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BACKGROUND: Chronic arsenic exposure is associated with cardiovascular abnormalities. Prolongation of the QT (time between initial deflection of QRS complex to the end of T wave) interval and profound repolarization [...]

The importance of prophylactic implantation of an implantable cardioverter-defibrillator (ICD), to prevent sudden deaths in patients with nonischemic dilated cardiomyopathy, is evaluated with the help of a study.

Background: Millions of people are at risk from the adverse effects of arsenic exposure through drinking water. Increasingly, non-cancer effects such as cardiovascular disease have been associated with drinking water arsenic exposures. However, most studies have been conducted in highly exposed populations and lacked individual measurements. Objective: To evaluate the association between cardiovascular disease and well-water arsenic exposure. Methods: We conducted a hospital based case control study in Inner Mongolia, China. Cases and controls were prospectively identified and enrolled from a large hospital in the Hangjin Hou area. Cases were patients diagnosed with cardiovascular disease and controls were patients free from cardiovascular disease, admitted for conditions unrelated to arsenic exposure. Water from the primary water source and toenail samples were collected from each subject and tested for inorganic arsenic. Results: Arsenic exposures were moderate with mean and median arsenic exposures of 8.9 µg/L and 13.1 µg/L, respectively. A total of 298 cases and 275 controls were enrolled. The adjusted odds ratio (AOR) and corresponding 95% confidence interval (95% CI) for a 10 µg/L increase in water arsenic were 1.19 (95% CI: 1.03, 1.38). Compared to exposures less than 10 µg/L, the AOR for water arsenic exposures above 40 µg/L was 4.05 (95% CI: 1.1-14.99, p = 0.04). Nail arsenic above 1.38 µg/g was also associated with an increased risk of cardiovascular disease. Conclusions: By using standardized case definitions and collecting individual measurements of arsenic, this study addressed several limitations of previous studies. The results provide further evidence of the association between cardiovascular disease and arsenic at moderate exposures. [ABSTRACT FROM AUTHOR]

Background: Multiple studies of heart failure patients demonstrated significant improvement in exercise capacity, quality of life, cardiac left ventricular function, and survival from cardiac resynchronization therapy (CRT), but the underenrollment of women in these studies is notable. Etiological and pathophysiological differences may result in different outcomes in response to this treatment by sex. The observed disproportionate representation of women suggests that many women with heart failure either do not meet current clinical criteria to receive CRT in trials or are not properly recruited and maintained in these studies. Methods: We performed a systematic literature review through May 2014 of clinical trials and registries of CRT use that stratified outcomes by sex or reported percent women included. One-hundred eighty-three studies contained sex-specific information. Results: Ninety percent of the studies evaluated included ≤35% women. Fifty-six articles included effectiveness data that reported response with regard to specific outcome parameters. When compared with men, women exhibited more dramatic improvement in specific parameters. In the studies reporting hazard ratios for hospitalization or death, women generally had greater benefit from CRT. Conclusions: Our review confirms women are markedly underrepresented in CRT trials, and when a CRT device is implanted, women have a therapeutic response that is equivalent to or better than in men, while there is no difference in adverse events reported by sex. [ABSTRACT FROM AUTHOR]

Background: An intravascular, percutaneously placed implantable defibrillator (InnerPulse percutaneous intravascular cardioverter-defibrillator [PICD]) with a right ventricular (RV) single-coil lead and titanium electrodes in the superior vena cava (SVC) and the inferior vena cava (IVC) has been developed. Objective: The purpose of this study was to compare defibrillation thresholds (DFTs) of the PICD to those of a conventional implantable cardioverter-defibrillator (ICD) in canines. Methods: Eight Bluetick hounds were randomized to initial placement of either a PICD or a conventional ICD. For PICD DFTs, a single-coil RV defibrillator lead was placed in the RV apex, and the device was positioned in the venous vasculature with electrodes in the SVC and IVC. With the conventional ICD, an RV lead was placed in the RV apex and an SVC coil was appropriately positioned. The ICD active can (AC) was implanted in a subcutaneous pocket formed in the left anterior chest wall and connected to the lead system. DFT was determined by a three-reversal, step up-down method to estimate the 80% success level. Two configurations were tested for the conventional ICD (#1: RV to SVC+AC; #2: RV to AC). A single configuration (RV to SVC+IVC) was evaluated for the PICD. Results: Mean PICD DFT was 14.8 ± 1.53 (SE) J. Conventional #1 configuration demonstrated mean DFT of 20.2 ± 2.45 J and #2 of 27.5 ± 1.95 J. The PICD had a significantly lower DFT than the better conventional ICD configuration (#1; mean difference 5.4 ± 2.1 J, P <.05, paired t-test, N = 8). Conclusion: The new intravascular defibrillator had a significantly lower DFT than the conventional ICD in this canine model. [ABSTRACT FROM AUTHOR]

When not enough women are included in many clinical trials, an information gap on medical device safety and effectiveness exists, which can make it difficult to detect sex-specific results. In this article we discuss potential reasons for the underrepresentation of women and the regulatory research conducted by the U.S. Food and Drug Administration (FDA) used in supporting regulatory decisions. We demonstrate that important differences in cardiovascular device performance between women and men exist. Furthermore, concrete steps are outlined on the possible ways these sex-specific results can be detected and how a recent FDA Action Plan and Guidance Document aim at encouraging female participation in clinical trials and the appropriate analysis thereof. [ABSTRACT FROM AUTHOR]

In the transplanted heart with biatrial anastomosis, atrial flutter is common and is am enable to catheter ablation. Although this arrhythmia is isthmus dependent, the unique atrial architecture with a suture line through the inferior vena cava-tricuspid annulus isthmus makes the substrate atypical. A cardiac transplant recipient with atrial flutter underwent successful catheter ablation. Five weeks after the procedure, the patient died of a myocardial infarction. The autopsy and histological findings are described and correlated with the electroanatomic map obtained during the ablation. Due to the atrial suture lines, atrial flutter following cardiac transplantation is an isthmus dependent arrhythmia with a different arrhythmogenic substrate. The electrical isthmus (atrial tissue from the tricuspid annulus to the suture line) in these heads is smaller than the anatomic isthmus. [ABSTRACT FROM AUTHOR]

Background Prior studies have suggested that women have better outcomes than men after cardiac resynchronization therapy-defibrillator (CRT-D) implantation. Objectives The purpose of this study was to compare mortality after CRT-D implantation by sex, QRS morphology, and duration. Methods Survival curves and covariate adjusted hazard ratios (HR) were used to assess mortality by sex in 31,892 CRT-D patients in the National Cardiovascular Data Registry (NCDR), implantable cardioverter defibrillator (ICD) registry between 2006 and 2009, with up to 5 years’ follow-up (median 2.9 years, interquartile range: 2.0 to 3.9 years). Patients were grouped by QRS morphology and 10-ms increments in QRS duration. Results Among patients with left bundle branch block (LBBB), women had a 21% lower mortality risk than men (HR: 0.79; 95% CI: 0.74 to 0.84; p < 0.001); however, there was no sex difference in non-LBBB (HR: 0.95; 95% CI: 0.85 to 1.06; p = 0.37). Longer QRS duration was associated with better survival in both sexes with LBBB, but not in patients without LBBB. Compared with women with LBBB and QRS of 120 to 129 ms, women with LBBB and QRS of 140 to 149 ms had a 27% lower mortality (HR: 0.73; 95% CI: 0.60 to 0.88; p = 0.001); this difference was 18% in men (HR: 0.82; 95% CI: 0.71 to 0.93; p = 0.003). Mortality in LBBB and QRS of 150 ms or longer compared with those with LBBB and QRS of 120 to 129 ms was similar between sexes (HR: 0.61 to 0.68; p < 0.001 for women and HR: 0.58 to 0.66; p < 0.001 for men). Sex interactions within 10-ms groups were not significant. Conclusions Among patients with LBBB who received CRT-D, mortality is lower in women than men. Additionally, longer QRS duration in LBBB is associated with better survival in both sexes. In contrast, there is no sex difference in patients without LBBB, regardless of QRS duration. Further studies should include a non-CRT comparator group to confirm these findings. [ABSTRACT FROM AUTHOR]