricular tachycardia (VT), supraventricular tachycardia (SVT) with aberrant conduction, or atrioventricular reentrant tachycardia (AVRT) with an accessory pathway.
Why do I have a wide complex tachycardia?
There are many reasons for QRS complexes to be widened (see Table 1). Any cause of a widened QRS complex can result in a sustained or nonsustained wide complex tachycardia if the rate is greater than 100 beats per minute.
Which is the correct diagnosis of wide QRS complex?
Any QRS complex morphology that does not look typical for right- or left-bundle branch block should strongly favor the diagnosis of VT. The wider the QRS complex, the more likely it is to be VT. In other words, the default diagnosis is VT, unless there is no doubt that the WCT is SVT with aberrancy.
What’s the difference between NCT and wide complex tachycardias?
NCT – Narrow complex tachycardias (QRS duration <0,12 seconds) indicate the ventricles are depolarized via the His-Purkinje system and thus the impulse originates in the atria (i.e the arrhythmia is supraventricular). WCT – Wide complex tachycardias (QRS duration ≥0,12 seconds) indicates the ventricles are not depolarized normally.