title: New criteria to increase the reliability of systolic time intervals in left bundle branch block and right ventricular pacing.
abstract: We measured the systolic time intervals (STI) in 14 patients (pts) with intermittent left bundle branch block (LBBB) in order to find correlations and comparisons in their values which might pertain to the individual patients, with (b) and without (a) LBBB. QS2I, PEP and the PEP/LVET ratio increased significantly (b) while the LVET I did not change. STI correlation was significant and improved further when the QS2 (b) was corrected by subtracting from it the QRS prolongation (b) in msec. All 7 pts with a PEP/LVET ratio (b) greater than 0.65 had an (a) ratio greater than 0.42 (normal limits for our laboratory), sensitivity 100%. Six of 7 patients with a PEP/LVET (b) less than 0.65 had an (a) ratio less than 0.42 (specificity 87.5%). For the individual patient with LBBB his STI can be quite accurately assessed by subtracting from his QS2 (b) the prolongation of the QRS (b) greater than 80 msec the length of the normal QRS duration. The above data were prospectively evaluated in 10 pts to whom intermittent right ventricular pacing was applied. We found that the correction of the QS2 interval for QRS prolongation permitted a very reliable calculation of the STI.
authors.affiliation: Department of Cardiology, Tzanio Hospital, Pireus Greece.
authors.forename: D V
authors.initials: DV
authors.lastname: Cokkinos
authors.forename: S
authors.initials: S
authors.lastname: Christoulas
authors.forename: C
authors.initials: C
authors.lastname: Trapalis
authors.forename: N
authors.initials: N
authors.lastname: Ioannou
authors.forename: N
authors.initials: N
authors.lastname: Diakoumakos
authors.forename: A
authors.initials: A
authors.lastname: Drakotos
authors.forename: S K
authors.initials: SK
authors.lastname: Edelman
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002036:Bundle of His / Q000503:physiopathology; D002037:Bundle-Branch Block / Q000503:physiopathology* / Q000628:therapy; D002304:Cardiac Pacing, Artificial; D004562:Electrocardiography; D005260:Female; D006352:Heart Ventricles / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D011446:Prospective Studies; D013599:Systole