Modulation of collision-induced changes in canine heart repolarization by cycle length

The possibility that cycle length modulates the electronic effect of activation sequence on repolarization was investigated in experiments using isolated canine cardiac Purkinje strands, in situ canine ventricular myocardium, and computer simulations. Action potential durations and refractory periods during one-way propagation were compared to those obtained during action potential collision. In both the computer simulations and the Purkinje strand experiments, collision decreased action potential duration more at long cycle lengths than at short cycle lengths. Comparably, collision of activation fronts in ventricular myocardium was associated with greater reductions in refractory period during pacing at long cycle lengths than at short cycle lengths. Theoretic considerations indicate that the magnitude of electrotonic effects of activation sequence on repolarization are directly related to action potential height and the square root of membrane resistance during repolarization and are inversely related to conduction velocity. In computer simulations and Purkinje strand experiments, changes in conduction velocity and action potential height elicited by decreasing cycle length could not fully account for the cycle length dependence of collision-induced changes in repolarization. Time-varying membrane resistance of a single cell was calculated in the simulations by briefly hyperpolarizing the membrane and determining the change in total ionic current. Membrane resistance during repolarization was less at short cycle lengths than at long cycle lengths. The results suggest the cycle length dependence of collision-induced changes in repolarization results largely from the effect of cycle length on membrane resistance during action potential repolarization, with changes in action potential height and conduction velocity playing a lesser role.     

The relationship between interpersonal problems,negative cognitions,and outcomes from cognitive behavioral group therapy for depression

Background

Interpersonal functioning is a key determinant of psychological well-being, and interpersonal problems (IPs) are common among individuals with psychiatric disorders. However, IPs are rarely formally assessed in clinical practice or within cognitive behavior therapy research trials as predictors of treatment attrition and outcome. The main aim of this study was to investigate the relationship between IPs, depressogenic cognitions, and treatment outcome in a large clinical sample receiving cognitive behavioral group therapy (CBGT) for depression in a community clinic.

Methods

Patients (N=144) referred for treatment completed measures of IPs, negative cognitions, depression symptoms, and quality of life (QoL) before and at the completion of a 12-week manualized CBGT protocol.

Results

Two IPs at pre-treatment, ‘finding it hard to be supportive of others’ and ‘not being open about problems,’ were associated with higher attrition. Pre-treatment IPs also predicted higher post-treatment depression symptoms (but not QoL) after controlling for pre-treatment symptoms, negative cognitions, demographics, and comorbidity. In particular, ‘difficulty being assertive’ and a ‘tendency to subjugate one's needs' were associated with higher post-treatment depression symptoms. Changes in IPs did not predict post-treatment depression symptoms or QoL when controlling for changes in negative cognitions, pre-treatment symptoms, demographics, and comorbidity. In contrast, changes in negative cognitions predicted both post-treatment depression and QoL, even after controlling for changes in IPs and the other covariates.

Limitations

Correlational design, potential attrition bias, generalizability to other disorders and treatments needs to be evaluated.

Conclusions

Pre-treatment IPs may increase risk of dropout and predict poorer outcomes, but changes in negative cognitions during treatment were most strongly associated with improvement in symptoms and QoL during CBGT.     

The role of weight bias and role-modeling in medical students’ patient-centered communication with higher weight standardized patients

ObjectivePatients with obesity may experience less patient-centered care. We assessed whether medical students’ implicit/explicit weight-related attitudes and perceptions of normative attitudes are associated with patient-centered care for patients with obesity.MethodsThird and fourth year medical students (N = 111) at one medical school completed a survey and participated in a patient care scenario with a standardized patient with obesity. Encounters were coded for patient-centered behavior. Predictors of patient-centered behaviors were assessed.ResultsStudent perceptions that negative attitudes about patients with obesity are normative in medical school were significantly associated with poorer patient-centered behaviors, including lower attentiveness (b=?0.19, p = 0.01), friendliness (b=?0.28, p < 0.001), responsiveness (b=?0.21, p = 0.002), respectfulness (b=?0.17, p = 0.003), interactivity (b=?0.22, p = 0.003), likelihood of being recommended by observers (b=?0.34, p < 0.001), and patient-centeredness index scores (b=?0.16, p = 0.002). Student reported faculty role-modeling of discrimination against patients with obesity predicted lower friendliness (b=?0.16, p = 0.03), recommendation likelihood (b=?0.22, p = 0.04), and patient-centeredness index score (b=?0.12, p = 0.03).ConclusionsNegative normative attitudes and behaviors regarding obesity in the medical school environment may adversely influence the quality of patient-centered behaviors provided to patients with obesity.Practice implicationsEfforts to improve patient-centered communication quality among medical trainees may benefit from intervention to improve group normative attitudes about patients with obesity.     

Psychosocial predictors of attitudes toward physician empathy in clinical encounters among 4732 1st year medical students: A report from the CHANGES study

Objective

Medical school curricula intended to promote empathy varies widely. Even the most effective curricula leave a significant group of students untouched. Pre-existing student factors influence their response to learning experiences. We examined the individual predictors of first semester medical students’ attitudes toward the value of physician empathy in clinical encounters.

Methods

First year students (n = 4732) attending a stratified random sample of 49 US medical schools completed an online questionnaire that included measures of dispositional characteristics, attitudes and beliefs, self-concept and well-being.

Results

Discomfort with uncertainty, close-mindedness, dispositional empathy, elitism, medical authoritarianism, egalitarianism, self-concept and well-being all independently predicted first year medical students’ attitudes toward the benefit of physician empathy in clinical encounters.

Conclusion

Students vary on their attitude toward the value of physician empathy when they start medical school. The individual factors that predict their attitudes toward empathy may also influence their response to curricula promoting empathic care.

Practice implications

Curricula in medical school promoting empathic care may be more universally effective if students’ preexisting attitudes are taken into account. Messages about the importance of physician empathy may need to be framed in ways that are consistent with the beliefs and prior world-views of medical students.