Stroke prevention in patients with atrial fibrillation: disease burden and unmet medical needs.

The incidence of atrial fibrillation (AF), as well as the related morbidity and mortality, is increasing in step with the aging of the US population. Frequently, AF leads to untoward outcomes, including a 5-fold increased risk of stroke, hospitalization, impaired quality of life, and decreased work productivity. Therapeutic decision making for patients with AF at risk for stroke is a process that varies from one physician to the next. This lack of consistency in care is compounded by disrupted communication among caregivers coupled with barriers to health care resources. Improved application of evidence-based treatment guidelines for the diagnosis, staging, and tracking of AF-associated stroke is needed, especially because patients with AF are at high risk. In addition to affecting practice guidelines, the latest anticoagulants are poised to change the standard of care for preventing stroke in patients with AF. These novel agents, with their greater safety and ease of administration, have the potential to improve treatment outcomes.

A new era of anticoagulation treatment: optimizing outcomes for atrial fibrillation.

Atrial fibrillation is a common condition that is associated with a high risk of stroke. In the present article, which is based on a roundtable discussion held on February 8, 2012, the faculty discuss various aspects of caring for patients with atrial fibrillation. These topics include the burden of the disease, stroke risk assessment, use of stroke prophylaxis, and improvement of outcomes.

Chronic physical activity mitigates cerebral hypoperfusion during central hypovolemia in elderly humans.

This study sought to test the hypothesis that orthostasis-induced cerebral hypoperfusion would be less severe in physically active elderly humans (ACT group) than in sedentary elderly humans (SED group). The peak O(2) uptake of 10 SED (67.1 +/- 1.4 yr) and 9 ACT (68.0 +/- 1.1 yr) volunteers was determined by a graded cycling exercise test (22.1 +/- 1.2 vs 35.8 +/- 1.3 ml.min(-1).kg(-1), P < 0.01). Baseline mean arterial pressure (MAP; tonometry) and middle cerebral arterial blood flow velocity (V(MCA); transcranial Doppler) were similar between the groups (SED vs. ACT group: 91 +/- 3 vs. 87 +/- 3 mmHg and 54.9 +/- 2.3 vs. 57.8 +/- 3.2 cm/s, respectively), whereas heart rate was higher and stroke volume (bioimpedance) was smaller in the SED group than in the ACT group. Central hypovolemia during graded lower body negative pressure (LBNP) was larger (P < 0.01) in the ACT group than in the SED group. However, the slope of V(MCA)/LBNP was smaller (P < 0.05) in the ACT group (0.159 +/- 0.016 cm/s/Torr) than in the SED group (0.211 +/- 0.008 cm/s/Torr). During LBNP, the SED group had a greater augmentation of cerebral vasomotor tone (P < 0.05) and hypocapnia (P < 0.001) compared with the ACT group. Baseline MAP variability and V(MCA) variability were significantly smaller in the SED group than in the ACT group, i.e., 0.49 +/- 0.07 vs. 1.04 +/- 0.16 (mmHg)(2) and 1.06 +/- 0.19 vs. 4.24 +/- 1.59 (cm/s)(2), respectively. However, transfer function gain, coherence, and phase between MAP and V(MCA) signals (Welch spectral estimator) from 0.08-0.18 Hz were not different between SED (1.41 +/- 0.18 cm.s(-1).mmHg(-1), 0.63 +/- 0.06 units, and 38.03 +/- 6.57 degrees ) and ACT (1.65 +/- 0.44 cm.s(-1).mmHg(-1), 0.56 +/- 0.05 units, and 48.55 +/- 11.84 degrees ) groups. We conclude that a physically active lifestyle improves the intrinsic mechanism of cerebral autoregulation and helps mitigate cerebral hypoperfusion during central hypovolemia in healthy elderly adults.

Pulmonary embolism mimicking anteroseptal acute myocardial infarction.

Pulmonary embolism (PE) is a potentially lethal condition that presents in patients with chest pain or shortness of breath. Although electrocardiograms (ECGs) typically demonstrate abnormalities associated with PE, ST-segment elevation, which can indicate anteroseptal acute myocardial infarction (AMI), has-on rare occasions-been noted on ECGs of patients with acute PE. The current report documents the case of a 57-year-old man who presented to the emergency department with chest pain. Findings from an ECG suggested anteroseptal AMI; however, cardiac catheterization indicated that the patient did not have critical ischemic heart disease. On further examination, the patient was found to have a massive bilateral PE. The present report emphasizes that physicians must investigate PE in all patients presenting with chest pain, dyspnea, or both, even in the face of ECG changes that are suggestive of a cardiac etiology. A brief discussion of the current theories of ST-segment elevation in the setting of PE is also included.

Physically active lifestyle enhances vagal-cardiac function but not central autonomic neural interaction in elderly humans.

UNLABELLED: The cause of the age-related impairment of arterial baroreflex function remains ill-defined; moreover, it is unknown whether this impairment results from aging per se or from an inactive lifestyle associated with aging. In this study, we sought to: 1) determine whether elderly individuals who maintained an active lifestyle had an enhanced carotid baroreflex function as compared with their sedentary counterparts; and 2) determine whether this difference was due in part to altered function of the arterial baroreceptor and/or altered central modulation. Eight healthy, sedentary (SED, 68+/-2 yr) and eight physically active (ACT, 68+/-1 yr) elderly men with peak O(2) consumption 25.5+/-1.2 vs 35.7+/-2.4 ml/min/kg (P<0.01), respectively, were assessed with carotid baroreceptor (CBR) function using 5s pulses of neck pressure or suction (ranging from +40 to -80 Torr) delivered to the carotid sinus region at rest and during lower body negative pressure (LBNP) of -15 and -40 Torr. Changes in heart rate (HR) and mean arterial pressure (MAP) were assessed for CBR-HR and CBR-MAP gains, respectively. Overall CBR-HR gains in a range of approximately 120 mmHg of carotid sinus pressure were greater (P<0.01) in ACT than SED at rest and during LBNP. The derived peak CBR-HR slopes between ACT and SED at rest were -0.32+/-0.07 vs -0.11+/-0.02 bpm/mmHg (P=0.007), respectively. However, there was no statistical difference (P=0.37) in CBR-MAP gains between the groups. Neither CBR-MAP (P=0.08) nor CBR-HR (P=0.41) gain was augmented by LBNP in the elderly. CONCLUSION: Active lifestyle enhances the CBR-HR reflex sensitivity as a result of the improved vagal-cardiac function in elderly people. Aging is associated with an absence of central autonomic interaction in the control of blood pressure regardless of physical fitness.

Improving diagnostic capabilities of medical students via application of cognitive sciences-derived learning principles.

PURPOSE: There is limited experimental evidence concerning how best to train students to perform differential diagnosis. We compared 2 different methods for training 2nd-year medical students to perform differential diagnosis (DDX) of heart failure: a traditional classroom-based lecture (control group) versus a cognitive sciences-based approach to DDX instruction implemented through a computer-based tutor (treatment group). METHODS: Following random assignment to either group, students were trained for 75 minutes, and then given a 40-item examination comprised of cases that varied along a typicality gradient from prototypical (easy) to less typical (hard). RESULTS: The treatment group diagnosed correctly significantly more test cases than the control group (74% versus 60%, respectively). The treatment group also diagnosed correctly significantly more cases at the extremes of the typicality gradient: 81% versus 65%, respectively, for the prototypical cases; 65% versus 48%, respectively, for the most difficult cases. CONCLUSION: The ability to perform differential diagnosis is enhanced by training based upon principles of cognitive sciences.

Diagnostic cardiac catheterization.

Preview The risks associated with diagnostic cardiac catheterization have declined through the years, but the question remains as to which patients should be referred for the procedure. In this article, Drs Walder and Schaller examine present guidelines for different types of heart disease and also review qualifications for performing cardiac catheterization.