[Show abstract][Hide abstract] ABSTRACT: Epidemiologic studies have demonstrated a morning excess of acute cardiovascular events, which has subsequently been refined to the 2 to 3 h after awakening. It is therefore reasonable to assume that some activity associated with awakening may trigger such cardiovascular events, with the assumption of an upright posture being of potential significance.
To identify and systematically review the literature to determine the effects of acute changes in posture on hemorheology and hemostasis.
Electronic databases MEDLINE, EMBASE, PSYCHINFO, and CINAHL (earliest date available to February 5, 2006) and conference abstracts were searched.
Studies examining the hemorheologic and hemostatic response to a change in posture from a supine position to an upright position were eligible for inclusion. Two reviewers independently selected the studies for inclusion.
The experimental evidence reviewed demonstrates that the assumption of an upright posture is associated with a significant degree of hemoconcentration, which is characterized by an increase in hematocrit and a decrease in plasma volume. Research examining the effect of postural change on hemostasis has been limited, although a small number of studies have demonstrated some significant changes in markers of coagulation, fibrinolysis, and platelet reactivity.
A sudden change in posture may act as a potential trigger for the onset of cardiovascular events occurring in the 3 h after awakening via effects on hemostasis and hemorheology. However, other possible triggering factors such as dehydration, mental stress, and physical exertion must also be considered.
[Show abstract][Hide abstract] ABSTRACT: To examine the prevalence and persistence of depression and anxiety in patients with atrial fibrillation (AF), and their effect on future quality of life (QoL) status.
The Beck Depression Inventory and State-Trait Anxiety Inventory were completed by 101 patients with AF (62 men; mean age +/- SD, 66.3 +/- 11.0 years), who were compared to 97 patients with hypertension (as "disease control" subjects) in sinus rhythm (64 men; mean age, 68.0 +/- 7.2 years) at baseline and at 6 months. QoL was ascertained at both time points using Dartmouth Care Cooperative Information Project charts.
At baseline among AF patients, symptoms of depression, state anxiety, and trait anxiety prevailed in 38%, 28%, and 38%, respectively; analogous data for hypertensive patients were 30%, 23%, and 22%. AF patients displayed higher levels of trait anxiety (p < 0.05), with no significant differences in baseline depression, state anxiety, and QoL between patients with AF and disease control subjects. Symptoms of depression and anxiety (state and trait) persisted at 6 months in 36.8% and 33.3%, respectively. Symptoms of depression (p < 0.001) and anxiety (p < 0.001) at baseline, female gender (p = 0.01), ethnicity (p = 0.01), and employment status (p = 0.03) were significantly correlated with QoL at 6 months in the patients with AF. Multiple regression analysis revealed that baseline depression score provided the best independent prediction of 6-month QoL (R(2) = 0.20), although gender and employment status also entered the model.
Approximately one third of AF patients have elevated levels of depression and anxiety, which persist at 6 months. Symptoms of depression were the strongest independent predictor of future QoL in these patients.
[Show abstract][Hide abstract] ABSTRACT: Physical activity and psychological stress are two potential triggers for the onset of acute coronary syndromes (ACS). To examine the mechanisms underlying this association, we systematically reviewed the literature to determine the effects of acute psychological stress and physical activity on haemorheology and haemostasis. Studies examining the haemorheological and haemostatic response to an acute bout of physical activity (i.e. <60 min) or laboratory psychological stress task were eligible for inclusion. The experimental evidence, although compromised by various methodological weaknesses, suggests that low and moderate intensity physical activity may be cardio-protective through beneficial effects on fibrinolytic system. High levels of physical activity, and psychological to a lesser extent, have been consistently associated with robust changes in haemorheology and haemostasis. Such findings imply that such activities may have the potential to trigger the onset of ACS, although in reality this may be limited sedentary individual and/or those with pre-existing vascular disease. In addition, the data also suggest that individuals may be at a greatest risk of stress-induced thrombogenesis in the period immediately following physical activity or psychological stress, rather than during the activity per se. In conclusion, psychological stress and physical activity may act as potential triggers for the onset of ACS via effects on haemostasis and haemorheology.
Thrombosis Research 01/2007; 120(6):819-47. · 3.13 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The impact of atrial fibrillation (AF) on patients' quality of life (QoL) has yet to be fully elucidated in a systematic manner. This article examines QoL in "general" patients with AF as well as the effects that rate and/or rhythm-control interventions have on QoL. Patients with AF have significantly poorer QoL compared with healthy controls, the general population, and other patients with coronary heart disease. Studies examining rate or rhythm-control strategies alone demonstrate improved QoL after intervention. Three of the four large randomized control trials (STAF, PIAF, RACE) comparing rate versus rhythm control demonstrated a greater improvement in QoL in patients receiving rate control. However, the AFFIRM trial revealed a similar improvement in QoL for both rate and rhythm-control groups. The data, although frequently compromised by various methodologic weaknesses, suggest that patients with AF have impaired QoL, and that QoL can be significantly improved through rate or rhythm-control strategies.
The American journal of medicine 06/2006; 119(5):448.e1-19. · 4.47 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This study examined the effects of hydration status on rheological and hemodynamic activity during rest, mental stress, postural stress, and combined mental/postural stress in 24 men when euhydrated and hyperhydrated. The stress tasks elicited hemoconcentration, although the effects were less pronounced during mental stress. Hyperhydration was associated with higher plasma volume throughout. All stress tasks also perturbed hemodynamic activity, irrespective of hydration status, with the exception of heart rate reactivity, which was attenuated when hyperhydrated. As expected the combined stress during euhydration was associated with an unfavorable rheological and cardiovascular profile, which may help explain the increased incidence of cardiovascular events in the morning.