Antiadrenergic therapy in the control of atrial fibrillation

Atrial fibrillation (AF) in heart failure develops commonly in older individuals and its prevalence increases as heart failure severity progresses. Because of deteriorating hemodynamics, patients with heart failure are at increased risk for developing AF and, conversely, AF in heart failure patients is associated with adverse hemodynamic changes. AF is believed to increase the mortality risk in heart failure, which may be minimized by treatment that includes the control of ventricular rate, prevention of thrombotic events, and conversion to normal sinus rhythm. Clinical guidelines recommend amiodarone or dofetilide in heart failure patients, but these drugs have certain drawbacks, such as an increased risk for bradyarrhythmias with amiodarone and proarrhythmic reaction with dofetilide. Some but not all clinical trials have suggested that rate control should be the primary therapeutic goal in high-risk heart failure patients with AF and, if unsuccessful, followed by rhythm control. The former is effectively achieved with rate-lowering beta-blockers alone or in combination with digoxin. Recent studies evaluating the effects of combination carvedilol/digoxin therapy demonstrate synergistic effects between the two drugs. This combination therapy decreased heart failure symptoms, effectively reduced ventricular rate, and improved ventricular function to a greater extent compared with that produced by either drug alone. Although digoxin alone is an effective heart failure treatment, its use as a single rate-control therapy is often ineffective in heart failure patients with AF associated with rapid ventricular response. Carvedilol is effective, alone or in combination, with digoxin in such heart failure patients with AF, and has been shown to reduce mortality risk in patients with chronic heart failure during prolonged therapy.     

CEREBRAL VENOUS THROMBOSIS OCCURRING DURING AN ECTOPIC PREGNANCY AND COMPLICATED BY INTRACRANIAL HYPERTENSION

Thrombosis of the cerebral dural sinuses and veins has been described since the early 19th century.^1,2 Clinically the process is characterised by diverse symptomatology and physical findings and in spite of advances in diagnostic radiological techniques it remains an under-recognised condition. It has been most commonly associated with sepsis, trauma, pregnancy, the puerperium and many other hypercoagulable states. We describe an apparently unique case of sagittal sinus thrombosis occurring during an ectopic pregnancy. This was subsequently complicated by intracranial hypertension in spite of clinical improvement and magnetic resonance imaging (MRI) evidence suggesting a return of venous patency. The clinical presentation, radiological features and management is discussed.     

Pulse pressure variation does not reflect stroke volume variation in mechanically ventilated rats with lipopolysaccharide‐induced pneumonia

相似文献   

Biventricular pacing in congestive heart failure: a boost toward finer living.

With 550,000 new cases each year, congestive heart failure is a major medical problem. Several medical therapies, including digoxin, angiotensin-converting enzyme inhibitors, and beta-blockers, have reduced the number of re-hospitalizations and slowed the progression of congestive heart failure. Angiotensin-converting enzyme inhibitors, some beta-blockers, and the combination of hydralazine with nitrates have improved survival. Despite these benefits, medical therapy frequently fails to improve quality of life. Biventricular pacing has been introduced to resynchronize mechanical and electrical asynchrony frequently observed in patients with heart failure. The most recent pacing trials show an improvement in quality of life and functional class. Long-term data are needed to determine the effect of biventricular pacing on survival. The acute hemodynamic studies suggest that resynchronization pacing therapy may predict a positive long-term benefit for many patients with congestive heart failure.     

Aneuploidy and percentage of S-phase cells determined by flow cytometry correlate with cell phenotype in childhood acute leukemia

Cellular DNA content distributions of propidium-iodide-stained bone marrow blasts were determined by flow cytometry (FCM) for 225 untreated children with acute leukemia and were correlated with leukemia cell phenotype and karyotype. Aneuploidy of the primary malignant stem line was detected in 54 cases (24%): 51 hyperdiploid and 3 hypodiploid. A second stem line with approximately twice the DNA content of the primary stem line was recognized by FCM in 28 cases (23 ALL, 5 ANLL) and may be an important source of leukemia cell heterogeneity. The degree of DNA content abnormality detected by FCM was highly correlated (r = 0.98) with the number of whole chromosome gains or losses in the leukemia karyotype. Aneuploidy detectable by FCM was more frequent in acute lymphoblastic leukemia (ALL) (52 of 173, 30.1%) than in acute nonlymphoblastic leukemia (2 of 52, 3.8%) (p less than 0.001). In the ALL group, aneuploidy was significantly correlated with the cell surface expression of common ALL antigen: 46 of 127 antigen-positive cases were aneuploid compared to 6 of 46 antigen-negative cases (p less than 0.003). Only 2 of 21 cases of T-cell ALL without common ALL antigen had detectable aneuploidy, which was significantly less than in the common ALL group (p = 0.02). The median percentage of cells in S- phase was significantly greater for B-cell and erythrocyte rosette- positive T-cell ALL, than for the other phenotypic subgroups. We conclude that aneuploidy and S-phase cell percentage are correlated with the state of leukemia cell differentiation. The biologic basis for the correlation is not established, but may be linked to the process of malignant transformation.