Electrical remodeling reflected by QRS and T vector changes following cardiac resynchronization therapy is related to survival in heart failure patients with left bundle branch block.

INTRODUCTION: We investigated changes in electrocardiographic spatial QRS and T vectors as markers of electrical remodeling before and after cardiac resynchronization therapy (CRT) and their association with altered outcome. METHODS AND RESULTS: In 41 patients with LBBB, ECGpost was recorded during intrinsic rhythm after interrupting CRT pacing and compared to the pre-implant ECGpre and the ECG during CRT (ECGCRT). Mean spatial angles between QRS and T vectors were determined with the Kors matrix conversion. Left ventricular ejection fraction (LVEF) was determined with nuclear isotope ventriculography before CRT implantation (LVEFpre) and at inclusion (LVEFpost). Following CRT, LVEF improved significantly from 26 ± 10 to 36 ± 14% (p=0.01). Duration of QRSpre (168 ± 15 ms) was not different from QRSpost (166 ± 15 ms). A smaller angle between QRSCRT and Tpost was related to a greater angle between Tpre and Tpost (Pearson's R -0.61 - p<0.001). During follow-up (30 ± 2 months) 9 patients (22%) died. Univariate Cox regression revealed higher mortality in the patients with lower LVEFpost (HR 1.10, p=0.01), a larger angle QRSCRTTpost (HR 1.03, p=0.03), a smaller angle QRSpreQRSpost (HR 0.97, p=0.03) and smaller angle TpreTpost (HR 0.95, p<0.01). After adjusting for LVEFpost, only smaller angle TpreTpost was associated with mortality (HR 0.96, p=0.03). CONCLUSIONS: Electrical remodeling can be quantified by measuring the angles between spatial QRS and T vectors before, during and after CRT. In absence of QRS duration changes, more extensive electrical remodeling is associated with a significantly better survival. QRS and T vector changes deserve further investigation to better understand the individual response to CRT.

Biopsy of focal liver lesions: guidelines, comparison of techniques and cost-analysis.

When a focal liver lesion is discovered, differentiation between a benign and malignant nature and further characterization are mandatory to guide further treatment. Histology remains the golden standard. Improving imaging techniques such as contrast enhanced Doppler ultrasonography, spiral CT and new MRI procedures are promising, but not 100% accurate. When there is any doubt, biopsy should be performed. Fine Needle Aspiration Biopsy (FNAB) has a high sensitivity and specificity (90-95%) in experienced hands, but has a high insufficient sampling rate (up to 15%). In a series of 245 Fine Needle Tru-cut Biopsies (FNTCB) of focal solid liver lesions performed at our institution, sensitivity and specificity for the diagnosis of malignancy were 86% and 100% respectively, with an overall accuracy of 88%. Positive predictive value was 100%, but negative predictive value was rather low (56%). Insufficient sampling rate was low (2.5%), and a more accurate histological characterization was possible compared to FNAB. Finally, the cost-analysis of different biopsy techniques is presented for the Belgian situation according to used materials, pathology procedures and hospitalization.