BACKGROUND: A lower left ventricular R wave (LVRW) and a higher left ventricular threshold (LVT) could be related to a greater extent of myocardial scarring and lower myocardial vitality.
PURPOSE: The purpose of this study was to analyze the value of left ventricular (LV) electrode measurements during the implant as predictors of mortality in patients with implantable cardioverter-defibrillator (ICD) with cardiac resynchronization therapy (CRT) in primary prevention.
METHODS: We retrospectively analyzed data of patients with implanted biventricular defibrillator between January 2010 and December 2013. CRT was indicated according to the guidelines of the ESC. During the implant, left ventricular sensing, impedance and threshold were measured. Clinical characteristics, left ventricular lead position and measurements, electrocardiography and echocardiography were evaluated before and after CRT. Statistical analysis SPSS 20. The variables were compared bye T-Student and Chi2. Multivariate analysis logistic regression. Statistical significance for p <0.05.
RESULTS: 43 patients were enrolled. Mean age was 72 y and 90% were men. Ischemic cardiomyopathy 49%. NYHA functional class III-IV 63%. LBBB was identified in 46,5% and permanent atrial fibrillation (AF) 35%. After the implant mean biventricular paced QRSd was 128±21ms. The mean duration of follow-up was 33.3±7.8 months. The mortality rate was 19% (N=8). The univariate analysis is detailed in table 1. With multivariate analysis, only a lower LVRW during the implant (6.1±3.1V vs 14.8±7.6V, OR 1.3, 95% CI 1.03-1.7, p=0.03) and a very low LVEF after the implant (32.5±10.9 Vs 45.9±10.6, OR 1.14, 95% CI 1.03-1.3, p=0,03) remained as independent predictors factors of mortality.
CONCLUSIONS: In our study, a lower left ventricular detection and a very low LVEF were independent predictors of mortality. However, a higher left ventricular threshold did not reach statistical significance. These variables could identify a subgroup of patients who would benefit from a closer follow-up.