Value of non-invasive and invasive studies in patients with bundle branch block, syncope and history of myocardial infarction

The prognosis of patients with bundle branch block (BBB) and myocardial inf arction (MI) is poor, particularly for patients suffering from syncope. The purpose of this study was to investigate tile diagnostic value of some tec hniques for the evaluation of the mechanism of syncope in patients with M1 and BBB and their prognosis. Methods We prospectively obtained the results: of clinical history, 24 Holt er monitoring, left ventricular ejection fraction (LVEF), signal-averaged E CG (SAECG) and programmed ventricular stimulation in 130 patients with sync ope, MI and BBB. 81 of them had right (R)BBB and 49 left (L)BBB. Results Ventricular tachycardia (VT) was identified as the main cause of sy ncope in patients with MI and BBB: 68% of them had inducible VT. The sensit ivity (se) and specificity (sp) of non sustained VT on Holter monitoring fo r the detection of VT were respectively 42(.)5 and 47% in patients with RBB B, 63 and 36% in those with LBBB; se and sp of LVEF < 40% were 67(.)5% and 65% in patients with RBBB, 85 and 9% in those with LBBB; se and sp of the c ombination of 2 of the 3 SAECG criteria, QRS duration > 155 ms, LAS duratio n > 30 ms and RMS 40 < 17 muV were respectively 50 and 57% in patients with RBBB; sc and sp of the combination of 2 of the 3 criteria QRS duration > 1 65 ms, LAS duration > 40 ms and RMS 40 < 17 muV were 73 and 55(.)5% in pati ents with LBBB. During the follow-up (4(.)7 years +/- 2(.)5), 12 patients d ied suddenly and 12 patients died from heart failure. Univariate and multiv ariate analysis revealed than only the induction of VT was a significant pr edictor of sudden death. A long QRS duration (> 165 ms) and induction of VT were independent predictors of total cardiac mortality. Conclusion Among noninvasive studies, only the determination of filtered QR S duration was a significant predictor of cardiac mortality in the case of a prolongation (> 165 ms). Sudden death was only predicted by the induction of sustained VT. Because of the high incidence of inducible sustained VT, the low value of Holter monitoring and decreased LVEF for the prediction of ventricular arrhythmias and the poor prognosis of patients with inducible VT and low LVEF, systematic programmed ventricular stimulation is indicated in patients with MI, syncope and BBB, whatever the Iron-invasive studies r esults. (C), 2001 The European Society of Cardiology.