Etude descriptive de l'insuffisance cardiaque chronique et suivi à six mois sous traitement bêtabloqueur dans le service de cardiologie du CHU de Pointe à Pitre/Abymes [Guadeloupe]

LYON1-BU Santé (693882101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Central retinal vein occlusion in a sickle cell trait carrier after a cycling race.: SCT and ophthalmologic complications

International audienceA 26-yr-old man with sickle cell trait (SCT) suddenly lost visual acuity in the left eye after a cycling race in hot tropical environment. The cause was massive central retinal vein occlusion (CRVO) with hemorrhaging that rapidly worsened to neovascular glaucoma. Although medically treated, the eye is now marked by total retinal detachment. Cardiovascular function assessment shows no electrocardiographic abnormalities, no anomaly in the supra-aortic tree, and no evidence of structural heart disease. Although normal coagulation markers values (i.e., activated partial thromboplastin time, prothrombin time, fibrinogen concentration, antithrombin III, factor V, proteins C and S) were observed 2.5 months after the clinical event, a transesophageal echocardiogram performed few hours after the incident revealed the presence of four thrombi in the left atrium suggesting a postexercise hypercoagulable state at that time. Hemorheological measurements at distance of the events demonstrated high red blood cell rigidity at baseline. Therefore, marked blood rheological impairment and activation of the coagulation pathway in response to the heavy and prolonged cycling race could have promoted CRVO in this cyclist carrying SCT. These data suggest that SCT could be considered as a risk factor for significant ocular complications when severe exercise is performed and support the idea that SCT is a contributing factor in blood rheology and vascular dysfunctions

Impaired oxygen uptake efficiency slope and off-transient kinetics of pulmonary oxygen uptake in sickle cell anemia are associated with hemorheological abnormalities

International audienceOxygen uptake efficiency slope (OUES) and excess post-exercise oxygen consumption (EPOC) are markers of physical fitness in the general population but have never been characterized in sickle cell anemia (SCA) where hematological and hemorheological properties are severely altered. Eight SCA patients and eleven healthy subjects (CONT) performed a submaximal incremental exercise conducted until the first ventilatory threshold (VT1). OUES was calculated from the data collected during the incremental period and EPOC parameters (amplitude [A] and time constant [τ]) were calculated from the data measured during exercise recovery. We found that OUES (p = 0.007) and A (p = 0.010) were lower, and τ (p = 0.035) was higher, in SCA patients compared to CONT subjects. OUES and τ were significantly correlated with hematocrit, red blood cell (RBC) deformability and RBC aggregates strength. Our findings suggest that both the abilities to use oxygen during exercise and to recover after a physical activity are impaired in SCA patients. This poor physical fitness seems to depend on the degree of anemia and RBC rheological alterations

Acute Moderate Exercise Does Not Further Alter the Autonomic Nervous System Activity in Patients with Sickle Cell Anemia

International audienceA decreased global autonomic nervous system (ANS) activity and increased sympathetic activation in patients with sickle cell anemia (SCA) seem to worsen the clinical severity and could play a role in the pathophysiology of the disease, notably by triggering vaso-occlusive crises. Because exercise challenges the ANS activity in the general population, we sought to determine whether a short (,15 min) and progressive moderate exercise session conducted until the first ventilatory threshold had an effect on the ANS activity of a group of SCA patients and a group of healthy individuals (CONT group). Temporal and spectral analyses of the nocturnal heart rate variability were performed before and on the 3 nights following the exercise session. Standard deviation of all normal RR intervals (SDNN), total power, low frequencies (LF) and high frequencies powers (HF) were lower but LF/HF was higher in SCA patients than in the CONT group. Moderate exercise did not modify ANS activity in both groups. In addition, no adverse clinical events occurred during the entire protocol. These results imply that this kind of short and moderate exercise is not detrimental for SCA patients

Delayed beneficial effect of acute exercise on red blood cell aggregate strength in patients with sickle cell anemia

International audienceBecause of the metabolic changes induced by a physical activity, the hemorheological properties of patients with sickle cell anemia could be further impaired and increase the risks for vaso-occlusive complications. However, few studies suggest that moderate physical activity could be beneficial rather than harmful in patients with sickle cell anemia (SCA). However, the definition of what can be considered as a moderate physical activity in SCA patients is imprecise. The present study tested the effects of a short incremental cycling exercise test conducted until the first ventilatory threshold on different biomarkers. Hematological and hemorheological parameters were compared between 8 patients with SCA and 13 healthy subjects (CONT) before, immediately after the end of the exercise and at 12, 36 and 60 hours after the exercise. We observed no significant hematological or hemorheological alteration induced by the exercise in the two groups. However, the exercise resulted in a delayed improvement of the red blood cell disaggregation threshold at 36 and 60 hrs after exercise in the SCA group which was paralleled to the decrease in the platelet count in this group. The present study suggests that such an exercise might be beneficial for microcirculatory blood flow

Spectral indices of heart rate variability.

<p>D-1: the night before exercise, D0: the night just after exercise, D1 and D2: the nights 1 and 2 days after exercise. Ptot: Total Power, LF: low frequencies, HF: high frequencies.</p

Temporal indices of heart rate variability.

<p>Values are mean ± SD. D-1: the night before exercise, D0: the following night after exercise, D1 and D2: the nights 1 and 2 days after exercise, HR: Heart rate, SDNN: standard deviation of all normal RR intervals, RMSSD: square root of the mean squared differences between adjacent normal RR intervals. *Significant group effect (<i>p<</i>0.05).</p