What is pre-excitation on ECG?

Pre-excitation describes the electrical phenomena occurring in the heart and seen on ECG in some cases due to the presence of an AP. When there is an associated tachyarrhythmia due to the presence of an AP or in patients who experience symptoms due to the AP, this disorder is termed pre-excitation syndrome (PES).

What is Orthodromic tachycardia?

Orthodromic AVRT refers to a reentrant tachycardia that uses the AV node–His bundle axis as the antegrade limb and the AP as the retrograde limp (Figs. 15.7 and 15.8). Orthodromic AVRT accounts for more than 90% of AVRTs and 20% to 30% of all sustained SVTs. 26,27. The rate usually is 170 to 220 beats per minute.

What does AVRT look like on ECG?

ECG features of AVRT with orthodromic conduction: Retrograde P waves are usually visible, with a long RP interval. QRS < 120ms unless pre-existing bundle branch block, or rate-related aberrant conduction.

Is WPW Antidromic vs Orthodromic?

Types of arrhythmias in WPW are AVRT (80%). There are two type of AVRT, orthodromic (90 to 95%) vs. antidromic (5%), other types are atrial fibrillation (AF) (10% to 30%), atrial flutter, and ventricular tachycardia/ventricular fibrillation [4-7].

Is AVRT and WPW the same?

How Is WPW Different From Typical AVRT? The difference between this typical AVRT and the AVRT seen with WPW is that, in WPW, the accessory pathway is capable of conducting electrical impulses in both directions — from the atrium to the ventricle as well as from the ventricle to the atrium.

How do you know if you have pre-excitation?

The presence of a short PR interval, frequently with a delta wave, defines the preexcitation syndrome. While no clear arrhythmia is associated with Lown-Ganong-Levine syndrome, patients with Wolff-Parkinson-White syndrome may have atrioventricular (AV) reentrant tachycardia or atrial fibrillation/flutter.

What causes orthodromic AVRT?

Orthodromic AVRT represent approximately 95% of all cases of AVRT and it arises when a premature atrial beat encounters a refractory accessory pathway but excitable atrioventricular node.

What is meant by orthodromic conduction?

Orthodromic, therefore, means conducting impulses in the normal or correct direction. Orthodromic denotes the propagation of an impulse along a conduction system (for example, nerve fiber) in the direction it normally travels.

What does AVRT stand for?

Atrioventricular reciprocating tachycardia (AVRT) is a macroreentrant tachycardia that needs an accessory pathway to bypass the regular conduction system.

Is AVRT a WPW?

Topic Overview. Wolff-Parkinson-White (WPW) syndrome is a heart rhythm problem that causes a very fast heart rate. WPW is one type of supraventricular tachycardia called atrioventricular reciprocating tachycardia (AVRT).

How can you tell the difference between AVRT and AVNRT in ECG?

In comparison to AVRT, which involves an anatomical re-entry circuit (Bundle of Kent), in AVNRT there is a functional re-entry circuit within the AV node.

What causes Orthodromic AVRT?