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PubMed1982

The influence of hemodialysis fistulas on circulatory dynamics and left ventricular function.

This study was designed to examine the influence of arteriovenous (A-V) fistulas on cardiac output and left ventricular performance in 13 uremic patients on regular hemodialysis. M-mode echocardiography and systolic time intervals were used to derive indices of left ventricular function, and cardiac output was measured by thermodilution. Measurements were performed before and after acute digital occlusion of the A-V fistulas. Occlusion of a single fistula caused systemic vascular resistance and the systolic diameter of the left ventricle to increase from 9.6 +/- 1 to 13.5 +/- 2 units (p less than 0.001) and from 3.2 +/- .3 to 3.4 +/- .4 (p less than 0.05) respectively. The increase in afterload caused a reduction in cardiac output from 11.0 +/- 1 to 9.6 +/- 1 l/min (p less than 0.001) and probably accounted for the minor, though not significant, "deterioration" in the indices of left ventricular function. Bilateral fistula occlusion in 8 patients exaggerated these changes, and the reduction in fractional shortening from 43 +/- 4 to 37 +/- 4% was significant at the 5% level. In two patients with severe left ventricular failure, fistula occlusion caused a more pronounced deterioration in cardiac performance. These results show that acute A-V fistula occlusion effectively lowers cardiac output and is, therefore, likely to be beneficial in the management of high output failure. However, when intrinsic left ventricular disease is the primary etiological factor in heart failure, fistula occlusion is unlikely to be helpful, and may worsen the hemodynamic derangement.

Adult↗

PubMed1997

Effect of high intensity exercise training on central hemodynamic responses to exercise in men with reduced left ventricular function.

OBJECTIVES: The aim of this study was to evaluate the effects of high intensity exercise training on left ventricular function and hemodynamic responses to exercise in patients with reduced ventricular function. BACKGROUND: Results of studies on central hemodynamic adaptations to exercise training in patients with chronic heart failure have been contradictory, and some research has suggested that training causes further myocardial damage in these patients after a myocardial infarction. METHODS: Twenty-five men with left ventricular dysfunction after a myocardial infarction or coronary artery bypass graft surgery were randomized to an exercise training group (mean age +/- SD 56 +/- 5 years, mean ejection fraction [EF] 32 +/- 7%, n = 12) or a control group (mean age 55 +/- 7 years, mean EF 33 +/- 6%, n = 13). Patients in the exercise group performed 2 h of walking daily and four weekly sessions of high intensity monitored stationary cycling (40 min at 70% to 80% peak capacity) at a residential rehabilitation center for a period of 2 months. Ventilatory gas exchange and upright hemodynamic measurements (rest and peak exercise cardiac output; pulmonary artery, wedge and mean arterial pressures; and systemic vascular resistance) were performed before and after the study period. RESULTS: Maximal oxygen uptake (VO2max) increased by 23% after 1 month of training, and by an additional 6% after month 2. The increase in VO2max in the trained group paralleled an increase in maximal cardiac output (12.0 +/- 1.8 liters/min before training vs. 13.7 +/- 2.5 liters/min after training, p < 0.05), but maximal cardiac output did not change in the control group. Neither stroke volume nor hemodynamic pressures at rest or during exercise differed within or between groups. Rest left ventricular mass, volumes and EF determined by magnetic resonance imaging were unchanged in both groups. CONCLUSIONS: High intensity exercise training in patients with reduced left ventricular function results in substantial increases in VO2max by way of an increase in maximal cardiac output combined with a widening of maximal arteriovenous oxygen difference, but not changes in contractility. Training did not worsen hemodynamic status or cause further myocardial damage.

Cardiac Output↗

PubMed2004

Assessment of left ventricular function in healthy subjects by pusled wave Doppler tissue imaging.

OBJECTIVE: To examine the clinical application of pulsed Doppler tissue imaging (DTI) for regional left ventricular function assessment in normal subjects. METHODS: We examined 50 healthy subjects (range 12-42 years, mean age 28.3 +/- 6.9 years) using pulsed Doppler tissue imaging to characterize the diastolic and systolic velocity profiles of mitral annulus. Recordings were made along the long axis in the apical 4-chamber, 2-chamber, and long apical views of 6 sites (posterior-septum, lateral, anterior, inferior, anterior-septum, posterior) at the mitral annulus. Myocardial velocities were determined with use of variance F statistical analysis. Correlation analysis was employed to test the relationship between age and mitral annular velocities. RESULTS: Both early diastolic and systolic velocities at the septum were lower than other sites. There were no differences in mitral annulus late diastolic velocities. Mean early diastolic and systolic velocities was negatively correlated with age. CONCLUSIONS: Doppler tissue imaging can directly reflect regional left ventricular function.

Adolescent↗

PubMed1994

Ambulatory monitoring of left ventricular function in patients with Parkinson's disease and postural hypotension.

Left ventricular (LV) function was continuously monitored using a radionuclide detector (VEST) after intravenous injection of 25 mCi technetium-99m labelled red blood cells in nine patients with Parkinson's disease and postural hypotension (group 1) and ten patients with Parkinson's disease but without postural hypotension (group 2). LV function and blood pressure were monitored in the supine position for 15 min (period A), upon changing posture from the supine to the upright position for 10 min (period B), and upon returning to the supine position for 10 min (period C). In group 1, the passage from period A to period B induced a significant decrease in end-diastolic volume, end-systolic volume and ejection fraction (all P < 0.01). In group 2, ejection fraction increased (P < 0.05) upon changing posture from the supine to the upright position. Ejection fraction (F = 33, P < 0.01), end-diastolic volume (F = 9, P < 0.05) and end-systolic volume (F = 10, P < 0.05) were significantly different between the two groups. In group 1, stroke volume, cardiac output and vascular peripheral resistance decreased from period A to period B (all P < 0.001). In group 2, no changes in stroke volume, cardiac output and vascular peripheral resistance were observed from period A to period B. All parameters were similar in the two groups during the periods A and C. Upon changing posture from the supine to the upright position, patients with Parkinson's disease and postural hypotension showed marked changes in parameters of LV function induced by vascular abnormalities.(ABSTRACT TRUNCATED AT 250 WORDS)

Electrocardiography, Ambulatory↗

PubMed1979

Echocardiographic indices of left ventricular function. A comparison.

Multiple M-mode echocardiographic indices of left ventricular function are currently in use, but their reliability is disputed. Therefore, we correlated echo ejection fraction (EF) using quadratic (Q) and cubic (C) formulae, percentage of minor axis shortening (%S), mean velocity of circumferential fiber shortening (mVCF), and peak VCF with angiographic EF in 37 subjects, including 10 normal subjects. None had echocardiographic segmental wall motion abnormalities. Significant linear correlations were found between angiographic EF and EFc (r = 0.78), %S (r = 0.77), EFQ(r = 0.68), peak VCF (r = 0.68), and mVCF (r = 0.58). However, for all indices, the scatter was too great to permit reliable quantitative estimations of angiographic EF based on echo date. Peak VCF was qualitatively the most reliable predictor of ventricular function, being greater than or equal to 2.00 circumference per second in 23 of 25 patients with angio EF greater than or equal to 55 percent and less than 2.00 circumferences per second in 11 of 12 with EF less than 55 (sensitivity [sens] 92 percent, specificity [spec] 92 percent). Mean VCF (sens 83 percent, spec 80 percent), %S (sens 50 percent, spec 96 percent), EFC (senc 58 percent, spec 96 percent), and EFQ (sens 58 percent, spec 92 percent) were less satisfactory. We conclude that echo indices are reliable only as qualitative parameters of ventricular function. Peak VCF appears to be the most sensitive and specific qualitative index now available.

Cineangiography↗

PubMed1977

Left ventricular function in massive pulmonary embolism.

Serial echocardiographic and angiographic measurements of left ventricular function were obtained in a patient with massive pulmonary embolism before and after pulmonary embolectomy. These data suggest that left ventricular dysfunction secondary to right ventricular failure is the results of markedly decreased left ventricular filling in this settings.

Echocardiography↗

PubMed1993

[Usefulness of Vmax and time constant in the evaluation of left ventricular function immediately after cardiac operation].

It is difficult to evaluate the cardiac function accurately, immediately after cardiac operation, because of the restriction of measurements and the variations of loading. To evaluate the exact cardiac function during and after cardiac surgery, we examined the usefulness of unloaded maximal shortening velocity of contractile element (Vmax) and time constant of isovolumic pressure fall (TC) in the condition of hasty changing of preload and afterload. In our experiment, we used canines as our subject. Following the sedation of the canines, the left ventricular pressure (LVP) curve was recorded by using the catheter-tip manometer which was introduced into the apex of the heart. The LVP was measured in the following instances: 1) at control condition, 2) 5 minutes after the administration of dobutamine of 2 or 5 micrograms/kg/min, 3) 5, 10, 15, and 30 minutes interval after the ligation of the left anterior descending artery (LAD). In every situations, preload and afterload were changed by the temporary occlusion of the inferior vena cava or descending thoracic aorta. Vmax and TC were analyzed easily only from the LVP by the personal computer. We used Grunkemeier's method to calculate Vmax which was analyzed only from the LVP curve. We presumed that the mean value of Vmax analyzed by Grunkemeier's method was almost the same as the data by Mason's method by calculating the mean value from the given number of heart beats. Because the correlation of two methods was linear, and furthermore the slope of this regression line was 0.97 and the Y-intercept was 0.19. Vmax was the index that was comparatively independent from the loading condition.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1991

Influence of dialysate exchange on cardiac left ventricular function in children treated with CAPD.

The influence of peritoneal dialysate exchange on the ventricular function in 11 children on continuous ambulatory peritoneal dialysis (CAPD) therapy was studied before and after instillation dialysate. Systolic blood pressure, pulse rate, and echocardiographical data (shortening fraction and pre-ejection period/left ventricle ejection time-ratio) were obtained before and after instillation. There were no differences present with respect to the measured parameters after the abdomen was filled. It is concluded that in children treated with CAPD the exchange of normal volumes of dialysate has no influence on the function of the left ventricle.

Child, Preschool↗

PubMed2000

Left ventricular function and autonomic nervous system balance during two different stages of the menstrual cycle.

We studied the left ventricular function and cardiac autonomic nervous system balance variations during two different stages of the menstrual cycle. These two variables, as well as plasmatic estradiol and progesterone concentrations, were measured in a drug-free state in 20 women (29+/-6 year-old) with regular menstrual periods. A clinical evaluation, an echo-Doppler and a Valsalva manoeuvre were performed in all the patients on the third day of their menstrual cycle (follicular phase) and three days prior to their next menstrual cycle (luteinizing phase). When comparing the results obtained in these two phases, a statistically significant increase was put forward in plasmatic estradiol (50.6+/-24 vs. 127.3+/-52.8 pg/ml) and progesterone (0.37+/-0.42 vs. 11.92+/-10.8 ng/ml) concentrations, Valsalva index (1.55+/-0.22 vs. 1.67+/-0.33; P=0.044) and E/A mitral wave ratio (1.63+/-0.36 vs. 1.75+/-0.35, P=0.02). The right and left atrial volumes, left ventricular volumes and ejection fraction were similar in the two menstrual phases studied. We conclude that the autonomic nervous system balance and the left ventricular diastolic function suffer significant changes during the luteinizing phase of the menstrual cycle in normal women.

Adult↗

PubMed2000

Nitric oxide inhibition intensifies the depressant effect of cocaine on the left ventricular function in anaesthetized pigs.

Myocardial ischaemia and left ventricular dysfunction have been described in cocaine users. Whether nitric oxide (NO) inhibition may potentiate the effects of cocaine on coronary circulation and ventricular function is still unknown. In order to test this hypothesis, 38 pentobarbital-anaesthetized pigs were instrumented for systolic blood pressure, coronary blood flow, left ventricular dp/dt, cardiac output, left ventricular end-diastolic and end-systolic lengths and shortening fraction. The pigs were randomized into three groups: control group: i.v. saline (n = 5); group 1: i.v. cocaine, 10 mg kg-1 over 20 min (n = 17); group 2: the same doses of cocaine 30 min after i.c. L-NAME 20 microg/kg min-1 infusion (n = 16). In order to know whether the observed effects were specific of NO inhibition, in five pigs i.c. L-arginine was simultaneously infused with L-NAME, in five pigs i.c. NTG, an endothelial-independent vasodilator, was simultaneously infused with L-NAME before cocaine was administered, and in nine additional pigs the proximal left anterior descending (LAD) flow was reduced to around 20% of the basal value by means of a mechanical occluder before cocaine was administered. Cocaine i.v did not change the coronary blood flow, while it induced a significant reduction in cardiac output, left ventricular dp/dt and shortening fraction (15 +/- 4-8 +/- 4%, P < 0.05). When cocaine was administered after L-NAME infused i.c. during 30 min, a significantly more severe reduction of the shortening fraction (12 +/- 3-4 +/- 2%, P < 0.0001) was induced; this effect was abolished by simultaneous perfusion of L-arginine i.c. NTG. The results when cocaine was administered after the 20% LAD flow reduction by mechanical occluder did not differ from those of cocaine alone. NO inhibition intensifies the cocaine-induced left ventricular dysfunction.

Anesthesia↗

PubMed1983

Correlation among water content, left ventricular function, coronary blood flow, and myocardial metabolism after hypothermic ischemic cardiac arrest.

Subendocardial ischemia is a common cause of death following ischemic cardiac arrest. We studied relationships among myocardial water content (WC), left ventricular function, coronary blood flow, and myocardial metabolism following ischemic cardiac arrest. Under cardiopulmonary bypass with hypothermia, 120 min of aortic occlusion was employed, and myocardial temperature was kept around 20 degrees C in 10 mongrel dogs. Left ventricular function (peak LVP, max dp/dt, LVEDP, LVSWI), coronary blood flow, myocardial enzymes (m-GOT, total CPK, MB-CPK), myocardial ATP and creatine phosphate (CP), and WC of the subendocardium of the left ventricle were measured. Data were obtained in the control state and immediately and 30 and 60 min after aortic unclamping. Significant negative correlations were obtained between WC and max dp/dt (r = -0.8384), coronary blood flow (r = -0.9928), ATP (r = -0.7038), and CP (r = -0.7835). Significant positive correlations were obtained between WC and LVEDP (r = 0.7525), m-GOT (r = 0.7638), and total CPK (r = 0.7079). These data suggest that myocardial edema results in depression of left ventricular function and metabolism.

Adenosine Triphosphate↗

PubMed2002

Impact of atrio-biventricular pacing to poor left-ventricular function after CABG.

AIMS: The relation between acute postoperative management of epicardial pacing and haemodynamic status in patients with poor left-ventricular function after coronary artery bypass grafting (CABG) demonstrates the importance of synchronous ventricular activation and contraction during the vulnerable early postoperative period. METHODS: in 22 patients (mean age - 69.3 +/- 5.4 years) with poor left-ventricular function (ejection fraction 29.8 +/- 4.8), we compared the postoperative haemodynamic parameters between atrio-biventricular, atrio-monoventricular and atrial pacing 3 - 24 hours after elective coronary artery revascularisation. Temporary epicardial pacing electrodes were placed on the right atrium and the paraseptal region of the left and right ventricle. The ventricular pacing modus was confirmed by surface electrocardiogram (EGG). We used overdrive rate pacing. RESULTS: In patients with left bundle branch block, atrio-left-ventricular and atrio-biventricular pacing increased cardiac index and decreased wedge pressure. Atrial pacing and atrio-right-ventricular pacing decreased cardiac index. In contrast, atrio-right-ventricular and atrio-biventricular pacing increased cardiac index in patients with right bundle brunch block. CONCLUSION: Atrio-biventricular pacing increased cardiac index and decreased wedge pressure compared with AAI pacing. In patients with wall-motion abnormalities and impaired cardiac conduction, a site-specific pacing therapy can help to optimize postoperative haemodynamics and reduce the application of inotropic substances.

Aged↗

PubMed2005

[Effects of a novel recombinant polypeptide from the sea anemone Anthopleura sp. on left ventricular function in dogs with acute cardiac insufficiency].

OBJECTIVE: To observe the effects of recombinant hk2a, a novel neurotoxin from the sea anemone Anthopleura sp., on left ventricular function of dogs with acute cardiac insufficiency. METHODS: Canine models of acute cardiac insufficiency were established by rapid ventricular pacing, in which the left ventricular ejection fraction (LVEF) was measured by Acuson ultrasound systems (Sequoia 512) at 0, 5, 15, 30 and 60 min, respectively, after intravenous injection of 30 microg/kg recombinant hk2a. The response of the canine models to hk2a treatments was observed in comparison with that of the dogs treated with Cedilanid (as positive control) and saline (as negative control). RESULTS: Intravenous injection of recombinant hk2a caused an immediate and significant increase in LVEF in the canine models of acute cardiac insufficiency (P<0.05), and the effect maintained for more than 30 min without significant effect on heart rate. Recombinant hk2a possessed such merits as quicker onset and greater potency in comparison with Cedilanid. CONCLUSION: Recombinant hk2a may significantly increase LVEF of the dogs with acute cardiac insufficiency.

Animals↗

PubMed1993

Early and late effects of rt-PA vs placebo on left ventricular function measured by nuclear ventriculography.

The aim of the study was the functional re-evaluation of 296 patients 12 to 18 months after a double-blind trial evaluating the effect of tissue plasminogen activator (rt-PA) versus placebo given within 5 h of onset of symptoms caused by an acute myocardial infarction. All patients underwent rest-stress radionuclide angiography (Egna). For each exercise level the global left ventricular ejection fraction (LVEF) was calculated together with an estimate of regional wall motion abnormalities (RWMA). A clear difference of the total workload and the peak workload was found between both therapeutic groups. Discriminant analysis evaluating four parameters (LVEF at peak exercise and at the endpoint and the workload at those levels) revealed a beneficial therapeutic effect. The RWM at rest showed only a difference in the apico-inferior region. There were less wall motion abnormalities in the treated group. Radionuclide analysis demonstrated a larger functional capacity and a better coordination of myocardial contractility during stress RNA one year after thrombolytic therapy. At rest, no major differences were found between the hospital stage and the follow-up in both therapeutic groups one year later.

Adult↗

PubMed2000

Comparison of the effects of fetal cardiomyocyte and skeletal myoblast transplantation on postinfarction left ventricular function.

OBJECTIVES: Transplantation of fetal cardiomyocytes improves function of infarcted myocardium but raises availability, immunologic, and ethical issues that justify the investigation of alternate cell types, among which skeletal myoblasts are attractive candidates. METHODS: Myocardial infarction was created in rats by means of coronary artery ligation. One week later, the animals were reoperated on and intramyocardially injected with culture growth medium alone (controls, n = 15), fetal cardiomyocytes (5 x 10(6) cells, n = 11), or neonatal skeletal myoblasts (5 x 10(6) cells, n = 16). The injections consisted of a 150-microL volume and were made in the core of the infarct, and the animals were immunosuppressed. Left ventricular function was assessed by echocardiography immediately before transplantation and 1 month thereafter. Myoblast-transplanted hearts were then immunohistologically processed for the expression of skeletal muscle-specific embryonic myosin heavy chain and cardiac-specific connexin 43. RESULTS: The left ventricular ejection fraction markedly increased in the fetal and myoblast groups from 39.3% +/- 3.9% to 45% +/- 3.4% (P =.086) and from 40.4% +/- 3.6% to 47.3% +/- 4.4% (P =.034), respectively, whereas it decreased in untreated animals from 40.6% +/- 4% to 36.7% +/- 2.7%. Transplanted myoblasts could be identified in all animals by the positive staining for skeletal muscle myosin. Conversely, clusters of connexin 43 were not observed on these skeletal muscle cells. CONCLUSIONS: These results support the hypothesis that skeletal myoblasts are as effective as fetal cardiomyocytes for improving postinfarction left ventricular function. The clinical relevance of these findings is based on the possibility for skeletal myoblasts to be harvested from the patient himself.

Animals↗

PubMed1990

Is pulsed Doppler echocardiography an adequate method to evaluate left ventricular function during filling in hypertensive patients?

Pulsed Doppler tracings of the mitral inflow are often proposed to describe left ventricular function during filling in hypertensive patients. The tracings are determined by the complex interaction of left atrial pressure and left ventricular relaxation, diastolic compliance and contractility of the left atrium. They strongly depend on preload and, thus, do not allow precise characterization of the left ventricle. In addition, they vary with age, heart rate and the site of measurement. The modifications caused by the presence of hypertensive hypertrophy are not specific: similar changes are seen for example, in the presence of hypertrophic cardiomyopathy or coronary heart disease, but are absent in highly trained athletes in spite of very significant physiologic hypertrophy.

Aging↗

PubMed1993

[Effects of 6,7-dimethoxycoumarin on left ventricular function and hemodynamics in anesthetized cats].

Scoparone (6,7-dimethoxycoumarin 1.25, 2.5, 5 mg.kg-1) influenced the cardiohemodynamic functions in anesthetized cats. After i.v. injection the LVP-dP/dt loops and blood pressure were decreased. Both the contractile and relaxant functions of the left ventricle were inhibited. These were demonstrated by the reduction of dP/dtmax, Vmax, Vce-dp40, LVSP, prolongation of LVET, diminution of -dP/dtmax, and extension of the constant time of isometric diastolic pressure decay (T value). The preload of the left ventricle, LVEDF, was raised and the afterload (MAP, TPB) was decreased: The systolic volume, systolic index, cardiac output, and cardiac index were decreased slightly. The parameters TTI and TTI x HR, which reflect the myocardial oxygen consumption, were reduced. Furthermore, the heart rate was decreased at 5 mg.kg-1. The results indicate that scoparone could suppress the myocardial activity.

Animals↗

PubMed1978

Effects of oxyfedrine on left ventricular function in patients several months after myocardial infarction.

Left ventricular (LV) function was investigated by left heart catheterization at rest and during exercise in 15 men 3--5 months after acute myocardial infarction. The effect of 8 mg oxyfedrine i.v. in 10 patients was compared to placebo in 5. The administration of oxyfedrine led to a significant decrease of LV end-diastolic pressure; an increase of LV dp/dt max, heart rate, LV ejection fraction and LV stroke work; and a shift of LV function curve indicating its improvement. These results give evidence for a positive inotropic effect of this drug which could have therapeutic implications in patients with impaired LV function after myocardial infarction.

Adult↗