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Recent advances in the identification of patients at risk of ventricular tachyarrhythmias: Role of ventricular late potentials

Circulation (Impact Factor: 14.95). 07/1987; 75(6):1091-6. DOI: 10.1161/01.CIR.75.6.1091
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    • "infarction period for the identification of patients predisposed to malignant ventricular arrhythmias [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] , but the presence of intraventricular conduction defects interferes with the detection of late potentials [23] [24] [25] [26] . "
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    ABSTRACT: The prognosis of patients with bundle branch block (BBB) and myocardial infarction (MI) is poor, particularly for patients suffering from syncope. The purpose of this study was to investigate the diagnostic value of some techniques for the evaluation of the mechanism of syncope in patients with MI and BBB and their prognosis. We prospectively obtained the results of clinical history, 24 h Holter monitoring, left ventricular ejection fraction (LVEF), signal-averaged ECG (SAECG) and programmed ventricular stimulation in 130 patients with syncope, MI and BBB. 81 of them had right (R)BBB and 49-left (L)BBB. Ventricular tachycardia (VT) was identified as the main cause of syncope in patients with MI and BBB: 68% of them had inducible VT. The sensitivity (se) and specificity (sp) of non sustained VT on Holter monitoring for the detection of VT were respectively 42.5 and 47% in patients with RBBB, 62 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 combination of 2 of the 3 SAECG criteria, QRS duration > 155 ms, LAS duration >30 ms and RMS 40 < 17 microV were respectively 50 and 57% in patients with RBBB; se and sp of the combination of 2 of the 3 criteria QRS duration >165 ms, LAS duration >40 ms and RMS 40 <17 microV were 73 and 55.5%) in patients with LBBB. During the follow-up (4.7 years +/- 2.5), 12 patients died suddenly and 12 patients died from heart failure. Univariate and multivariate analysis revealed than only the induction of VT was a significant predictor of sudden death. A long QRS duration (> 165 ms) and induction of VT were independent predictors of total cardiac mortality. Among noninvasive studies, only the determination of filtered QRS 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 non-invasive studies results.
    Europace 08/2001; 3(3):187-94. DOI:10.1053/eupc.2001.0174 · 3.05 Impact Factor
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    • "Previous studies have found a significant correlation between electrically inducible ventricular tachyarrhythmias (VT) and LPs in patients with coronary artery disease [2] [3] [4] [5] . However, a recent report from the MUSTT trial [6] shows a poor correlation between LPs and VT inducibility. "
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    ABSTRACT: Late potentials (LPs) in the terminal portion of the QRS complex are commonly sought to identify post-myocardial infarction patients prone to ventricular tachyarrthythmias (VT) or sudden death. More recent time frequency signal processing tools have been shown to provide new parameters for the quantification of LPs and abnormal activities buried within the QRS complex. The study population comprised 23 myocardial infarction patients with documented sustained VT (MI+VT), 40 myocardial infarction patients without VT (MI - VT) and 31 normal subjects. The reproducibility of the method was tested in an additional set of 66 patients. The signal-averaged high-resolution electrocardiograms (HRECGs) were quantified by deconstructing the unfiltered X, Y and Z leads using a 511-orthogonal wavelet network. Using receiver operating characteristics (ROC) curves and discriminant analysis applied to the wavelet coefficients, we extracted the most significant wavelets to classify the post MI patients. These wavelets detected time-frequency alterations both in the ST segment and within the QRS complex, characterizing patients prone to VTs. The same statistical methods were applied to the conventional time-domain measurements. The combined application in our population of the orthogonal wavelet deconstruction method and discriminant analysis had 91% sensitivity and 95% specificity, an improvement of 22% and 25%, respectively, compared with the conventional time domain method. Reproducibility was 82%. In post-myocardial infarction patients, orthogonal wavelet transforms can detect alterations in high-frequency components within the QRS and ST segment. Our findings support the view that wavelet-related parameters are more relevant than those of the time domain method in predicting subsequent malignant tachyarrhythmias.
    Europace 05/2000; 2(2):141-53. DOI:10.1053/eupc.2000.0091 · 3.05 Impact Factor
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