Parameters Of Left Ventricular Performance Research Articles

Influence of mitral transcatheter edge-to-edge repair in patients with severe mitral regurgitation on left ventricle function

Aim. To study the changes of left ventricular (LV) contractile function in patients with severe mitral valve (MV) insufficiency with assessment of global longitudinal strain (GLS) indicators and LV myocardial function after the mitral transcatheter edge-to-edge repair (TEER) within 12-month follow-up.Material and methods. The study consisted of 43 patients with severe mitral regurgitation (MR) as follows: 23 patients with functional MR (FMR), 20 patients with degenerative MR (DMR). A comprehensive echocardiographic study, including speckle tracking echocardiography, was performed at baseline, 4-5 days, 6 and 12 months after TEER. Standard structural and functional indicators of the LV, LV GLS and myocardial performance parameters were assessed.Results. The early postoperative period (4-5 days) was characterized by a decrease in global constructive work (GCW) (FMR group — from 977 [684; 1253] to 857 [736; 1488] mm Hg%, (p=0,038); DMR group — from 1458 [1283; 1848] to 1350 [1010; 1488] mm Hg% (p=0,011)), an increase in global wasted work (GWW) (FMR group — from 177 [130; 280] to 336 [242; 388] mm Hg% (p=0,004); DMR group — from 128 [81; 172] to 216 [164; 279] mm Hg% (p=0,043)), which was accompanied by a decrease in myocardial efficiency (FMR group — from 81,5 [77; 87] to 76 [73; 79]%, (p=0,021); DMR group — from 90 [85; 93] to 82 [79; 85]% (p=0,018)). After 12-month follow-up, there was a significant increase in GCW relative to the initial values in both cohorts of patients as follows: FMR group — to 1128 [890; 1711] mm Hg% (p=0,048); DMR group — to 1818 [1478; 2034] mm Hg% (p<0,001). There was also an increase in GWW in the FMR group to 255 [214; 363] mm Hg% (p=0,024) and in the DMR group to 230 [140; 270] mm Hg% (p=0,043). There were no significant improvement of LV GLS in both groups.Conclusion. The early postoperative period after TEER was characterized by a temporary deterioration in all LV performance parameters, which recovered by 6 and 12 months of follow-up. Myocardial function restoration by one year of follow-up was noted due to an increase in GCW. LV GLS and ejection fraction did not change significantly by 1 year of follow-up compared to baseline values.

The Impact of Left Ventricular Performance and Afterload on the Evaluation of Aortic Valve Stenosis: A 1D Mathematical Modeling Approach.

The transaortic valvular pressure gradient (TPG) plays a central role in decision-making for patients suffering from severe aortic stenosis. However, the flow-dependence nature of the TPG makes the diagnosis of aortic stenosis challenging since the markers of cardiac performance and afterload present high physiological interdependence and thus, isolated effects cannot be measured directly in vivo. We used a validated 1D mathematical model of the cardiovascular system, coupled with a model of aortic stenosis, to assess and quantify the independent effect of the main left ventricular performance parameters (end-systolic (Ees) and end-diastolic (Eed) elastance) and principal afterload indices (total vascular resistance (TVR) and total arterial compliance (TAC)) on the TPG for different levels of aortic stenosis. In patients with critical aortic stenosis (aortic valve area (AVA) ≤ 0.6 cm2), a 10% increase of Eed from the baseline value was associated with the most important effect on the TPG (-5.6 ± 0.5 mmHg, p < 0.001), followed by a similar increase of Ees (3.4 ± 0.1 mmHg, p < 0.001), in TAC (1.3 ±0.2 mmHg, p < 0.001) and TVR (-0.7 ± 0.04 mmHg, p < 0.001). The interdependence of the TPG left ventricular performance and afterload indices become stronger with increased aortic stenosis severity. Disregarding their effects may lead to an underestimation of stenosis severity and a potential delay in therapeutic intervention. Therefore, a comprehensive evaluation of left ventricular function and afterload should be performed, especially in cases of diagnostic challenge, since it may offer the pathophysiological mechanism that explains the mismatch between aortic severity and the TPG.

Acute and Chronic Changes in Myocardial Work Parameters in Patients with Severe Primary Mitral Regurgitation Undergoing Transcatheter Edge-to-Edge Repair

The noninvasive assessment of myocardial work (MW) allows for the evaluation of left ventricular (LV) performance by considering the effect of LV afterload. This study aims to evaluate the acute and chronic impact of transcatheter edge-to-edge repair (TEER) on MW parameters and LV remodeling in patients with severe primary mitral regurgitation (PMR). A total of 71 patients (age: 77 ± 9 years, females: 44%) with moderate-to-severe or severe PMR (effective regurgitant orifice: 0.57 ± 0.31 cm2; regurgitant volume: 80 ± 34 mL; LV end-systolic diameter: 42 ± 12 mm) underwent TEER after a global assessment by the heart team. MW indices were evaluated before the procedure, at hospital discharge, and at 1-year follow-up. LV remodeling was described as the percentage variation in LVEDV between baseline and 1-year follow-up. TEER caused an acute reduction in LVEF, global longitudinal strain (GLS), global MW index (GWI), work efficiency (GWE), and mechanical dispersion (MD) and a significant increase in wasted work (GWW). One year after the procedure, GLS, GWI, GWE, and MD recovered, whereas GWW remained significantly impaired. Baseline GWW (β = -0.29, p = 0.03) was an independent predictor of LV reverse remodeling at 1-year follow-up. In patients with severe PMR undergoing TEER, the acute reduction in LV preload causes significant impairment to all the parameters of LV performance. Baseline GWW was the only independent predictor of LV reverse remodeling, suggesting that a lower myocardial energetic efficiency in the context of chronic preload increase might impact the left ventricular response to mitral regurgitation correction.

Left Ventricular Dysfunction Following the Ross-Konno Reconstruction is Independent of the Operation.

The Ross-Konno (RK) operation is a well-established surgical treatment for combined left ventricular outflow tract obstruction and aortic valve pathology in children. Prior study has demonstrated that mechanical and electrical dyssynchrony exist post-RK compared to normal controls. The purpose of this study was to evaluate myocardial function pre- and post-RK as defined by echocardiography.Patients undergoing the RK operation (n = 13; median age: 1.3years; range: 0.5-13.3years) were evaluated by echocardiography at defined timepoints: pre-RK, post-RK, 1-year post-RK, and 2years post-RK. Defined parameters of left ventricular performance were analyzed: systolic mechanical dyssynchrony (M-Dys), global left ventricular circumferential strain (GCS), and diastolic relaxation fraction (DRF). Patients with post-operative atrioventricular block (n = 6) were analyzed separately.No pre- versus post-RK differences existed in M-Dys, GCS, or DRF in patients both with and without post-RK atrioventricular block. Further, 1- and 2-year follow-up post-RK demonstrated significant heterogeneity in evaluated parameters of function with no pre- and post-RK differences in M-Dys, GCS, or DRF.Mechanical dyssynchrony exists post-RK reconstruction in both short- and long-term follow-up yet these echocardiographic parameters of ventricular performance are independent of the RK operation. Further study is, therefore, warranted to define causal relationships for observed short- and long-term ventricular dysfunction post-RK as the findings of the present study suggest a deleterious mechanism apart from the technical RK reconstruction.

The Effect of External Radiotherapy to the Left Ventricle Systolic Function in Locally Advanced Breast Cancer Patients

Background: Locoregional management in breast cancer patients includes surgery and radiation. Radiation increases the risk of the decreasing of cardiac ventricular performance and known as cardiotoxicity. This study aims to analyze the relationship between radiation exposure in locally advanced breast cancer patients with the left ventricular systolic function. Methods: The subjects in this study were patients with locally advanced breast cancer who underwent external radiation therapy after surgery procedure at Dr. Soetomo General Hospital in January 2021 – April 2021. Examination of left ventricular performance parameters was carried out using an invasive method, the transthoracic echocardiography. The performance parameters examined were left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS). Results: A total of 45 patients were recruited in this study. Twenty-two patients (22/45; 48.9%) underwent radiation therapy from the left side and 23 patients (23/45; 51.1%) from the right side. After external radiation, the number of patients with left ventricular dilatation were increased. On the left side, there were 6 patients (6/22; 27.6%) who experienced dilatation compared to before radiation (3 patients), while on the right side of the body there were 8 patients (8/22; 34.8%) who experienced dilatation compared to before radiation (6 patients). There was an increase in the number of patients who experienced a decrease in EFT and EFB after radiation, although the association was not significant. Almost all patients experienced a decrease in GLS values ​​after radiation (44/45; 97.8%). Conclusion: There was an increase in the number of patients with left ventricular dilatation and decrease in EFT and EFB values after external radiation. Decreased GLS values ​​were found in almost all patients who underwent external radiation in this study. Keywords: Radiation, locally advanced breast cancer, LVID, ejection fraction, GLS.

High intensity one‐legged cycling improves functional sympatholysis and aerobic fitness in chronic heart failure

Exercise intolerance and fatigue during daily activities are primary symptoms in patients with chronic heart failure (CHF). The poor correlation between the hemodynamic parameters of left ventricular performance and perceived symptoms suggests that other factors such as muscle mal perfusion plays a role in determining exercise capacity. The purpose of this study was to investigate the peripheral hemodynamic response to high intense one‐legged cycling. Leg hemodynamics were measured before and after 6 weeks of high intensity interval one‐legged cycling (90% one‐legged cycling max 4×4 min intervals with each leg, 3 times per week) in seven heart failure patients (age: 58±4 years; LVEF 34±5%; BMI 25.8±1.8 kg/m2; VO2 peak: 2.1±0.2 l/min) at rest and during one‐legged knee extensions with without arterial tyramine infusion. Data were analyzed by repeated measures two‐way ANOVA and Tuckey's honestly significant difference (HSD) post hoc procedure. Exercise training increased VO2 peak (2.2±0.2 vs. 2.5±0.3 l/min: P&lt;0.05), Wattmax during two‐legged cycling (153±14 vs. 163±24 Watt; P&lt;0.05), Wattmax during one‐legged knee extensor exercise (36±10 vs. 52±9 Watt; P&lt;0.05) and 6 min walking distance (553±48 vs. 595±59 m; P&lt;0.05). Arterial tyramine infusion lowered leg blood flow and leg vascular conduction at rest (P&lt;0.05) with no difference before and after the training intervention. Arterial tyramine infusion during one‐legged knee extensions, lowered leg blood flow before the training intervention (P&lt;0.05), whereas tyramine did not lower leg blood flow after the training intervention. These results suggest that high intensity one‐legged cycling improves functional sympatholysis during exercise and is beneficial for patients with chronic heart failure in regards to exercise capacity and functionality.

Glucose Tolerance and Left Ventricular Pressure-Volume Relationships in Frequently Used Mouse Strains

We investigated glucose tolerance and left ventricular contractile performance in 4 frequently used mouse strains (Swiss, C57BL/6J, DBA2, and BalbC) at 24 weeks. Glucose tolerance was tested by measuring blood glucose levels in time after intraperitoneal glucose injection (2 mg/g body weight). Left ventricular contractility was assessed by pressure-conductance analysis. Peak glucose levels and glucose area under the curve were higher (all P < .05) in C57BL/6J (418 ± 65 mg/dL and 813 ± 100 mg·h/dL) versus Swiss (237 ± 66 mg/dL and 470 ± 126 mg·h/dL), DBA2 (113 ± 20 mg/dL and 304 ± 49 mg·h/dL, P < .01), and BalbC mice (174 ± 55 mg/dL and 416 ± 70 mg·h/dL). Cardiac output was higher (all P < .05) in Swiss (14038 ± 4530 μL/min) versus C57BL/6J (10405 ± 2683 μL/min), DBA2 (10438 ± 3251 μL/min), and BalbC mice (8466 ± 3013 μL/min). Load-independent left ventricular contractility assessed as recruitable stroke work (PRSW) was comparable in all strains. In conclusion, glucose tolerance and load-dependent left ventricular performance parameters were different between 4 mice background strains, but PRSW was comparable.

Symptomatic and hemodynamic benefit of pentaerythrityl tetranitrate and hydralazine in a case of congestive heart failure

Sirs, A 69-year-old caucasian man was admitted to the Emergency Department for worsening dyspnea (NYHA II–III) and paroxysmal nocturnal dyspnea. The symptoms had appeared in the last months and had progressively worsened through the last 6 weeks. He referred no angina or syncope. The patient’s clinical history was absolutely negative and he reported none of the major cardiovascular risk factors. A physical exam was essentially unremarkable except for the presence of bilateral basal crepitations and mild bilateral ankle edema. Blood pressure was 100/ 60 mmHg. An ECG showed atrial fibrillation with a ventricular rate of 130/min and no sign suggestive of acute ischemia. Blood analysis showed elevated creatinine (1.6 mg/dl) and BNP (750 pg/ml). All other parameters, including C-reactive protein, were normal. Therapy with loop diuretics, 100 mg aspirin and amiodarone was started. On the first day after admission, the patient was asymptomatic and his heart rate was 90/min, and ECG showed atypical atrial flutter with irregular AV conduction. Echocardiography showed a dilated left ventricle (end-diastolic volume 130 ml) with global hypokinesia and an ejection fraction of 25%. Both atria were dilated, and there was a mild to moderate (secondary) mitral insufficiency. On day 5 after admission, a cardiac magnetic resonance and a coronary angiography excluded the presence of coronary artery disease, prior myocardial infarction and of signs suggestive of myocarditis. Left and right heart catheterization showed data compatible with heart failure (Table 1), and moderate to severe mitral regurgitation. The patient was discharged with a diagnosis of dilated cardiomyopathy and was prescribed amiodarone, spironolactone (25 mg o.d.), low-dose b-blockers (carvedilol 6.25 mg b.i.d), angiotensin converting enzyme (ACE)-inhibitors (ramipril 2.5 mg o.d.), low-molecular weight heparin (followed by oral anticoagulants). An electrophysiology examination was scheduled for the next 6 weeks. Further, since the patient appeared to be hemodynamically stable after initiating therapy with the above drugs, hydralazine (25 mg b.i.d.) and the oral organic nitrate pentaerythrityl tetranitrate (PETN, 50 mg t.i.d) were also added. Six weeks later, the patient was admitted again for the scheduled electrophysiology examination and follow-up right heart catheterization. He had scrupulously followed the therapy prescribed and had been essentially asymptomatic since discharge, and his mean heart rate was 80/ min. At this time, echocardiography, as well as left and right heart catheterization showed a marked improvement in the parameters of left ventricular performance (Table 1; Fig. 1). The mitral regurgitation was only mid-grade. The patient underwent the electrophysiology examination and successful cavotricuspid isthmus ablation. We describe a case of dilated cardiomyopathy in which medical treatment with a combination of antineurohormonal drugs and nitrate/hydralazine led to a dramatic improvement in symptoms and hemodynamic variables. Organic nitrates are widely used in the therapy of patients with chronic congestive heart failure, especially in North America [1], and the coadministration with the vasodilator and antioxidant [2] hydralazine has been associated with improvements in exercise tolerance, left ventricular size, systolic function, ischemia, cardiac remodeling [3] and, ultimately, mortality in African Americans [4]. Of note, this benefit appears to be T. Gori (&) T. Munzel 2. Medizinische Klinik, Universitatsmedizin der Johannes Gutenberg-Universitat Mainz, Mainz, Germany e-mail: tommaso.gori@ukmainz.de; tomgori@hotmail.com

Effect of tirofiban plus clopidogrel and aspirin on primary percutaneous coronary intervention via transradial approach in patients with acute myocardial infarction

Aspirin and clopidogrel can improve myocardial reperfusion and alleviate myocardial injury during percutaneous coronary intervention (PCI). Whether the addition of intravenous tirofiban during this procedure produces further benefit has not been clarified in ST segment elevation myocardial infarction (STEMI) patients. We evaluated this on STEMI patients who underwent primary PCI (p-PCI) via transradial artery approach. Consecutive patients were randomized into tirofiban group (n=72) or placebo group (n=78). Angiographic analysis included initial and final thrombolysis in myocardial infarction (TIMI) flow grade (TFG), corrected TIMI frame count (CTFC) and TIMI myocardial perfusion grade (TMPG) of the thrombotic vessel. Platelet aggregation rate (PAR), creatine phosphokinase (CPK), CPK isoenzyme MB (CPK-MB) and troponin I levels were measured and TIMI definitions were used to assess bleeding complications. Left ventricular performance parameters were investigated with equilibrium radionuclide ventriculography. Major adverse cardiac events (MACE) were followed up for 6 months. The cases of TFG 0 and 1 before PCI, TFG 0 when first crossing of guide wire were less, and the cases of TFG 3 after PCI was more in tirofiban group than those in placebo group. The final CTFC was fewer and the incidence of no reflow phenomenon was lower, as well the percentage of final TFG 3 was higher in tirofiban group than those in placebo group (all P<0.05). Mean peak CPK-MB was significantly lower, while the left ventricular performance parameters 1 week after PCI were much more improved in tirofiban group than those in the placebo group. PAR was significantly decreased shortly after tirofiban infusion. The incidence of 6-month MACE in tirofiban group was obviously lower than that in the placebo group. No statistical difference was noted between the two groups with regard to bleeding complications. Intravenous tirofiban infusion, in addition to aspirin and clopidogrel in STEMI patients with p-PCI via transradial artery access, can quickly inhibit platelet aggregation, loosen occlusive thrombus, improve myocardial reperfusion and reduce incidence of MACE with few complications of vessel access and bleeding.

Impact of physical exercise on alterations in the skeletal muscle in patients with chronic heart failure

Chronic heart failure (CHF) is a condition characterized by exercise intolerance. The level of activity tolerated by an individual cannot be predicted by classical parameters of left ventricular performance. Therefore, considerable attention has been focused on the role of peripheral factors such as skeletal muscle, which are determinants of work capacity. In recent years, many alterations in the skeletal muscle have been described in patients with chronic heart failure. This knowledge has dramatically changed the treatment of patients with CHF. Previously, patients were asked to avoid excessive strain and physical exercise. Recently, however, patients are asked to participate in a supervised physical training program to increase their exercise capacity and to counteract the molecular changes occurring in the skeletal muscle. This review will focus on molecular and biochemical alterations especially in the skeletal muscle and how these alterations are influenced by exercise training finally contributing to better skeletal muscle performance.

Left Ventricular Diastolic Performance in Neonates

The left ventricular (LV) diastolic performance of infants who were in a stable post-treatment condition in the neonatal intensive care unit was evaluated using echocardiography. The study group comprised 55 infants (Stable infant group, SI) and the parameters of LV performance were: LV propagation velocity (Vp) by color M-mode Doppler echocardiography (CMD), peak E wave, peak A wave, and the E/A ratio of transmitral flow. In a second set of measurements, a subset of 10 infants (patent ductus arteriosus (PDA) infant group, PI) were evaluated for LV diastolic performance during closure of PDA. The mean Vp in the SI was 27.2+/-7.3 cm/s and a positive correlation was observed between Vp and gestational age (r = 0.477, p = 0.0002). In the PI, Vp did not change significantly during closure of the PDA (from 23.3+/-8.2 cm/s to 27.5+/-8.4 cm/s); however, the E/Vp ratio decreased significantly with closure (from 3.14+/-0.83 to 2.12+/-0.68, p = 0.0051). The measurement of Vp by CMD can be considered a parameter for the evaluation of LV diastolic performance, even in the neonatal period. The LV diastolic performance of the infant is maintained from immediately after birth to spontaneous closure of the PDA.

Failure of Recombinant Human Growth Hormone Treatment to Improve Congestive Heart Failure in Hypopituitarism

Growth hormone (GH) deficiency decreases left ventricular (LV) contractility, induces LV chamber dilatation and promotes progression to congestive heart failure. It is, however, controversial, whether GH replacement therapy in addition to standard medical heart failure therapy should be considered as routine treatment in GH deficient patients with heart failure. In the present report of a 64-year-old GH deficient patient with heart failure, we demonstrate by using Doppler echocardiography, magnetic resonance imaging and 31P NMR spectroscopy that even a 12 month period of GH replacement therapy had no sustained effect on morphometric or functional parameters of LV performance nor on clinical signs or symptoms of heart failure. It is concluded that GH replacement therapy should currently not be regarded as standard heart failure therapy in patients with GH deficiency and should only be employed under careful monitoring including close follow-up in a standardized way.

Magnetic resonance imaging analysis of cardiac cycle events in diabetic rats: the effect of angiotensin-converting enzyme inhibition.

Non-invasive magnetic resonance imaging (MRI) was used to characterize changes in left and right ventricular cardiac cycles following induction of experimental, streptozotocin (STZ)-induced, diabetes in male Wistar rats at different ages. The effects of the angiotensin-converting enzyme (ACE) inhibitor captopril upon such chronic physiological changes were then evaluated, also for the first time. Diabetes was induced at the age of 7 weeks in two experimental groups, of which one group was subsequently maintained on captopril (2 g l(-1))-containing drinking water, and at 10 and 13 weeks in two further groups. The fifth group provided age-matched controls. All groups (each n = 4 animals) were scanned consistently at 16 weeks, in parallel with timings used in earlier studies that employed this experimental model. Cine magnetic resonance (MR) image acquisition provided transverse sections through both ventricles at twelve time points covering systole and most of diastole. These yielded reconstructions of cardiac anatomy used to derive critical functional indices and their dependence upon time following the triggering electrocardiographic R waves. The left and right ventricular end-diastolic (EDV), end-systolic (ESV) and stroke volumes (SV), and ejection fractions (EF) calculated from each, control and experimental, group showed matching values. This confirmed a necessary condition requiring balanced right and left ventricular outputs and further suggested that STZ-induced diabetes produced physiological changes in both ventricles. Absolute left and right ventricular SVs were significantly altered in all diabetic animals; EDVs and EFs significantly altered in animals diabetic from 7 and 10 but not 13 weeks. When normalized to body weight, left and right ventricular SVs had significantly altered in animals diabetic from 7 and 10 weeks but not 13 weeks. Normalized left ventricular EDVs were also significantly altered in animals diabetic from 7 and 10 weeks. However, normalized right ventricular EDVs were significantly altered only in animals made diabetic from 7 weeks. Diabetic hearts showed major kinetic changes in left and right ventricular contraction (ejection) and relaxation (filling). Both the initial rates of volume change (dV/dt) in both ventricles and the plots of dV/dt values through the cardiac cycle demonstrated more gradual developments of tension during systole and relaxation during diastole. Estimates of the derived left ventricular performance parameters of cardiac output, cardiac power output and stroke work in control animals were comparable with human values when normalized to both body (or cardiac) weight and heart rate. All deteriorated with diabetes. Comparisons of experimental groups diabetic from 7 weeks demonstrated that captopril treatment relieved the alterations in critical volumes, dependence of SV upon EDV, kinetics of systolic contraction and diastolic relaxation and in the derived indicators of ventricular performance. This study represents the first demonstration using non-invasive MRI of early, chronic changes in diastolic filling and systolic ejection in both the left and the right ventricles and of their amelioration by ACE inhibition following STZ-induction of diabetes in intact experimental animals.

Should normothermia be restored and maintained during resuscitation after trauma and hemorrhage?

Although hypothermia often occurs after trauma and has protective effects during ischemia and organ preservation, it remains unknown whether maintenance of hypothermia or restoring the body temperature to normothermia during resuscitation has any deleterious or beneficial effects on heart performance and organ blood flow after trauma-hemorrhage. Male rats underwent laparotomy (i.e., induced trauma) and were exsanguinated to and maintained at a mean arterial pressure of 40 mm Hg until 40% of the maximum shed volume was returned in the form of Ringer's lactate. Body temperature decreased from approximately 36.5 degrees C to below 32 degrees C. The animals were then resuscitated with four times the volume of maximal bleedout with Ringer's lactate. In one group, body temperature was rewarmed to 37 degrees C during resuscitation. In another group, body temperature was maintained at hypothermia (32 degrees C) for 4 hours after resuscitation. In an additional group, the body temperature was kept at 37 degrees C during hemorrhage as well as during resuscitation. Left ventricle performance parameters such as maximal rate of left ventricular pressure increase and decrease (+/-dP/dt(max)) were measured up to 4 hours. Cardiac output and regional blood flow were determined by radioactive microspheres at 4 hours after the completion of resuscitation. The maintenance of normothermia during hemor. rhage or prolonged hypothermia after resuscitation depressed the left ventricular performance parameters, cardiac output, and regional blood flow in various organs. Rewarming the body to normothermia during resuscitation, however, significantly increased heart performance, cardiac output (from hypothermia 16.2 +/- 1.4 to 22.3 +/- 1.4 mL/min per 100 g body weight,p < 0.05) and total hepatic blood flow (from hypothermia 117.5 +/- 5.3 to 166.0 +/- 9.3 mL/min per 100 g tissue, p < .05). Our data indicate that restoration of normothermia during resuscitation improves cardiac function and hepatic blood flow compared with hypothermia.

Administration of ATP-MgCl2after Trauma–;Hemorrhage and Resuscitation Restores the Depressed Cardiac Performance

Although adenosine triphosphate (ATP)-MgCl2has been shown to improve cardiac performance under normal and postischemic conditions, it is not known whether this agent has any salutary effects on cardiac performance following trauma–;hemorrhage and crystalloid resuscitation. To determine this, rats underwent laparotomy (i.e., trauma induction) and were bled to and maintained at a mean arterial pressure of 40 mm Hg until 40% of the maximum shed blood volume was returned in the form of Ringer's lactate. The animals were then resuscitated with four times the volume of shed blood using Ringer's lactate over 60 min and received either ATP-MgCl2(50 μmole/kg body wt) in 1 ml volume or an equivalent volume of normal saline intravenously over 95 min. MaximumdP/dtduring contraction as well as relaxation (±dP/dtmax) and ventricular peak systolic pressure (VPSP) were determined 15 min prior to the end of resuscitation and every 30 min thereafter for 4 hr after the completion of resuscitation. The results indicate that both −dP/dtmaxand +dP/dtmaxdecreased significantly beginning at 0 and 2 hr after the completion of resuscitation, respectively, and remained depressed throughout the duration of the study in saline-treated animals. In addition, VPSP was significantly depressed at 2–;4 hr after resuscitation. Treatment with ATP-MgCl2, however, restored these parameters. Moreover, the depressed heart rate was also restored following ATP-MgCl2administration. Since ATP-MgCl2restores various left ventricular performance parameters, this agent appears to be a promising adjunct for improving cardiac function after trauma and hemorrhage, even in the absence of blood resuscitation.

Pentoxifylline maintains hepatocellular function and improves cardiac performance during early sepsis.

Although pentoxifylline (PTX) produces various beneficial effects after endotoxemia, it remains unknown whether this agent attenuates the depressed hepatocellular function and improves heart performance during early sepsis. The aim of this study, therefore, was to determine whether PTX maintains hepatocellular function and improves cardiac function during the early hyperdynamic stages of polymicrobial sepsis. Rats were subjected to sepsis by cecal ligation and puncture (CLP). At 1 hour after CLP, PTX (50 mg/kg body weight), or an equal volume of saline, was infused intravenously over 30 minutes. At 2 or 5 hours after CLP (i.e., early hyperdynamic stages of sepsis), hepatocellular function was assessed by in vivo indocyanine green clearance. Cardiac output was determined by dye dilution. Left ventricular performance parameters such as maximal rates of left ventricular pressure rise and fall (+/-dP/dtmax), ventricular peak systemic pressure, etc., were determined using a heart performance analyzer. The results indicate that hepatocellular function was significantly depressed at 2 and 5 hours after CLP. Administration of PTX, however, maintained hepatocellular function to sham levels. Although cardiac output increased after CLP with or without PTX treatment, this agent markedly improved cardiac performance as evidenced by significantly higher + dP/dtmax and ventricular peak systemic pressure as well as other heart performance parameters. Pentoxifylline appears to be a useful adjunct for maintaining hepatocellular function and improving cardiac performance during the early hyperdynamic stages of polymicrobial sepsis.

Pentoxifylline Restores the Depressed Cardiac Performance after Trauma-Hemorrhage and Resuscitation

Although studies have shown that pentoxifylline (PTX) improves tissue perfusion and hepatocellular function after trauma-hemorrhage and resuscitation, it is not known whether this agent has any beneficial effects on left ventricular performance under such conditions. To study this, rats underwent laparotomy (i.e., trauma induced) and were bled to and maintained at a blood pressure of 40 mm Hg until 40% of the maximum shed blood volume was returned in the form of Ringer's lactate. The animals were then resuscitated with four times the volume of shed blood with Ringer's lactate over 60 min, following which PTX (50 mg/kg body wt) or an equivalent volume of normal saline was infused intravenously over 100 min. Maximum dP/dtduring contraction (+dP/dtmax) and relaxation (−dP/dtmax), maximum rate of a “pressure-normalized” change in ventricular pressure during ventricular contraction (dP/dtmax/P), and ventricular peak systemic pressure (VPSP) were determined at 15 min before the completion of resuscitation and every 30 min up to 4 hr after resuscitation. The results indicated that both +dP/dtmaxand −dP/dtmaxdecreased significantly beginning at 0.5 h after resuscitation and remained depressed throughout the study period in saline-treated animals. In addition, VPSP was significantly depressed at 2.5 to 4 hr after resuscitation. Treatment with PTX, however, significantly improved the above parameters as well as dP/dtmax/Pand heart rate. Since PTX restores various left ventricular performance parameters, this agent appears to be a useful adjunct for improving cardiac function after trauma and hemorrhagic shock, even in the absence of blood resuscitation.

Beat-to-beat variability of left ventricular indexes measured by acoustic quantification: Influence of heart rate and respiration—Correlation with M-mode echocardiography

Influence of heart rate and respiration on beat-to-beat variability of left ventricular indexes measured by acoustic quantification was examined. These indexes were correlated with their counterparts measured by M-mode echocardiography. Parameters of left ventricular performance were recorded for 1 full minute in 43 children with a mean age of 5.9 ± 3.9 years. Beat-to-beat variability was documented. The effect of respiration on such variability was examined in another 10 subjects. A wide range of heart rates and respiration did not show significant influence on the degree of variance among these parameters. The indexes measured correlated well with their counterparts measured by M-mode echocardiography. Acoustic quantification separated those with normal from those with abnormal left ventricular function with the same statistical significance as did M-mode echocardiography. A moderate degree of beat-to-beat variability occurs in acoustic quantification-derived left ventricular indexes. Heart rate variability and respiration do not influence the beat-to-beat variance of parameters of left ventricular performance measured with the acoustic quantification. Excellent correlation was documented between this technique and M-mode echocardiography.

Global and regional parameters of left ventricular performance in healthy subjects during rest and exercise assessed by radionuclide ventriculography

The aim of our study was to analyze numerous global and regional parameters of left ventricular (LV) performance during rest and exercise, in the group of 14 healthy subjects, by quantitative gated equilibrium ventriculography in left anterior oblique view (45 degrees). The global LV parameters at rest vs. exercise in our study were: heart rate 68.9 +/- 18.4 vs. 137.5 +/- 38.6; systolic blood pressure (mmHg) 121.8 +/- 18.2 vs. 178.6 +/- 31.2; diastolic blood pressure (mmHg) 82.1 +/- 10.8 vs. 90.7 +/- 12.4; double product 8,368.6 +/- 2,308.8 vs. 24,589.3 +/- 8,357.8; global ejection fraction (%) 61.9 +/- 15.4 vs. 72.8 +/- 12.8, end-diastolic volume index (ml/m2) 82.5 +/- 23.2 vs. 96.9 +/- 27.8; end-systolic volume index (ml/m2) 31.8 +/- 19.8 vs. 26.9 +/- 15.4; stroke volume index (ml/m2) 50.6 +/- 17.6 vs. 70.0 +/- 22.6; peak emptying rate (EDV/s) 3.4 +/- 2.6 vs. 8.3 +/- 3.8 and peak filling rate (EDV/s) 3.6 +/- 2.6 vs. 9.6 +/- 3.8. A significant difference (p < 0.05) between rest and exercise was found for all parameters. The highest values of LV regional ejection fraction were found in anterolateral and posterolateral region, while the lowest values were observed in inferoseptal and inferior regions. During exercise a significant increase of regional ejection fraction was found in all regions. The highest percent of radius shortening during rest was in anterolateral and posterolateral regions, and lowest in inferoseptal and inferior regions. The same sequence was found during exercise, and the difference in percent of radius shortening, between rest and exercise was significant in all regions. The observed normal values of global and regional parameters of LV function during rest may serve as a contribution for referent values. Our results on regional ejection fraction and the percent of radius shortening in rest, and their change during exercise, offer the possibility of additional information in the investigation of cardiac patients by means of radionuclide ventriculography.

What's the Price to be Paid for Rate Response: AV Sequential Versus Ventricular Pacing?

The purpose of this study was to compare the effects of atrioventricular (AV) sequential and ventricular pacing at rest and during exercise on parameters of left ventricular performance. Twenty-five patients were studied by means of first pass radionuclide angiography. Pacing rates increased significantly (P less than 0.001) during exercise in both pacing modes, resulting in a significant increase in the cardiac index (P less than 0.001). Pulmonary transit times decreased significantly (P less than 0.001) during exercise in both pacing modes with a significantly shorter pulmonary transit time for AV sequential pacing at rest (P less than 0.01) and during exercise (P less than 0.05), indicating impaired left ventricular function in ventricular pacing. Regional left ventricular wall movement deteriorated significantly during exercise in both pacing modes (P less than 0.02), with a significantly worse performance during ventricular pacing at rest (P less than 0.05) and during exercise (P less than 0.05). Therefore, the price to be paid for rate response is a deterioration of regional wall movement. An additional loss of AV synchrony worsens the situation. It is concluded that rate modulated pacing requires preservation of AV coordination to optimize left ventricular performance.