in: AYBAK 2019: Cardiology and Cardiovascular Surgery 1 , Mustafa Paç, Editor, Akademisyen Kitapevi, Ankara, pp.39-51, 2019
Twelve derivation electrocardiography (ECG) obtained both during sinus
rhythm and tachycardia may give important clues about the tachycardia mechanism. Information obtained from ECG may not only be valuable for clinical
diagnosis but also increase the safety and success of electrophysiological study
(EPS) and ablation procedures.
Tachycardia with QRS duration <120 ms is considered to be a ‘narrow QRS
complex tachycardia’ and tachycardia with QRS duration ≥ 120 ms is considered
to be a ‘wide QRS complex tachycardia’ on surface ECG. Narrow QRS complex
tachycardias are usually of supraventricular origin; however certain rare type
ventricular tachycardias (VT) may also manifest themselves with narrow QRS
on ECG. Differential diagnosis for the wide QRS complex tachycardia includes
VT, aberrantly conducted supraventricular tachycardia (SVT) and preexcitation.
In this chapter wide QRS complex tachycardias will be evaluated and clues
from surface ECG will be emphasized for each type of wide QRS complex tachycardia.