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.

Occupational exposure to trichloroethylene and risk of non-Hodgkin lymphoma and its major subtypes: a pooled InterLymph [correction of IinterLlymph] analysis.

OBJECTIVES: We evaluated the association between occupational exposure to trichloroethylene (TCE) and risk of non-Hodgkin lymphoma (NHL) in a pooled analysis of four international case-control studies. METHODS: Overall, the pooled study population included 3788 NHL cases and 4279 controls. Risk of NHL and its major subtypes associated with TCE exposure was calculated with unconditional logistic regression and polytomous regression analysis, adjusting by age, gender and study. RESULTS: Risk of follicular lymphoma (FL), but not NHL overall or other subtypes, increased by probability (p=0.02) and intensity level (p=0.04), and with the combined analysis of four exposure metrics assumed as independent (p=0.004). After restricting the analysis to the most likely exposed study subjects, risk of NHL overall, FL and chronic lymphocytic leukaemia (CLL) were elevated and increased by duration of exposure (p=0.009, p=0.04 and p=0.01, respectively) and with the combined analysis of duration, frequency and intensity of exposure (p=0.004, p=0.015 and p=0.005, respectively). Although based on small numbers of exposed, risk of all the major NHL subtypes, namely diffuse large B-cell lymphoma, FL and CLL, showed increases in risk ranging 2-3.2-fold in the highest category of exposure intensity. No significant heterogeneity in risk was detected by major NHL subtypes or by study. CONCLUSIONS: Our pooled analysis apparently supports the hypothesis of an increase in risk of specific NHL subtypes associated with occupational exposure to TCE.

Inferior and anterior QRS fragmentation have different prognostic value in patients who received an implantable defibrillator in primary prevention of sudden cardiac death.

AIMS: QRS fragmentation (fQRS) has been proposed as a predictor of sudden cardiac death (SCD) and all-cause mortality in ischemic (ICM) and non-ischemic cardiomyopathy patients. However the value of fQRS in patients with a LVEF <35% is a matter of debate. METHODS: All consecutive patients with an indication for an ICD in primary prevention of SCD were included in a retrospective registry from 1996 until 2013. Twelve lead electrocardiograms before implant were analyzed for the presence of fQRS in different regions. Adjusted Cox regression analysis for first appropriate ICD shock (AS) and all-cause mortality was performed. RESULTS: In total 407 patients were included with a mean follow-up of 4.2±3.3y (age 60.6±11.9y, 15.7% female and 52.8% ICM). fQRS was present in 46.7% of patients, predominantly inferior (30.7%) followed by anterior (21.4%) and lateral (11.1%) coronary artery territories. fQRS was significantly more prevalent in ICM (p=0.004). Inferior fQRS was an independent predictor of a first AS within 1y (HR 2.55, 95%CI 1.28-5.07) and 3y (HR 1.90, 95%CI 1.14-3.18) after implantation. Whereas, anterior fQRS was an independent predictor of all-cause mortality within 1y (HR 4.58, 95%CI 1.29-16.19), 3y (HR 3.92, 95%CI 1.77-8.65) and the complete follow-up (HR 2.22, 95%CI 1.33-3.69). Lateral fQRS was only a predictor of late (>3y of follow-up) all-cause mortality (HR 2.04, 95%CI 1.09-3.81). CONCLUSIONS: fQRS in a specific coronary artery territory might be promising to discriminate arrhythmic from mortality risk. Inferior fQRS was a predictor of early arrhythmia, while anterior fQRS was related to mortality.

T-Wave Alternans Is Linked to Microvascular Obstruction and to Recurrent Coronary Ischemia After Myocardial Infarction.

The purpose of this study is to investigate the relationship between T-wave alternans (TWA), infarct size and microvascular obstruction (MVO) and recurrent cardiac morbidity after ST elevation myocardial infarction (STEMI). One hundred six patients underwent TWA testing 1-12 months and 57 patients underwent cardiac magnetic resonance imaging (MRI) in the first 2-4 days after STEMI. During follow-up (3.5 ± 0.5 years), death (n = 2), ventricular tachycardia (n = 3), supraventricular tachycardia (n = 4), heart failure (n = 3) and recurrent coronary ischemia (n = 25) were observed. After multivariate analysis, positive TWA (HR2.59, CI1.10-6.11, p0.024) and larger MVO (HR1.08, CI1.01-1.16, p0.034) were associated with recurrent angina or ACS. Presence of MVO was correlated with TWA (Spearman rho 0.404, p0.002) and the impairment of LVEF (-0.524, p < 0.001). Patients after STEMI remain at a high risk of symptoms of coronary ischemia. The presence of MVO and TWA 1-12 months after STEMI is related to each other and to recurrent angina or ACS.

Mortality of Italian lead smelter workers.

OBJECTIVES: The purpose of this study was to evaluate the health consequences of employment in the lead-smelting industry. METHODS: A mortality study of 1388 workers and laborers in production and maintenance departments was conducted in an Italian lead-smelting plant. The vital status of cohort members was determined from 1950 to 1992. Standardized mortality ratios were calculated for specific causes of death on the basis of national and regional reference rates. The relative risk for selected causes of death was also modeled as a function of age, calendar period, latency, and duration of employment with Poisson regression analysis. RESULTS: A significant 4.5-fold excess mortality from pneumoconiosis and other diseases of the respiratory system was observed, but the risk of pneumoconiosis did not show a significant trend by duration of employment. Mortality from all cancers, stomach cancer, and lung cancer was lower than expected. The standardized mortality ratios for genitourinary diseases and kidney cancer were not significantly elevated, but the Poisson regression analysis showed that both risks increased significantly by duration of employment. CONCLUSIONS: These findings provide limited evidence that long-term employment in lead-smelting plants increases the risk of genitourinary diseases and kidney cancer. The observed increase in mortality from pneumoconiosis and other diseases of the respiratory system was more likely related to silica exposure in other workplaces.

Lung cancer mortality among female mine workers exposed to silica.

A mortality cohort study (1951-1988) was conducted on 526 female workers in two lead and zinc mines in southwestern Sardinia (Italy), 310 of whom had been exposed to silica. Women exposed to silica showed a nonsignificant 38% increase in the standardized mortality ratio (SMR) for nonmalignant respiratory diseases, which was highest and statistically significant among women at the mine with the highest exposure to silica (SMR = 217; 95% confidence interval [CI] = 104, 400; based on 10 observed and 4.6 expected deaths). Five deaths from lung cancer also occurred among those exposed to silica (SMR = 283; 95% CI = 91,660), but the excess was not related to the level or duration of exposure. No information was available concerning lifestyle risk factors in this cohort. However, smoking was quite rare among Sardinian women at the time cohort members worked, so it may be presumed that very few of them were smokers.