title: Frequency analysis of QRS complex with bundle branch block in patients with and without sustained ventricular tachycardia.
abstract: To distinguish patients with bundle branch block (BBB) and sustained ventricular tachycardia (s-VT) from patients with BBB but without s-VT, a frequency analysis of the QRS complex was performed in 71 patients. Frequency analysis of the QRS complex of patients with left bundle branch block (LBBB) showed that patients with s-VT had significantly larger areas and area ratios between 50 and 100 Hz in the X lead than patients without s-VT (area: -0.905 +/- 0.231 vs -1.195 +/- 0.286. area ratio: -0.783 +/- 0.230 vs -1.125 +/- 0.310; P < 0.05). The area and area ratios from 100 to 200 Hz in the Z lead were also larger in patients with s-VT. The highest predictive accuracy using the area ratio from 50 to 100 Hz in the X lead was 86%, with a sensitivity and specificity of 83% and 88%, respectively. In cases with LBBB, time domain analysis showed no significant difference between patients with s-VT and those without s-VT. Frequency analysis of the QRS complex may be useful for distinguishing LBBB patients with s-VT from those without s-VT.
authors.affiliation: Department of Internal Medicine, National Sasayama Hospital, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Yoneda
authors.forename: S
authors.initials: S
authors.lastname: Itoh
authors.forename: T
authors.initials: T
authors.lastname: Fujimoto
authors.forename: H
authors.initials: H
authors.lastname: Kurogane
authors.forename: Y
authors.initials: Y
authors.lastname: Yoshida
mesh_terms: D000328:Adult; D000368:Aged; D002037:Bundle-Branch Block / Q000150:complications / Q000503:physiopathology*; D004562:Electrocardiography / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D017180:Tachycardia, Ventricular / Q000150:complications / Q000175:diagnosis*