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J M Rippe

Publications and source records attributed to J M Rippe.

34 records · Page 2Linked to original sources
PubMed1991

Development of a single-stage submaximal treadmill walking test.

An equation was developed to estimate maximal oxygen uptake (VO2max, ml.kg-1.min-1) based on a single submaximal stage of a treadmill walking test. Subjects (67 males, 72 females) aged 20-59 yr completed 4-min stages at 0, 5, and 10% grades walking at a constant speed (2.0-4.5 mph) and then performed a VO2max test. Heart rate and respiratory gas exchange variables were measured during the test. Multiple regression analysis (N = 117) to estimate VO2max from the 4-min stage at 5% grade yielded the following model (R2 = 0.86; SEE = 4.85 ml.kg-1.min-1): VO2max = 15.1 + 21.8*SPEED (mph) -0.327*HEART RATE (bpm) -0.263*SPEED*AGE (yr) + 0.00504*HEART RATE*AGE + 5.98*GENDER (0 = Female; 1 = Male). The constant and all coefficients were highly significant (P less than 0.01). To assess the accuracy of the model in a cross-validation group (N = 22), an estimated VO2max value was obtained using the above model. Estimated VO2max then was regressed on observed VO2max yielding the following equation (R2 = 0.92): ESTIMATED VO2max = 0.15 + 1.03*OBSERVED VO2max. The intercept and slope of this equation were not significantly different from 0 and 1, respectively. For 90.9% of the subjects in the cross-validation group, residual scores were within the range of +/- 5 ml.kg-1.min-1. In conclusion, this submaximal walking test based on a single stage of a treadmill protocol provides a valid and time-efficient method for estimating VO2max.

Adult↗
PubMed1988

Walking for health and fitness.

Recent studies have linked regular physical activity with reduced likelihood of developing coronary heart disease. Even low- and moderate-intensity exercise such as walking, when carried out consistently, is associated with important cardiovascular health benefits. Walking has also been shown to reduce anxiety and tension and aid in weight loss. Regular walking may help improve cholesterol profile, help control hypertension, and slow the process of osteoporosis. Recent physiological studies have demonstrated that brisk walking provides strenuous enough exercise for cardiovascular training in most adults. A recently developed submaximal 1-mile walk test provides a simple and accurate means for estimating aerobic capacity and guiding exercise prescription. These new insights and tools will assist the clinician in the prescription of safe and effective walking programs.

Coronary Disease↗
PubMed1987

Estimation of VO2max from a one-mile track walk, gender, age, and body weight.

The purpose of this investigation was to explore an alternative field test to estimate maximal oxygen consumption (VO2max) using a one-mile walk test. VO2max was determined in 343 healthy adult (males = 165, females = 178) subjects 30 to 69 yr using a treadmill protocol (mean +/- SD: VO2max = 37.0 +/- 10.7 ml X kg-1 X min-1). Each subject performed a minimum of two, one-mile track walks as fast as possible. The two fastest walks (T1, T2) with elapsed times within 30 s were used for subsequent analyses. Heart rates were monitored continuously and recorded every one-quarter mile. Multiple regression analysis (best sub-sets) to estimate VO2max (l X min-1) yielded the following predictor variables: track walk-1 time (T1); fourth quarter heart rate for track walk-1 (HR 1-4); age (yr); weight (lb); and sex (1 = male, 0 = female). The best equation (N = 174) was: VO2max = 6.9652 + (0.0091*WT) - (0.0257*AGE) + (0.5955*SEX) - (0.2240*T1) - (0.0115*HR1-4); r = 0.93, SEE = 0.325 l X min-1. Comparing observed and estimated VO2max values in a cross-validation group (N = 169) resulted in r = 0.92, SEE = 0.355 l X min-1. Generalized and sex-specific equations to estimate VO2max (ml X kg-1 X min-1) were also generated. The accuracy of estimation as expressed by SEE was similar among the equations. The results indicate that this one-mile walk test protocol provides a valid sub-maximum assessment for VO2max estimation.

Adult↗
PubMed1984

Mitral valve prolapse and spasm of normal coronary arteries: report of four cases and review of the literature.

The association between mitral valve prolapse (MVP) and atypical chest pain has been well-described. Numerous theories have been proposed to explain this association. A number of lines of evidence suggest that underlying ischemia may cause chest pain in some patients with MVP. We have recently evaluated 4 patients with chest pain syndromes who had angiographic evidence of MVP and spasm of angiographically normal coronary arteries. The possibility that coronary spasm is the underlying etiology of chest pain in some patients with mitral valve prolapse raises a theoretical argument against beta-blockade in these patients. Three of our patients were successfully treated with calcium channel blockers.

Adult↗
PubMed1979

Multiple floppy valves: an echocardiographic syndrome.

Echocardiograms of 400 patients with mitral valve prolapse examined at the Peter Bent Brigham Hospital between 1974 and 1977 were reviewed. Eleven patients (3 per cent) were found to have prolapse (10 patients) or large excursion of the tricuspid valve (one patient) and large excursion of the aotric valve (four patients) or dilatation of the aotric root (seven patients) in addition to mitral valve prolapse. Two of these 11 patients underwent mitral valve replacement, and myxomatous degeneration of the valves was noted on pathologic examination. Almost half of the patients with multiple floppy valves (five of 11) had symptoms of congestive heart failure. In contrast to reported series of isolated mitral valve prolapse, in which female preponderance has been documented, 10 of the 11 patients were male. The syndrome of multiple floppy valves may represent either a unique entity or a more advanced form of the same process which underlies mitral valve prolapse.

Adult↗
PubMedDate not supplied

Hemodynamics and left ventricular function: a comparison between adult racing greyhounds and greyhounds completely untrained from birth.

Trained racing greyhounds are known to have cardiomegaly, higher mean arterial pressure and cardiac indices and lower systemic arterial resistances at rest than mongrel dogs. In order to distinguish between those hemodynamic and left ventricular functional characteristics that are inborn in the greyhound as opposed to those which are acquired through training, we studied 9 adult (mean age 22.9 +/- 4.2 [S.D.] months) trained racing greyhounds within 8 days of the cessation of training and 9 adult greyhounds raised under sedentary conditions (mean age 21.7 +/- 1.4 months). Seven healthy adult mongrel dogs served as additional controls. Right and left heart catheterizations of chloralose-anesthetized animals included hemodynamic and left ventricular functional measurements before and after volume loading with 500 ml 6% dextran in normal saline. Heart weight/body weight ratios were the same in both trained and untrained greyhounds, favoring the concept that the cardiomegaly of greyhounds is genetic and not acquired. Trained greyhounds had significantly decreased systemic vascular resistance, increased cardiac index and stroke volume, and a tendency (non significant) toward elevated systemic arterial pressure in comparison to mongrels. Life-long untrained adult greyhounds had hemodynamic measurements that did not differ from mongrels; they also had significantly higher systemic vascular resistances and lower cardiac indices than trained greyhounds. Some hemodynamic characteristics of the trained adult greyhound dog are not present in completely untrained greyhounds and are the result of either training alone or training superimposed on genetic predisposition.

Animals↗
PubMedDate not supplied

Studies of systolic mechanics and diastolic behavior of the left ventricle in the trained racing greyhound.

Despite much interest in the effects of exercise on the myocardium, and the need to develop animal models which mimic conditions leading to cardiac hypertrophy, little attention has been focused on the trained racing greyhound. The current study compared two groups of anesthetized trained racing greyhounds (a total of 20 animals, 12 of whom were maintained for serial studies and 8 of whom were sacrificed for anatomic correlations) with 3 detrained greyhounds and 6 comparably sized mongrels. Systemic blood pressures, right and left heart pressures, ventricular mechanics and indices of diastolic behavior were compared. All measured indices of contractility (dp/dt, dp/dtDP40, Vce and Vmax) were lower in trained racing greyhounds than in mongrels although none achieved statistical significance. No significant difference in diastolic behavior was found between trained greyhounds and mongrels. While caution should be applied because of the small numbers of animals and the use of anesthesia, the lower than expected contractility found in trained racing greyhounds may reflect increased parasympathetic tone in the immediate post-training period. The normal diastolic behavior of the trained greyhound left ventricle contrasts to abnormal diastolic behavior found in models of chronic pressure overload.

Animals↗
PubMedDate not supplied

Effects of the cessation of training on left ventricular function in the racing greyhound. Serial studies in a model of cardiac hypertrophy.

Exercise-induced cardiac hypertrophy has been associated with normal resting left ventricular function and, after cessation of training, variable degrees of regression. The racing greyhound is an animal with cardiac hypertrophy said to be part congenital and part exercise-induced. Racing greyhounds underwent serial cardiac catheterization three times during an 8-month period after cessation of racing/training to determine the functional consequences of the cessation of training. At the end of 8 months of inactivity the animals' hearts were excised and weighed in order to compare heart weight/body weight (HW/BW) ratios with those obtained in a group of racing greyhounds killed within one month, 19 +/- 16 days (mean +/- SD), of the cessation of training. Comparison of HW/BW ratios failed to reveal a significant difference between the serially studied group, 12.1 +/- 1.9 g/kg (mean +/- SD), and the more recently exercising group, 12.7 +/- 1.4 g/kg (mean +/- SD) of dogs. After 2 months of inactivity, 9 of 12 greyhounds in the serially studied group showed increases in max dP/dt and dP/dt normalized to a pressure of 50 mmHg. Modified pre-ejection period and peak negative dP/dt also increased significantly (p less than .004) during this same period. No further changes in these variables were found at the final 8-month study. Our failure to demonstrate a difference in HW/BW ratios between these two groups of dogs suggests that the exercise-induced component of cardiac hypertrophy in the trained racing greyhound is probably very small and, if it exists, regresses very early (less than 1 month). Changes in contractility indices that were observed occurred after this time period (between 1 and 2 months) and are therefore probably not due to regression of cardiac hypertrophy.

Animals↗
PubMedDate not supplied

Obesity and cardiovascular disease risk: research update.

The obesity epidemic has reached unprecedented proportions in Western society. Evidence continues to accumulate that obesity is associated with significant morbidity and mortality and in particular that it is an independent risk factor for cardiovascular disease (CVD). The association of obesity with CVD and its risk factors, including hypertension, dyslipidemia, glucose intolerance, and impaired hemostasis is becoming more clearly understood. An increasing body of data indicates that risk factors tend to cluster in obese individuals and may act synergistically to increase these people's risk for CVD. Individuals with disproportionate visceral adiposity are at significantly greater risk for CVD. Adult weight gain also underlies the development of many risk factors and augments the risk of CVD. Physicians can play a vital and active role in the prevention and treatment of obesity and overweight and thereby reduce patients' CVD risk.

Cardiovascular Diseases↗
PubMedDate not supplied

Fascicular conduction disturbances following aortocoronary bypass surgery: the role of hypothermia versus potassium-arrest cardioplegia.

Two hundred and sixty six consecutive patients who underwent aortocoronary bypass surgery at our institution were studied to assess the incidence of developing new fascicular conduction disturbance. The first 66 patients (Group I) were operated on using systemic hypothermia and ventricular fibrillation while the next 200 patients (Group II) were operated on using systemic hypothermia plus 4 degrees C potassium cardioplegia. Twelve patients in Group I (18%) developed new fascicular conduction defects, an incidence similar to previous studies of patients operated on using similar conditions. A significantly higher incidence of new fascicular conduction defects occurred in Group II patients where 87 patients (43.5%) developed new defects (p less than .001). The most likely explanations for the marked increase in fascicular conduction defects in Group II patients were either local effects of high concentrations of potassium on the conduction system or excessive cooling of the posterior wall of the heart.

Adult↗