Craig K. Ewart

Biobehavioral variables and mortality or cardiac arrest in the Cardiac Arrhythmia Pilot Study (CAPS)

The frequency of ventricular premature complexes and the degree of impairment of left ventricular ejection fraction are major predictors of cardiac mortality and sudden death in the year after acute myocardial infarction. Recent studies have implicated psychosocial factors, including depression, the interaction of social isolation and life stress, and type A-B behavior pattern, as predictors of cardiac events, controlling for known parameters of disease severity. However, results tend not to be consistent and are sometimes contradictory. The present investigation was designed to test the predictive association between biobehavioral factors and clinical cardiac events. This evaluation occurred in the context of a prospective clinical trial, the Cardiac Arrhythmia Pilot Study (CAPS). Five-hundred two patients were recruited with greater than or equal to 10 ventricular premature complexes/hour or greater than or equal to 5 episodes of nonsustained ventricular tachycardia, recorded 6 to 60 days after a myocardial infarction. Baseline behavioral studies, conducted in approximately 66% of patients, included psychosocial questionnaires of anxiety, depression, social desirability and support, and type A-B behavior pattern. In addition, blood pressure and pulse rate reactivity to a portable videogame was assessed. The primary outcome was scored on the basis of mortality or cardiac arrest. Results indicated that the type B behavior pattern, higher levels of depression and lower pulse rate reactivity to challenge were significant risk factors for death or cardiac arrest, after adjusting statistically for a set of known clinical predictors of disease severity. The implication of these results for future research relating behavioral factors to cardiac endpoints is discussed.

Circuit weight training in cardiac patients

This was a prospective, randomized evaluation of the safety and efficacy of 10 weeks of circuit weight training in patients, aged 35 to 70 years, with documented coronary artery disease. Circuit weight training refers to the performance of a series of weight-lifting exercises using a moderate load with frequent repetitions. Patients had participated in a supervised cardiac rehabilitation program for a minimum of 3 months before the study. Control patients (n = 20) continued with their regular exercise consisting of a walk/jog and volleyball program, while the experimental group (n = 20) substituted circuit weight training for volleyball. No sustained arrhythmias or cardiovascular problems occurred. The experimental group significantly increased treadmill time from 619 to 694 seconds while the treadmill time of the control group did not change. Strength in the experimental group increased by an average of 24% while there was no change in the control patients. Circuit weight training appears to be safe, and to result in significant increases in aerobic endurance and musculoskeletal strength compared with traditional exercise used in cardiac rehabilitation programs.

Self-efficacy mediates strength gains during circuit weight training in men with coronary artery disease.

Motivation to engage in health-promoting exercise has been ascribed to global personality traits such as self-esteem or athletic self-confidence. Self-Efficacy Theory challenges this view by proposing that highly specific estimates of personal capabilities mediate adoption of new or difficult behavior patterns. We tested this assumption by measuring self-efficacy perceptions in 40 men with coronary artery disease who participated in an experiment evaluating effects of circuit weight training (CWT). Specific self-efficacy estimates were assessed during baseline strength/endurance testing and after 10 wk participation in CWT or volleyball. Correlational analyses of self-efficacy in relation to performance on strength/endurance tests strongly supported the contention that adoption of novel activities is governed by highly specific self-perceptions. Participation in CWT produced greater strength and endurance gains than did volleyball, and these changes were accompanied by increased self-efficacy in CWT subjects for activities resembling the training tasks. The assertion that self-efficacy perceptions directly mediate involvement in challenging physical activities was supported by multiple regression analyses. These revealed that pre-training self-efficacy judgments predicted post-test strength gains even after controlling for baseline strength, type of training and frequency of participation in exercise sessions.

Effects of school-based aerobic exercise on blood pressure in adolescent girls at risk for hypertension.

OBJECTIVES This study evaluated the effects of aerobic exercise physical education on blood pressure in high-risk, predominantly African-American, adolescent girls. METHODS Ninth-grade girls (n = 99) with blood pressure above the 67th percentile were randomized to 1 semester of aerobic exercise classes or standard physical education classes. RESULT The study was completed by 88 girls. At posttest, only members of the aerobic exercise group increased their estimated cardiorespiratory fitness. The aerobic exercise group had a greater decrease in systolic blood pressure than the standard physical education group (P < .03). CONCLUSIONS Aerobic exercise physical education is a feasible and effective health promotion strategy for high-risk adolescent girls.

Negative affect, gender, and expressive style predict elevated ambulatory blood pressure in adolescents.

Excessive blood pressure elevations during daily activities increase cardiovascular risk and may be related to individual differences in emotionality and expressive style. Emotional traits and ambulatory blood pressure were measured during a typical school day in 228 Black and White adolescents at risk of developing essential hypertension. Trait affect (depression, anger) predicted prevailing blood pressure levels; this association was moderated by gender, social setting (in classroom vs. with friends), and nonverbal expressive style. Relationships between emotion and blood pressure were not explained by obesity, smoking, or alcohol use. The uniform environment and regimen of the school made it possible to attribute variations in prevailing blood pressure to personality differences involving ways adolescents perceive and negotiate their social world.

Reducing blood pressure reactivity during interpersonal conflict: Effects of marital communication training.

Blood pressure fluctuations evoked by environmental stimuli may contribute to sustained hypertension. Mastering effective coping skills might reduce these reactions and make long-term blood pressure control easier to achieve. We evaluated the effect of communication training on blood pressure reactivity of hypertensive patients during marital arguments in a laboratory setting. Following assessment of blood pressure reactivity and basal blood pressure level, 20 patients and their partners were assigned either to (a) marital communication training or (b) an assessment-only control group. At posttest, subjects who has mastered the reflective problem-solving techniques engaged in fewer hostile exchanges during marital discussions than did the untrained controls. Trained subjects also achieved a significantly greater reduction in systolic reactivity (−8.8 mmHg) evoked by discussion tasks than did the control subjects (−3.5 mmHg). Communication training may provide a means to improve blood pressure control in certain individuals.

Relation of psychosocial and stress reactivity variables to ventricular arrhythmias in the Cardiac Arrhythmia Pilot Study (CAPS)

Both animal and human data implicate psychosocial distress and cardiovascular reactivity in response to challenge in the etiology of sudden cardiac death. In this study, the relation of these biobehaviorial factors to frequency of ventricular premature complexes, a predictor of sudden death was investigated. The study population was made up of patients enrolled in the National Heart, Lung, and Blood Institutes Cardiac Arrhythmia Pilot Study (CAPS). Ventricular premature complexes (VPCs) were assessed by multiple, 24-hour ambulatory electrocardiographic recordings. Patients completed trait psychosocial measures assessed at baseline and state psychosocial measures assessed periodically during a 1-year follow-up period. Psychosocial measures included self-reports of depression, anxiety, anger and type A behavior pattern. A competitive challenge using a video game was used as a stressor to elicit cardiovascular reactivity and was administered at baseline and during follow-up sessions. Cardiovascular reactivity was defined as peak level during stressor exposure minus the mean of resting levels for systolic and diastolic blood pressure and pulse rate. Results indicated that biobehavioral factors were not associated with diurnal VPC rates. Furthermore, biobehavioral factors did not predict response to antiarrhythmic therapy. Based upon the results of this study, it is speculated that the established relation between behavioral factors and sudden death may not be mediated by VPC rates.

Relationships between self-efficacy and mood before and after exercise training

Background Exercise improves physiological function and may improve mood. Some psychologists suggest that mood changes are mediated predominately by self-efficacy rather than physical ability. We examined self-efficacy, mood, aerobic power, and strength in men undergoing exercise training and antihypertensive therapy of calcium-channel and beta-blocking drugs. Because beta blockers limit the physiological benefits of exercise, we evaluated psychological responses independent of physiological gains. Methods Fifty-one men (25–59 years) with mild hypertension were randomized to diltiazen (calcium-channel blocker), propranolol (beta-blocker), or placebo. Subjects completed 10 weeks of circuit weight training, and walking, jogging, or cycling. Study variables included Profile of Mood States (POMS), self-efficacy (SE) for arms and legs, maximal oxygen uptake, and maximal strength for arm and leg exercises. Results Baseline aerobic power, POMS, and SE scores were unrelated. POMS did not relate to strength. Arm SE related to arm and leg strength. Leg SE related to leg strength only. After training, aerobic power increased in the diltiazem and placebo groups, but not in the propranolol group. Strength, and arm and leg SE increased in all groups. After training, POMS tension/anxiety and total mood disturbance decreased and vigor/alertness increased in all groups. Gains in aerobic power and strength were not related to mood or SE changes. Results Tension/anxiety, depression/dejection, confusion/bewilderment, and total mood disturbance changes related to SE changes. Conclusions Thus, psychological changes were unrelated to physical ability. Self-efficacy and several mood dimensions were related. The data suggest that changes in mood may be mediated by changes in perceived abilities.

Elevated Blood Pressure

Behavioral interventions to modify diet, activity, and emotional stress constitute the recommended initial treatment for mild essential hypertension in children and should accompany pharmacological therapy in more severe cases (Task Force on Blood Pressure Control in Children, 1987; referred to hereafter as the Second Task Force). The first concern is to ensure that the blood pressure evaluation process itself does not generate excessive anxiety and negative self-labeling on the part of child and family (Bloom & Monterossa, 1981; Bergman & Stamm, 1967). If, upon repeated assessment, the child’s blood pressure is found to be significantly elevated, this can usually be presented as a timely cue to start changing life-style patterns that could lead to health problems later on. Behavioral assessment and intervention efforts then focus on modifying diet habits, increasing physical activity, and reducing excessive emotional stress.

Self-Efficacy and Recovery from Heart Attack

Coronary heart disease continues to be the leading health threat to citizens of developed nations; in the United States alone, diseases of the heart and vasculature cause over a half-million premature deaths annually while contributing to nearly as many cases of preventable disability (Gunby, 1992). One’s chances of surviving a heart attack (acute myocardial infarction, AMI) have increased in recent years due to important innovations in emergency and postcoronary care. Yet survivors still face disabling difficulties that most health care providers are ill-prepared to detect and poorly equipped to treat (Ben-Sira & Eliezer, 1990; Fontana, Kerns, Rosenberg, & Colonese, 1989).