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At least 1,099 records · Page 61Linked to original sources
PubMed2003

Improved regional left ventricular function after successful satellite cell grafting in rabbits with myocardial infarction.

OBJECTIVE: To evaluate whether satellite cells injected into infarct areas in rabbits remain viable during 6 weeks follow-up and can improve cardiac function as assessed by echocardiography. METHODS: Myocardial infarction was induced in 16 New Zealand white rabbits, by ligation of the marginalis sinistra artery. Tissue from gluteus muscle biopsies was dissected into small pieces and cultured. Within 2-3 weeks the cells were expanded by 2-3 orders of magnitude and were fluorescent labeled. Single cell pellets for resuspension at >10(6)/1 ml were directly injected into the infarct areas in 8 rabbits. In 8 additional rabbits, 1 ml saline was injected (control). Regional left ventricular function was assessed weekly by 2-D echocardiography until animals were sacrificed. Analysis was performed blind and independently by two experienced echocardiographers, based on the American Society of Echocardiography scheme. RESULTS AND DISCUSSION: Six treated and five control rabbits completed the study. One week after the artery occlusion, left ventricular function scoring did not differ between groups, mean 8.7+/-1.6 vs 8.3+/-1.9 (P=0.74). At 6 weeks post-injection, echocardiographic score was significantly better in the treated group, mean 2.6+/-0.9 vs 6.9+/-2.1 (P=0.002). The treated group showed significant gradual segmental improvement between the first week up to week 6. After sacrifice, macro and microscopic transmural areas showed typical changes of myocardial infarction. Histochemical staining identified viable grafted cells in high density 6 weeks post-transplantation in all grafted hearts. CONCLUSION: Autologous satellite cells (skeletal myofiber), can be successfully grafted into rabbit hearts following myocardial infarction and may induce improved regional left ventricular function.

Animals↗
PubMed1996

Unilateral changes of sympathetic tone to the heart impair left ventricular function.

BACKGROUND: Different regions within the left ventricle are preferentially supplied by the left or right sympathetic system. In order to characterize different influences of left vs right sympathetic lateralization on LV function, haemodynamic effects of right and left stellate ganglion stimulations (RSGS and LSGS) as well as a right sympathetic block (RSB) were compared. METHODS: Seven alpha-chloralose anaesthetized open chest dogs were instrumented for measurement of LV pressure (tip manometers) and regional LV wall thickness (WT, sonomicrometry) in the antero-apical wall (AW, innervated by right stellate ganglion) and postero-basal wall (PW, left stellate ganglion). Timing of regional myocadial wall motion was evaluated by the phase of the first Fourier transform of the WT signals, LV asynchrony by the phase difference (phi) between both regions, and LV diastolic function by the time constant of isovolumic relaxation (tau). Measurements were performed before and after RSB (5 ml of lidocaine 1%); in 6 dogs of this group, RSGS and LSGS (4 V, 0.2 ms, 20 Hz) were performed before RSB. In order to investigate a regional inotropic stimulation without systemic effect, 6 additional dogs received intracoronary noradrenaline injections (NIC, 0.25 microgram) into the left circumflex artery perfused myocardium. RESULTS: LSGS and NIC led to an earlier PW-motion within the cardiac cycle (phase reduction by 40.0 +/- 15.0 degree (SEM) and 55.5 +/- 11.2 degrees) and RSGS induced an earlier AW-motion (by 33.7 +/- 15.2 degrees). After RSB, AW-motion was delayed (38.1 +/- 9.2 degrees). The consequence was an asynchronous wall motion pattern after all interventions (change in phi: LSGS-64.7 +/- 18.7 degrees, RSGS 41.1 +/- 15.7 degrees, NIC -74.5 +/- 17.4 degrees, RSB -52.6 +/- 14.6 degrees), and a prolonged relaxation (tau increase: RSGS 9.4 +/- 1.9, NIC 8.3 +/- 1.5, RSB 3.7 +/- 0.8 ms). CONCLUSION: Unilateral increases as well as decreases of sympathetic tone to the heart result in an asynchronous wall motion pattern and an impaired LV relaxation.

Animals↗
PubMed1997

[Assessment of left ventricular function by pressure-volume loop in VSD and TOF before and after operation].

This study estimates the perioperative left ventricular function of VSD and TOF by using Pressure-Volume (PV) loop. The most characteristic hemodynamic change of VSD is a decreased volume load. Although ejection fraction significantly decreased after the operation, this change did not mean a deteriorated left ventricular contractility. Emax, which is an index of left ventricular contractility on PV loop, improved and pressure-volume area (PVA) which is correlated with 02 consumption of left ventricule was reduced. Mechanical efficiency of left ventricular energetic state did not significantly change. Left ventricular volume and ejection fraction in TOF slightly increased after the operation. Increased ejection fraction reflected a compensation to volume overload after surgery. Emax slightly decreased and PVA increased. Meanwhile mechanical efficiency increased after the operation indicating well preserved ventricular contractility. In particular, the shape of PV loop of both VSD and TOF eventually became usual square after operation due to recover of the isovolumic contraction and relaxation phase. These characteristics had better to be concerned for improvement of surgical techniques as in conotruncal repair, particularly in TOF in the setting of better quality of life with low atrial pressure.

Child↗
PubMedDate not supplied

Impact of acute myocardial edema on left ventricular function.

Studies of the impact of myocardial edema on left ventricular (LV) systolic function show conflicting results. We sought to evaluate the impact of increased myocardial water content (MWC) on LV systolic and diastolic function. Anesthetized dogs (n = 12) were instrumented with myocardial ultrasonic crystals and an LV micromanometer. Systolic function was measured by preload recruitable stroke work (PRSW) and dP/dt(max). Diastolic function was measured by -dP/dt(max) and the isovolumic relaxation constant tau (t). Myocardial water content (MWC) was determined using microgravimetry. In six dogs (coronary sinus hypertension, CSH group) we produced myocardial edema by inflating a coronary sinus balloon for 2 h (30-40 mm Hg). In six other dogs (Plegisol, PLEG group) cardiopulmonary bypass (CPB) was initiated (12.3 +/- 0.8 min), the aorta was cross-clamped (117 +/- 19 s), and 700 mL 4 degrees C crystalloid, hyperkalemic cardioplegic solution (Plegisol) was administered into the aortic root (62 +/- 4 mm Hg). After declamping and reperfusion (7.2 +/- 1.0 min), the dogs were separated from CPB. Myocardial function parameters and MWC were measured for 2 h after edema generation. In the CSH group, MWC significantly increased from 75.9 +/- 0.3% to 77.6 +/- 0.3% (p < .05). In the PLEG group, MWC increased from 75.8 +/- 0.3% to 77.7 +/- 0.3% (p < .05). PRSW and dP/dt(max) did not decrease in either group. Diastolic parameters did not change significantly. We conclude that acute myocardial edema without myocardial injury does not impair LV function.

Acute Disease↗
PubMed2004

Pre- and postoperative assessment of left ventricular function by magnetic resonance imaging and 2-D-echocardiography in patients undergoing left ventricular aneurysmectomy.

BACKGROUND: Left ventricular (LV) aneurysms may complicate myocardial infarctions. Reliable quantification of LV functional parameters is mandatory to predict clinical outcome in patients undergoing LV aneurysmectomy. We compared global LV function measured by magnetic resonance (MR) and 2-D-echocardiography in patients before and after aneurysmectomy. METHODS: 31 patients (23 male), mean age 64 (range 35 - 85) years with an LV aneurysm (25/31 anterior MI, 5/31 inferior MI, 1/31 both) were enrolled. MR and echocardiography were performed directly before and 3 - 65 (median 8) days after surgery. MR studies were performed on a 1.5 Tesla scanner. End-diastolic and end-systolic volumes and diameters (EDV/ESV, EDD/ESD), ejection fraction (EF) and stroke volume (SV) were determined. Echocardiography was performed to determine EF, EDD and ESD. NYHA class was assessed before and 3 months after surgery. RESULTS: After aneurysmectomy MR analysis showed a decrease in EDV (255 +/- 68 ml to 202 +/- 59 ml) ( p < 0.001) and ESV (186 +/- 71 ml to 134 +/- 53 ml; p < 0.001); EF increased (28 +/- 10 % to 35 +/- 12 %; p < 0.001); EDD/ESD decreased ( p < 0.01). Compared to echocardiography, a low correlation was found in EF before/after surgery r = 0.76/r = 0.69 and ESD r = 0.43/r = 0.60, respectively. In EDD a good correlation was found before surgery (r = 0.81), and a lower correlation after surgery (r = 0.72). NYHA class improved from 3.0 +/- 0.5 before to 1.8 +/- 0.8 after operation ( p < 0.001). CONCLUSION: Resection of an LV aneurysm results in a mean improvement of 25 % in LV function, and improved clinical outcome. In asymmetric ventricles with aneurysms MR proved to be superior as a sensitive and non-invasive tool compared to conventional 2-D-echocardiography.

Adult↗
PubMed1991

Seismocardiography for monitoring changes in left ventricular function during ischemia.

Seismocardiography is a new noninvasive technique for recording cardiac vibrations. Changes in the recorded waves have been correlated with acute and chronic changes in left ventricular function. In this report, we describe a patient who developed ischemia induced by coronary angiography in the cardiac catheterization laboratory. The patient's seismocardiogram showed distinct changes during the ischemic episode that actually preceded the onset of symptoms and resolved after nitroglycerin therapy. The patient's seismocardiographic recordings were significantly different from the recordings from five control individuals. This observation suggests that seismocardiography may be helpful for monitoring left ventricular function during episodes of myocardial ischemia.

Cardiac Catheterization↗
PubMed1993

[Left ventricular function during hypoxia--II: Effects of intramyocardial pH].

We investigated the effects of intramyocardial acidosis on cardiac function during hypoxia in mongrel dogs (n = 50). Intramyocardial pH in subendocardium of left ventricle was measured continuously using a pH electrode. During hypoxia (PaO2 = 20 mmHg) caused by inhalation of low oxygen fraction, intramyocardial pH decreased significantly following initial enhancement. Intramyocardial pH correlated significantly with arterial pH, base excess, lactic acid (LA) levels, coronary venous PcO2, and coronary venous-arterial PcO2 difference. There were significant correlations between intramyocardial pH with maximum rate of rise of left ventricular pressure (LV dp/dt max), left ventricular end-diastolic pressure (LVEDP), LVEDP/LVP and the time constant of exponential isovolumic left ventricular pressure fall. High arterial LA levels tended to cease myocardial LA uptake and production, turning LA balance into zero. LV dp/dt max was low in such a condition. Myocardial LA production decreased intramyocardial pH, but LV dp/dt max was maintained at high levels of LA production. These observations suggest that myocardial LA production maintains left ventricular function with the increase of ATP by acceleration of anaerobic glycolysis. In conclusion, during hypoxia, intramyocardial acidosis was caused by the increase of arterial LA level, myocardial anaerobic glycolysis and ATP breakdown, and it worsened left ventricular contractile function and relaxation. Arterial LA levels can play a major part in intramyocardial acidosis, but the increase in myocardial LA production might be beneficial to left ventricular contractile function.

Animals↗
PubMed1998

Assessment of left-ventricular function.

There are three distinct phases of the cardiac cycle (contraction, active relaxation, and passive relaxation) which should be examined in order to perform a thorough assessment of global left-ventricular function. Accurate measurements of left-ventricular pressure and volume are necessary to assess these phases of the cardiac cycle. The ideal index of contractility is sensitive to the intropic state of the heart, but insensitive to loading conditions, heart rate, and cardiac size. Indices of contractility may be derived from various aspects of the phase of contraction including isovolumic contraction, the end-systolic pressure-volume relationship, the phase of ejection, and the stress-strain relationship. The indices of contractility most commonly employed and arguably closest to 'ideal' are preload recruitable stroke work, an ejection phase index; the dP/dt - end-diastolic volume relationship, an isovolumic contraction phase index; and end-systolic elastance, an index derived from the end-systolic pressure-volume relationship. The active phase of relaxation is most commonly assessed by the time constant (tau) of the exponential ventricular pressure decline that occurs during the isovolumic period of relaxation. The value for tau varies inversely with ventricular function and reflects the active, energy consuming process of relaxation. tau is influenced by many of the same factors which influence contractility. The end-diastolic pressure-volume relationship reflects the passive properties of the left ventricle and may be used to obtain a measure of diastolic stiffness. The end-diastolic pressure-volume relationship is curvilinear (exponential) when end-diastolic pressures are varied over a wide range, but may be approximated by a linear relationship during low filling pressures. Diastolic stiffness is influenced by the viscoelastic properties of the heart, pericardial constraint, the atrioventricular pressure gradient, and ventricular interaction. Knowledge of the indices of the three phases of the cardiac cycle and their interactions are important to the understanding and interpretation of ventricular function in health and disease.

Animals↗
PubMed1996

Echocardiography assessment of left ventricular function in the critically ill.

Echocardiography is fast becoming the technique of choice for noninvasive evaluation of left ventricular function in the critically ill patient. Current technology allows for assessment of overall left ventricular performance and for diastolic and systolic function. Doppler technology has greatly enhanced the diagnostic capability of two-dimensional echocardiography. The critical care physician should be aware not only of currently available techniques, but also those which will be used in the routine care of the critically ill subject in the foreseeable future.

Critical Care↗
PubMed1993

Effects of intravenous milrinone on left ventricular function in ischemic and idiopathic dilated cardiomyopathy.

M-mode echocardiography and Doppler were used to assess the effects of phosphodiesterase inhibition on subendocardial function in dilated cardiomyopathy, and in particular, to study interactions with both systolic and diastolic left ventricular function. Twelve adult patients with dilated cardiomyopathy were studied (6 ischemic in origin and 6 idiopathic), 7 of whom were being considered for cardiac transplantation. Cardiac index increased without significant change in heart rate or blood pressure. Longitudinal mitral ring motion, which had been uniformly reduced, increased markedly after intravenous milrinone. Left ventricular cavity size decreased, and shortening fraction, posterior wall thickness, and rates of posterior wall thickening and thinning increased markedly. Left atrial pressure decreased, and isovolumic relaxation time increased. However, the peak velocity and duration of the transmitral E wave increased, with no change in the A wave. Improved longitudinal (subendocardial) function was reflected by improved posterior wall dynamics, and early filling, possibly by augmentation of restoring forces. Thus, severely reduced subendocardial function in dilated cardiomyopathy is potentially reversible, with marked effects on systolic and diastolic function. These previously unrecognized actions of milrinone provide further evidence to justify its short-term use in supporting the severely depressed myocardium.

Cardiomyopathy, Dilated↗
PubMed2004

Erythropoietin improves left ventricular function and coronary flow in an experimental model of ischemia-reperfusion injury.

BACKGROUND: Recent studies show that erythropoietin (EPO) plays a protective role in brain ischemia. In this condition, administration of EPO protects neurons from ischemic damage. Recently, it has been shown that in patients with chronic heart failure (CHF), EPO treatment improved cardiac function. In the present study we assessed the role of EPO and EPO-receptor (EPO-R) in the heart. METHODS AND RESULTS: We studied the presence and functionality of the EPO-R in isolated rat hearts in the Langendorff set-up. Hearts were perfused for 20 min with 10 U/ml EPO or vehicle. Immunohistochemistry revealed the presence of the EPO-R on endothelial cells, fibroblasts and to a lesser extent cardiomyocytes. Furthermore, perfusion with EPO resulted in a 50% increase in the phosphorylated MAP kinases p42/p44. To evaluate the protective role of EPO in cardiac ischemia, we performed low-flow (0.6 ml/min) ischemia/reperfusion experiments in isolated rat hearts. Administration of EPO (10 U/ml) reduced the cellular damage by 56% (P<0.05) during reperfusion, diminished apoptosis by 15% (P<0.05) and resulted in a significantly improved recovery of left ventricular pressure (P=0.02) and coronary flow (P=0.01). CONCLUSION: The present data suggest that a functional EPO-R is present in rat adult cardiac tissue and that exogenous EPO administration improves cardiac function after ischemia/reperfusion injury.

Animals↗
PubMed1984

Temporal evolution of changes in left ventricular function induced by cold pressor stimulation. An assessment with radionuclide angiography and gold 195m.

The evolutionary changes in left ventricular function induced by cold pressor stimulation were investigated at 90 second intervals by rapid sequential first pass radionuclide angiography using the short half life tracer gold 195m. The results in 12 subjects with normal coronary arteries were compared with those in 12 patients with coronary artery disease. Left ventricular ejection fraction fell significantly from resting values in both groups after 1 minute of cold pressor, but only in patients with coronary disease was the significant fall maintained at 2.5 and 4 minutes. In both groups, the maximum decrease in ejection fraction occurred after 1 minute, whereas the maximum rise in systolic blood pressure occurred after 2.5 minutes. New abnormalities of regional ventricular function developed in 10 normal subjects after 1 minute of cold, with a total of 12 new abnormal segments. Only two such segments were seen at the later stages of imaging. Twenty one new segments developed after 1 minute in the coronary disease group, and 13 segments remained abnormal after 4 minutes. Three patients, two of whom had left main stem stenoses, showed persistent abnormalities of ventricular function after 2 minutes of recovery from cold stimulation. Thus left ventricular function changes rapidly during a period of cold stimulation in both those without and those with coronary disease. When the cold pressor test is used with multiple gated equilibrium imaging, the timing of imaging may be crucial to the results and interpretation of the test. The discordance between functional changes and rise in blood pressure is further evidence that alterations in afterload are not solely responsible for cold induced abnormalities.

Adult↗
PubMed1998

Acute effects of transmyocardial laser revascularization on left-ventricular function: an haemodynamic and echocardiographic study.

While the lesions produced by transmyocardial laser revascularisation (TMLR) induce scar formation, it is important to determine whether this procedure can be deleterious for the left-ventricular function, which is already impaired by the underlying ischaemic process in some patients. Ten channels were drilled in the left lateral wall of the hearts of ten pigs (mean weight, 61 +/- 8.2kg) with a Holmium:YAG laser. Haemodynamic measurements and echocardiographic assessment of left-ventricular function were performed before the TMLR procedure, 5 and 30 min after, and lastly after 5 min of pacing at a rate increased by 30% of the baseline value. Echocardiographic assessment was in the short axis at the level of the laser channels, and included left-ventricular ejection fraction and segmental wall motility of the lasered area (scale 0-3:0 = normal 1 = hypokinesia, 2 = akinesia, 3 = dyskinesia). Values at 5 and 30 min were compared with baseline values; the difference was considered significant if p < 0.05. Haemodynamical values were stable throughout all the procedures. The ejection fraction showed a slight but significant decrease 5 min after the creation of the channels (60.4 +/- 6.8% vs 54 +/- 7.6%, p=0.02) and recovered at 30min. The segmental motility score of the involved areas increased to 1 after 5 min in five animals, and came back to 0 at 30 min except in one animal. Even with pacing no segmental dysfunction occurred. The reversibility of the segmental hypokinesia induced by TMLR, as well as the absence of pace-induced dysfunction 30 min after the procedure strongly suggest the inocuity of TMLR in this experimental set-up.

Animals↗
PubMed1992

[Late postoperative left ventricular function and ventricular hypertrophy after prosthetic valve replacement for aortic regurgitation].

Forty-two of 50 patients, who had undergone aortic valve replacement for acquired aortic regurgitation from Jan 1979 to Dec 1985, received late postoperative cardiac catheterization two years after operation. Their ages ranged between 10 and 69 years old (mean +/- S.D., 45.8 +/- 12.2 y.o.) and 37 men and 13 women were included. Postoperative left ventricular end-diastolic volume (LVEDV), end-systolic volume (LVESV) and left ventricular mass (LVM) decreased significantly compared to preoperative levels, respectively (p less than 0.001). Both postoperative left ventricular end-systolic stress/end-systolic volume ratio (LVESS/ESVI) and tension volume ejection fraction (TVEF) increased significantly (p less than 0.01) compared to preoperative levels. Positive correlations were recognized between preoperative and postoperative values in LVESV, LVM, LVESS/ESVI, TVEF and LVEF. In the patients who had showed preoperative values of LVEDVI less than 180 ml/m2, LVESVI less than 90 ml/m2 and LVEF more than 0.52, their postoperative values were expected to be normal. There were also negative correlations between LVESVI and LVEF, and between LVM and contractile properties. Nineteen patients, who had recovered normal ventricular volumes at the time of postoperative cardiac catheterization, showed normal LV dimensions and % fractional shortening between five and ten years after operation. These results demonstrate the limitation of recovery in LVM and contractile properties in spite of normalization in ventricular volume and ejection performance.

Adolescent↗
PubMed1999

Intracoronary shunt prevents left ventricular function impairment during beating heart coronary revascularization.

OBJECTIVE: Beating heart coronary revascularization is becoming increasingly popular world-wide. Temporary occlusion of the coronary artery is often required in order to perform the anastomosis. An alternative method to maintain perfusion is to use an intracoronary shunt. In this study, we monitored global left ventricular function and regional wall motion in the presence or absence of a shunt using transesophageal echocardiography (TEE). METHOD: Left ventricular wall motion score index (WMSI), wall motion score (WMS) in the left anterior descending (LAD) coronary artery territory, and ejection fraction (EF%) were measured by multiplane TEE during construction of the left internal mammary artery (LIMA)-LAD coronary artery anastomosis in 40 patients undergoing revascularization with or without the use of a shunt. WMSI was assessed preoperatively, 1, 3 and 6 min during the construction of the anastomosis and after 5 min of reperfusion. WMS was assessed at 6 min during anastomosis and after 5 min of reperfusion. EF% was calculated preoperatively, 5 min into the construction of the anastomosis, and 5 min after reperfusion. RESULTS: During construction of the anastomosis, when the shunt was used, there were no changes in WMSI, WMS in the LAD territory or EF%. A significant decline in these parameters was seen in the group in which the shunt was not used, although on reperfusion all the values returned to baseline control. CONCLUSION: (i) occlusion of the LAD to perform the anastomosis results in temporary impairment in left ventricular function with complete recovery on reperfusion; (ii) the use of an intracoronary shunt presumably by maintaining myocardial perfusion prevents deterioration in ventricular function; (iii) from this data it seems therefore advisable to use an intracoronary shunt in patients with unstable angina, poor left ventricular function, or in cases in which a longer time to perform the anastomosis is anticipated.

Aged↗
PubMed2005

Endothelin-1 receptor antagonist prevents deterioration of left ventricular function and coronary flow reserve in brain-dead canine heart.

BACKGROUND: Rapid hemodynamic deterioration is caused by induction of brain death, but the exact mechanism is still uncertain. The aim of this study was to investigate the contribution of endothelin-1 by using endothelin-1 receptor antagonist (TAK-044) in a canine brain-death model. METHODS: Dogs were divided into 2 groups: (1) the TAK group, in which TAK-044 was intravenously injected 30 minutes before brain-death induction at a dose of 3 mg/kg; and (2) the control group. Brain death was induced by rapid inflation of a sub-durally placed balloon catheter. Left ventricular function and coronary flow reserve was compared between the 2 groups. RESULTS: Brain death caused a transient hyperdynamic response followed by hemodynamic deterioration after 60 minutes in both groups. Left ventricular function, evaluated by the slope of the end-systolic pressure-volume relation was significantly decreased from 7.7 +/- 0.6 to 3.7 +/- 0.3 mm Hg/ml (p < 0.01) in the control group, but was not decreased in the TAK group (7.7 +/- 0.8 to 7.3 +/- 0.9 mm Hg/ml, p = 0.75). Coronary flow reserve, measured by direct injection of acetylcholine (3 microg) into the coronary artery, was significantly reduced at 60 minutes after brain death in the control group (264.8% to 176.6%, p < 0.01), but not in the TAK group (291.2% to 301.3%, p = 0.84). Exactly the same results were obtained when sodium nitroprusside (SNP; 100 microg) was administered. CONCLUSIONS: TAK-044 can prevent the deterioration of left ventricular function and coronary flow reserve that follows induction of brain death, suggesting that endothelin-1 could play an important role in hemodynamic deterioration by impairment of coronary microcirculation after brain death.

Animals↗
PubMed1994

[The variable effect of coronary reperfusion on survival and left-ventricular function: how do thrombolytics act?].

The favourable effects of thrombolytic therapy on survival after acute myocardial infarction can not be attributed solely to a partial recovery of systolic left ventricular function. This is mainly due to the fact that with the current therapeutic regimens early, optimal tissue reperfusion is obtained in only a small percentage of patients with an acute myocardial infarction. However, recanalization of an occluded coronary vessel in itself has beneficial effects by mechanisms other than salvage of ischemic myocardium and preservation of left ventricular function. In view of the striking relationship between reperfusion (early or late) and survival as recently demonstrated by the GUSTO study, new therapeutic developments must be aimed at increasing the percentage of early, optimal and persistent reperfusion.

Coronary Circulation↗