The dynamic function of the atrial diastole of the heart and motion of venous valves in humans

Association between lower extremity venous insufficiency and duration of atrial fibrillation

OBJECTIVE

Physiologic studies have shown that atrium has an active role in venous blood return from lower extremity. In this context we investigated the association between AF and chronic venous disease (CVD).

METHODS

In this observational study we included 392 AF patients which were divided into two groups (chronic AF, 218 (56%)) and non-chronic. AF, 174 (44%)). These two groups were compared in terms of CVD after matching conventional risk factors for CVD.

RESULTS

CEAP classification was different between chronic and non-chronic patients (C0-C2: 72% vs 47%; C3-C6: 28% vs 53% <0.001). Chronic AF patients had also higher rate of venous reflux on Doppler ultrasound (38% vs 16% P < 0.05). There was a correlation between AF duration, right atrial volume index and CEAP classification respectively (rho:0.314 p < 0.001), (rho:0.258, p < 0.001).

CONCLUSION

Prevalence of CVD is higher in patients with chronic AF. In addition, atrial volume is directly correlated with CVD.

Structural evidence for a new elaborate 3D-organization of the cardiomyocyte lateral membrane in adult mammalian cardiac tissues

AIMS

This study explored the lateral crest structures of adult cardiomyocytes (CMs) within healthy and diseased cardiac tissue.

METHODS AND RESULTS

Using high-resolution electron and atomic force microscopy, we performed an exhaustive quantitative analysis of the three-dimensional (3D) structure of the CM lateral surface in different cardiac compartments from various mammalian species (mouse, rat, cow, and human) and determined the technical pitfalls that limit its observation. Although crests were observed in nearly all CMs from all heart compartments in all species, we showed that their heights, dictated by the subsarcolemmal mitochondria number, substantially differ between compartments from one species to another and tightly correlate with the sarcomere length. Differences in crest heights also exist between species; for example, the similar cardiac compartments in cows and humans exhibit higher crests than rodents. Unexpectedly, we found that lateral surface crests establish tight junctional contacts with crests from neighbouring CMs. Consistently, super-resolution SIM or STED-based immunofluorescence imaging of the cardiac tissue revealed intermittent claudin-5-claudin-5 interactions in trans via their extracellular part and crossing the basement membrane. Finally, we found a loss of crest structures and crest-crest contacts in diseased human CMs and in an experimental mouse model of left ventricle barometric overload.

CONCLUSION

Overall, these results provide the first evidence for the existence of differential CM surface crests in the cardiac tissue as well as the existence of CM-CM direct physical contacts at their lateral face through crest-crest interactions. We propose a model in which this specific 3D organization of the CM lateral membrane ensures the myofibril/myofiber alignment and the overall cardiac tissue cohesion. A potential role in the control of sarcomere relaxation and of diastolic ventricular dysfunction is also discussed. Whether the loss of CM surface crests constitutes an initial and common event leading to the CM degeneration and the setting of heart failure will need further investigation.

Primary pulmonary arterial hypertension with preserved right ventricular function leads to lower extremity venous insufficiency

Objectives

Pulmonary hypertension with heart failure is related to venous insufficiency. However, there is no clear data whether pulmonary arterial hypertension with preserved right ventricular function cause venous insufficiency. In this study, we aim to investigate the relation between pulmonary arterial pressure with venous insufficiency in pulmonary arterial hypertension patients with preserved right ventricular function.

Methods

Between January 2012 and October 2014, 38 patients with a diagnosis of pulmonary arterial hypertension and 47 control group patients were included. Venous disability score and venous segmental disease score of both groups were calculated in order to measure venous insufficiency. The relationship between venous disability score and venous segmental disease scores and mean pulmonary arterial pressure and World Heart Organization functional capacity was examined.

Results

Total venous segmental disease score (5 ± 3.9 vs. 2 ± 1.8 p < 0.001), right venous segmental disease score (2.6 ± 2.2 vs. 1 ± 0.9 p < 0.001), left venous segmental disease score (2.4 ± 2.2 vs. 1 ± 0.9 p < 0.001), and venous disability scores (2.2 ±1 vs. 1.6 ± 0.7 p < 0.001) of patients with pulmonary arterial hypertension were higher than the control group. While the total venous segmental disease score was highly related to mean pulmonary arterial pressure (r = 0.829, p < 0.001), the venous disability score was only weakly related (r = 0.343, p = 0.037). Total venous segmental disease score (r = 0.606, p < 0.001) and venous disability scores (r = 0.601, p < 0.001) were moderately related with World Health Organization functional capacity intensity.

Conclusions

The degree of venous insufficiency increase in accordance with the mean pulmonary arterial pressure even in patients with preserved right ventricular function.