David Wrisley

The prognostic value of functional capacity in patients with mild to moderate heart failure.

Thirty patients with ischemic (n = 14) or idiopathic dilated (n = 16) cardiomyopathy were followed long-term to determine the prognostic value of measuring entry exercise capacity. At the time of referral for management of symptomatic heart failure, studies included radionuclide angiography, M-mode echocardiography, 24-hour Holter and graded exercise testing with measured oxygen peak consumption (peak VO2). Inclusion criteria were NYHA class II (n = 16) or III (n = 14) despite at least 3 months of treatment with digitalis and diuretics, left ventricular ejection fraction less than 50%, left ventricular end-diastolic diameter (LVEDD) greater than 50 mm, and exercise capacity limited by dyspnea or fatigue. Patients were treated with diuretics (100%), digitalis (83%), and vasodilators (60%) and were followed for at least 6 months (mean 15). The 1-, 2- and 3-year cumulative survival rates were 75.4%, 70.2%, and 70.2%, respectively. Univariate predictors of survival included measured peak VO2 (p = 0.0026), as well as age, estimated peak VO2 (based on exercise time), presence of left bundle branch block, LVEDD, and frequency of ventricular arrhythmias. Multivariate analysis revealed that measured peak VO2 was the single best independent predictor of survival (p less than 0.001). We conclude that assessment of functional capacity provides useful independent prognostic information in patients with mild to moderate heart failure.

Aerobic Requirements of Arm Ergometry: Implications for Exercise Testing and Training

In brief: To compare the oxygen cost of submaximal and maximal arm and leg exercise, ten healthy men (mean age 28 years) underwent multistage arm and leg ergometer tests using standard open circuit calorimetry. VO2 during arm exercise was greater than leg exercise at any given work load. Peak work load during arm work (675 kpm-min(-1)) was only 55% of the peak work load during leg work (1,230 kpm-min(-1)). VO2 max during arm work (10.5 mets) was 80% of the VO2 max during leg work (13.2 mets). Since arm performance tends to be a poor predictor of leg performance and vice versa, arm ergometry appears to be the preferred exercise mode for the functional evaluation of select patients.

Cardiorespiratory Responses to Arm and Leg Ergometry in Women

In brief: To compare the cardiorespiratory responses to arm vs leg exercise in women with those previously reported for men, ten healthy women (mean age 29.8 years) underwent separate arm and leg ergometer tests to measure oxygen consumption (VO2) during submaximal and maximal exercise. VO2 during arm exercise was greater than that during leg exercise at any given submaximal work load. At maximal exercise, however, cardiorespiratory responses were generally greater during leg exercise. VO2 max during arm and leg ergometry was 1.60 and 2.02 liters·min−1, respectively. Although women have a lower arm VO2 max than men, it appears that their aerobic capacity for arm work is not disproportionately inferior to mens.