Fully automatic estimation of global left ventricular systolic function using deep learning in transoesophageal echocardiography.

Aims: To improve monitoring of cardiac function during major surgery and intensive care, we have developed a method for fully automatic estimation of mitral annular plane systolic excursion (auto-MAPSE) using deep learning in transoesophageal echocardiography (TOE). The aim of this study was a clinical validation of auto-MAPSE in patients with heart disease.

Methods And Results: TOE recordings were collected from 185 consecutive patients without selection on image quality.

Continuous monitoring of left ventricular function in postoperative intensive care patients using artificial intelligence and transesophageal echocardiography.

Background: Continuous monitoring of mitral annular plane systolic excursion (MAPSE) using transesophageal echocardiography (TEE) may improve the evaluation of left ventricular (LV) function in postoperative intensive care patients. We aimed to assess the utility of continuous monitoring of LV function using TEE and artificial intelligence (autoMAPSE) in postoperative intensive care patients.

Methods: In this prospective observational study, we monitored 50 postoperative intensive care patients for 120 min immediately after cardiac surgery.

Automatic assessment of left ventricular function for hemodynamic monitoring using artificial intelligence and transesophageal echocardiography.

We have developed a method to automatically assess LV function by measuring mitral annular plane systolic excursion (MAPSE) using artificial intelligence and transesophageal echocardiography (autoMAPSE). Our aim was to evaluate autoMAPSE as an automatic tool for rapid and quantitative assessment of LV function in critical care patients. In this retrospective study, we studied 40 critical care patients immediately after cardiac surgery.

Wrist ballistocardiography and invasively recorded blood pressure in healthy volunteers during reclining bike exercise.

Ballistocardiogram (BCG) features are of interest in wearable cardiovascular monitoring of cardiac performance. We assess feasibility of wrist acceleration BCG during exercise for estimating pulse transit time (PTT), enabling broader cardiovascular response studies during acute exercise and improved monitoring in individuals at risk for cardiovascular disease (CVD). We also examine the relationship between PTT, blood pressure (BP), and stroke volume (SV) during exercise and posture interventions.

Postoperative Pulmonary Complications After Cardiac Surgery: The VENICE International Cohort Study.

Objective: Postoperative pulmonary complications (PPC) remain a main issue after cardiac surgery. The objective was to report the incidence and identify risk factors of PPC after cardiac surgery.

Design: An international multicenter prospective study (42 international centers in 9 countries).

No evidence of cardiac stunning or decoupling immediately after cardiopulmonary bypass for elective coronary surgery.

Background: There is significant uncertainty regarding the timing of onset of cardiovascular stunning after cardiac surgery. Cardiovascular stunning is affecting both contractility (Ees) and arterial load. Arterial load may be represented by arterial elastance (Ea) and participates in ventriculo-arterial coupling through the Ea/Ees ratio, giving information on efficiency and performance.

Ventriculo-arterial interaction may be assessed by Oscillatory Power Fraction.

The rate of energy transfer from the left ventricle to the aorta is viewed in terms of mean power (MP) and total power (TP). The difference between MP and TP is due to the pulsatility of the circulation and is known as oscillatory power (OP). OP is considered the energy spent to accelerate the blood flow.

Post cardiac surgery stunning reduces stroke work, but leaves cardiac power output unchanged in patients with normal ejection fraction.

This study assesses positional changes in cardiac power output and stroke work compared with classic hemodynamic variables, measured before and after elective coronary artery bypass graft surgery. The hypothesis was that cardiac power output was altered in relation to cardiac stunning. The study is a retrospective analysis of data from two previous studies performed in a tertiary care university hospital.

Intensive care doctors' preferences for arterial oxygen tension levels in mechanically ventilated patients.

Background: Oxygen is liberally administered in intensive care units (ICUs). Nevertheless, ICU doctors' preferences for supplementing oxygen are inadequately described. The aim was to identify ICU doctors' preferences for arterial oxygenation levels in mechanically ventilated adult ICU patients.

Human cardiomyocyte calcium handling and transverse tubules in mid-stage of post-myocardial-infarction heart failure.

Aims: Cellular processes in the heart rely mainly on studies from experimental animal models or explanted hearts from patients with terminal end-stage heart failure (HF). To address this limitation, we provide data on excitation contraction coupling, cardiomyocyte contraction and relaxation, and Ca handling in post-myocardial-infarction (MI) patients at mid-stage of HF.

Methods And Results: Nine MI patients and eight control patients without MI (non-MI) were included.

Reduced reactive hyperemia may explain impaired flow-mediated dilation after on-pump cardiac surgery.

In previous studies, Flow Mediated Dilation (FMD) was used to study the effect of cardiac surgery on endothelial function. This study investigated the effect of on-pump cardiac surgery on FMD and reactive hyperemia. The FMD-response and reactive hyperemia were measured in 25 patients the morning before- and the first morning after cardiac surgery.

Minimally invasive beat-by-beat monitoring of cardiac power in normal hearts and during acute ventricular dysfunction.

Cardiac power, the product of aortic flow and blood pressure, appears to be a fundamental cardiovascular parameter. The simplified version named cardiac power output (CPO), calculated as the product of cardiac output (CO) in L/min and mean arterial pressure (MAP) in mmHg divided by 451, has shown great ability to predict outcome in a broad spectrum of cardiac disease. Beat-by-beat evaluation of cardiac power (PWR) therefore appears to be a possibly valuable addition when monitoring circulatory unstable patients, providing parameters of overall cardiovascular function.

Cardiac power parameters during hypovolemia, induced by the lower body negative pressure technique, in healthy volunteers.

Background: Changes in cardiac power parameters incorporate changes in both aortic flow and blood pressure. We hypothesized that dynamic and non-dynamic cardiac power parameters would track hypovolemia better than equivalent flow- and pressure parameters, both during spontaneous breathing and non-invasive positive pressure ventilation (NPPV).

Methods: Fourteen healthy volunteers underwent lower body negative pressure (LBNP) of 0, -20, -40, -60 and -80 mmHg to simulate hypovolemia, both during spontaneous breathing and during NPPV.

Synchronizing thermodilution cardiac output measurements with spontaneous breathing does not improve precision.

Introduction: Measuring cardiac output (CO) with the pulmonary artery catheter intermittent bolus thermodilution technique (PAC-IBTD) is less precise with spontaneous breathing compared to controlled ventilation. We aimed to test if precision could be improved in spontaneous breathing by synchronizing the measurement with respiration or using instructed respiration in 18 post-operative cardiac surgery patients.

Methods: We performed eight CO measurements with PAC-IBTD using cold saline in three different situations; in random order: 1) random compared to respiration, 2) timed to the start of expiration, and 3) synchronized with a slow exhalation through a PEP-flute.

The Precision of Pulmonary Artery Catheter Bolus Thermodilution Cardiac Output Measurements Varies With the Clinical Situation.

Objective: To investigate the effects of ventilatory mode, injectate temperature, and clinical situation on the precision of cardiac output measurements.

Design: Randomized, prospective observational study.

Setting: Single university hospital.

Cardiac function assessed by exercise echocardiography on the first morning after coronary artery bypass grafting.

Cardiac surgery patients are urged to resume light physical activity on the first postoperative day, even if cardiac function may not have recovered fully after the operation. To elucidate the postoperative recovery process, we examined cardiac surgery patients with exercise echocardiography before and on the first day after the operation. Patients undergoing on-pump coronary artery bypass grafting were examined with echocardiography during semirecumbent cycle exercise.

Elevated arterial lactate concentrations early after coronary artery bypass grafting are associated with increased anaerobic metabolism in skeletal muscle.

Objective: To assess the effect of coronary artery bypass grafting with cardiopulmonary bypass on muscle perfusion, oxygen extraction, and lactate release during postoperative rest and exercise.

Design: Prospective observational study.

Setting: University hospital.

Cardiac power integral: a new method for monitoring cardiovascular performance.

Cardiac power (PWR) is the continuous product of flow and pressure in the proximal aorta. Our aim was to validate the PWR integral as a marker of left ventricular energy transfer to the aorta, by comparing it to stroke work (SW) under multiple different loading and contractility conditions in subjects without obstructions in the left ventricular outflow tract. Six pigs were under general anesthesia equipped with transit time flow probes on their proximal aortas and Millar micromanometer catheters in their descending aortas to measure PWR, and Leycom conductance catheters in their left ventricles to measure SW.

High-intensity knee extensor training restores skeletal muscle function in COPD patients.

Improving reduced skeletal muscle function is important for optimising exercise tolerance and quality of life in chronic obstructive pulmonary disease (COPD) patients. By applying high-intensity training to a small muscle group, we hypothesised a normalisation of muscle function. Seven patients with COPD performed 6 weeks (3 days·week(-1)) of high-intensity interval aerobic knee extensor exercise training.

A dose-response study of levosimendan in a porcine model of acute ischaemic heart failure.

Objectives: Levosimendan is a novel inotropic agent claimed to improve myocardial contractility by a calcium-sensitizing effect. Our aim was to evaluate dose-dependent effects of levosimendan on left ventricular (LV) contractility and energetic properties in an acute, ischaemic heart failure porcine model.

Methods: Six pigs were used in an anaesthetized in vivo open-chest model.

Impact of competitive flow on wall shear stress in coronary surgery: computational fluid dynamics of a LIMA-LAD model.

Aims: Competitive flow from native coronary vessels is considered a major factor in the failure of coronary bypass grafts. However, the pathophysiological effects are not fully understood. Low and oscillatory wall shear stress (WSS) is known to induce endothelial dysfunction and vascular disease, like atherosclerosis and intimal hyperplasia.

Prophylactic treatment with levosimendan: a retrospective matched-control study of patients with reduced left ventricular function.

Objective: Levosimendan is a calcium-sensitising inotropic agent and a vasodilator used in the treatment of heart failure. Post-cardiotomy cardiac failure is more common in patients with a low preoperative left ventricular ejection fraction (LVEF). We aim at investigating how prophylactic treatment with levosimendan before weaning from cardiopulmonary bypass (CPB) affects postoperative haemodynamics and outcome in patients with low preoperative LVEF.

Different graft flow patterns due to competitive flow or stenosis in the coronary anastomosis assessed by transit-time flowmetry in a porcine model.

Objective: To assess whether coronary graft flow patterns are affected differently by native coronary competitive flow or by stenosis of the coronary anastomosis.

Methods: Nine pigs (65-70 kg) underwent off-pump grafting of the left internal mammary artery to the left anterior descending artery (LAD). Transit-time flow patterns in the mammary grafts were recorded under four different conditions: (1) baseline flow (proximal LAD occluded), (2) full competitive flow, (3) partial competitive flow and (4) after creation of a stenosis in the anastomosis.

Endothelial dysfunction induced by post-prandial lipemia: complete protection afforded by high-intensity aerobic interval exercise.

Objectives: This study was designed to study the effect of exercise and a high-fat meal (HFM) on endothelial function.

Background: Post-prandial lipemia and exercise oppose each other in terms of cardiovascular risk; however, the mechanism of their interaction is not well understood.

Methods: Endothelial function was assessed by brachial artery flow-mediated dilation (FMD) in 8 healthy men before and after an HFM preceded (16 to 18 h) by rest, a single bout of continuous moderate-intensity exercise (CME), and high-intensity interval exercise (HIIE).