Parallel to significant functional improvement and echocardiographic reverse remodeling and resynchronization, our data indicate that CRT induces favorable changes in the neurohumoral system.

Cerebral blood flow increases upon the transition from rest to moderate exercise, but becomes affected when the ability to raise CO (cardiac output) is limited. HR (heart rate) is considered to contribute significantly to the increase in CO in the early stages of dynamic exercise. The aim of the present study was to test whether manipulation of the HR response in patients dependent on permanent rate-responsive ventricular pacing contributes to the increase in CO, MCA V(mean) [mean MCA (middle cerebral artery) velocity] and work capacity during exercise. The effect of setting the pacemaker to DSS ('default' sensor setting) compared with OSS ('optimized' sensor setting) on blood pressure, CO, SV (stroke volume) and MCA V(mean) was evaluated during ergometry cycling. From rest to exercise at 75 W, the rise in HR in OSS [from 73 (65-87) to 116 (73-152) beats/min; P<0.05] compared with DSS [70 (60-76) to 97 (67-117) beats/min; P<0.05] was larger. There was an increase in SV during exercise with DSS, but not with OSS, such that, at all workloads, SVs were greater during DSS than OSS. The slope of the HR-CO relationship was larger with DSS than OSS (P<0.05). From rest to exercise, MCA V(sys) (systolic MCA velocity) increased in OSS and DSS, and MCA V(dias) (diastolic MCA velocity) was reduced with DSS. No changes were observed in MCA V(mean). Manipulation of the pacemaker setting had no effect on the maximal workload [133 (100-225) W in OSS compared with 129 (75-200) W in DSS]. The results indicate that, in pacemaker-dependent subjects with complete heart block and preserved myocardial function, enhancing the HR response to exercise neither augments CO by a proportional offset of the exercise-induced increase in SV nor improves cerebral perfusion.

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Aims A recent study suggested that women with heart failure and heart failure reduced ejection fraction might hypothetically need lower doses of angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers ( = renin-angiotensin-system inhibitors) and β-blockers than men to achieve the best outcome. We assessed the current medical treatment of heart failure reduced ejection fraction in men and women in a large contemporary cohort and address the hypothetical impact of changing treatment levels in women. Methods This analysis is part of a large contemporary quality of heart failure care project which includes 5320 (64%) men and 3003 (36%) women with heart failure reduced ejection fraction. Detailed information on heart failure therapy prescription and dosage were collected. Results Women less often received renin-angiotensin-system inhibitors (79% vs 83%, p < 0.01), but more often β-blockers (82% vs 79%, p < 0.01) than men. Differences in guideline-recommended target doses between sexes were relatively small. Implementing a hypothetical sex-specific dosing schedule (at 50% of the current recommended dose in the European Society of Cardiology guidelines in women only) would lead to significantly higher levels of women receiving appropriate dosing (β-blocker 87% vs 54%, p < 0.01; renin-angiotensin-system inhibitor 96% vs 75%, p < 0.01). Most interestingly, the total number of women with >100% of the new hypothetical target dose would be 24% for β-blockers and 52% for renin-angiotensin-system inhibitors, which can be considered as relatively overdosed. Conclusion In this large contemporary heart failure registry, there were significant but relatively small differences in drug dose between men and women with heart failure reduced ejection fraction. Implementation of the hypothetical sex-specific target dosing schedule would lead to considerably more women adequately treated. In contrast, we identified a group of women who might have been relatively overdosed with increased risk of side-effects and intolerance.

After 1 month of individual optimization of rate response pacemakers, exercise capacity was improved and maximum HR increased, although QOL remained unchanged. Accessible pacemaker sensor algorithms are mandatory for individual optimization.