Sex Differences in Left Ventricular Electrical Dyssynchrony and Outcomes with Cardiac Resynchronization Therapy

BACKGROUND: Women seem to derive more benefit from cardiac resynchronization therapy (CRT) than men, even after accounting for the higher burden of risk factors for nonresponse often observed in men. OBJECTIVE: To assess for sex-specific differences in left ventricular (LV) electrical dyssynchrony as a contributing electrophysiological explanation for the greater degree of CRT benefit among women. METHODS: We compared the extent of baseline LV electrical dyssynchrony, as measured by the QRS area (QRSA), among men and women with left bundle branch block (LBBB) undergoing CRT at Duke University (n = 492, 35% women) overall and in relation to baseline QRS characteristics using independent sample t tests and Pearson correlation coefficients. Cox regression analyses were used to relate sex, QRSA, and QRS characteristics to the risk of cardiac transplantation, LV assist device implant, or death. RESULTS: Although the mean QRS duration (QRSd) did not differ by sex, QRSA was greater for women vs men (113.8 μVs vs 98.2 μVs, P < .001), owing to differences in the QRSd <150 ms subgroup (92.3 ± 28.7 μVs vs 67.6 ± 26.2 μVs, P < .001). Among those with nonstrict LBBB, mean QRSd was similar but QRSA was significantly greater among women than men (96.0 ± 25.0 μVs vs 63.6 ± 26.2 μVs, P < .001). QRSA was similar among men and women with strict LBBB (P = .533). Female sex was associated with better long-term outcomes in an unadjusted model (hazard ratio 0.623, confidence interval 0.454–0.857, P = .004) but sex no longer predicted outcomes after accounting for differences in QRSA. CONCLUSIONS: Our study suggests that sex-specific differences in LV dyssynchrony contribute to greater CRT benefit among women. Standard QRSd and morphology assessments seem to underestimate the extent of LV electrical dyssynchrony among women with LBBB

Funding of Studies Supporting IA Guideline Recommendations in Cardiovascular Medicine—A Systematic Review

Each guideline recommendation from the American Heart Association and the American College of Cardiology includes an indication of the level of supporting evidence and the associated strength of recommendation with “IA” recommendations representing those with the highest quality supporting evidence and the least amount of uncertainty for benefit. In this analysis, study type and funding sources were systematically tabulated across these IA guideline recommendations over the past 5 years. Nearly half of studies supporting IA guideline recommendations were randomized controlled trials (45%). Overall, about one third of studies supporting IA recommendations were publicly funded (34.9%) with slightly more funded through industry sources (43.5%). Funding sources varied based on the type of intervention being studied with randomized controlled trials of device, diagnostic, and pharmacological interventions reflecting predominantly industry‐funded studies. Over time, studies supporting IA cardiology guideline are funded by industry about twice as often as public sources. Thus, data of adequate quality to support cardiovascular guideline recommendations come from a variety of sources

Substituent Effects in the Pyridinium Catalyzed Reduction of CO2 to Methanol: Further Mechanistic Insights

A series of substituted pyridiniums were examined for their catalytic ability to electrochemically reduce carbon dioxide to methanol. It is found that in general increased basicity of the nitrogen of the amine and higher LUMO energy of the pyridinium correlate with enhanced carbon dioxide reduction. The highest faradaic yield for methanol production at a platinum electrode was 39 ± 4 % for 4-aminopyridine compared to 22 ± 2 % for pyridine. However, 4-tertbutyl and 4-dimethylamino pyridine showed decreased catalytic behavior, contrary to the enhanced activity associated with the increased basicity and LUMO energy, and suggesting that steric effects also play a significant role in the behavior of pyridinium electrocatalysts. Mechanistic models for the the reaction of the pyridinium with carbon dioxide are considered