Effects of exercise on gallbladder volume and motility in obese women

PURPOSE: Comparatively few prospective studies have investigated the relationship between physical activity and gallbladder motility, and the results are controversial. Exercise may affect gallbladder motility via neural or hormonal mechanisms. The purpose of this study was to evaluate the possible effects of aerobic exercise on gallbladder motility in a group of obese women without gallstones. PATIENTS AND METHODS: Twenty-three obese women (age 41.2+/-10.3 years, body mass index 40.7+/-6.7 kg/m(2)) were included in the study. Following an overnight fast, fasting and postprandial (15, 30, 45, 60, 75, 90, 120, and 150 minute) volumes and ejection fractions were evaluated with real-time ultrasonography before exercise. For all subjects, the exercise regimen consisted of daily 45-minute walking sessions at 60-80% of maximum heart rate for 4 weeks except weekends. Gallbladder volume and ejection fraction were again evaluated after exercise. RESULTS: Fasting and postprandial (15, 30, 45, 60, 75, 90, 120, and 150 minute) volumes were 38.6+/- 10.9, 32.8+/- 8.8, 27.6/- 8.1, 22.7+/- 8.5, 21.4+/- 7.2, 20.8+/- 7.0, 22.8+/- 7.3, 29.6 +/- 7.0, and 36.8+/- 6.2 cm(3) before the exercise period, respectively, and 40.8+/- 18.9, 29.9+/-11.2, 25.3+/- 9.2, 22.4+/-8.5, 19.6+/-7.8, 17.7+/- 6.8, 17.8+/- 7.3, 23.1+/-10.8, and 29.0+/-14.4 cm(3) after the exercise period, respectively. Postprandial (15, 30, 45, 60, 75, 90, 120, and 150 minute) ejection fractions were 13.5+/-15.9, 27.4+/-15.4, 39.5+/-20.0, 43.2+/-16.7, 44.3+/-17.3, 37.5 +/- 23.5, 23.5 +/-25.1, and 5.5+/- 21.6% before the exercise period, respectively, and 22.6+/- 20.1, 34.6+/-14.5, 42.0+/-13.6, 49.2+/-12.6, 53.1+/-14.1, 52.6+/-16.1, 43.6+/-17.0, and 29.2+/- 26.5% after exercise, respectively. After the exercise period, the 75, 90, 120, and 150 minute volumes were lower (p< 0.05, p< 0.05, p< 0.05, p< 0.01) and the 90, 120, and 150 minute ejection fractions were higher than before exercise (p< 0.05, p < 0.05, p< 0.01). CONCLUSIONS: Our study showed that exercise decreased late-phase postprandial gallbladder volume and increased late-phase postprandial gallbladder motility in these obese women.     

Rate-dependent AV delay optimization in cardiac resynchronization therapy

BACKGROUND: During cardiac resynchronization therapy (CRT), cardiac performance is dependent on an optimized atrioventricular delay (AVD). However, the optimal AVD at different heart rates has not been defined yet during CRT. METHOD: The effects of an increase in heart rate by pacing or physical exercise on optimal AVD were studied in 36 patients with biventricular pacemakers/defibrillators. The velocity time integral (VTI) in the left ventricular outflow tract (LVOT) was measured with pulsed Doppler either at three different paced heart rates in the supine position or in seated position before and after physical exercise. RESULTS: The baseline AVD was optimized to 99 +/- 19 ms in the supine and 84 +/- 22 ms in the seated position. When the heart rate was increased by DDD pacing, there was a positive linear relationship between an increase in heart rate, in AVD and in VTI (LVOT-VTI + 0.047 cm/s per 10 beats per minute (bpm) heart rate increase per 20 ms increase in AVD, P = 0.007). A similar but more pronounced relationship was found after physical exercise in the seated position (LVOT-VTI + 0.146 cm/s per 10 bpm heart rate increase per 20 ms increase of AVD, P = 0.013). This effect was observed in patients with and without AV block and mitral regurgitation. CONCLUSIONS: In conclusion, the systolic performance of the dilated ventricle, which depends on an elevated preload, is critically affected by the appropriate timing of the AVD during exercise. In contrast to normal pacemaker patients, in CRT the relatively short baseline AVD should be prolonged at increased heart rates. Further studies with other means of measuring exercise cardiac performance are needed to confirm these unexpected findings.     

Decisional balance for exercise: adaptation of an instrument for older Mexican American women

The purpose of this study was to adapt and test an instrument to measure decisional balance for exercise with older Mexican American women. Items were derived from a Decisional Balance Scale (DBS) developed by Marcus, Rakowski, and Rossi (1992) and a focus group with Mexican American women aged 60 to 86 years. The adapted Spanish-English DBS was administered to 75 Mexican American women (38 exercisers and 37 non-exercisers). A factor analysis yielded a positive and a negative factor. Alpha coefficients were .95 for the positive factor and .79 for the negative factor. Decisional balance for exercise was significantly more positive for the exercisers than for the non-exercisers and was positively related to exercise readiness and habitual activity. The findings suggest that the adapted Spanish-English DBS can be used in exercise and activity research with older Mexican American women.     

Test of the health promotion model as a causal model of commitment to a plan for exercise among Korean adults with chronic disease

The purpose of this study was to test seven constructs (prior experience of exercise, perceived health status, exercise benefits, exercise barriers, exercise self-efficacy, social support for exercise, and options for exercise) from the health promotion model (HPM) as a causal model of commitment to a plan for exercise in a sample of 400 Korean adults with chronic disease. Using structural equation modeling (SEM), we found that all fit indices indicated a good fit. The final model accounted for 54% of the variance in commitment to a plan for exercise. Prior experience with exercise and exercise benefits were the factors most highly related. Health professionals can assess prior experience and emphasize personally relevant benefits of exercise in designing intervention programs to help Korean adults with chronic disease become more physically active.     

Pulmonary arterial hypertension: the key role of echocardiography

Given the nonspecific nature of its early symptoms and signs, pulmonary arterial hypertension (PAH) is often diagnosed in its advanced stages. Although clinical assessment is essential when initially evaluating patients with suspected PAH, echocardiography is a key screening tool in the diagnostic algorithm. It not only provides an estimate of pulmonary pressure at rest and during exercise, but it may also help to exclude any secondary causes of pulmonary hypertension, predict the prognosis, monitor the efficacy of specific therapeutic interventions, and detect the preclinical stage of the disease.     

Hematological changes following a marathon race in male and female runners

Summary The subjects of this experiment were well-trained men (6) and women (4) participating in a marathon race in Phoenix, Arizona, on a cool, cloudy, windy day. Venous blood was collected one week prior to the run, immediately after, and 4,8, and 24 h after the race. There were no significant changes in hematocrit, hemoglobin, or red blood cell counts following the race. The sample collected immediately after the race showed a pronounced leucocytosis. Differential counts showed that this increase in white blood cell count was limited to polymorphonuclear cells, suggesting that an inflammatory response to stress of the race was involved. Percentage changes in blood volume, red blood cell volume, and plasma volume were calculated from hematocrit and hemoglobin changes. These changes showed that there was reduction of plasma volume of 8% for females and 13% for males immediately after the race, with return to initial values within 8 h. We suggest that the increase in protein following the race was contributed by the flow of lymph from muscle to the vascular compartment.This study was supported by an Arizona State University faculty grant-in-aid; the Dean's Research Fund, Arizona State University; and Technicon Corporation (Terrytown, NY)     

Dynamic electrocardiography V the “imaginary cardiac vector” hypothesis: Experimental evaluation

This paper experimentally evaluates the “imaginary cardiac vector” hypothesis, that the cardiac vector is not a real vector. We have previously shown on theoretical grounds that the basis of the cardiac vector is invalid in that Einthoven used scalar, not vector, procedures. Attempts by subsequent workers to compensate for the theoretical flaws have not succeeded. The concept of the “cardiac vector” which they have invented has the dimensions of an imaginary entity. Experimental measurement of isopotential maps derived from dipoles in a volume conductor demonstrates that these dipoles do not summate vectorially. Isopotential maps of the thoracic surface confirm that this applies to the human ECG.An imaginary “man-frog” cardiac vector loop is demonstrated using a lead from a man and a lead from a frog. This illustrates that the “imaginary cardiac vector” is a tenable concept. Finally, a crucial test of the hypothesis is reported which demonstrates that exercise causes deviations of the so-called cardiac vector in opposite directions, simultaneously, in different VCG lead systems. Since a physical entity can only be in one place and move in one direction at a particular instant, this experiment invalidates the “real cardiac vector” hypothesis. This strongly suggests that the cardiac vector is a brilliant, but imaginary, construction with immense clinical value, especially in the interpretation of the sequence of depolarization. Nevertheless, it obstructs analysis of the real basis of the electricity of the heart.     

RENAL, ADRENAL AND VASCULAR CHANGES DURING INHIBITION OF CONVERTING ENZYME WITH CAPTOPRIL

1. In rats treated continuously with captopril (80 μg/h, i.p.), for 2 days, blood pressure decreased and adrenal angiotensin II receptor concentration was decreased from 160 fmol/mg protein (s.e.m.=9) in controls to 131 fmol/mg protein (s.e.m. = 7, P < 0.01, n= 10). However, after 5 days of continuous treatment, blood pressure had returned to normal and adrenal receptor concentrations in treated rats were not significantly different from controls (180 fmol/mg, s.e.m. = 11 and 203 fmol/mg protein s.e.m. = 14 respectively, 0.1>P>005). 2. Vascular reactivity, defined as the pressor response to exogenous angiotensin II, increased concurrently by 166 and 33% respectively. 3. In anaesthetized dogs (n= 8), captopril (1.5 mg/kg, i.v.) caused a fall in blood pressure, and urine bradykinin excretion increased from 1 08 (s.e.m.=0 14) to 1 64 μg/h (s.e.m.=0 33, P < 0 025) at 15 min. Renal blood flow increased significantly (P < 0 01) with no change in glomerular filtration rate, and there was no change in either renal venous or arterial blood bradykinin levels. 4. Thus, converting enzyme inhibition produces transient secondary changes in angiotensin receptors and vascular reactivity. Increased urine bradykinin probably reflects decreased catabolism of intrarenal bradykinin. The hypotensive effect of captopril may be due in part to raised levels of bradykinin in the kidney.     

Comparative evaluation of intravenous phenytoin,procainamide and practolol in the acute treatment of ventricular arrhythmias

Summary Ten patients with a persistent ventricular arrhythmia, but no other sign of heart disease, were studied by means of an exercise test performed 4 times with a fixed work load, over 30–40 min. No drug was given in the first exercise test and in the others phenytoin, procainamide or practolol were chosen at random for i. v. administration. Blood samples for determination of plasma concentration were frequently collected. The ECG was recorded continuously during the exercise test and was analysed minute by minute. Despite plasma levels within the suggested therapeutic range, only procainamide showed a statistically significant antiarrhythmic effect in this group of patients.     

Ventricular arrhythmias in relation to coronary artery stenosis and left ventricular performance

The relationship between ischaemic heart disease and occurrenceof ventricular arrhythmias has been studied in a prospectiveinvestigation of 41 patients with severe stable angina pectoris.The patients had a median age of 54 years (range 38–67).Following the therapeutic evaluation of the patients, they weresubjected to exercise testing, 24 h ambulatory ECG monitoring,selective coronary arteriography, ventriculography and cardiaccatheterization. Nineteen patients had been under treatmentwith a beta blocking agent, 16 with verapamil, three with bothand three had not been receiving any anti-anginal treatment.The treatment was discontinued over a period of three days priorto coronary arteriography and haemodynamic measurements. A comparisonof the patients under treatment with a beta blocking agent andthose receiving verapamil demonstrated no difference in thenon-invasive and invasive variables. Ventricular arrhythmias were found in only one patient duringexercise testing. The occurrence of ST segment deviation duringexercise was not correlated with the number of stenotic coronaryvessels due to low maximum heart rate and treatment. A heartrate during maximum exercise of < 120/min was observed significantlymore frequently in patients with multivessel disease. The data of the 24 h Holter monitoring were analysed in orderto evaluate whether the prevalence (percentage number of patientswith ventricular ectopic beats) or the persistence (number of6 h periods with ventricular ectopic beats) is the better indicatorof myocardial function and coronary artery anatomy. The resultsdemonstrated a significant correlation between a high persistenceand elevated left ventricular enddiastolic presure, high dp/dt/_max/P,reduced ejection fraction as well as the number of stenoticcoronary arteries and hypokinetic segments in the left ventricularwall. The latter correlation especially applies when the hypokinesiais localized to the anterior wall of the left ventricle. It is concluded from this investigation that a high persistenceof ventricular arrhythmias during 24 h of ECG monitoring reflectsmultivessel disease and poor left ventricular function. Thecombination of a high persistence of complicated ventriculararrhythmias and only a slight rise in heart rate during maximumexercise can possibly identify a group with an especially highrisk of sudden cardiac death.