马拉松赛对中老年人心脏结构、功能和血清酶的影响

为了了解中老年人马拉松赛后心脏结构、功能和血清磷酸肌酸激酶及同功酶变化的特点,对参加加拿大国家马拉松赛的10名50—73岁的马拉松运动员进行观察并与10名50岁以下的马拉松运动员作了比较,发现50岁以上有训练的马拉松运动员有较好的血管调节功能和良好的心脏代偿能力。血清磷酸肌酸激酶同功酶的变化,反映了马拉松跑对老年人心脏的影响。     

A method for measuring mean circumferential fiber shortening rate from gated blood pool scans

Ejection fraction and ejection rate are easily obtained from gated cardiac images, but no method is available for calculating mean circumferential fiber shortening rate. We assumed that the cube root of left ventricular end-diastolic volume or counts is proportional to the minor axis of the left ventricle at end-diastole or end-systole. Mean circumferential fiber shortening rate is then equal to the [cube root of the end-diastolic volume (count) minus cube root of end-systolic volume (count)] divided by [cube root of end-diastolic volume (count) multiplied by the ejection time]. In 250 contrast ventriculograms, the standard mean circumferential fiber shortening rate (MCFSR) and that derived by the cube root method correlated well (r = 0.94). The mean value of MCFSR (0.85 +/- 0.35) was greater than the cube root value (0.75 +/- 0.35) (P less than 0.001). The regression equation was y = 0.86x + 0.02. Similar correlations were obtained from gated radionuclide images using a semiautomated program (r = 0.93) in 24 subjects or completely automated program (r = 0.85) in 28 patients. The regression equation between MCFSR and that derived from the cube root of counts for the semiautomated program was y = 0.82x + 0.04 and for the automated program was y = 0.84x + 0.004. Similar correlations, slopes, and intercepts were seen using circumferential fractional shortening for angiographic data when correlated with both the semiautomated and automated gated blood pool scan programs. These data indicate that MCFSR and circumferential fractional shortening may be obtained from gated blood pool images using cube root estimates of end-diastolic and end-systolic radii with a high degree of correlation with the standard contrast ventriculographic technique.     

Quantitative relationship between global left ventricular thallium uptake and blood flow: effects of propranolol, ouabain, dipyridamole, and coronary artery occlusion

The quantitative relationship between fractional myocardial thallium uptake and radioactive microsphere-determined flow was studied in 33 open chest dogs under baseline conditions during increased coronary flow (dipyridamole), decreased coronary flow (propranolol and coronary artery stenosis), inhibition of Na-K ATPase (ouabain), and regional infarction. Myocardial contents of thallium and microspheres were compared in left ventricular (LV) biopsies taken 5, 10, 15, 30, and 60 min after thallium injection, expressed as fractions of injected dose. Maximal LV thallium uptake occurred 10 min after injection and the 10-min values were therefore used for subsequent comparisons. Combining all dogs, fractional LV thallium content (% injected dose) correlated well with fractional LV blood flow (% cardiac output) (r = 0.95). However, for fractional LV flows in the low, normal, or moderately elevated range (LV flow/cardiac output less than 9%), thallium content consistently exceeded flow by about 15%. This relationship was not altered by ouabain or regional ischemia or infarction. For greatly elevated fractional LV flows (greater than 9%), thallium content was not significantly different from flow. To explain these differences, myocardial and systemic extraction fractions for thallium were determined in eight dogs with a dual tracer method. At baseline, myocardial extraction fraction was significantly greater than systemic (88 +/- 0.4% compared with 75 +/- 1%, p less than 0.001). During dipyridamole, myocardial extraction fraction decreased and myocardial and systemic values were no longer significantly different (82 +/- 1% compared with 79 +/- 1%). These results show that the fraction of injected thallium dose taken up by the LV myocardium exceeds the delivered fraction of cardiac output over a wide range of LV flows, and is not altered by ouabain-induced inhibition of sodium-potassium ATPase or regional myocardial infarction. This difference is explained by a greater myocardial than systemic extraction fraction for thallium. During high LV flows produced by dipyridamole, fractional LV thallium uptake and flow become similar as myocardial and systemic extraction fractions equalize.     

Sex-specific characteristics of cardiac function, geometry, and mass in young adult elite athletes

PURPOSE: To study young adult elite athletes with age- and sex-matched sedentary controls to assess sex-specific differences for left ventricular (LV) and right ventricular (RV) volumes and mass as well as for LV contraction and relaxation. MATERIALS AND METHODS: A total of 23 male athletes (mean age 25 +/- 4 years, training 22 +/- 7 hours/week in rowing, swimming, or triathlon) and 20 female athletes (mean age 24 +/- 4 years, training 19 +/- 5 hours/week in rowing, swimming, or triathlon) and age- and sex-matched sedentary controls (21 male/17 female) underwent cardiovascular magnetic resonance (CMR) imaging (1.5 Tesla). Cardiac phase contrast imaging using a black-blood k-space segmented gradient echo sequence was used for analysis of cardiac contraction and relaxation and steady-state free-precession cine images were acquired for determination of cardiac volumes and mass. RESULTS: Male and female athletes showed similar increases in LV and RV volume and mass indices when compared to controls (ranging between 15% and 42%). No sex-specific differences in training effect on LV and RV volumes, mass indices, and ejection fractions, as well as LV to RV ratios of these volume and mass indices (parameters of balanced LV and RV dilatation and hypertrophy) were observed (all P for interaction >0.05). Similarly, no sex-specific differences in training effect on cardiac contraction and relaxation were found (all P for interaction >0.05). CONCLUSION: Young adult elite athletes do not show sex-specific adaptive structural and functional changes to exercise training in accordance with the benign nature of the hypertrophy associated with athlete's heart.     

Left ventricular dimensions during isometric exercise in aortic valve incompetence assessed by M-mode echocardiography and gated equilibrium radionuclide angiography

We compared M-mode echocardiographic and gated equilibrium radionuclide angiography assessment of the left ventricular (LV) dimensions at rest and during isometric exercise in 18 patients with chronic aortic valve incompetence. The two methods showed a satisfactory correlation when comparing LV size at rest and during exercise (LV end-diastolic dimension in echocardiography vs LV end-diastolic volume in radionuclide angiography, r = 0.80, P less than 0.01 at rest and r = 0.81, P less than 0.01 at rest and r = 0.75; P less than 0.01 during exercise), but fractional shortening in echocardiography and ejection fraction in radionuclide angiography did not correlate (r = 0.27, not significant (NS) at rest and r = 0.34, NS during exercise). Thus echocardiography and radionuclide angiography describe LV dimensions at rest and during handgrip exercise in a similar fashion, documenting the concordance of these noninvasive methods to describe LV size in aortic incompetence at rest and during exercise.     

Right ventricular function in healed myocardial infarction in man. A cineangiographic assessment

To evaluate the frequency of right ventricular dysfunction following recovery from myocardial infarction (MI) and the relationship of segmental right ventricular (RV) wall motion abnormalities to left ventricular (LV) function or location of coronary arterial stenosis, biplane right and left ventricular cineangiograms were obtained in 100 consecutive patients (4 +/- 3 months post MI). Thirty (group A) had anterior MI and significant stenosis or obstruction of left anterior descending artery (LAD). The remaining 70 patients had inferior MI. They were divided into three groups according to the site of the main coronary stenosis or obstruction and corresponding LV akinesia: right coronary artery (RCA) proximal to the acute marginal artery (RMA), (group B: 32 patients), RCA distal to the RMA (group C: 18 patients), left circumflex artery (LCF), (group D: 18 patients). RV and LV end-diastolic volume index (EDV), end-systolic volume index (ESV), stroke volume (SV) and ejection fraction (EF) have been determined. RV segmental wall motion was assessed in RAO and LAO projection by determining the percentage of systolic shortening (+ delta R) along 11 hemiaxes. Mean axial shortening (delta R) of the RV inferior and free walls were considered. When compared with that in 10 normal subjects, RV end-diastolic volume (RVEDV), RV end-systolic volume (RVESV) were increased and RV ejection fraction (RVEF) was lower in patients with anterior or inferior MI. Inferior delta R exhibited comparable sequential changes in the three groups of inferior MI and similar LVEF alteration.(ABSTRACT TRUNCATED AT 250 WORDS)     

A method for measuring mean circumferential fiber shortening rate from gated blood pool scans

Ejection fraction and ejection rate are easily obtained from gated cardiac images, but no method is available for calculating mean circumferential fiber shortening rate. We assumed that the cube root of left ventricular end-diastolic volume or counts is proportional to the minor axis of the left ventricle at end-diastole or end-systole. Mean circumferential fiber shortening rate is then equal to the [cube root of the end-diastolic volume (count) minus cube root of end-systolic volume (count)] divided by [cube root of end-diastolic volume (count) multiplied by the ejection time]. In 250 contrast ventriculograms, the standard mean circumferential fiber shortening rate (MCFSR) and that derived by the cube root method correlated well (r=0.94). The mean value of MCFSR (0.85±0.35) was greater than the cube root value (0.75±0.35) (P<0.001). The regression equation was y=0.86x+0.02. Similar correlations were obtained from gated radionuclide images using a semiautomated program (r=0.93) in 24 subjects or completely automated program (r=0.85) in 28 patients. The regression equation between MCFSR and that derived from the cube root of counts for the semiautomated program was y=0.82x+0.04 and for the automated program was y=0.84x+0.004. Similar correlations, slopes, and intercepts were seen using circumferential fractional shortening for angiographic data when correlated with both the semiautomated and automated gated blood pool scan programs. These data indicate that MCFSR and circumferential fractional shortening may be obtained from gated blood pool images using cube root estimates of end-diastolic and end-systolic radii with a high degree of correlation with the standard contrast ventriculographic technique.Supported by the Medical Research Service of the Veterans Administration Medical Center and NIH Research Grant HL 17682, awarded by the National Heart, Lung and Blood Institute     

Alterations in cardiac morphology and function in elite multi-disciplinary athletes.

Early echocardiographic studies of left ventricular (LV) morphology and function focused on single discipline athletes, primarily endurance and strength trained. To date there are few studies examining multi-disciplinary trained athletes. The present echocardiographic study examined LV morphology and function in 18 elite triathletes (swimming, cycling, and running) and 11 elite modern pentathletes (running, swimming, shooting, fencing, and show-jumping) compared with age- and sex-matched controls. Elite triathletes demonstrated significantly (p < 0.05) increased LV wall thickness and cavity dimensions together with LV mass, both in absolute terms and scaled for body surface area, compared with controls. Elite modern pentathletes demonstrated significantly (p < 0.05) increased LV wall thickness with a non-significant increase in LV internal diameter. Despite significant LV enlargement, the distribution of hypertrophy and diastolic filling indices were normal in both triathletes and modern pentathletes and significantly increased in the triathletes. It is concluded that multi-disciplinary training results in variations in LV morphology. The inciting stimulus resulting in LV enlargement in triathletes is associated with prolonged endurance activity, together with an isometric component accompanying cycling. In contrast, elite modern pentathletes experience a reduced endurance component combined with a high isometric component associated with fencing.     

Left ventricular function during interval and steady state exercise.

PURPOSE: Interval training (INT) is a commonly used method of exercise training in both athletic and clinical populations. Although we generally understand left ventricular (LV) function during steady state (SS) exercise, there are no data regarding LV function during INT. METHODS: We studied eight healthy, physically active volunteers during upright cycle ergometry during 15 min of both SS and INT, at the same average power output (90% individual anaerobic threshold), using first pass radionuclide ventriculography. During INT (60s/60s), measures of LV function were made during work (220 W) after 4 and 12 min and during recovery (120 W) after 7 and 15 min. These were compared with the average of four temporally matched measures made during SS (170 W). RESULTS: During INT, LV ejection fraction increased from rest (67 +/- 6%) to 77 +/- 5, 80 +/- 5, 77 +/- 5 and 79 +/- 4% after 4, 7, 12, and 15 min, respectively. During SS, LV ejection fraction was not significantly different at rest (70 +/- 4%) or during exercise (76 +/- 4, 79 +/- 4, 80 +/- 3, and 81 +/- 3%) after 4, 7, 12, and 15 min, respectively. Other measures of LV function (HR, BP, LV volumes, cardiac output, systemic vascular resistance, peak emptying, and filling rates) were likewise similar during temporally matched measurements during INT and SS. CONCLUSIONS: Although there were the expected transitions of ejection fraction with work and recovery, the overall hemodynamic picture during INT was very similar to SS. These data suggest that LV function during INT is not substantially different to that during SS.     

Injection of adeno-associated viral vector encoding vascular endothelial growth factor gene in infarcted swine myocardium: MR measurements of left ventricular function and strain

PURPOSE: To prospectively investigate the long-term effect of adeno-associated viral (AAV) vector-encoding vascular endothelial growth factor gene (VEGF) (AAV-VEGF) on left ventricular (LV) mass and volumes, as well as on regional contractility and circumferential strain, in a swine model of reperfused myocardial infarction. MATERIALS AND METHODS: All experimental procedures received approval from the institutional committee on animal research. Of 16 pigs subjected to reperfused myocardial infarction, six were treated, six were controls, and four died during the ischemic intervention. In six animals, cardiac-specific AAV-VEGF was injected into the periinfarcted and infarcted myocardium 1 hour after reperfusion. Magnetic resonance (MR) imaging was performed at 3 days and 8 weeks after infarction by using cine, tagged, and delayed enhancement (with gadoterate meglumine) sequences to measure global and regional LV function and infarct size. At postmortem examination, tissue samples stained with isolectin B4, Masson trichrome, and hematoxylin-eosin were used to characterize injured myocardium. Two-tailed Student t test was used for statistical analysis. RESULTS: Six treated animals showed no change in mean LV ejection fraction after 8 weeks (40.3%+/-0.9 [standard error of the mean] vs 41.0%+/-0.7) in contrast to a decrease measured in six control animals (41.4%+/-0.7 vs 36.1%+/-0.6, P<.001). AAV-VEGF improved wall thickening and circumferential strain in periinfarcted and remote myocardium. A greater reduction in gadoterate meglumine-enhanced infarct area was measured in treated animals (18.6%+/-1.5 of the LV mass at 3 days vs 9.8%+/-1.0 of the LV mass at 8 weeks, P<.001) compared with control animals (17.7%+/-2.0 vs 14.8%+/-1.0, P=.008). Findings at histopathologic evaluation indicated an increase in vascular density and a decrease in myocyte diameter in the periinfarcted myocardium of treated, compared with control, animals. CONCLUSION: Angiogenesis and arteriogenesis induced by VEGF genes improved regional myocardial strain and wall thickening and preserved ejection fraction after infarction.     

Left ventricular morphology in junior and master resistance trained athletes

PURPOSE: The objective of this cross-sectional investigation was to assess the effects of short (< 5 yr) versus long-term (> or = 18 yr) resistance training (RT) on left ventricular (LV) dimensions and mass. METHODS: The subjects for this study were 20 elite male powerlifters (8 junior athletes [JA], mean +/- SD, age: 21.1 +/- 1.2 yr and 12 master athletes [MA], age: 46.0 +/- 5.5 yr) and 19 age-matched male controls (8 young controls [YC], age: 21.8 +/- 2.8 yr and 11 middle-aged controls [MAC], age: 46.8 +/- 4.4 yr). Two-dimensionally guided transthoracic M-mode echocardiograms were performed at rest to quantify LV systolic and diastolic cavity dimension (LVIDs and LVIDd, respectively), ventricular septal wall thickness (VST), posterior wall thickness (PWT), LV mass (LVM), and LV systolic function as measured as fractional shortening (FS). RESULTS: Short- or long-term RT was not associated with a significant alteration in LVIDd (JA: 53.2 +/- 4.5 mm, YC: 52.1 +/- 3.7 mm, MA: 53.0 +/- 5.1 mm, MAC: 51.8 +/- 4.4 mm), LVIDs (JA: 33.5 +/- 4.8 mm, YC: 32.9 +/- 3.4 mm, MA: 33.0 +/- 4.4 mm, MAC: 31.4 +/- 3.7 mm), VST (JA: 9.4 +/- 0.9 mm, YC: 9.4 +/- 0.9 mm, MA: 9.4 +/- 1.6 mm, MAC: 9.7 +/- 0.9 mm), PWT (JA: 9.2 +/- 0.9 mm, YC: 9.4 +/- 0.9 mm, MA: 9.0 +/- 1.1 mm, MAC: 9.5 +/- 1.0 mm), LVM (JA: 184.6 +/- 36.1 g, YC: 179.0 +/- 26.5 g, MA, 183.3 +/- 58.1 g, MAC: 184.1 +/- 38.1 g), or FS (JA: 0.37 +/- 0.1%, YC: 0.37 +/- 0.05%, MA: 0.38 +/- 0.1%, MAC: 0.40 +/- 0.04%). CONCLUSIONS: These findings suggest that short or long-term RT as performed by elite junior and master powerlifters does not alter LV morphology or systolic function.     

End-systolic stress–velocity relation and circumferential fiber velocity shortening for analysing left ventricular function in mice

Traditionally, analysing left ventricular (LV) performance relies on echocardiography by evaluating shortening fraction (SF) in mice. SF is influenced by load conditions. End-systolic stress–velocity (ESSV) relation and circumferential fiber velocity (VcF) shortening are more relevant parameters for evaluating systolic function regardless load conditions particularly in mice's models of heart failure.     

大鼠运动力竭后肠系膜毛细血管血流动力学变化的研究

以当代微循环理论和血液流变学理论为基础,运用当代微循环研究方法,走出离体研究的缺陷。采用显微电视录像和图像处理技术,观察并测量了运动力竭后大鼠肠系膜毛细血管血流动力学的变化。结果发现：力竭性运动引发微循环障碍,使毛细血管收缩,红细胞流速降低,血流量减少,血浆层厚度减小,红细胞变形性降低,毛细血管红细胞压积升高。说明力竭性运动会导致微循环灌流异常和物质交换障碍。从微循环的角度为探讨运动疲劳机理提供了实验依据。     

应用彩色多普勒时实显象评价高原训练对滑雪运动员左室功能的影响

中国国家集训队12名越野滑雪运动员于长白山进行为期三周高原训练。本文报道了应用彩色多普勒测试和观察高原训练对运动员左室功能的影响。分析比较高原训练前后测试结果显示,运动员安静时心搏量(SV)、心输出量(CO)、左室射血分值(EF)、短轴缩短率(ES)以及左室容积(EDV、ESV)均有显著变化,但组间差异较大。其特点是:男子组以增强左室收缩为主,呈力量型改变。文章指出,高原训练高度和训练手段对于左心功能改变有密切关系。认为在海拔2300—2500米高度、突出强度训练可能趋向力量型改变;在1600—1800米高度、突出耐力训练可能趋向容积型改变。     

The relationship of early versus two-minute recovery echocardiographic values following maximal effort resistance exercise

Two-dimensionally directed M-mode echocardiography was used to measure left ventricular systolic function following maximal dynamic resistance exercise (RE). Upright measurements were made from the long axis parasternal view at rest, 20 seconds post-exercise, and two minutes post-exercise. Thirty-two successful studies were recorded from a total of 37 trained and untrained male subjects who were heterogeneous as to mode and level of training. Resistance-trained men averaged 3.8 +/- 2.4 yrs of training for 9.7 +/- 3.0 hr/wk, and endurance-trained men averaged 6.4 +/- 3.9 yr of training at 202.5 +/- 112.6 km/wk of cycling, running, and swimming. The trained men competed at the state or regional level. The RE protocol (knee extensions) was performed as follows: Set 1 (10 s rest) Set 2 (10 s rest) Set 3 60% 1-RM@8 reps 60% 1-RM@8 reps 60% 1-RM to fatigue. The RE protocol produced significant post-exercise reductions in end-systolic diameter (p less than 0.0002) and significant post-exercise increases in fractional shortening (p less than 0.0001) and velocity of circumferential fiber shortening (p less than 0.0002). The inotropic variables were still significantly different at two minutes post-exercise compared to the 20 second measure, suggesting that early recovery is a better approximation of maximal values. Velocity of circumferential fiber shortening at 20 seconds and two minutes was significantly correlated (r = 0.39) and fractional shortening was not (r = 0.34) at these serial measurement times.(ABSTRACT TRUNCATED AT 250 WORDS)     

Abnormal left ventricular ejection fraction response to mental stress and exercise in cardiomyopathy

Background

A decline in left ventricular (LV) ejection fraction in response to mental stress and exercise is regarded as an indicator of myocardial ischemia. In patients with LV dysfunction, the ejection fraction is sensitive to afterload, which increases during stress. Thus, the effects of mental stress and exercise on LV systolic function in patients with cardiomyopathy were examined.

Methods

The ambulatory nuclear VEST (Capintec, Inc., Ramsey, N.J.) was used to monitor LV ejection fraction in patients with cardiomyopathy (10 idiopathic and 9 ischemic). Patients underwent a series of mental stress tests (serial 7s, Stroop color, and Paced auditory addition) and treadmill exercise. Heart rate, systolic blood pressure, and LV ejection fraction were measured.

Results

Mental stress and exercise increased heart rate and systolic blood pressure. For idiopathic cardiomyopathy, LV ejection fraction decreased during serial 7s, Stroop color, Paced auditory addition and exercise by ?8%±6%, ?7%±5%, ?7%±3%, ?9%±10%, respectively. For ischemic cardiomyopathy, LV ejection fraction declined by ?4%±3%, ?7%±5%, ?6%±3%, ?2%±6% during the same stress tests. There was no difference between the idiopathic and ischemic groups. Each patient showed a 5% or greater decline in LV ejection fraction during one mental stress test. There was an inverse relation between changes in LV ejection fraction and systolic blood pressure during all mental stress tests and exercise (r=?0.47, p<0.0001).

Conclusions

In patients with depressed baseline systolic function, the decline in systolic function during mental stress and exercise could be related in part to increases in LV afterload.     

Left ventricular dimensions during isometric exercise in aortic valve incompetence assessed by M-mode echocardiography and gated equilibrium radionuclide angiography

We compared M-mode echocardiographic and gated equilibrium radionuclide angiography assessement of the left ventricular (LV) dimensions at rest and during isometric exercise in 18 patients with chronic aortic valve incompetence. The two methods showed a satisfactory correlation when comparing LV size at rest and during exercise (LV end-diastolic dimension in echocardiography vs LV end-diastolic volume in radionuclide angiography, r=0.80, P0.01 at rest and r=0.81, P0.01 during exercise; LV end-systolic dimension in echocardiography vs LV end-systolic volume in radionuclide angiography, r=0.81, P0.01 at rest and r=0.75; P0.01 during exercise), but fractional shortening in echocardiography and ejection fraction in radionuclide angiography did not correlate (r=0.27, not significant (NS) at rest and r=0.34, NS during exercise). Thus echocardiography and radionuclide angiography describe LV dimensions at rest and during handgrip exercise in a similar fashion, documenting the concordance of these noninvasive methods to describe LV size in aortic incompetence at rest and during exercise.     

Magnetic resonance imaging quantification of left ventricular dysfunction following coronary microembolization

Microembolization is common after coronary interventions, and therefore this MRI study aimed to quantify the effect of coronary microembolization on left ventricular (LV) function. The left anterior descending artery (LAD) was selectively catheterized in an XMR suite (Philips Medical Systems, Best, The Netherlands) in eight pigs to deliver MR contrast media to measure the LAD territory using first‐pass perfusion and for intracoronary delivery of the embolic agent. Cine, tagged, and delayed contrast‐enhanced MRI (DCE‐MRI) was performed to assess LV volumes, ejection fraction, radial and circumferential strain, and viability at baseline, 1 h, and 1 week after microembolization. Histopathology and histochemical staining were used to characterize and measure the extent of microinfarction. The LAD territory was 35% ± 2% LV mass. Patchy microinfarction on DCE‐MRI at 1 week was 22.0% ± 3.6% LAD territory (7.5% LV mass). Microembolization caused persistent decline in ejection fraction (baseline = 49% ± 1%, 1 h = 29% ± 1%, P = 0.02 and 1 week = 36% ± 1%, P = 0.03) and increased end‐diastolic (79.6 ± 3.9 ml, 85.5 ± 4.5 ml, P = 0.03 and 92.4 ± 6.2 ml, P = 0.06, respectively) and end‐systolic (40.8 ± 2.1 ml, 60.2 ± 3.4 ml, P = 0.02 and 59.3 ± 4.8 ml, P = 0.03, respectively) volumes. The microembolized territory was manifested as dysfunctional regions for 1 week on cine and tagged MRI. Histopathology revealed occlusive microemboli surrounded by necrotic tissue undergoing repair. Microinfarction was visualized after coronary microembolization and caused LV dysfunction disproportionate to the size of myocardial damage. It also changed LV geometry and decreased radial and circumferential strain over the course of 1 week. Magn Reson Med, 2009. © 2008 Wiley‐Liss, Inc.     

Systolic and diastolic cardiac dysfunction early after the initiation of doxorubicin therapy: significance of gender and concurrent mediastinal radiation

Diastolic and systolic left ventricular (LV) function may be affected early after the initiation of doxorubicin therapy. However, the role of mediastinal radiation and other cytotoxic agents in the production of these early cardiac effects is unclear. In this study LV diastolic and systolic function were assessed before and after doxorubicin (223+/-122 mg.m-2; range, 40-618) in 33 patients. After doxorubicin, LV ejection fraction declined (0.61+/-0.08 to 0.56+/-0.08, P=0.0008), peak filling rate decreased (3.38+/-1.10 to 2.82+/-0.62 end diastolic volumes/s, P=0.006), and time to peak filling rate increased (162+/-39 to 182+/-45 ms, P=0.04). The changes in LV systolic and diastolic function were not related to doxorubicin dose and the use of other cytotoxic agents; the decrease in LV ejection fraction with doxorubicin was more notable in men and in patients who received mediastinal irradiation concurrently with doxorubicin. It is concluded that the use of doxorubicin was associated with the simultaneous early development of LV systolic and diastolic dysfunction. Male gender and concurrent mediastinal irradiation were independent influences, but doxorubicin dose and the use of other cytotoxic agents were not associated with worse cardiac dysfunction.     

Relationship of radionuclide indexes of cardiac function during interventions: Volume loading,afterload stress,exercise, and pacing

We compared three radionuclide indexes of cardiac function: (1) the ejection fraction (EF), (2) the mean ejection rate (ER), and (3) the mean velocity of circumferential fiber shortening (MVCF) during volume loading, phenylephrine hydrochloride stress, exercise, and atrial pacing. All behaved in a similar (linear) fashion, allowing appropriate hemodynamic conclusions to be drawn using either index. During atrial pacing, the ejection fraction declined, when velocity indexes increased—suggesting that the ejection fraction may not be a suitable index to characterize alterations in inotropic state during rapid alterations in heart rate, particular in the absence of angina pectoris. This may result from the reductions in cardiac volume for the duration of pacing, where the velocity index is preserved. In most circumstances excluding atrial pacing, ejection fraction during interventions is an adequate index of the change of myocardial contractile state. Overall, radionuclide angiography is an excellent technique to characterize acute hemodynamic interventions, with ejection fraction, in general, the simplest and most reliable of cardiac indexes during stress interventions. Supported in part from a grant from the research service of the Veterans Administration Hospital