Cardiac function and maximal exercise capacity early after acute myocardial infarction.

The purpose of the study was to assess the relationship between left and right ventricular function measured at rest and maximal exercise capacity in patients with recent acute myocardial infarction (AMI). Forty-three male patients (Killip Class I, n = 36; Killip Class II, n = 7) with a wide range of left ventricular (LV) function and size underwent graded bicycle exercise testing less than 4 weeks after AMI (mean 21 days, 17-27). None of the patients had exercise limiting factors other than dyspnoea and fatigue. Left and right ventricular ejection fractions were determined by a radionuclide ventriculographic method which also allowed determination of absolute LV volumes and actual LV peak filling rate. LV ejection fraction had a weak association to estimated maximal oxygen uptake (VO2 max) (r = 0.37). No association was found between LV size, LV stroke volume, or LV peak filling rate and estimated VO2 max. Similarly, right ventricular ejection fraction showed no correlation to estimated VO2 max. Patients with well preserved LV function had a higher exercise induced increase in systolic blood pressure than patients with reduced LV function, but the increase in systolic blood pressure could not be used to estimate LV function with any reasonable accuracy. We conclude that the maximal exercise capacity of patients with recent AMI is virtually independent of their left and right ventricular function determined at rest, and that exercise testing and radionuclide ventriculography should be regarded as complementary procedures in the evaluation of patients with AMI.     

Effects of verapamil on left ventricular diastolic filling in children with hypertrophic cardiomyopathy

The effects of oral verapamil on resting left ventricular (LV) diastolic filling were examined in 10 children and adolescents with hypertrophic cardiomyopathy. Measurements of diastolic filling were made from gated technetium-99m radionuclide angiograms with postbeat rejection of data outside a 5% RR-interval window. LV time-activity curves were generated and the rapid-filling phase fit with a 3 degrees polynomial to calculate the peak filling rate and the time from end-systole to the point of peak filling. All patients had a radionuclide angiogram performed before and after 0.25 to 3 years of oral verapamil therapy. Verapamil did not change the LV ejection fraction but increased the peak filling rate (3.24 +/- 0.15 to 4.62 +/- 1.05 end-diastolic volume/s,p less than 0.01) and reduced the time to peak filling (217 +/- 57 to 168 +/- 63 ms, p less than 0.01). An increase in exercise endurance as measured by exercise treadmill test and subjective symptomatic improvement were also seen after verapamil therapy. Thus, in children with hypertrophic cardiomyopathy, symptomatic improvement and LV diastolic filling parameters improved with long-term oral verapamil.     

Restrictive filling pattern predicts pulmonary hypertension and is associated with increased BNP levels and impaired exercise capacity in patients with heart failure

BACKGROUND: Left ventricular (LV) diastolic dysfunction is a common finding in patients with systolic heart failure (HF). Severe diastolic dysfunction, which is defined as LV restrictive filling pattern (RFP), is associated with more severe HF, increased sympathetic activity and reduced exercise capacity. It has also been shown to be a predictor of lower survival rate in patients with HF. AIM: To evaluate associations between LV diastolic RFP and BNP levels, systolic pulmonary pressure and exercise capacity in patients with clinically stable HF. METHODS: In 56 patients with HF and low LVEF a standard echocardiographic study and cardiopulmonary exercise test were performed. Levels of BNP using RIA method were also measured. RESULTS: Restrictive filling pattern (E/A >2 or 1< E/A <2 and DTE < or =130 ms) was diagnosed in 26 patients. The RFP group showed increased levels of BNP (90.6+/-66 vs. 50.4+/-61 pg/ml; p=0.003), significantly reduced peak VO2 (15.4+/-4.1 vs. 17.8+/-4.9 ml/kg/min; p=0.046), increased VE/VCO2 slope (36.3+/-5.9 vs. 31.9+/-6.3; p=0.01), and elevated PASP (pulmonary artery systolic pressure measured by echo-Doppler) (49.3+/-13.8 vs. 37.2+/-12.6 mmHg; p=0.02). Prevalence of pulmonary hypertension was significantly higher in the RFP group. A significant correlation between DTE and peak VO2 (r=0.28; p=0.02) and inverse correlations between DTE and BNP levels (r=-048; p=0.003), VE/VCO2 slope (r=-0.35; p=0.02) and PASP (r=-0.39; p=0.03) were found. In logistic regression analysis only RFP was independently associated with pulmonary hypertension. CONCLUSIONS: The restrictive filling pattern is an independent predictor of pulmonary hypertension and is associated with increased BNP levels and worse result of cardiopulmonary exercise test.     

Correlates and prognostic implication of exercise capacity in chronic congestive heart failure

Previous studies have shown poor correlations between exercise tolerance and measurements of left ventricular (LV) function during rest in patients with congestive heart failure (CHF). To further evaluate the determinants of exercise tolerance and their relation to prognosis, we performed rest and exercise hemodynamic measurements and blood pool scintigraphy in 27 patients with CHF. All patients were treated with digitalis and diuretic drugs, but not vasodilator drugs. Exercise capacity was assessed by maximal oxygen consumption (VO2max) during upright bicycle ergometry. Both right ventricular (RV) and LV ejection fractions were measured by radionuclide techniques, and arterial, right atrial and pulmonary artery pressures, cardiac output, and derived hemodynamic indexes were determined. As a group, patients with severely impaired exercise tolerance (group 1, VO2max less than 10 ml/min/kg) had significantly higher rest pulmonary capillary wedge and right atrial pressures (30 +/- 4 vs 23 +/- 6 and 12 +/- 4 vs 7 +/- 2 mm Hg, respectively) than those with a VO2max of 10 to 18 ml/min/kg (group 2). They also had lower LV and RV ejection fractions (16 +/- 4% vs 21 +/- 4% and 19 +/- 12% vs 27 +/- 7%, respectively). However, overlap among individual patients was considerable, and only pulmonary capillary wedge pressure at rest correlated significantly (r = 0.69, p less than 0.001) with VO2max.(ABSTRACT TRUNCATED AT 250 WORDS)     

Mechanisms of exercise limitation in hypertrophic cardiomyopathy.

To assess the relation of exercise capacity to indexes of systolic and diastolic function in hypertrophic cardiomyopathy, 81 patients underwent two-dimensional echocardiography, technetium-99m equilibrium radionuclide angiography acquired in list mode and maximal, symptom-limited, treadmill exercise testing with measurement of maximal oxygen consumption (VO2 max). VO2 max for the group was 13.9 to 49.3 (mean 25.4) ml/min per kg. Thirty-six patients (44%) achieved less than or equal to 70% of age-predicted VO2 max. Patients with such a degree of limitation were more likely to be in New York Heart Association functional class II or III (23 of 36 vs. 14 of 45; p = 0.005); there was no such relation between VO2 and the incidence and magnitude of rest left ventricular outflow tract pressure gradient greater than 30 mm Hg (11 of 36 vs. 11 of 45; p = NS and 58 +/- 24 vs. 65 +/- 19 mm Hg; p = NS). In the 22 patients with a left ventricular outflow tract gradient, the ratios of peak ejection to peak filling rate and of atrial contribution to left atrial dimension were related to percent of the age-predicted VO2 max (r = 0.49, p = 0.02 and r = 0.54, p less than 0.02). These ratios reflect impaired left ventricular systolic performance and atrial systolic failure, respectively. Stepwise discriminant analysis revealed these two ratios to be the two strongest predictors (p = 0.0001) of patients with a left ventricular outflow tract gradient whose VO2 max was less than or equal to 70% of the age-predicted value (sensitivity 90%, specificity 100%).(ABSTRACT TRUNCATED AT 250 WORDS)     

Peak exercise left ventricular performance in normal subjects and in athletes assessed by first-pass radionuclide angiography.

The role of Frank-Starling law of the heart in determining the increase in cardiac output during exercise in humans is still controversial (e.g., the mechanisms responsible for the enhancement of left ventricular [LV] filling during the shortened diastolic interval). Ten weight lifters, 12 swimmers and 12 sedentary subjects who underwent maximal upright bicycle exercise testing were studied. First-pass radionuclide angiography was performed both at rest and at peak exercise using a multicrystal gamma camera. Compared with resting values, heart rate and cardiac index at peak exercise increased by 101 +/- 16 beats/min (p less than 0.001) and 6.7 +/- 2.8 liters/min/m2 (p less than 0.001) in weight lifters, by 96 +/- 9 beats/min (p less than 0.001) and 9.5 +/- 2 liters/min/m2 (p less than 0.001) in swimmers, and by 103 +/- 9 beats/min (p less than 0.001) and 7.3 +/- 1.8 liters/min/m2 (p less than 0.001) in sedentary subjects. Stroke volume increased by 20.5 +/- 9.8 ml/m2 (p less than 0.001) in swimmers only. End-diastolic volume at peak exercise did not change in weight lifters and in swimmers; it decreased by 8.2 +/- 8.6 ml/m2 (p less than 0.01) in sedentary subjects. A significant correlation was found between the decrease in end-systolic volume and the increase in peak rapid filling rate at peak exercise in all 3 groups (r = 0.65, p less than 0.05 in weight lifters; r = 0.59, p less than 0.05 in swimmers; r = 0.67, p less than 0.05 in sedentary subjects.(ABSTRACT TRUNCATED AT 250 WORDS)     

brain natriuretic peptide levels predict functional capacity in patients with chronic heart failure

OBJECTIVES: The goal of this study was to determine if brain natriuretic peptide (BNP) levels are associated with exercise capacity in patients with chronic heart failure (HF). BACKGROUND: Plasma levels of BNP are increased subject to the degree of systolic and diastolic left ventricular dysfunction in patients with chronic HF. Exercise testing is useful to assess functional capacity and prognosis in chronic HF. METHODS: We prospectively studied 70 consecutive patients with chronic HF (60.3 +/- 10.4 years, 51 men) referred for cardiopulmonary exercise testing. Resting BNP was obtained after 10 min of supine rest before symptom-limited bicycle exercise testing. RESULTS: In patients with chronic HF, BNP levels correlated with oxygen uptake (VO(2)), both at anaerobic threshold (VO(2)AT: r = -0.54, p < 0.001) and peak exercise (peak VO(2): r = -0.56, p < 0.001). Impairment of ventilatory efficiency (EqCO(2): r = 0.43, p < 0.001) and maximum exercise level (W % predicted: r = -0.44, p < 0.05) correlated less well with BNP. There was a significant inverse correlation between left ventricular ejection fraction and BNP (r = -0.50, p < 0.05). Brain natriuretic peptide discriminated well chronic HF patients with a peak VO(2) <10 ml/min/kg (area under the receiver operating characteristic [ROC] 0.93) or <14 ml/min/kg (area under the ROC 0.72). A BNP >316 pg/ml was associated with a risk ratio of 6.8 (95% confidence interval, 2.3 to 19.8) for a reduced exercise capacity with a peak VO(2) <14 ml/min/kg. CONCLUSIONS: Brain natriuretic peptide is clearly associated with exercise capacity in chronic HF. Brain natriuretic peptide levels show a significant correlation with the impairment of VO(2) at peak exercise and anaerobic threshold. Brain natriuretic peptide is able to differentiate between chronic HF patients with moderately and severely impaired exercise capacity.     

The effect of left ventricular systolic function on maximal aerobic exercise capacity in asymptomatic patients with coronary artery disease

The purpose of this study was to examine the relationship between maximal O2 uptake (VO2max) and left ventricular systolic function in patients with coronary artery disease. We studied 27 patients, age 50 +/- 10 years (mean +/- SD), who were asymptomatic and able to attain true VO2max. VO2max was defined by the leveling-off criterion and/or a respiratory exchange ratio of 1.15 or greater. Left ventricular ejection fraction was determined by gated cardiac blood pool imaging. In patients whose ejection fraction decreased with exercise, VO2max was 21 +/- 4 vs 27 +/- 4 ml/kg/min in those whose ejection fraction increased (p less than .001). Systolic blood pressure/end-systolic volume relation was shifted upward and to the right in the former group in response to peak exercise. In contrast, the pressure-volume relation was shifted upward and to the left in patients whose ejection fraction increased with exercise. Ejection fraction at rest did not correlate with VO2max. There was a significant but weak correlation between peak exercise ejection fraction and VO2max (r = .43, p less than .025). Left ventricular exercise reserve, i.e., the change in ejection fraction from rest to exercise, correlated with VO2max (r = .77, p less than .0002), maximal O2 pulse (r = .50, p less than .005), and maximal heart rate during treadmill exercise (r = .61, p less than .001). Maximal heart rate during treadmill exercise correlated with VO2max (r = .70, p less than .0002).(ABSTRACT TRUNCATED AT 250 WORDS)     

Relation between left ventricular functional reserve during exercise and resting systolic loading conditions in chronic aortic regurgitation

The relation between systolic loading conditions at rest and left ventricular (LV) functional response to exercise was assessed in 31 patients with aortic regurgitation (AR) (20 asymptomatic, 11 symptomatic) and 10 control subjects. Peak and end-systolic wall stress determined from echocardiography and cuff systolic pressure at rest were used as indirect measures of LV systolic loading and were compared with LV ejection fraction response to handgrip and bicycle exercise by radionuclide ventriculography. Both peak and end-systolic wall stress were significantly higher in both asymptomatic (164 +/- 33 and 90 +/- 25 X 10(3) dynes/cm2) and symptomatic (196 +/- 33 and 134 +/- 17 X 10(3) dynes/cm2) patients with AR than in the control subjects (125 +/- 22 and 61 +/- 14 X 10(3) dynes/cm2 p less than 0.01), and correlated inversely with the changes in LV ejection fraction during handgrip (r = -0.63 and r = -0.73) and bicycle (r = -0.68 and r = 0.87) exercise. In patients with AR, resting systolic loading conditions closely reflect LV functional reserve during exercise.     

Impact of left ventricular diastolic function on exercise capacity in patients with chronic mitral regurgitation: an exercise echocardiography study

BACKGROUND: Mitral regurgitation (MR) is known as one of the most frequent causes of heart failure and sudden death. In spite of increasing prevalence of MR, there have been no available data on cardiac determinants of exercise capacity in patients with chronic MR. HYPOTHESIS: This study aimed to investigate cardiac determinants of exercise capacity in patients with chronic MR. METHODS: We consecutively enrolled 32 patients (11 men, mean age: 44 +/- 14 years) who had greater than moderate MR with normal left ventricular (LV) systolic function (LV ejection fraction >50%). Conventional echocardiographic indices and parameters measured by Doppler tissue imaging at septal side of mitral annulus were obtained before exercise. Mitral regurgitation fraction, forward stroke volume, pulmonary venous flow velocities, and systolic pulmonary artery pressure (sPAP) were also obtained with standard methods. RESULTS: Left ventricular ejection fraction was 61 +/- 6% and MR fraction was 48 +/- 13%. All patients finished a symptom-limited treadmill exercise test with a peak heart rate of >85% of predicted maximum heart rate. Mean exercise time was 9.95 +/- 2.17 min, corresponding to 11 +/- 2 metabolic equivalents. Among pre-exercise echocardiographic variables, only early diastolic mitral annulus velocity (E') and pulmonary venous reversal flow velocity (PVa) showed a significant correlation with exercise time (r = 0.44, p = 0.011, and r = -0.40, p = 0.040, respectively), which persisted after multivariate analysis (p = 0.011 and 0.038, respectively). Other parameters such as systolic mitral annulus velocity, resting and postexercise sPAP, forward stroke volume, LV size, LV ejection fraction, left atrial size, and regurgitant fraction showed no significant correlation. CONCLUSIONS: Left ventricular diastolic function is an important determinant of exercise capacity in patients with chronic MR. Both E' and PVa, accepted surrogate estimates for LV diastolic function, may be useful for identifying patients with chronic MR and with poor exercise capacity.     

Systemic and left ventricular responses to exercise stress in asymptomatic patients with valvular aortic stenosis.

Patients with heart disease may have myocardial ischemia or left ventricular (LV) dysfunction without symptoms. The exercise responses of 14 asymptomatic patients with valvular aortic stenosis (AS) were studied using treadmill testing, thallium-201 scintigraphy and radionuclide angiography. Compared with age- and gender-matched control subjects, patients with AS demonstrated reduced exercise tolerance (10.7 +/- 2.5 vs 13.3 +/- 4.2 min; p = 0.06) and maximal oxygen consumption (26.7 +/- 6.3 vs 36.3 +/- 9.5 ml O2/min/kg; p = 0.004) associated with decreased peak systolic blood pressure response to exercise (177 +/- 18 vs 214 +/- 42 mm Hg; p less than 0.004). Ten of 14 patients developed ST-segment depression during exercise, only 3 of whom had reversible thallium defects. Patients with AS tended to have greater LV ejection fractions at rest (65 +/- 11 vs 58 +/- 7; p = 0.08) and significantly decreased early peak filling rates (4.8 +/- 1.3 vs 6.1 +/- 0.6 stroke volume/s; p = 0.003) compared with those of control subjects. During maximal supine exercise, patients with AS had less of an increase in ejection fraction (2 +/- 9 vs 15 +/- 7%; p less than 0.001) associated with a decrease in end-diastolic (-7 +/- 15 vs +5 +/- 16%; p = 0.06) and stroke (-6 +/- 17 vs +30 +/- 13%; p less than 0.001) volumes from baseline measurements.(ABSTRACT TRUNCATED AT 250 WORDS)     

Left ventricular apical rotation is related to ambulatory blood pressure and body mass in healthy elderly females

OBJECTIVE: The interaction between left ventricular (LV) apical rotation, blood pressure (BP) and body mass in elderly females may reveal mechanisms involved in the syndrome of diastolic heart failure. METHODS: Thirty-one healthy females, age 69-84 years, were studied with echocardiography, ambulatory BP and an exercise capacity (VO2peak) test. RESULTS: LV apical short-axis loops were eligible for speckle tracking analysis in 27 subjects. Peak apical rotation (PAR) correlated inversely with diastolic BP (r = -0.47, p = 0.01). PAR correlated positively with stroke volume and body weight (p<0.05), but not with VO2peak (n = 19, p = ns). PAR also correlated with peak rotation velocity in systole (r = 0.76, p<0.0001) and in diastole (r = 0.58, p = 0.001). Diastolic peak rotation velocity correlated with mitral E wave peak velocity (r = 0.48, p = 0.01). There was a significant reduction in LV volumes during the 4 years of follow-up. CONCLUSIONS: In healthy elderly females, there seems to be an interaction between LV apical rotation, BP and body mass. Peak apical rotation and peak diastolic rotation velocity correlate with indices of LV filling and ejection, indicating that suction, a crucial element for effective early LV filling, may be preserved in healthy elderly subjects. Suction deteriorates with elevations of the arterial BP. An age- and BP-related reduction in LV end-diastolic volume may represent an additional impediment to LV filling. Both features may contribute to the development of LV diastolic dysfunction and to episodes of diastolic heart failure.     

Value of the Bruce protocol to determine peak exercise oxygen consumption in patients evaluated for cardiac transplantation

BACKGROUND: Peak exercise oxygen consumption (peak VO2) is an important discriminator of survival in patients with systolic heart failure and is used to select ambulatory patients for transplantation. The major trials assessing the relationship between peak VO2 and survival have used a variety of low-level exercise protocols. It is unknown how peak VO2 measured in this patient population by the more vigorous Bruce treadmill protocol compares with that obtained on less intense protocols. METHODS: We studied 15 patients (50 +/- 12 years old) with severe heart failure (left ventricular ejection fraction 23.5% +/- 8.6%). Patients randomly performed 3 exercise tests with the Bruce treadmill, modified Naughton treadmill, and modified bicycle protocols within 14 days. To determine the ability of this patient population to perform the Bruce protocol, we also retrospectively analyzed the ability of 84 patients to perform this test on their initial evaluations at our center. RESULTS: All patients reached the anaerobic threshold (AT) on all 3 protocols. The Bruce and modified Naughton treadmill protocols resulted in similar peak VO2 percent predicted peak VO2, and VO2 at AT values (17.7 +/- 3.8 mL/kg/min, 57.2% +/- 21.1% and 15.4 +/- 4.1 mL/kg/min vs 18.0 +/- 4.7 mL/kg/min, 58.1% +/- 22.5% and 15.6 +/- 4.4 mL/kg/min, respectively). Peak VO2 and VO2 at AT on both treadmill protocols were higher than those obtained with bicycle testing (15.3 +/- 3.1 and 11.8 +/- 3.0 mL/kg/min, P <.05). Exercise duration was shorter with the Bruce and bicycle protocols (6.2 +/- 2.2 and 6.7 +/- 2.4 minutes, respectively) compared with the modified Naughton protocol (9.7 +/- 4.3 minutes, both P <.005). In addition, 79 of the 84 patients (94%) evaluated were able to complete the Bruce protocol and reach AT. CONCLUSIONS: The Bruce protocol was more time efficient than the modified Naughton protocol and yielded similar peak VO2, percent predicted peak VO2, and VO2 at AT values. Bicycle exercise may underestimate peak VO2 values. The form of exercise should be considered when assessing peak VO2 criteria for transplant listing.     

Relation of "inotropic reserve" to functional capacity in heart failure secondary to ischemic or nonischemic cardiomyopathy

Exercise capacity in patients with dilated cardiomyopathy, measured by peak oxygen consumption (VO(2)) during exercise, has virtually no relation to resting left ventricular (LV) function. We hypothesized that exercise-induced inotropic reserve may explain some of the variation between peak VO(2) and resting LV function. Treadmill stress echocardiography was performed simultaneously with peak VO(2) measurements in 35 patients with dilated cardiomyopathy. Resting and immediate postexercise echocardiographic images were scored for change in segmental contractility using the American Society of Echocardiography 16-segment system. Segment scores were summed and divided by 16 to determine the wall motion index. Right ventricular (RV) function was quantified on a 4-point scale. Patients had a mean age of 52 +/- 12 years (8 women) and a mean ejection fraction of 30 +/- 10 (25 nonischemic patients). Average peak VO(2) was 17.0 +/- 6 ml/kg/min. Patients were divided into 2 groups by peak VO(2): a high VO(2) group, >17 ml/kg/min (17 patients) and a low VO(2) group, < or =17 ml/kg/min (18 patients). LV ejection fraction was similar between the high and low VO(2) groups (31 +/- 9% vs 28 +/- 11%, p = NS) as were etiology of heart failure, medications used, and LV volume. In the high VO(2) group, wall motion index improved from 2.28 +/- 0.20 to 2.12 +/- 0.31 during exercise (p = 0.009). There was no improvement in the low VO(2) group. Resting RV function was significantly better in the high VO(2) group (1.4 +/- 0.8 vs 0.6 +/- 0.6 p = 0.004). Therefore, in patients with dilated cardiomyopathy and similar resting LV function, the presence of demonstrable LV inotropic reserve and preserved RV function partially account for variation in exercise performance.     

Left ventricular hypertrophy and impaired diastolic filling in essential hypertension. Diastolic mechanisms for systolic dysfunction during exercise

Left ventricular ejection fraction is normal at rest but may respond abnormally to exercise in many patients with essential hypertension. To assess the determinants of the abnormal ejection fraction response to exercise, we performed radionuclide angiography at rest and during exercise in 41 hypertensive patients without coronary artery disease. In 22 patients (group 1), the ejection fraction increased more than 5% during exercise; in the other 19 patients (group 2), the ejection fraction either increased by less than 5% or decreased with exercise. Left ventricular diastolic filling was impaired at rest in patients in group 2 compared with group 1, with reduced peak filling rate (2.5 +/- 0.4 vs. 3.1 +/- 0.7 end-diastolic volume/sec; p less than 0.01) and prolonged time to peak filling rate (175 +/- 28 vs. 153 +/- 22 msec; p less than 0.01). Impaired diastolic filling in group 2 was associated with less augmentation in end-diastolic volume during exercise compared with group 1 (p less than 0.01). These observations were not dependent on the threshold value that was arbitrarily chosen to define an abnormal ejection fraction response, as there were significant correlations for the entire group between the magnitude of change in ejection fraction with exercise and both the resting peak filling rate (r = 0.46) and the change in end-diastolic volume with exercise (r = 0.62).(ABSTRACT TRUNCATED AT 250 WORDS)     

Cardiopulmonary exercise variables in diastolic versus systolic heart failure

The response to cardiopulmonary exercise (CPX) in patients with heart failure (HF) with normal left ventricular (LV) ejection fractions (EFs) is not well characterized. To determine if CPX testing could distinguish between patients with HF with normal EFs (>50%; i.e., diastolic HF) and those with decreased EFs (> or =50%; i.e., systolic HF), CPX responses were compared between 185 patients with systolic HF (79% men, mean age 62.6 +/- 10.9 years) and 43 with diastolic HF (54% men, mean age 67.4 +/- 9.8 years) enrolled in a phase II multicenter clinical trial. All patients were evaluated with echocardiography and a standardized CPX test as part of the trial. CPX variables, including oxygen uptake at peak exercise (peak VO(2)) and the slope of the ventilation/carbon dioxide production ratio (VE/VCO(2)), were determined and analyzed by core laboratory personnel. Echocardiographic measurements included the LV EF, the E/A ratio, filling time, cavity volumes, right ventricular function, and mitral regurgitation. Patients in the diastolic HF group tended to be older (p <0.08), with more women (p <0.006) and with greater body mass indexes (p <0.02), than those in the systolic HF group. There was no significant difference in the use of beta blockers or the incidence of coronary artery disease. Patients with diastolic HF had decreased E/A ratios (0.9 +/- 0.4 vs 1.4 +/- 1.1, p <0.02, diastolic HF vs systolic HF) and increased filling times (30.4 +/- 3.2 vs 26.5 +/- 4.7 ms, p <0.01, diastolic HF vs systolic HF). No significant differences in peak VO(2) (14.4 +/- 1.9 vs 15.6 +/- 3.2 ml/kg/min, p = 0.06, diastolic HF vs systolic HF) were observed. The VE/VCO(2) ratios for the 2 groups were abnormal and comparable (32 2 +/- 7.5 vs 34.0 +/- 8.3, p = 0.3, diastolic HF vs systolic HF). In conclusion, the CPX response in patients with diastolic HF and systolic HF is markedly abnormal and indistinguishable with regard to peak VO(2) and ventilation despite marked differences in the LV EF.     

Hemodynamic characteristics during treadmill and bicycle exercise in chronic heart failure: mechanism for different responses of peak oxygen uptake

The exercise capacity of patients with chronic heart failure (CHF) is greater when assessed by the treadmill rather than the bicycle ergometer, but the mechanism of this difference has not been clarified. The present study aimed to determine the difference between the hemodynamics of these exercise modes and the mechanism underlying the different peak oxygen uptake (VO2). Patients (n = 18) underwent a bicycle test and treadmill test using individual ramp protocols. Respiratory gas analysis and hemodynamic measurements with an opti-catheter were performed during both exercise tests. The peak VO2 was significantly larger in the treadmill test than the bicycle test (1410+/-292 vs. 1630+/-331 ml/min, p<0.001). Both the peak cardiac output (Q; 10.2+/-2.2 vs. 10.9+/-2.1 L/min, p<0.001) and the peak arteriovenous oxygen difference (a-v 02 diff; 13.9+/-1.5 vs. 15.0+/-1.2 vol%, p<0.001) were also significantly higher in the treadmill test. The relative contribution of Q and a-v O2 diff to the increased peak VO2 was equivalent, which suggests that both Q and a-v O2 diff. Contribute equally to the different peak VO2 responses in CHF.     

Left ventricular diastolic filling pattern predicts cardiopulmonary determinants of functional capacity in patients with congestive heart failure

BACKGROUND: Abnormalities of diastolic function are an important determinant of exercise intolerance in patients with heart failure. However, the relation between left ventricular filling pattern and cardiopulmonary exercise performance has not been adequately studied. METHODS: Thirty-one patients with idiopathic (n = 14) or ischemic (n = 17) dilated cardiomyopathy, demonstrated by coronary angiography, and radionuclide ejection fraction 30.5% +/- 9% underwent cardiopulmonary exercise testing with a modified Naughton protocol and a complete echocardiographic study. Patients were subdivided into restrictive and nonrestrictive groups according to their Doppler transmitral flow pattern. Gas exchange data were measured during exercise testing. The relation of left ventricular filling pattern to cardiopulmonary parameters was assessed in both groups. RESULTS: Exercise duration was similar in the restrictive and nonrestrictive groups but significant differences were found in oxygen consumption (VO(2)) at peak exercise (14.3 +/- 2.4 vs 20.4 +/- 4.7 mL/kg per minute; P <.001) and at the anaerobic threshold (VO(2AT)) (13 +/- 2.2 vs 17.3 +/- 3 mL/kg per minute; P <.001). Simple linear regression analysis revealed that both peak VO(2) and VO(2AT) were significantly correlated with the ratio of peak early (E wave) to late (A wave) transmitral filling velocity, early filling deceleration time, atrial filling fraction, and A-wave velocity but not with left ventricular ejection fraction. Multivariate regression analysis gave only the peak A-wave velocity as an independent predictor for both peak VO(2) and VO(2AT). CONCLUSIONS: In patients with heart failure, abnormalities of diastolic function are the most important determinant of exercise intolerance. A restrictive transmitral flow pattern by Doppler echocardiography is a marker of diminished cardiopulmonary exercise performance in these patients.     

Impaired cardiac performance in elderly patients with growth hormone deficiency

Several evidences indicate that GH and/or insulin-like growth factor I (IGF-I) are involved in the regulation of cardiovascular function. In patients with childhood and adulthood-onset GH deficiency (GHD), the impairment of cardiac performance is manifest primarily as a reduction in the left ventricular (LV) mass (LVM), inadequacy of LV ejection fraction both at rest and at peak exercise, and abnormalities of LV diastolic filling. No study has been reported to date in elderly GHD patients that investigated cardiac function. In particular, it is unknown whether cardiac function is modified in accordance with patients' age as a physiological response to aging, as in normal subjects the rate and extent of LV filling are reduced with age. This study was designed to evaluate heart morphology and function, by echocardiography and equilibrium radionuclide angiography, respectively, in rigorously selected elderly patients with GHD but without evidence of other complications able to affect cardiac performance. Eleven patients with hypopituitarism (6 men and 5 women, aged 60-72 yr) and 11 sex- age- and body mass index-matched healthy subjects entered this study. None of the patients and controls presented with or had previously suffered from other concomitant diseases, such as diabetes mellitus, coronary artery diseases, long-standing hypertension, and hyperthyroidism, which could affect cardiac function. All patients had been previously operated on via the transsphenoidal and/or transcranic route for nonfunctioning pituitary adenoma, meningioma, or craniopharyngioma, and 6 of them had been irradiated. Eight patients had FSH/LH insufficiency, 5 had TSH insufficiency, and 6 had ACTH insufficiency, appropriately replaced. All subjects were tested with the combined arginine plus GHRH test showing a GH response below 9 microg/L. No significant difference was found in plasma IGF-I levels (49.2 +/- 8.5 vs. 71.8 +/- 7.5 microg/L) between patients and controls. However, IGF-I levels were lower than the normal range in 8 patients and 3 controls. Interventricular septum thickness (9.1 +/- 0.2 vs. 9.1 +/- 0.2 mm), LV posterior wall thickness (9.1 +/- 0.2 vs. 9.0 +/- 0.2 mm), and LVM after correction for body surface area (97.6 +/- 1.8 vs. 99.9 +/- 1.5 g/m2) were similar in patients and controls. Similarly, the LV ejection fraction at rest was similar in patients and controls (57.1 +/- 2% vs. 63.2 +/- 2.5%; P = NS), and it was normal (> or = 50%) in all controls and in 10 of 11 patients. By contrast, the LV ejection fraction at peak exercise was markedly depressed in elderly GHD patients compared to age-matched controls (51 +/- 2.5% vs. 73.3 +/- 3%; P < 0.001). A normal response (> or = 5% increase compared to basal value) of LV ejection fraction at peak exercise was found in 8 controls (72.7%) and in 2 of 11 patients (18.2%). No difference was found in the peak rate of LV filling, whether peak filling rate was normalized to end-diastolic volume (2.5 +/- 0.2 vs. 2.6 +/- 0.2 end-diastolic volume/s) or stroke volume (4.3 +/- 0.3 vs. 4.0 +/- 0.3 stroke volume/s), between patients and controls. Finally, exercise duration was significantly shorter in elderly GHD patients than in age-matched controls (7.2 +/- 2.1 vs. 9.1 +/- 0.2 min; P < 0.01). In the patient group, the GH peak after arginine plus GHRH test was significantly correlated with the LV ejection fraction at rest (r = 0.822; P < 0.01), whereas IGF-I was significantly correlated with the peak rate of LV filling whether the peak filling rate was normalized to end-diastolic volume (r = -0.863; P < 0.001) or stroke volume (r = -0.616; P < 0.05) or expressed as the ratio of peak filling rate to peak ejection fraction rate (r = -0.736; P < 0.01). Disease duration was significantly correlated with heart rate at peak exercise (r = 0.614; P < 0.05) and with systolic and diastolic blood pressures both at rest (r = 0.745; P < 0.01 and r = 0.650; P < 0.05) and at peak exercise (r = 0.684; P < 0.05 and r =     

Impaired left ventricular filling and regional diastolic asynchrony at rest in coronary artery disease and relation to exercise-induced myocardial ischemia

Impaired left ventricular (LV) diastolic filling at rest is frequently observed in patients with coronary artery disease (CAD) who have normal LV systolic function and no previous infarction. To test the hypothesis that abnormal diastolic function at rest might reflect the functional severity of CAD, as estimated by exercise-induced ischemia, the relation between regional and global LV diastolic function at rest and during exercise-induced ischemia was evaluated in 49 patients with radionuclide angiography. All patients had normal systolic function at rest. Group 1 (n = 26) patients manifested a normal ejection fraction response to exercise and group 2 (n = 23) patients an abnormal response. Data obtained from 22 age-comparable normal volunteers were used for comparison. Although regional and global diastolic function were not different between normal subjects and group 1 patients, peak filling rate was lower in group 2 patients than in normal subjects (2.5 +/- 0.8 vs 3.2 +/- 0.6 end-diastolic counts/s; p less than 0.01). Moreover, regional diastolic asynchrony, as assessed from the radionuclide data by using a regional sector analysis of the LV region of interest, was greater in group 2 patients (46 +/- 44 ms) than in both normal subjects (25 +/- 16 ms; p less than 0.05) and group 1 patients (23 +/- 16 ms; p less than 0.05). Thus, among patients with CAD and with normal LV systolic function at rest, impaired LV filling and regional asynchrony predict a greater degree of exercise-induced ischemia, suggesting a greater extent of jeopardized myocardium.