Effects of upright and supine position on cardiac rest and exercise response in aortic regurgitation

The effects of upright and supine position on cardiac response to exercise were assessed by radionuclide ventriculography in 15 patients with moderate to severe aortic regurgitation (AR) and in 10 control subjects. In patients with AR, heart rate was higher during upright exercise, but systolic and diastolic blood pressure and left ventricular (LV) output were similar during both forms of exercise. LV stroke volume and end-diastolic volume were not altered during supine exercise. LV end-systolic volume increased and ejection fraction decreased during supine exercise, but both were unchanged during upright exercise. Of 15 patients, 5 in the upright and 12 in the supine position had an abnormal LV ejection fraction response to exercise (p less than 0.01). Right ventricular ejection fraction increased and regurgitant index decreased with both forms of exercise and was not significantly different between the 2 positions. Thus, posture is important in determining LV response to exercise in patients with moderate to severe AR.     

Mechanisms for an abnormal radionuclide left ventricular ejection fraction response to exercise in patients with chronic, severe aortic regurgitation.

To clarify the mechanisms for an abnormal radionuclide left ventricular (LV) ejection fraction response to exercise in patients with chronic, severe aortic regurgitation (AR), we studied seven control patients and 21 patients with AR. We used exercise radionuclide angiography and catheterization of the right and left sides of the heart to obtain a calculation of LV chamber elastance. The control and AR groups had similar heart rates, systolic blood pressure responses to exercise, and exercise durations. In both patient groups, LV end-diastolic volume did not change with exercise. In contrast to the decrease in LV end-systolic volume (p less than 0.05) and increase in LV ejection fraction (p less than 0.01) in the control group, LV end-systolic volume in the patients with AR increased, resulting in little change in their LV ejection fraction. By stepwise multiple regression analysis, the radionuclide LV ejection fraction at peak exercise in patients with AR was determined by the LV chamber elastance, LV end-systolic volume, and stroke volume at peak exercise (cumulative r = 0.79, p less than 0.02); the change in radionuclide LV ejection fraction from rest to peak exercise was determined by the corresponding change in systemic vascular resistance, regurgitant index, and LV end-diastolic and end-systolic volumes (cumulative r = 0.88, p less than 0.02). These data demonstrate that in patients with AR, the radionuclide LV ejection fraction at peak exercise is principally determined by the cumulative effects of chronic, severe AR on LV systolic chamber performance, and the change in radionuclide LV ejection fraction from rest to peak exercise is principally established by peripheral vascular responses.     

Gamma-angiography during exercise in chronic aortic insufficiency. Development of ventricular function and regurgitation

Twenty-three patients with chronic aortic incompetence (17 men and 6 women) aged 27 to 71 years (average 51 years) underwent sequential gamma-angiography at rest and during the different levels of exercise and recovery phase to investigate the evolution of ventricular function and regurgitant fraction and so, guide therapy. The radionuclide indices of left ventricular function (end diastolic and end systolic indexed volumes, global ejection fraction, regional wall motion) and the regurgitant fractions were calculated and compared with clinical, echocardiographic, angiographic and haemodynamic data. The changes observed on effort during gamma-angiography allowed identification of 3 groups of patients: Group I: compensated aortic incompetence with a normal left ventricular ejection fraction (0.69 +/- 0.1), a moderate regurgitant fraction (40 per cent +/- 20 per cent) and, during exercise, a stable left ventricular end diastolic volume index (less than 5 per cent variation), an end systolic volume index which decreased (average-13 per cent), an ejection fraction which increases (by more than 0.05 in 62.5 per cent of cases) and with good global and regional wall motion. Group II: intermediate cases with a left ventricular ejection fraction of 0.62 +/- 0.09 and a regurgitant fraction of 60 +/- 16 per cent. Individual variations were observed with this group which either resembled those of Group I or those of Group III.(ABSTRACT TRUNCATED AT 250 WORDS)     

Left ventricular volume and ejection fraction response to exercise in aortic regurgitation

To test the hypothesis that left ventricular (LV) performance in aortic regurgitation (AR) can be more completely characterized by measurement of LV volumes in addition to ejection fraction (EF), 27 asymptomatic patients (Group 1), and 22 symptomatic patients (Group 2), and 10 control subjects were studied at rest and during upright bicycle exercise using the first-pass technique and a multicrystal scintillation camera. LV end-diastolic volume was measured by the area-length method. In the control group end-diastolic volume increased 14%, end-systolic volume decreased 22%, and EF increased 22% with exercise. In contrast, in Group 1 patients with AR, end-diastolic volume was elevated at rest and during exercise. The 18% decrease in end-diastolic volume during exercise was significantly different from the control response (p less than 0.01). End-systolic volume was also elevated at rest and during exercise, but the 30% decrease during exercise was a response not significantly different from the control. Although mean EF increased 15% in these patients, EF at peak exercise was significantly lower than that in the controls. In Group 2 patients with AR, resting EF was reduced, the EF response to exercise was abnormal, and end-diastolic and end-systolic volume responses to exercise were significantly different from those in Group 1: end-diastolic volume did not change and end-systolic volume increased. In contrast to the fairly uniform volume responses among all Group 1 patients, there were 2 subgroups based on volume changes within Group 2: 7 of 22 had a decrease in end-diastolic volume and end-systolic volume during exercise and 8 of 22 showed an increase in end-diastolic and end-systolic volume during exercise. In conclusion, LV volumes at rest and exercise give more information about LV functional reserve in symptomatic patients with AR than do EF responses alone, and may be useful in separating symptomatic patients who show a normal end-systolic volume response to exercise from those in whom worsening failure develops during exercise.     

Left ventricular volume response to exercise in normal and coronary artery disease patients

The left ventricular (LV) volume response to supine exercise (EX) was studied in 15 normal volunteers (mean age 44, asymptomatic, with normal resting ECG and treadmill stress test) and 28 coronary artery disease patients (CAD, documented by cardiac catheterization) with no previous myocardial infarction. Each individual underwent stress gated equilibrium radionuclide angiography (RNA) and was on no medication. A nongeometric count based LV volume programme developed in our laboratory (correlation to biplane cineangiography R = .98), was used to calculate end diastolic volume index (EDI), end systolic volume index (ESI), stroke volume index (SVI), cardiac index (CI), and ejection fraction (EF). In normal individuals, end diastolic volume did not change from rest to exercise, while end systolic volume decreased by an average of 16%. In the patients with coronary artery disease, however, both end diastolic volume and end systolic volume increased (14% and 15% respectively). Furthermore, our preliminary data suggest that the extent of the changes may be dependent upon the extent of the underlying CAD. While all the CAD patients had an increase in their end diastolic volumes, there was no change in the end systolic volume in those with single vessel disease, an 11% increase in patients with double vessel disease and a 19% in patients with triple vessel disease.     

Left ventricular filling in sickle cell anemia

M-mode echocardiography was performed on 11 normal black subjects and 38 patients with sickle cell anemia while they were at rest to evaluate their left ventricular (LV) systolic and diastolic function. The patients with sickle cell anemia were also evaluated by radionuclide exercise tests and, based on their ejection fraction (EF) response, were separated into 2 groups: a group with a normal EF response to exercise (73 +/- 9%, mean +/- standard deviation) and a group with an abnormal EF response to exercise (53 +/- 9%). Computer-assisted analysis of the M-mode echocardiograms identified abnormalities of diastolic function (impaired left ventricular filling) in patients with sickle cell anemia compared with the normal subjects. The abnormal EF response group had significantly more impaired diastolic function and did less exercise than the normal EF response group. Both groups of patients had a decrease in left ventricular end-diastolic volume during exercise. The patients with sickle cell anemia had abnormalities of systolic and diastolic function on echocardiographic and radionuclide testing. The abnormalities in diastolic and systolic function assumed greater significance at the increased heart rates associated with exercise, accounting for the decrease in left ventricular end-diastolic volume and the abnormal EF response, and contributed to exercise intolerance in patients with sickle cell anemia.     

Left ventricular ejection fraction response during exercise in asymptomatic systemic hypertension

To study the effect of mild-to-moderate elevations in diastolic blood pressure (BP) on systolic left ventricular (LV) function, 28 hypertensive patients and 20 normal subjects underwent upright exercise first-pass radionuclide angiography. All were asymptomatic, had normal rest and exercise electrocardiographic findings and no evidence of LV hypertrophy or coronary artery disease. LV function at rest was similar in the 2 groups, but with exercise hypertensive patients had a greater end-systolic volume (69 +/- 19 vs 51 +/- 19 ml, p less than 0.002) and lower ejection fraction (EF) (0.59 +/- 0.09 vs 0.72 +/- 0.07, p less than 0.0001), stroke volume (101 +/- 28 vs 130 +/- 36 ml, p less than 0.005) and peak oxygen uptake (23 +/- 7 vs 33 +/- 9 ml/kl/min, p less than 0.05). Hypertensive patients were separated into 3 groups: group 1-12 patients with an increase in EF with exercise greater than or equal to 0.05; group 2-7 patients with a change in EF with exercise less than 0.05; and group 3-9 patients with a decrease in EF with exercise greater than or equal to 0.05. Group 3 hypertensive patients were older, had a higher heart rate at rest and lower peak oxygen uptake. Rest LV function was similar in the 3 hypertensive subgroups, but exercise end-systolic volumes were higher in groups 2 and 3. Exercise thallium-201 images was normal in all but 1 of 14 hypertensive group 2 or 3 patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

Contribution of systolic and diastolic abnormalities to heart failure with a normal and a reduced ejection fraction

Heart failure (HF) has traditionally been divided into HF with a reduced ejection fraction (EF; systolic HF) and HF with a normal EF (diastolic HF). Both groups have reductions in exercise tolerance, neurohumoral activation, and abnormal left ventricular (LV) filling dynamics and impaired relaxation. Although the normal EF indicates that pump performance is adequately compensated, some of the patients with HF and a normal EF have reduced longitudinal systolic velocity indicating cardiac muscular contractile dysfunction. Regardless of EF, the severity of HF and its prognosis and degree of exercise intolerance are closely related to the degree of diastolic filling abnormalities. Patients with HF and a reduced EF have ventricular dilatation and elongated myocytes, whereas patients with HF and a normal EF do not. Thus, patients with HF have diastolic abnormalities regardless of EF and many patients with HF and a normal EF have contractile abnormalities despite preserved systolic pump performance. Heart failure with a normal EF and a reduced EF differs in the systolic LV pump performance and the type of remodeling. The mechanism of the differing remodeling responses is not known, but aging, sex differences, and diabetes may contribute.     

Comparison of effects of isometric and supine bicycle exercise on left ventricular performance in patients with aortic regurgitation and normal ejection fraction at rest

The effects of handgrip and supine bicycle exercise on hemodynamics and left ventricular (LV) performance were compared in 25 patients with moderate to severe aortic regurgitation (AR) and normal LV ejection fraction at rest (greater than or equal to 50%) and in 10 control subjects. In both groups, heart rate, systolic blood pressure, rate-pressure product, and LV output were higher during supine bicycle exercise. Compared with the controls, in patients with AR, stroke volume was unchanged during supine bicycle exercise. LV end-diastolic volume increased during handgrip exercise but was unchanged during supine bicycle exercise. LV end-systolic volume increased and ejection fraction decreased during both forms of exercise. Of 25 patients with AR, 15 (60%) during handgrip exercise and 19 (76%) during supine bicycle exercise had an abnormal ejection fraction response (p less than 0.05). In patients with moderate to severe AR and normal LV ejection fraction at rest, both handgrip and supine bicycle exercise induced LV dysfunction. An abnormal LV ejection fraction response occurred more often with supine bicycle exercise. Handgrip exercise may be a useful alternative method for detecting LV dysfunction in patients with AR in whom adequate bicycle exercise cannot be accomplished.     

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.     

Evaluation of myocardial deformation in patients with sickle cell disease and preserved ejection fraction using three-dimensional speckle tracking echocardiography

Background: Sickle cell disease (SCD) is a hemoglobinopathy that affects one in 500 African Americans. Although it is well established that patients with SCD have left ventricular (LV) diastolic dysfunction, it is not clear whether they have subtle LV systolic dysfunction despite preserved ejection fraction (EF). We used three-dimensional speckle tracking echocardiography (3DSTE) to assess changes in both systolic and diastolic LV function in SCD. Methods: Transthoracic real time 3D images were obtained (Philips iE33) in 56 subjects, including 28 stable outpatients with SCD (age 33 ± 7 years) and 28 normal controls (age 35 ± 9 years). 3DSTE was performed using prototype software (4DLV Analysis, TomTec) to obtain LV volume and deformation time curves, from which indices of systolic and diastolic LV function were calculated. Results: In SCD patients, 3DSTE-derived LV filling parameters were significantly different from normal controls, reflecting an increase in both rapid and atrial filling volumes and prolonged active relaxation, depicted by a decrease in filling volume fractions at fixed times and an increase in rapid filling duration. Global LV systolic function was not only preserved but increased compared to controls, as reflected by significantly increased global longitudinal strain. Importantly, twist angle and torsion as well as radial and circumferential components of 3D strain were similar in both groups. Conclusions: 3DSTE was able to confirm diastolic dysfunction, as expected in some patients with SCD. However, 3DSTE strain analysis did not reveal any changes in LV systolic function. These findings provide novel insight into the pathophysiology of the cardiovascular complications of SCD.     

Radionuclide angiographic evaluation of left ventricular performance at rest and during exercise in patients with aortic regurgitation

Radionuclide angiographic evaluation of LV performance at rest and during exercise in patients with AR have shown that an abnormal EF response to exercise may be observed in asymptomatic patients with normal resting LV function. The EF response to exercise has been correlated with a number of clinical and exercise measurements; important among these are the slope of the systolic pressure-to-end-systolic volume, end-systolic volume, cardiac index, pulmonary capillary wedge pressure, and wall stress. The changes in the regurgitant fraction, EF, and LV volume have shown considerable individual variability; they have also allowed a better understanding of the circulatory responses during exercise. Radionuclide angiography provides a reliable and reproducible method of measuring the rest LVEF that is important in the timing and the outcome of valve replacement. The value of the EF response to exercise in patient management is not yet clear; it is possible that other radionuclide-derived measurements at rest or during exercise, such as the systolic pressure-to-end-systolic volume relationship, and the end-systolic volume may provide complementary information to that provided by the EF.     

急性心肌梗死后早期左室功能变化的研究

为探讨急性心肌梗死（ＡＭＩ）发病后３ 周内不同时间左室功能的动态变化,应用彩色多普勒二维超声心动图对３２ 例ＡＭＩ患者分别于发病后１ 周、２ 周和３ 周连续测量并计算左室收缩功能和舒张功能的各项指标,并对其结果作对比分析。结果发现３２ 例ＡＭＩ患者中,１８例（５６％ ）有左室功能的降低,其主要变化为:左室舒张末期和收缩末期容积显著增加,而射血分数、短轴缩短率、平均周边纤维缩短速率明显降低（Ｐ＜ ０．０１）,二尖瓣舒张早期峰值血流速度减慢,晚期峰值血流速度增加。从ＡＭＩ后１ 周到３ 周,左室功能进行性发展,以左室容积的增加最为突出。可见ＡＭＩ后左室功能严重受损,其中左室容积的改变可作为早期评价左室功能的一个良好指标     

Cardiac correlates of exercise induced pulmonary hypertension in patients with chronic heart failure due to left ventricular systolic dysfunction

BACKGROUND: Patients with chronic heart failure (CHF) due to left ventricular systolic dysfunction (LVSD) may develop pulmonary hypertension at rest and during exercise. The cardiac correlates of pulmonary hypertension have been ascertained in the resting state, but seldom during exercise in these patients. AIMS: We sought to determine the cardiac correlates of exercise induced pulmonary hypertension in patients with LVSD by monitoring the estimated pulmonary artery systolic pressure (PASP) by continuous Doppler echocardiography during semirecumbent bicycle exercise. METHODS: Eighty-five patients (mean age 57 +/- 13 years, 75% male) with CHF due to LVSD (LV ejection fraction [EF] <45%, mean LVEF 26 +/- 8%) were studied. RESULTS: Mitral effective regurgitant orifice area and E-wave were independent predictors of resting PASP. Resting PASP and exercise induced changes in PASP were unrelated (r =-0.08, P = 0.45). Decrease in LV end-systolic volume, increase in left atrial (LA) area, resting LV asynchrony, and decreased tricuspid annular plane systolic excursion (TAPSE) were independent predictors of exercise PASP. CONCLUSIONS: Resting LV asynchrony, impaired LV contractile reserve, and increase in LA dilatation correlate with the severity of exercise induced pulmonary hypertension in patients with CHF due to LVSD, while right ventricular systolic dysfunction is inversely related to the severity of exercise induced pulmonary hypertension.     

Myocardial asynchronism is a determinant of changes in functional mitral regurgitation severity during dynamic exercise in patients with chronic heart failure due to severe left ventricular systolic dysfunction.

AIMS: Functional mitral regurgitation (MR) and myocardial asynchronism occur commonly in patients with dilated cardiomyopathy and affect adversely their prognosis and symptoms. The aim of this study was to evaluate the mechanisms of changes in MR severity during dynamic exercise in patients with chronic heart failure (CHF). METHODS AND RESULTS: Seventy patients with CHF due to left ventricular (LV) systolic dysfunction [LV ejection fraction (EF) <40%] and functional MR were studied. All were in sinus rhythm. Medications were left unchanged for the study. Each patient performed a maximal symptom-limited exercise test with continuous 2D-Doppler echocardiography. Mitral regurgitant volume (RV) and effective regurgitant orifice (ERO) were determined at rest and during exercise. LV asynchrony using Doppler tissue imaging and interventricular asynchrony using conventional pulsed-Doppler were evaluated at rest. Resting LV EF averaged 25+/-8%. Mean resting LV and interventricular mechanical delays were 56+/-50 and 43+/-37 ms, respectively. The overall median values for mitral ERO and RV did not significantly change during dynamic exercise (11 [7-16] vs. 11 [6-21] mm2 and 14 [10-22] vs. 12 [9-23] mL, respectively). However, changes in mitral ERO and RV were individually variable and significantly correlated with the degree of LV asynchronism (r=0.66, P<0.0001 and r=0.66, P<0.0001, respectively). CONCLUSION: Changes in MR are variable during dynamic exercise. LV asynchronism at rest substantially contributes to worsening of functional MR during dynamic exercise in patients with CHF due to LV systolic dysfunction.     

Left ventricular volume and ejection fraction response to exercise in chronic congestive heart failure: difference between dilated cardiomyopathy and previous myocardial infarction

To determine if cause influences the left ventricular (LV) volume and ejection fraction (EF) response to exercise, 24 patients with chronic congestive heart failure (CHF) (13 dilated cardiomyopathy [DC], CHF-DC group; 11 previous myocardial infarction [MI], CHF-MI group) and 6 age-matched control subjects underwent simultaneous hemodynamic monitoring and radionuclide ventriculography during semiupright bicycle exercise. Both CHF groups had similar hemodynamic values, LV volumes and EF at rest. Exercise hemodynamics were also similar, but LV volume and EF responses to exercise were different. In the CHF-DC group LV end-diastolic volume increased by 15% during exercise, significantly less (p less than 0.01) than the 44% increase in CHF-MI group. During exercise, EF increased in CHF-DC group, but did not change in CHF-MI group because of a larger increase in end-systolic volume. The slope of mean pulmonary wedge pressure-LV end-diastolic volume relation was steeper in CHF-DC group than in CHF-MI group (p less than 0.01). The study suggests that LV volume and EF response to exercise in patients with CHF depends on the origin of the CHF.     

Regulation of cardiac output during upright exercise in patients with aortic regurgitation

The change in cardiac output during upright exercise in patients with aortic regurgitation (AR) is not well known. We measured left ventricular (LV) ejection fraction (EF) and volume, regurgitant fraction (RF), total cardiac output and forward cardiac output at rest, and peak upright exercise by means of radionuclide angiography in ten normal subjects and 15 patients with AR. In the normal subjects, there was no significant change in the end-diastolic volume but there was a significant decrease in the end-systolic volume (p = 0.0001) and a significant increase in EF (p = 0.0001). The increase in cardiac output during exercise was due to increases in both stroke volume and heart rate. In patients with AR, there was a significant decrease during exercise in RF (53 +/- 15% at rest, and 45 +/- 15% during exercise; p = 0.03), and in end-diastolic and end-systolic volume (p = 0.02, and p = 0.003, respectively). The EF increased during exercise (p = 0.003). The total stroke volume did not change (68 +/- 19 ml/m2 at rest, and 67 +/- 14 ml/m2 during exercise; p, NS). Thus, in patients with AR, individual changes in EF, RF, and volume are quite variable, but as a group a decrease in RF and an increase in heart rate contribute to the increase in forward flow. The total stroke volume may not increase during exercise, despite an increase in EF and a decrease in end-systolic volume because of a concomitant decrease in end-diastolic volume.     

Left and right ventricular function during symptom-limited exercise in patients with isolated mitral stenosis

Ventricular function during exercise in patients with mitral stenosis has not been widely studied. Accordingly, 20 patients with isolated mitral stenosis were assessed during supine, symptom-limited equilibrium radionuclide ventriculographic studies. All patients had a normal left ventricular (LV) ejection fraction at rest (greater than or equal to 50 percent), and all were in sinus rhythm. Left ventricular ejection fraction rose (p less than 0.001) from 64 +/- 9 percent at rest to 74 +/- 11 percent during exercise. This normal response was due solely to a decrease (p less than 0.01) in exercise LV end-systolic volume. A significant (p less than 0.01) decrease in end-diastolic volume during exercise limited the increase in ejection fraction during exercise. The decrease in end-diastolic volume during exercise caused stroke volume to remain unchanged; cardiac output rose according to heart rate alone. Right ventricular (RV) ejection fraction did not rise with exercise due to an increase in end-systolic volume. With exercise, LV end-diastolic volume was smaller (p less than 0.05) with severe mitral stenosis compared to mild mitral stenosis. With exercise, RV ejection fraction was decreased (p less than 0.05) with severe compared to mild mitral stenosis. In conclusion, LV function during exercise is normal in patients with normal resting LV ejection fraction. A decrease in LV diastolic filling with exercise prevents a rise in stroke volume, and cardiac output increases by heart rate alone. With, exercise, RV ejection fraction does not rise, due to an increase in RV end-systolic volume.     

Cardiac Manifestations of Exhaustive Exercise in Nonathletic Adults: Does Cardiac Fatigue Occur?

The aim of the study was to examine the impact of prolonged exercise leading to physical exhaustion on left ventricular (LV) systolic and diastolic function in untrained healthy subjects, and to examine cardiovascular determinants of exercise performance. Twenty-four nonathletic healthy adults (14 males, 10 females; mean age 42 +/- 11 years) were exercised on a treadmill at 70% of maximal oxygen consumption until physical exhaustion occurred after an average of 84 +/- 39 minutes. Two-dimensional and Doppler echocardiography was performed before and 15 minutes after exercise to assess LV function and geometry, and right ventricular (RV) systolic function. After prolonged exercise, LV ejection fraction and geometry were unchanged, but LV end-diastolic volume, end-systolic volume, and stroke volume decreased. However, due to a higher heart rate (HR), cardiac output increased at 15 minutes post exercise. RV fractional shortening was unchanged. LV peak early to atrial filling velocity ratio decreased post exercise, with an increase in percent atrial contribution. However, less preload-dependent variables of LV diastolic function such as deceleration time, LV inflow propagation rate, mitral annular tissue Doppler and myocardial performance index were unchanged. Preexercise stroke volume and HR were the only predictors (r = 0.86, P < 0.01) of exercise duration. However, age, resting blood pressure, indices of systolic and diastolic function, and LV geometry were not predictors. Prolonged exercise leading to physical exhaustion is not associated with systolic or diastolic dysfunction. Reduced early LV diastolic filling and the relative increase in left atrial contribution seen with prolonged exercise are likely due to preload reduction rather than true diastolic dysfunction.     

Effect of angiotensin converting enzyme inhibitors and beta-blockers on left ventricular remodeling after coronary artery bypass graft surgery

Preventing left ventricular (LV) remodeling after coronary artery bypass graft surgery (CABG) is important to avoid long-term congestive heart failure. The present study evaluated the effects of angiotensin converting enzyme inhibitors (ACEIs) and beta-blockers on LV remodeling. Twenty-three patients with angina pectoris and 36 with old myocardial infarction underwent CABG. We assessed end diastolic volume index (EDVI), end systolic volume index (ESVI), and ejection fraction (EF) using left ventriculography before and after CABG. Changes in EDVI, ESVI, and EF were studied in the ACEI, beta-blocker, and control groups. Although EDVI was reduced in the ACEI group, ESVI and EF improved only slightly, whereas in the group given beta-blockers, ESVI was reduced, EF improved, and EDVI was minimally reduced. These results indicate that ACEIs and beta-blockers both protect against LV remodeling, although through different mechanisms.