Differential diagnosis of Narrow QRS tachycardia

강북삼성병원

순환기내과 이성호

Narrow QRS SVT

• Tachyarrhythmia >100 beats/min

• QRS duration<120msec

N Engl J Med 2012;367:1438-48.

Proportion of paroxysmal SVT by age

Heart rhythm1:393,2004

50-60%

10%

30%

Circulation;108:1871,2003

Electrocardiographic Features

• Assess of regularity of SVT

• Atrial activity (P waves)

-comparison with a normal baseline ECG

-sl. alteration in the QRS, ST segment, T wave

-Carotid sinus massage, Adenosine

Differential SVT dx based on atrial activity

Braunwald’s heart disease 2014

R/O Inappropriate sinus tachycardia, underlying hyperthyroidism

Typical AVNRT (slow fast)

Pseudo R

Pseudo S

Baseline ECG (no psudo R, psudo S)

Different types of AVNRT

Clinical arrhythmology and electrophysiology 2012

90%

Clinical arrhythmology and electrophysiology 2012

Typical AVNRT with intermittent 2:1 AV block (10%)

Clinical arrhythmology and electrophysiology 2012

Orthodromic AVRT (Rt posteroseptal concealed BT)

Long RP SVT

AT (LA) after AF RFCA

Algorithm for localization of AT based on P wave morphology

Focal AT with 2:1 AV conduction

Clinical arrhythmology and electrophysiology 2012

Macroreentrant AT (AFL) with 2:1 AV conduction

Clinical arrhythmology and electrophysiology 2012

Multifocal AT

Clinical arrhythmology and electrophysiology 2012

R/O multifocal AT

Typical counterclockwise AFL

Regular SVT

2:1 Typical AFL

Termination of arrhythmia

• Continuous ECG tracing during carotid sinus massage or adenosine

• Termination of the tachycardia with a P wave after the last QRS complex ->AVRT, typical AVNRT

• Termination of the tachycardia with a QRS complex->AT, atypical AVNRT, PJRT

• Tachycardia continues despite AV block->AT or AFL

Spontaneous termination of AVRT using concealed superoparaseptal BT

Clinical arrhythmology and electrophysiology 2012

Fast-slow (atypical) AVNRT terminating spontaneously

Clinical arrhythmology and electrophysiology 2012

Arrhythmia & Electrophysiology Review 2016;5(3):210–224.

Adenosine

• Adenosine

– blocks the AVN and not BT

– blocks slow pathway but not affect fast pathway

• Termination of SVT with QRS

- exclude orthodromic AVRT, unusual AVNRT

- AT, PJRT, Atypical AVNRT

AVRT c concealed septal BT

Clinical arrhythmology and electrophysiology 2012

Atypical AVNRT slow slow type, Termination to adenosine

A-V relationship

• AV block during SVT->exclude AVRT, uncommon during AVNRT

favor AT

• Variation of the P/QRS relationshipSpontaneous change in PR and RP with fixed A-A interval

->favor AT, exclude AVRT

Spontaneous tachycardia CL with constant VA interval->AVRT

AT with variable RP interval

Clinical arrhythmology and electrophysiology 2012

R/O AT

Effect of BBB

Orthodromic AVRT (concealed superoseptal BT)

Thank you