Determinants of Subsidiary Ventricular Pacemaker Suppression in Man

To investigate the relative contribution of the duration and rate of overdrive to subsidiary ventricular pacemaker suppression, in six patients with complete heart block after His-bundle ablation, ventricular overdrive stimulation studies were performed. The studies, which were spread over a mean follow-up period of 745 days, were carried out invasively with a temporary lead (one patient) as well as nonin-vasively with the implanted pacemakers and chest wall inhibition (five patients). The overdrive pacing rate was increased in steps of 10 beats/min, and the pacing duration was 15, 30, 60, 90, and 120 seconds at each level. A recovery period of 2 minutes was allowed after each overdrive stimulation. Incremental ventricular overdrive stimulation at increasing pacing durations consistently caused progressive suppression of ventricular impulse formation. Nonparamelric variance analysis demonstrated a significant (P < 0.0001) influence of both the pacing rate and duration on ventricular recovery time. Nonlinear regression showed an exponential increase in recovery time with incremental pacing rate and a biphasic increase in recovery time with incremental pacing duration. Beyond a pacing duration of 60 seconds ventricular impulse suppression was primarily dependent upon the pacing rate. A nonlinear regression model was applied to predict the number of heals required for return of the escape rhythm toward prepacing control values. The predicted maximum mean number of beats was 15.4 ± 5.9 and independent of the rate and duration of pacing, although, the initial temporary instability of the escape rhythm was directly related to the degree of overdrive.     

新生儿B组链球菌感染的预防

B组链球菌也称为无乳链球菌,是导致新生儿患病和死亡的重要原因之一,可导致败血症、肺炎和脑膜炎。过去十年间,针对B组链球菌主要是预防早发感染,所谓早发感染是指发生于出生后1周内的新生儿感染。采取的预防措施是给感染B组链球菌的孕妇和新生儿选择性地服用抗生素,以减少或消除B组链球菌的垂直传播。目前,尚没有其他办法能完全预防新生儿B组链球菌败血症的发生,在分娩期内对母亲的预防或者结合分娩后对新生儿的预防,可分别使新生儿早发疾病的发病率减少80%和95%。1病因和危险因素已经证实,高达30%的女性阴道和直肠、肛门携带B组链球菌,…     

Implantable Cardioverter Defibrillator Clinic Casualties: Inadvertent Reprogramming During Routine Implantable Cardioverter Defibrillator Follow-Up

On one occasion during a busy ICD follow-up clinic, the preceding patient's parameters for rate, PDF, and delay were inadvertently programmed into the subsequent patient's generator using the CPIProgrammer Model 2035. This occurred after capacitor reformation, without pressing the "Program" button. The source of this reprogramming error was failure to clear the programmer memory of the previous patient's data, usually achieved by turning the programmer off between patients (or selecting "New Patient" from the menu). At our next ICD follow-up clinic, we purposely did not turn off the programmer between two sets of patients. On both occasions the above finding was repeated and confirmed. These observations indicate the potential for serious reprogramming errors that can occur simply by not clearing the programmer's memory between clinic patients.     

Mitochondrial myopathies: an unusual cause of hypotonia in infants and children

Children frequently undergo muscle biopsy for the workup of hypotonia under general anaesthesia which poses unique risks in patients with undiagnosed muscle disease. Mitochondrial myopathies are a relatively newly recognized cause of myopathy and multisystem disease in both adults and children. The diagnosis is complex. In addition to causing myopathy, there are metabolic derangements present in some cases that may be life-threatening. We present three cases of children with hypotonia where the diagnosis was suspected in two patients, and confirmed in the third. The question of whether patients with mitochondrial myopathies are at increased risk for developing malignant hyperthermia is discussed.     

Women Gain Weight 1 Year After Smoking Cessation While Dietary Intake Temporarily Increases

Objective To examine the relationship of dietary change to weight change in women who quit smoking and remained abstinent for 1 year.Methods For 1 year, 582 women participating in smoking cessation classes were studied. Weight, diet, and physical activity were measured at baseline and at 1, 6, and 12 months after smoking cessation. Multivariate regression models were used to predict 1-year weight change for the 139 women who remained abstinent.Results Women gained, on average, 9.9 lb over a 1-year period while increasing their intake of energy for 1 and 6 months but returning to baseline levels by 1 year. Sucrose, total carbohydrate, and fat intake increased significantly for the first month; fat and total carbohydrate intake remained at an increased level for 6 months. In unadjusted analyses, older women and those who smoked more cigarettes gained more weight than younger women and lighter smokers; lighter and heavier women gained more weight than women of intermediate weight. In adjusted analyses, age remained a significant factor and number of cigarettes remained of borderline significance. Change in energy intake was predictive of weight change only in women with the highest energy intake at baseline.Applications Dietitians should acknowledge that most women who quit smoking gain weight in the short term. Although many women increase their energy intake, change in energy level is only one factor in weight change. Over the long term, women with high baseline intakes appear to be able to affect their weight change by reducing their energy intake. J Am Diet Assoc. 1996; 96:1150-1155.     

Loss of control and inability to abstain: the measurement of and the relationship between two constructs in male alcoholics

The constructs “loss of control” and “inability to abstain” have been used extensively in alcohol research. Examination of the literature, however, reveals inconsistencies in the ways researchers have operationalized and measured these constructs and a dearth of empirical investigation of the validity of the constructs. The current study examines a number of methods of operationalizing loss of control and inability to abstain and investigates the relationship of the two constructs with each other. Ninety-seven male alcoholics who participated in an outpatient conjoint alcoholism treatment study provided data on pre-treatment alcohol consumption and self-report measures of lifetime drinking behavior. Nine interview or questionnaire items that best approximated items used in the literature to measure inability to abstain and loss of control were chosen for analysis. Items measuring both constructs were highly intercorrelated and were associated more strongly with quantity rather than frequency of alcohol consumption, suggesting significant overlap between the constructs. None of the items were associated with a particular drinking pattern. The results provide support for a unitary dimension of impaired control, as used in the alcohol dependence syndrome, and suggest that the value of loss of control and inability to abstain as distinct and meaningful constructs should be reconsidered.