Internal Medicine

0521779407-22 CUNY1086/Karliner 0 521 77940 7 June 4, 2007 21:23

Ventricular Tachycardia 1529

Signs & Symptoms

■Depending on co-existing cardiac conditions and rate of ventricular

response: Dizziness, hypotension, shortness of breath, near syncope

and syncope, exacerbation of CHF and angina

tests

■Basic Tests

➣12-lead ECG:

➣Regular wide QRS complexes tachycardia. No 1:1 P-QRS relation-

ship

➣Brugada criteria:

Rs complex in all precordial leads (100% specific for VT)

Beginning of R to nadir of S interval >100 ms in any precordial

lead (98%)

➣A-V dissociation (98%)

➣RBBB QRS: V1: predominantly positive in (R, qR or Rs); V6: QS,

qRs or R/S <1

➣LBBB QRS: V1: R wave width >30 ms, notched downstroke of the

S wave, onset of QRS to nadir of the S wave >60 ms; V6: QR, QS,

QrS or Rr’

➣Other diagnostic features: fusion or capture QRS during VT, pres-

ence of Q waves during tachycardia

➣Special Cases:

Idiopathic left ventricular tachycardia: RBBB with R/S < 1 in

V5 and V6; mostly superior QRS axis

Idiopathic right ventricular outflow tachycardia: LBBB with

inferior QRS axis

Brugada Syndrome: elevated J wave in V1 to V2 (baseline ECG)

Right ventricular dysplasia: epsilon wave in V1 to V2, inverted

T wave in V1 to V3, isolated increase in QRS (110 ms) in V1 to

V2 (baseline ECG)

■Specific Diagnostic Test

➣Electrophysiology study for induction and mapping of VT, to

diagnose bundle branch block and fascicular re-entrant VT

➣Genotyping of congenital long QT-syndrome and arrhythmo-

genic right ventricular dysplasia (generally not required for clin-

ical practice)

differential diagnosis

■SVT with aberrantly conducted QRS complexes or SVT from WPW

syndrome