In patients with heart failure, atrial fibrillation may exacerbate ventricular dysfunction and symptoms. In this study, catheter ablation was performed to restore sinus rhythm in patients with heart failure and refractory atrial fibrillation. The results show improvement in the left ventricular ejection fraction, symptoms, exercise capacity, and quality of life.

Patients with infrequent episodes of atrial fibrillation and only mild heart disease may not be good candidates for prophylactic antiarrhythmic therapy or radiofrequency ablation. This study shows that as-needed therapy with oral flecainide or propafenone is very effective in terminating acute episodes of atrial fibrillation outside the hospital, thus reducing the need for hospitalization and emergency room care. Although this approach is effective, it is applicable to only about 10 percent of patients with episodic atrial fibrillation.

In a multicenter trial comparing two approaches to in vitro fertilization among women under 36 years of age, the transfer of a single fresh embryo followed by the transfer of a single previously frozen embryo (if the first cycle was unsuccessful) resulted in a marked reduction in the rate of multiple gestations without a substantial decrease in the rate of live births.

The results support the use of single fresh-embryo transfers to reduce the high risk of multiple births associated with the routine transfer of two embryos.

A father and two of his children were found to have acute myeloid leukemia (AML) and an identical germ-line mutation in the CEBPA gene. The product of this gene, C/EBP, participates in the differentiation of early myeloid cells.

The lack of functional C/EBP probably played a key role in the development of AML in members of this family. Because somatic mutations of CEBPA can also occur in sporadic cases of AML, the role of this gene in hematopoiesis and myeloid leukemia merits further study.

A 77-year-old woman with a history of hypertension treated with metoprolol presents for her annual examination. She reports no new symptoms. The examination is remarkable only for an irregular heart rate. Electrocardiographic testing reveals atrial fibrillation at an average rate of 75 beats per minute. She has no history of arrhythmia, coronary disease, valvular disease, diabetes, alcohol abuse, or transient ischemic attack or stroke. What should her physician advise?

The epidemiology of acute gastrointestinal illness is complex. The relevant infectious agents may spread from person to person or they may be acquired from a common food or environmental source, often water, but also from animal exposure. This article examines direct human-to-human spread of acute gastrointestinal illness, defined as a syndrome of vomiting, diarrhea, or both that begins abruptly in otherwise healthy persons and is most often self-limited.

A 38-year-old woman presented to the emergency room for evaluation of shortness of breath and jaundice. The previous day, several hours after she had attended a wedding, a headache developed, she had mild dizziness, and she noticed that her urine was dark brown. The day after the wedding, she awoke with mild shortness of breath and yellow discoloration of her eyes and skin.

The authors discuss the vaccine industry in the United States and explain why the nation is vulnerable to vaccine shortages. They describe the Institute of Medicine's proposal for a federal subsidy program to provide stronger incentives for companies to develop new vaccines and to manufacture existing ones.