Significant Increase In Cardiac Output Research Articles

Discussion of hemodynamic optimization strategies and the canonical understanding of hemodynamics during biventricular mechanical support in cardiogenic shock: does the flow balance make the difference?

BackgroundMechanical circulatory support (MCS) devices may stabilize patients with severe cardiogenic shock (CS) following myocardial infarction (MI). However, the canonical understanding of hemodynamics related to the determination of the native cardiac output (CO) does not explain or support the understanding of combined left and right MCS. To ensure the most optimal therapy control, the current principles of hemodynamic measurements during biventricular support should be re-evaluated.MethodsHere we report a protocol of hemodynamic optimization strategy during biventricular MCS (VA-ECMO and left ventricular Impella) in a case series of 10 consecutive patients with severe cardiogenic shock complicating myocardial infarction. During the protocol, the flow rates of both devices were switched in opposing directions (+ / − 0.7 l/min) for specified times. To address the limitations of existing hemodynamic measurement strategies during biventricular support, different measurement techniques (thermodilution, Fick principle, mixed venous oxygen saturation) were performed by pulmonary artery catheterization. Additionally, Doppler ultrasound was performed to determine the renal resistive index (RRI) as an indicator of renal perfusion.ResultsThe comparison between condition 1 (ECMO flow > Impella flow) and condition 2 (Impella flow > VA-ECMO flow) revealed significant changes in hemodynamics. In detail, compared to condition 1, condition 2 results in a significant increase in cardiac output (3.86 ± 1.11 vs. 5.44 ± 1.13 l/min, p = 0.005) and cardiac index (2.04 ± 0.64 vs. 2.85 ± 0.69, p = 0.013), and mixed venous oxygen saturation (56.44 ± 6.97% vs. 62.02 ± 5.64% p = 0.049), whereas systemic vascular resistance decreased from 1618 ± 337 to 1086 ± 306 s*cm−5 (p = 0.002). Similarly, RRI decreased in condition 2 (0.662 ± 0.05 vs. 0.578 ± 0.06, p = 0.003).ConclusionsTo monitor and optimize MCS in CS, PA catheterization for hemodynamic measurement is applicable. Higher Impella flow is superior to higher VA-ECMO flow resulting in a more profound increase in CO with subsequent improvement of organ perfusion.Graphical

Mechanisms of adaptation to high intensity exercise in hypertrophic cardiomyopathy

Abstract Background Many individuals with hypertrophic cardiomyopathy (HCM) demonstrate exercise limitation. For a proportion this may be related to their overall cardiorespiratory fitness influenced by physical activity habits, body mechanics, or habitus. In others there is evidence of central and/or peripheral pathophysiology. However, some individuals with HCM demonstrate favourable adaptation to exercise. In the SAFE-HCM study, participants who underwent 12 weeks of high intensity exercise showed significant improvement in exercise indices including peak VO2, VO2/kg at anaerobic threshold (AT), time to AT, and overall exercise time compared to a usual care group. Purpose There have been no studies investigating the mechanistic adaptation(s) to exercise in HCM. This sub-study aimed to identify whether the observed improvements in exercise indices were attributable to central or peripheral adaptation. Methods Eighty patients with HCM (45.7±8.6 years) underwent baseline clinical, quality of life and psychological assessment. Individuals were randomised to a 12-week high intensity exercise programme (n=40) or usual care (n=40). Baseline evaluation was repeated at 12 weeks. The Fick equation (oxygen uptake (VO2) = cardiac output (CO) X (arterial-venous oxygen content (a-vO2 difference)) was used to assess whether central and/or peripheral adaptation was responsible for observed improvements. 2D speckle tracking imaging was utilised to calculate left ventricular longitudinal strain from the apical 2-, 3- and 4 chamber views (EchoPAC, V202, GE Healthcare). Results 12-weeks of high intensity exercise training produced a statistically significant increase in CO (1.1±0.4 L/min, CI (0.2,2.0), p=0.016) compared with the usual care group. There was no difference in the change in a-vO2 difference between groups (p=0.682) suggesting central adaptation to high intensity exercise. This was driven by an increase in stroke volume (SV) (6.1±3.0ml, CI (0.1,12.2), p=0.047) rather than an increase in heart rate (0.6±3.6 bpm, CI (-6.6,7.7), p=0.874). However, there was no change in resting myocardial deformation to account for the observed improvement in CO. Analysis of strain data demonstrated no difference in resting regional 4Ch (-0.7±0.6, CI (-1.9, 0.5), p=0.270) 3Ch (-1.1±0.9, CI (-2.8, 0.6), p=0.201), 2Ch (-1.3±0.9, CI (-3.1, 0.5), p=0.162) or average global longitudinal strain (0.9±0.6, CI (-2.2,0.3), p=0.144) between groups at 12 weeks. Conclusion Favourable central adaptations, predominantly driven by an increase in SV, enable improvements in exercise capacity following a high intensity exercise programme. Further studies are required to understand the physiological processes underlying this adaptation including assessment of myocardial deformation at peak exercise

Impact of intravenous fluid administration on cardiac output and oxygenation during cardiopulmonary resuscitation

BackgroundThe effect of intravenous fluid (IVF) administration during cardiopulmonary resuscitation (CPR) is an unexplored factor that may improve cardiac output (CO) during CPR. The aim of this study was to determine the effect of IVF administration on CO and oxygenation during CPR.MethodsThis experimental animal study was performed in a critical care animal laboratory. Twenty-two Landrace-Yorkshire female piglets weighing 27–37 kg were anesthetized, intubated, and placed on positive pressure ventilation. Irreversible cardiac arrest was induced with bupivacaine. CPR was performed with a LUCAS 3 mechanical compression device. Pigs were randomized into IVF or no-IVF groups. Pigs in the IVF group were given 20 mL/kg of Plasma-Lyte (Baxter International, Deerfield, IL USA), infused from 15 to 35 min of CPR. CPR was maintained for 50 min with serial measurements of CO obtained using ultrasound dilution technology and partial pressure of oxygen (PaO2).ResultsA mixed-effects repeated measures analysis of variance was used to compare within-group, and between-group mean changes in CO and PaO2 over time. CO and PaO2 for the piglets were measured at 10-min intervals during the 50 min of CPR. CO was greater in the IVF compared with the control group at all time points during and after the infusion of the IVF. Mean PaO2 decreased with time; however, at no time was there a significant difference in PaO2 between the IVF and control groups.ConclusionsAdministration of IVF during CPR resulted in a significant increase in CO during CPR both during and after the IVF infusion. There was no statistically significant decrease in PaO2 between the IVF and control groups.

EFFECT OF LEVOSEMINDAN ON OUTCOME OF CORONARY ARTERY BYPASS GRAFTING SURGERY IN PATIENT WITH IMPAIRED LEFT VENTRICULAR SYSTOLIC FUNCTION

Background: Coronary artery bypass grafting (CABG) is often complicated by hemodynamic instability, especially in cases with decreased left ventricular ejection fraction (LVEF). Levosimendan as inotropic agent can be used in those patients. Objective: To assess morbidity and mortality rates up to 6 months following CABG surgery in patients with LVEF equals 35%, who were given Levosimendan. Patients and methods: 40 patients with preoperative LVEF ≤ 35% underwent elective CABG were retrospectively analyzed between March 2020 and April 2022 at Al-Azhar University Hospitals. Levosemindan was used in continuously-given bolus-free infusion at a range from 0.05 to 0.2 ug/kg/min prior surgery. Hemodynamic and outcome parameters were registered and statistically analyzed. Results: A significant improvement was recorded in EF% from 32.8% to 35.9% then 39.4% after one week and 6 months respectively; it was associated with significant increase in cardiac output from 5.22 liter per minute to 6.3 L/min and 6.1 L/min after one week and 6 months respectively. MAP was also increased from 63.44 mmHg to 80.4 mmHg and 84.6 mmHg after one week and 6 months respectively. 80% of patients showed no complications; on the other hand, 5% of them had low cardiac output syndrome (LCOS), 5% needed IABP, 5% rapid AF, and 5% needed reoperation due to bleeding. On the other hand, postoperative (later) complications included the following: severe sternal wound infection in 2 cases (5%), and chronic AF in one case (2.5%); the overall mortality rate was 10%. Conclusion: levosimendan has a beneficial effect in improving hemodynamic state; in addition, it aids the reduction of hospital and ICU stays, along with the ability to reduce the incidence of LCOS and mortality rate.

Fluid bolus administration in children, who responds and how? A systematic review and meta-analysis.

Fluid boluses are frequently utilized in children. Despite their frequency of use, there is little objective data regarding the utility of fluid boluses, who they benefit the most, and what the effects are. This study aimed to conduct pooled analyses to identify those who may be more likely to respond to fluid boluses as well as characterize clinical changes associated with fluid boluses. A systematic review of the literature and meta-analysis was conducted to identify pediatric studies investigating the response to fluid boluses and clinical changes associated with fluid boluses. A total of 15 studies with 637 patients were included in the final analyses with a mean age of 650 days ± 821.01 (95% CI 586 to 714) and a mean weight of 10.5kg ± 7.19 (95% CI 9.94 to 11.1). The mean bolus volume was 12.14 ml/kg ± 4.09 (95% CI 11.8 to 12.5) given over a mean of 19.55 min ± 10.16 (95% CI 18.8 to 20.3). The following baseline characteristics were associated with increased likelihood of response [represented in mean difference (95% CI)]: greater age [207.2 days (140.8 to 273.2)], lower cardiac index [-0.5ml/min/m2 (-0.9 to -0.3)], and lower stroke volume [-5.1ml/m2 (-7.9 to -2.3)]. The following clinical parameters significantly changed after a fluid bolus: decreased HR [-5.6bpm (-9.8 to -1.3)], increased systolic blood pressure [7.7 mmHg (1.0 to 14.4)], increased mean arterial blood pressure [5.5 mmHg (3.1 to 7.8)], increased cardiac index [0.3ml/min/m2 (0.1 to 0.6)], increased stroke volume [4.3ml/m2 (3.5 to 5.2)], increased central venous pressure [2.2 mmHg (1.1 to 3.3)], and increased systemic vascular resistance [2.1 woods units/m2 (0.1 to 4.2)]. Fluid blouses increase arterial blood pressure or cardiac output by 10% in approximately 56% of pediatric patients. Fluid blouses lead to significant decrease in HR and significant increases in cardiac output, stroke volume, and systemic vascular resistance. Limited published data are available on the effects of fluid blouses on systemic oxygen delivery.

Non-invasive cardiac output monitoring before and after baby extubation – A feasibility study (NICOMBabe study)

BackgroundMechanical ventilation induces changes in intrapleural, intrathoracic and intra-abdominal pressure. These changes have various implications on cardiac output (CO). AimsThe aim of this study was to determine the feasibility of measuring changes in CO after elective extubation in neonates using the principle of transthoracic bioreactance (TBR). Study designThis was a prospective observational cohort study in a level III neonatal centre. CO, stroke volume (SV) and heart rate were measured continuously for 2 h before and 2 h after elective extubation by TBR. SubjectsNeonates undergoing elective extubation were eligible for enrolment. Outcome measuresThe primary outcome of the study was change in CO post elective extubation. ResultsTen neonates were enrolled, seven (70 %) had a statistically significant decrease in CO after extubation, three (30 %) infants had a statistically significant increase in CO after extubation. Changes in CO were primarily driven by changes in SV and the pattern of change was related to patent ductus arteriosus (PDA) status prior to extubation. ConclusionExtubation significantly influences CO in neonatal patients and the pattern of change appears to be related to PDA status.

Novel Methods for Predicting Fluid Responsiveness in Critically Ill Patients-A Narrative Review.

In patients with acute circulatory failure, fluid administration represents a first-line therapeutic intervention for improving cardiac output. However, only approximately 50% of patients respond to fluid infusion with a significant increase in cardiac output, defined as fluid responsiveness. Additionally, excessive volume expansion and associated hyperhydration have been shown to increase morbidity and mortality in critically ill patients. Thus, except for cases of obvious hypovolaemia, fluid responsiveness should be routinely tested prior to fluid administration. Static markers of cardiac preload, such as central venous pressure or pulmonary artery wedge pressure, have been shown to be poor predictors of fluid responsiveness despite their widespread use to guide fluid therapy. Dynamic tests including parameters of aortic blood flow or respiratory variability of inferior vena cava diameter provide much higher diagnostic accuracy. Nevertheless, they are also burdened with several significant limitations, reducing the reliability, or even precluding their use in many clinical scenarios. This non-systematic narrative review aims to provide an update on the novel, less employed dynamic tests of fluid responsiveness evaluation in critically ill patients.

Anti-S2 peptides target cardiac myosin for in vivo responses

Chemically synthesized peptides designed to modulate the unfolding of cardiac myosin S2 were conjugated to heart targeting molecule for injection into live mice. Fluorescently labeled peptides confirmed that some of the peptides reached the heart. Fluorescence detected by superresolution microscopy in the walls of the coronary artery, extracellular matrix, t-tubules, and sarcomeres suggested a possible route for the peptides reaching the myosin S2 in vivo. Echocardiography measurements indicated that IV injection of 20 nmol of the fluorescently labeled Destabilizer peptide that induces an unfolded conformation of the myosin S2 led to a statistically significant increase in cardiac output in 24 hrs.

Oral treprostinil improves pulmonary vascular compliance in pulmonary arterial hypertension

Oral treprostinil has been shown to improve exercise capacity and delay disease progression in patients with pulmonary arterial hypertension (PAH), but its effects on hemodynamics are not well-characterized. The FREEDOM-EV trial was a Phase III, international, placebo-controlled, double-blind, event-driven study in 690 participants with PAH who were taking a single oral PAH therapy. FREEDOM-EV demonstrated a significantly reduced risk for clinical worsening with oral treprostinil taken three times daily and did not uncover new safety signals in PAH patients. Sixty-one participants in the FREEDOM-EV trial volunteered for a hemodynamics sub-study. Pulmonary artery compliance (PAC), a ratio of stroke volume to pulmonary pulse pressure, significantly increased from Baseline to Week 24 in the oral treprostinil group compared with the placebo group (geometric mean 26.4% active vs. -6.0% placebo; ANCOVA p=0.007). There was a significant increase in cardiac output in the oral treprostinil group compared to the placebo group (geometric mean 11.3% active vs. -6.4% placebo; ANCOVA p=0.005) and a corresponding significant reduction in pulmonary vascular resistance (PVR) (geometric mean -21.5 active vs. -1.8% placebo; ANCOVA p=0.02) from Baseline to Week 24. These data suggest that increased compliance contributes to the physiological mechanism by which oral treprostinil improves exercise capacity and delays clinical worsening for patients with PAH.

Abstract 11340: Increasing Mean Arterial Pressure or Cardiac Output in Comatose Out-of-Hospital Cardiac Arrest Patients Undergoing Targeted Temperature Management: Effects on Cerebral Tissue Oxygenation

Introduction: There are few data regarding the effects of norepinephrine-uptitration on global and regional hemodynamics in cardiac intensive care patients. Methods: We prospectively studied 10 OHCA patients at our cardiac intensive care unit. The trial consisted of 5 phases. The first 4 phases were achieved by titrating norepinephrine to reach targets of mean arterial pressure (MAP). First a MAP of 65 mmHg, second 75 mmHg, third 85 mmHg, fourth 65 mmHg again. The fifth phase was with a constant MAP of 65 mmHg but aiming at an increased PaCO2 from 6.5-7.3 kPa to increase cardiac output. During each phase, 20 minutes steady state was achieved before measurements. We measured hemodynamic variables with a Swan-Ganz catheter, arterial and mixed venous blood gases, and near-infrared spectroscopy at the forehead (cerebral oxygen saturation). Results: To obtain a MAP at 85 mmHg, norepinephrine was increased from 0.11±0.02 to 0.18±0.02 μg · kg–1 · min–1 (P < 0.001). Norepinephrine uptitration significantly increased MAP, systemic vascular resistance and pulmonary artery pressure, without affecting cardiac output or heart rate. After phase 3, norepinephrine was decreased to basal values, and all variables returned to baseline. Increasing pCO2, resulted in a significant increase in cardiac output and cerebral oxygen saturation, while decreasing systemic vascular resistance. MAP (and NE dose) was unaffected by increasing pCO2. Conclusions: A short-term increase in MAP with norepinephrine in resuscitated OHCA-patients is associated with increased SVR and PVR without affecting cardiac output or NIRS of the brain. An increase in CO caused by an increase in pCO2 and thereby a decreased SVR increased NIRS potentially improving brain oxygenation.

Increasing mean arterial pressure or cardiac output in comatose out-of-hospital cardiac arrest patients undergoing targeted temperature management: Effects on cerebral tissue oxygenation and systemic hemodynamics

IntroductionFew data exist on the effects of increasing norepinephrine doses or increasing arterial CO2 (PaCO2) on hemodynamics and cerebral oxygenation in comatose out-of-hospital cardiac arrest (OHCA) patients. MethodsWe prospectively studied 10 resuscitated OHCA-patients undergoing targeted temperature management (36C°). The trial consisted of 5 phases with 20 minutes steady state in-between: Phase 1–4 were increasing doses of norepinephrine to reach targets of mean arterial pressure (MAP). First 65, second 75, third 85, fourth 65 mmHg again. In the fifth phase, MAP was constant while PaCO2 was increased to 6.5–7.3 kPa to increase cardiac output. Primary outcome was cerebral near-infrared spectroscopy (NIRS). Secondary outcomes were hemodynamic variables from Swan-Ganz catheters and blood samples from the radial artery and jugular bulb. ResultsTo reach a MAP at 85 mmHg, norepinephrine was increased from 0.11 ± 0.02 to 0.18 ± 0.02 µg/kg/min (P < 0.001). Norepinephrine uptitration significantly increased systemic vascular resistance (SVR) and pulmonary vascular resistance, without affecting cardiac output, heart rate or cerebral oxygenation.Increasing PaCO2, resulted in a significant increase in cardiac output and cerebral NIRS, but arterial-venous cerebral oxygen-uptake decreased. Norepinephrine demand to keep MAP at 65 mmHg was unaffected by increasing PaCO2. ConclusionsA short-term increase in MAP with norepinephrine in resuscitated comatose cardiac arrest-patients is associated with increased SVR and pulmonary vascular resistance without affecting cardiac output or cerebral NIRS. Increased cardiac output caused by an increase in PaCO2 increased cerebral NIRS, but not cerebral oxygen uptake.

Cardiac changes following arteriovenous fistula creation in a mouse model.

Arteriovenous fistula (AVF) creation may negatively affect cardiac structure and function and impact cardiovascular mortality. The objective of this study was to develop and characterize the cardiac changes following AVF creation in a murine AVF model. AVFs were constructed using the carotid artery and jugular vein in C57BL/6 mice. Sham-operated AVF mice served as the control group. 2D-echocardiography was performed prior to AVF creation (baseline) and at 7 and 21 days after creation in AVF and sham-operated mice. Picrosirius red was used to stain the left ventricle for collagen production. The cardiac output (CO), left ventricular end diastolic (LVEDD) and systolic (LVESD) diameter, and end-diastolic (LVEDV) and systolic (LVESV) volume was significantly increased at 7 and 21 days in AVF compared to sham-operated mice. There was also a significant increase in CO, LVEDD, LVESD, LVEDV, and LVESV from baseline to 21 days within the AVF group, but not the sham-operated mice. There was a significant decrease in ejection fraction and fractional shortening at 21 days in AVF compared to sham-operated mice. Picrosirius red was significantly more prominent around both the perivascular and interstitial areas of the cardiac tissue from AVF mice compared to sham-operated AVF mice at 21 days. The creation of an AVF in our murine model leads to cardiac changes such as increased cardiac output, left ventricular dilation, and cardiac fibrosis, while showing reductions of ejection fraction and fractional shortening.

The physiological effects of cardiac resynchronization therapy on aortic and pulmonary flow and dynamic and static components of systemic impedance.

BackgroundPatients who improve following cardiac resynchronization therapy (CRT) have left ventricular (LV) remodeling and improved cardiac output (CO). Effects on the systemic circulation are unknown.ObjectiveTo explore the effects of CRT on aortic and pulmonary blood flow and systemic afterload.MethodsAt CRT implant patients underwent a noninvasive assessment of central hemodynamics, including wave intensity analysis (n = 28). This was repeated at 6 months after CRT. A subsample (n = 11) underwent an invasive electrophysiological and hemodynamic assessment immediately following CRT. CRT response was defined as reduction in LV end-systolic volume ≥15% at 6 months.ResultsIn CRT responders (75% of those in the noninvasive arm), there was a significant increase in CO (from 3 ± 2 L/min to 4 ± 2 L/min, P = .002) and LV dP/dtmax (from 846 ± 162 mm Hg/s to 958 ± 194 mm Hg/s, P = .001), immediately after CRT in those in the invasive arm. They demonstrated a significant increase in aortic forward compression wave (FCW) both acutely and at follow-up. The relative change in LV dP/dtmax strongly correlated with changes in the aortic FCW (Rs 0.733, P = .025). CRT responders displayed a significant reduction in afterload, and a decrease in systemic vascular resistance and pulse wave velocity acutely; there was a significant decrease in acute pulmonary afterload measured by the pulmonary FCW and forward expansion wave.ConclusionImproved cardiac function following CRT is attributable to a combination of changes in the cardiac and cardiovascular system. The relative importance of these 2 mechanisms may then be important for optimizing CRT.

Respiratory Modulated Pacing Improves Outcomes in Heart Failure

Heart failure is a leading cause of mortality and morbidity globally. Current cardiac pacemakers pace the heart rate at regular monotonic intervals. However, heart rate is dynamic, with greater heart rate variability (HRV) being a positive prognostic indicator of cardio-vascular health. HRV changes rhythmically with breathing, termed respiratory sinus arrythmia (RSA). This is an evolutionary conserved phenomenon thought to be controlled by the parasympathetic nervous system. RSA is prominent in children and healthy adults but absent in many cardiovascular diseases, including heart failure. We hypothesised that pacing the heart with novel respiratory modulated pacing would improve outcomes in heart failure with reduced ejection fraction compared to conventional monotonic pacing. Heart failure was induced in adult Romney sheep by a microembolisation technique. Eight to ten weeks post embolization sheep were implanted with an arterial pressure probe, diaphragmatic electrodes, aortic flow probe, coronary artery flow probe, a pacing lead on the left atria, and split into three groups. RSA paced (n = 5), monotonically paced (n = 5), and time control (n = 5). One week baseline recording was followed by four weeks of pacing, and one week off-pace, before terminal experiments and tissue collection. All recordings were in conscious animals. Respiratory modulated pacing was generated by a proprietary device (Ceryx medical) which receives input from the diaphragmatic electrodes to pace the heart with real time respiratory modulation. RSA pacing resulted in a significant increase in cardiac output (4 weeks of pacing: Δ RSA: 1.4 ± 0.5, Δ Mono: -1.2 ± 1.0, Δ TC: -0.2 ± 1.2 L/min), and ejection fraction (4 weeks of pacing: ΔRSA: 10.6 ± 9.2, Δ Mono: -4.8 ± 4.5, ΔTC: -3.0 ± 3.4 %) compared to monotonic pacing, with no difference in heart rate between groups. The increase in cardiac output was not associated with a change in MAP, indicating total peripheral resistance was reduced. RSA also caused a significant reduction in apnea incidence, suggesting improvement in respiratory instabilities. Reinstalling RSA may be a novel therapeutic target for improving outcomes in heart failure and opens the possibility of new device-based therapies in other diseases of cardiac inefficiency. We propose that the next generation of pacemakers should incorporate respiratory modulation.

Effects of cardiac pacemakers on left ventricular volumes and function assessed by 3D echocardiography, Doppler method, and global longitudinal strain

BackgroundMany previous studies reported the negative effects of right ventricular (RV) pacing on the left ventricular (LV) structure and ejection fraction. Studying pacing hemodynamics is essential to understand these detrimental effects. In this study, we tried to understand RV pacing effects on LV volumes and function using advanced tools like 3D echo and global longitudinal strain (GLS). This was a prospective study of 175 consecutive patients (LVEF>50%) presented permanent pacing. Of 175 patients, only 50 patients met study criteria, divided into two groups (single or dual pacing). LV volumes and function were assessed by full-volume 3D echocardiography and GLS before pacing, at 1-week and 6-month post-pacing. Cardiac output (COP) was calculated by pulsed wave Doppler method and 3D echo.ResultsDoppler method results were similar to 3D echo in calculating SV and COP. At 1-week post pacing, both groups showed a significant decrease in SV due to a drop in EDV while ESV did not change significantly. Despite the drop in SV, there was a significant increase in cardiac output (COP) due to achieving higher heart rates post-pacing. There was a significant drop in EF and GLS in both groups.At 6 months, SV continued to decrease with a corresponding decrease in COP and LVEF. This drop in SV was due to a significant increase in ESV while EDV did not show a significant change at a 6-month follow-up. Also, the drop EF and GLS became more significant.There were no significant differences between both groups regarding the changes in LV volumes (EDV, ESV, SV), LVEF or GLS throughout the study (pre-pacing, at 1-week and 6-months post pacing). However, dual-chamber pacing group provided higher heart rates and as a result higher COP than the single-chamber group.ConclusionsRV pacing led to a significant drop in LV COP, ejection fraction (EF), and GLS over short- and long-term duration. Dual chamber pacing provided higher COP than a single chamber pacing. This was due to tracking the S. A node with pacing at higher heart rates not due to an increase in SV and preserving atrioventricular synchrony. Both Doppler method and 3D echo can be used to calculate SV and COP.

Comparative study between effects of single and dual chamber pacemaker on stroke volume, cardiac output and strain using 3D echocardiography, pulsed Doppler method and global longitudinal strain (GLS)

Abstract Background Dual-chamber cardiac pacing is thought to deliver higher clinical benefits as compared with single-chamber ventricular pacing. During the last two decades, 3D-echocardiography developed from a sophisticated, time-consuming method preferably used as a scientific tool towards a routine clinical approach. At present, available evidence suggested that 3D echocardiography provided improved accuracy and reproducibility over 2D methods for LV volume and function calculation. It was also more useful for early detection of volumetric changes associated with changes in cardiac hemodynamics. Methods This was an observational study of fifty consecutive patients without structural heart disease and preserved ejection fraction (EF&amp;gt;50%) presented with high grade atrioventricular block for permanent pacemaker implantation. They were assigned to receive a single-chamber ventricular pacemaker (23patients) or a dual-chamber pacemaker (27 patients). Stroke volume and cardiac output was assessed by full volume 3D echo and pulsed wave Doppler before implantation, at one-week and 6-months after implantation. For the Doppler method, LVOT diameter was measured for each patient at baseline and same value was used at follow up to avoid any confounding factors. GLS was measured at all visits. Results At one-week post pacing, both groups showed a significant decrease in SV due to a drop in EDV while ESV did not change significantly. There was a significant increase in cardiac output (COP) more in dual-chamber pacing group than in the group with single-chamber pacing. However, there were no significant differences between both groups regarding stroke volume (SV), end-systolic volume (ESV), end-diastolic volume (EDV) or ejection fraction (EF) during all time intervals (pre-pacing, at one-week and 6-months post pacing). GLS showed equal decrease in both groups. At 6 months, SV continued to decrease, and COP showed significant decrease. This drop in SV and COP was due to a significant increase in ESV while EDV did not show significant change at 6-month follow up. There was no significant difference between full volume 3D and Doppler methods regarding SV and COP values at all time intervals in both groups. GLS showed additional equal decrease in both groups. Conclusion Dual chamber pacing provided higher COP than single chamber pacing. This is due to pacing at higher heart rates, not due to increase in SV by maintaining atrioventricular synchrony. It was shown in both experimental and clinical studies that RV pacing leads to ventricular dyssynchrony, similar to that of left bundle branch block with subsequent electrical, mechanical and anatomical changes leading to detrimental effects on left ventricular structure and function. Both groups showed significant drop in GLS plus SV, COP and EF at 6-months due to significant increase in ESV. 2D echocardiography and Doppler method were not inferior to 3D echocardiography regarding calculation of SV and COP. Haemodynamics of single &amp; dual pacing Funding Acknowledgement Type of funding source: None

Obstetric blood loss: priorities in the infusion solutions choice

Objective. To study the effect of Rheosorbilact on the main life support systems in patients with massive blood loss in obstetrics.&#x0D; Materials and methods. The study was carried out in 56 puerperas with massive blood loss during obstetric operations for placenta previa. Surgical intervention was performed under general multicomponent anesthesia with mechanical ventilation. After the end of the operation, the patients were on prolonged mechanical ventilation for 4-6 h until the main life support systems were stabilized. With the purpose of infusion therapy were used Rheosorbilact (13-15 ml/kg), 0.9 % sodium chloride solution (25-30 ml/kg) and blood components. The main life support systems were assessed by non-invasive monitoring of central and peripheral hemodynamics and autonomic nervous system.&#x0D; Results and discussion. Blood loss was 1500-2000 ml, which developed within 20 min from the moment of the start of the operation. Taking into account the pharmacological properties of the drugs used, infusion therapy began with a jet intravenous injection of Rheosorbilact followed by the introduction of 0.9 % sodium chloride. After 30 min from the onset of bleeding and the administration of infusion-transfusion therapy, a significant increase in cardiac output over the initial parameters was noted. At the same time, the epicardial fat volume (EFV) significantly decreased by 4.4 %. 30 min after the end of the infusion-transfusion therapy, a stable hemodynamic profile was noted. 4 h after the end of the infusion therapy, there was an increase in cardiac output and MDP relative to the original value, a decrease in post-load and heart rate, an increase in EFV by 8.1 % (p&lt;0.05). SI decreased by 54.6 % (p&lt;0.05). Diuresis significantly increased to 1.75 ml/kg/h. The initial intravenous infusion was with Rheosorbilact. Considering that the transition of extracellular fluid into the vascular bed is a rather slow process, the transfusion of a hyperosmolar solution exceeding the plasma pressure is more justified. Within 30 min from the start of infusion therapy, the hemodynamic profile stabilized.&#x0D; Conclusions. In acute massive blood loss, the use of Rheosorbilact allows you to quickly, effectively and safely correct the deficit in circulating blood volume. Primary targeted hemodynamic support with the use of a low-volume hyperosmolar infusion of Rheosorbilact makes it possible to achieve hemodynamic stabilization with a smaller infusion volume due to interstitial redistribution of fluid into the vascular bed.

Cardiac output improvement by pecavaptan: a novel dual-acting vasopressin V1a/V2 receptor antagonist in experimental heart failure.

AimsArginine vasopressin (AVP) mediates deleterious effects via vascular V1a and renal V2 receptors in heart failure (HF). Despite positive short‐term decongestive effects in phase II HF studies, selective V2 receptor antagonism has shown no long‐term mortality benefit, potentially related to unopposed V1a receptor activation. We compared the novel dual V1a/V2 receptor antagonist pecavaptan with the selective V2 receptor antagonist tolvaptan in pre‐clinical HF models.Methods and resultsIn vitro IC50 determination in recombinant cell lines revealed similar receptor selectivity profiles (V2:V1a) of tolvaptan and pecavaptan for human and dog AVP receptors, respectively. Two canine models were used to compare haemodynamic and aquaretic effects: (i) anaesthetised dogs with tachypacing‐induced HF, and (ii) conscious telemetric dogs with a non‐invasive cardiac output (CO) monitor. Tolvaptan and pecavaptan exhibited no differences in urinary output. In HF dogs, pecavaptan counteracted the AVP‐induced increase in afterload and decrease in CO (pecavaptan: 1.83 ± 0.31 L/min; vs. tolvaptan: 1.46 ± 0.07 L/min, P < 0.05). In conscious telemetric animals, pecavaptan led to a significant increase in CO (+0.26 ± 0.17 L/min, P = 0.0086 vs. placebo), in cardiac index (+0.58 ± 0.39 L/min/m2, P = 0.009 vs. placebo) and a significant decrease in total peripheral resistance (−5348.6 ± 3601.3 dyn × s/cm5, P < 0.0001 vs. placebo), whereas tolvaptan was without any significant effect.ConclusionsSimultaneous blockade of vascular V1a and renal V2 receptors efficiently induces aquaresis and counteracts AVP‐mediated haemodynamic aggravation in HF models. Dual V1a/V2 antagonism may lead to improved outcomes in HF.

Экспериментальное моделирование холинореактивности головного мозга при черепно-мозговой травме: влияние на центральную гемодинамику

Актуальность. Наибольшее значение в формировании ответа на черепно-мозговую травму (ЧМТ) имеет первичная реакция медиаторных систем центральной нервной системы в острый период, когда формируются основные патогенетические сдвиги. Цель исследования: определение влияния холинореактивности (активации или блокады центральных холинергических систем; ЦХС) на летальность, неврологический дефицит и состояние центральной гемодинамики в остром периоде ЧМТ. Материалы и методы. Травму моделировали при свободном падении груза на фиксированную голову животного. Для активации ЦХС крысам до травмы вводили холина альфосцерат (глиатилин; 6 мг/кг), для блокировки — биперидена гидрохлорид (акинетон; 0,6 мг/кг). Неврологический дефицит оценивали по 100-балльной шкале Тодда. Параметры центральной гемодинамики определяли методом тетраполярной импедансной грудной реографии. Результаты. Активация ЦХС в остром периоде ЧМТ приводила к уменьшению летальности и неврологического дефицита. Отмечено существенное увеличение сердечного выброса и снижение сопротивления сосудов (гипердинамический тип). Блокада ЦХС сопровождалось значительным неврологическим дефицитом, снижением сердечного выброса и артериального давления на фоне увеличения сопротивления сосудов (гиподинамический тип). Выводы. Результаты подтвердили ключевую роль ЦХС в реализации реакции на ЧМТ и обосновали возможное направление дальнейших исследований — применение холиномиметиков центрального типа действия для купирования неврологических нарушений. Ограничением активации ЦХС может быть перегрузка миокарда с формированием посттравматической миокардиодистрофии.

Changes in vascular access blood flow: Etiological factors and clinical implications.

Records of 10,000 QVA measurement performed in 549 patients over 20 years were used as retrospective and anonymized data source, making ethical commission involvement unnecessary. Two approaches are used to elucidate association of QVA changes with different factors: analyses of smaller cohorts in which both the QVA and the respective factor were measured (e.g. association of QVA with cardiac output (CO)), or-in case of rare phenomena-a form of a well illustrated case reports was used (e.g. association of QVA and Kt/V). Significant increase in CO after permanent VA creation (3-4-fold of the QVA value) was found. Impact of intradialytic CO changes on QVA is attenuated by relatively stable VA resistance compared to systemic resistance. Blood pressure impact is much stronger and it should therefore be noted at each QVA measurement. As reproducibility of different QVA measurement methods varies, use of the same method should be preferred. Direction of the arterial needle insertion in VA affects the QVA measured, especially in synthetic grafts, too. Also patient's own QVA variability may be quite high. All this makes KDOQI/EBPG recommended acceptable QVA drops too strict, they should be revised. In re-stenoses prone patients, measurement intervals should be shortened, too. QVA values are significantly affected by many factors. Their knowledge appears essential for safe and effective VA surveillance and management.