Differentiation of Beats of Ventricular and Sinus Origin Using a Self-Training Neural Network

Despite advances in the computerized detection of arrhythmias, arrhythmia recognition by morphological waveform analysis still poses a difficult problem. Artificial neural networks, computer algorithms that are self-trained by an analog of biological synaptic modification to perform pattern recognition, hold great promise for the differentiation of various cardiac rhythms. The goal of this study was to differentiate beats of sinus and ventricular origin on a global basis and on a patient-specific basis by the use of artificial neural network analysis. Neural networks were trained to recognize digitized intracardiac electrograms (9 patients) and surface electrocardiograms (11 patients) obtained during sinus rhythm and ventricular tachycardia. After training, sinus rhythm or ventricular tachycardia beats were input into the neural network, and classified as to their origin. By the use of modified receiver operating characteristic curve plots, it was possible to differentiate with high sensitivity and specificity between beats of sinus origin and ventricular origin in all patients. The addition of high amounts of noise to the beats did not markedly degrade the performance of the surface ECG neural networks, and still allowed high sensitivity in differentiating beats of sinus origin from beats of ventricular origin, especially when noise was added to the training set. Neural networks provided sensitive and specific detection of cardiac electrical activity during sinus rhythm and ventricular tachycardia, and may play an important role in allowing development of improved arrhythmia recognition and management systems.     

Effectiveness of a Pregnancy Smoking Cessation Program

OBJECTIVE: To evaluate two nursing approaches to promoting smoking cessation during initial antenatal visits. DESIGN: Experimental, with assignment to interventions using a random, alternate-day strategy and blind assessment of smoking at baseline, 1 month postintervention, 36 weeks' gestation, and 6 weeks postpartum. SETTING/PARTICIPANTS: 224 daily smokers, fewer than 31 weeks gestation, during first prenatal visit, at a teaching hospital antenatal clinic. INTERVENTIONS: An evening class providing guidance on a self-help program for 2 hours on a group basis or 20 minutes on an individual basis during the prenatal appointment. MAIN OUTCOME MEASURE: Smoking cessation, confirmed by urinary cotinine levels. RESULTS: All women assigned to the referral intervention received a referral, but none attended the classes. In contrast, 93% assigned to the immediate intervention received the intervention. The group receiving immediate intervention had two to three times higher rates of cessation at all follow-up periods, with significant differences at the 1-month follow-up. There were certain similarities between the groups. CONCLUSION: Cessation interventions should be administered during the first prenatal visit.     

The ‘Age+5’ Rule: Comparisons of Dietary Fiber Intake Among 4- to 10-Year-Old Children

Objective To determine children's sources of dietary fiber and to identify the food group choices made by those who met the “age+5” rule, which recommends that children daily consume an amount of fiber that is equal to their age plus an additional 5 g fiber.

Design This study used 24-hour dietary recalls and 1-day food records to assess the nutrient intake and food group choices of children who did and did not meet the recommendations of the age+5 rule.

Subjects The 1989-1991 US Department of Agriculture Continuing Survey of Food Intakes by Individuals provided the study sample of 603 children between the ages of 4 and 6 years and 782 children between the ages of 7 and 10 years.

Statistical analyses Differences in nutrient and food group intakes between age categories were determined by t tests.

Results Only 45% of 4- to 6-year-olds and 32% of 7- to 10-year-olds consumed adequate fiber to meet the age+5 rule. Those who met the age+5 rule did so by consuming significantly more high- and low-fiber breads and cereals, fruits, vegetables, legumes, nuts, and seeds. Children with low fiber intakes had significantly higher energy-adjusted intakes of fat and cholesterol, whereas those who met the age+5 rule had significantly higher energy-adjusted intakes of dietary fiber, vitamins A and E, folate, magnesium, and iron.

Applications The majority of the children had low intakes of dietary fiber, suggesting that they are at risk for future chronic disease. Parents and school foodservice personnel should strive to offer fiber-rich foods to children so their acceptance and consumption of them will be increased. J Am Diet Assoc. 1998;98:1418-1423.     

GENETIC AND NEUROBIOLOGICAL BASIS OF ALCOHOL-SEEKING BEHAVIOR

Through selective breeding, rat lines exhibiting high and lowalcohol drinking preference have been developed as useful animalmodels for studying the neurobiological basis of alcohol-seekingbehavior. The identified differences between lines in neurotransmitterfunctioning allows the evaluation of receptor agonist/antagonistcompounds that might be efficacious in the treatment of alcoholcraving and dependendence.