Search Results Heading

MBRLSearchResults

mbrl.module.common.modules.added.book.to.shelf
Title added to your shelf!
View what I already have on My Shelf.
Oops! Something went wrong.
Oops! Something went wrong.
While trying to add the title to your shelf something went wrong :( Kindly try again later!
Are you sure you want to remove the book from the shelf?
Oops! Something went wrong.
Oops! Something went wrong.
While trying to remove the title from your shelf something went wrong :( Kindly try again later!
    Done
    Filters
    Reset
  • Discipline
      Discipline
      Clear All
      Discipline
  • Is Peer Reviewed
      Is Peer Reviewed
      Clear All
      Is Peer Reviewed
  • Item Type
      Item Type
      Clear All
      Item Type
  • Subject
      Subject
      Clear All
      Subject
  • Year
      Year
      Clear All
      From:
      -
      To:
  • More Filters
      More Filters
      Clear All
      More Filters
      Source
    • Language
2,194 result(s) for "Heart Function Tests - methods"
Sort by:
Blinded, randomized trial of sonographer versus AI cardiac function assessment
Artificial intelligence (AI) has been developed for echocardiography 1 – 3 , although it has not yet been tested with blinding and randomization. Here we designed a blinded, randomized non-inferiority clinical trial (ClinicalTrials.gov ID: NCT05140642; no outside funding) of AI versus sonographer initial assessment of left ventricular ejection fraction (LVEF) to evaluate the impact of AI in the interpretation workflow. The primary end point was the change in the LVEF between initial AI or sonographer assessment and final cardiologist assessment, evaluated by the proportion of studies with substantial change (more than 5% change). From 3,769 echocardiographic studies screened, 274 studies were excluded owing to poor image quality. The proportion of studies substantially changed was 16.8% in the AI group and 27.2% in the sonographer group (difference of −10.4%, 95% confidence interval: −13.2% to −7.7%, P  < 0.001 for non-inferiority, P  < 0.001 for superiority). The mean absolute difference between final cardiologist assessment and independent previous cardiologist assessment was 6.29% in the AI group and 7.23% in the sonographer group (difference of −0.96%, 95% confidence interval: −1.34% to −0.54%, P  < 0.001 for superiority). The AI-guided workflow saved time for both sonographers and cardiologists, and cardiologists were not able to distinguish between the initial assessments by AI versus the sonographer (blinding index of 0.088). For patients undergoing echocardiographic quantification of cardiac function, initial assessment of LVEF by AI was non-inferior to assessment by sonographers. The impact of artificial intelligence in cardiac function assessment is evaluated by a blinded, randomized non-inferiority trial of artificial intelligence versus sonographer initial assessment of the left ventricular ejection fraction.
Coronary Atheroma Regression and Plaque Characteristics Assessed by Grayscale and Radiofrequency Intravascular Ultrasound After Aerobic Exercise
The aim of the present study was to investigate effects of aerobic interval training (AIT) versus moderate continuous training (MCT) on coronary atherosclerosis in patients with significant coronary artery disease on optimal medical treatment. Thirty-six patients were randomized to AIT (intervals at ≈ 90% of peak heart rate) or MCT (continuous exercise at ≈ 70% of peak heart rate) 3 times a week for 12 weeks after intracoronary stent implantation. Grayscale and radiofrequency intravascular ultrasounds (IVUS) were performed at baseline and follow-up. The primary end point was the change in plaque burden, and the secondary end points were change in necrotic core and plaque vulnerability. Separate lesions were classified using radiofrequency IVUS criteria. We demonstrated that necrotic core was reduced in both groups in defined coronary segments (AIT −3.2%, MCT −2.7%, p <0.05) and in separate lesions (median change −2.3% and −0.15 mm3, p <0.05). Plaque burden was reduced by 10.7% in separate lesions independent of intervention group (p = 0.06). No significant differences in IVUS parameters were found between exercise groups. A minority of separate lesions were transformed in terms of plaque vulnerability during follow-up with large individual differences between and within patients. In conclusion, changes in coronary artery plaque structure or morphology did not differ between patients who underwent AIT or MCT. The combination of regular aerobic exercise and optimal medical treatment for 12 weeks induced a moderate regression of necrotic core and plaque burden in IVUS-defined coronary lesions.
The Effect of Strict Volume Control Assessed by Repeated Bioimpedance Spectroscopy on Cardiac Function in Peritoneal Dialysis Patients
Adequate fluid management plays an important role in decreasing cardiovascular risk in peritoneal dialysis (PD) patients. We evaluated whether strict volume control monitored by bioimpedance spectroscopy (BIS) affects cardiac function in PD patients. This study is a secondary analysis of a multicentre, prospective, randomized, controlled trial. Fluid overload was assessed by the average overhydration/extracellular water (OH/ECW) at baseline, 6 months and 12 months. Patients were categorized as time-averaged overhydrated (TA-OH/ECW ≥15%) or normohydrated (TA-OH/ECW <15%), and echocardiographic parameters were compared between groups. Among a total of 151 patients, 120 patients exhibited time-averaged normohydration. Time-averaged overhydrated patients had a significantly higher left atrial (LA) diameter and E/e′ ratio and a lower left ventricular (LV) ejection fraction at 12 months than time-averaged normohydrated patients. LA diameter, end-systolic volume and end-diastolic volume were decreased at 12 months compared to baseline in time-averaged normohydrated patients only. TA-OH/ECW was independently associated with ejection fraction at 12 months (β = −0.190; p = 0.010). TA-OH/ECW, but not OH/ECW at 12 months, was an independent risk factor for LV dysfunction (odds ratio 4.020 [95% confidence interval 1.285–12.573]). Overhydration status based on repeated BIS measurements is an independent predictor of LV systolic function in PD patients.
Tracking changes in cardiac output: methodological considerations for the validation of monitoring devices
Background Until now, tools for continuous cardiac output (CO) monitoring have been validated as if they were tools for snapshot measurements. Most authors have compared variations in cardiac output between two time-points and used Bland–Altman representations to describe the agreement between these variations. The impacts of time and of repetitive measurements over time are not taken into consideration. Purpose This special article proposes a conceptual framework for the validation of CO monitoring devices. Four quality criteria are suggested and studied: (1) accuracy (small bias), (2) precision (small random error of measurements), (3) short response time and (4) accurate amplitude response. Because a tolerance is obviously admitted for each of these four criteria, we propose to add as a fifth criterion the ability to detect significant CO directional changes. Other important issues in designing studies to validate CO monitoring tools are reviewed: choice of patient population to be studied, choice of the reference method, data acquisition method, data acceptability checking, data segmentation and final evaluation of reliability. Conclusion Application of this framework underlines the importance of precision and time response for clinical acceptability of monitoring tools.
Functional compared to anatomical imaging in the initial evaluation of patients with suspected coronary artery disease: An international, multi-center, randomized controlled trial (IAEA-SPECT/CTA study)
To test the hypothesis that, in the initial evaluation of patients with suspected coronary artery disease (CAD), stress myocardial perfusion imaging (MPI) would result in less downstream testing than coronary computed tomographic angiography (CCTA). In this international, randomized trial, mildly symptomatic patients with an intermediate likelihood of having CAD, and asymptomatic patients at intermediate risk of cardiac events, underwent either initial stress-rest MPI or CCTA. The primary outcome was downstream noninvasive or invasive testing at 6 months. Secondary outcomes included cumulative effective radiation dose (ERD) and costs at 12 months. We recruited 303 patients (151 MPI and 152 CTA) from 6 centers in 6 countries. The initial MPI was abnormal in 29% (41/143) and CCTA in 56% (79/141) of patients. Fewer patients undergoing initial stress-rest MPI had further downstream testing at 6 months (adjusted OR 0.51, 95% CI 0.28-0.91, P = 0.023). There was a small increase in the median cumulative ERD with MPI (9.6 vs. 8.8 mSv, P = 0.04), but no difference in costs between the two strategies at 12 months. In the management of patients with suspected CAD, a strategy of initial stress MPI is substantially less likely to require further downstream testing than initial testing with CCTA. Trial registration: clinicaltrials.gov identification number NCT01368770.
The effect of supplemental oxygen on perioperative brain natriuretic peptide concentration in cardiac risk patients – a protocol for a prosprective randomized clinical trial
Background Elevated postoperative N -terminal pro-B-type natriuretic peptide (NT-proBNP) concentrations are predictive for cardiac adverse events in noncardiac surgery. Studies indicate that supplemental oxygen decreases sympathetic nerve activity and might, therefore, improve cardiovascular function. Thus, we will test the effect of perioperative supplemental oxygen administration on NT-proBNP release after surgery. Methods/design We will conduct a single-center, double-blinded, randomized trial at the Medical University of Vienna, including 260 patients with increased cardiac risk factors undergoing moderate- to high-risk noncardiac surgery. Patients will be randomly assigned to receive 80% versus 30% oxygen during surgery and for 2 h postoperatively. The primary outcome will be the difference in maximum NT-proBNP release after surgery. As secondary outcomes we will assess the effect of supplemental oxygen on postoperative maximum troponin T concentration, oxidation-reduction potential, von Willebrand factor concentration and perioperative fluid requirements. We will perform outcome measurements 2 h after surgery, on postoperative day 1 and on postoperative day 3. The NT-proBNP concentration and the oxidation-reduction potential will also be measured within 72 h before discharge. Discussion Our trial should determine whether perioperative supplemental oxygen administration will reduce the postoperative release of NT-proBNP in patients with preoperative increased cardiovascular risk factors undergoing noncardiac surgery. Trial registration ClinicalTrials.gov, ID: NCT03366857 . Registered on 8th December 2017.
Impact of early haemodynamic goal-directed therapy in patients undergoing emergency surgery: an open prospective, randomised trial
Haemodynamic goal-directed therapies (GDT) may improve outcome following elective major surgery. So far, few data exist regarding haemodynamic optimization during emergency surgery. In this randomized, controlled trial, 50 surgical patients with hypovolemic or septic conditions were enrolled and we compared two algorithms of GDTs based either on conventional parameters and pressure pulse variation (control group) or on cardiac index, global end-diastolic volume index and stroke volume variation as derived from the PiCCO monitoring system (optimized group). Postoperative outcome was estimated by a composite index including major complications and by the Sequential Organ Failure Assessment (SOFA) Score within the first 3 days after surgery (POD1, POD2 and POD3). Data from 43 patients were analyzed (control group, N = 23; optimized group, N = 20). Similar amounts of fluid were given in the two groups. Intraoperatively, dobutamine was given in 45 % optimized patients but in no control patients. Major complications occurred more frequently in the optimized group [19 (95 %) versus 10 (40 %) in the control group, P  < 0.001]. Likewise, SOFA scores were higher in the optimized group on POD1 (10.2 ± 2.5 versus 6.6 ± 2.2 in the control group, P  = 0.001), POD2 (8.4 ± 2.6 vs 5.0 ± 2.4 in the control group, P  = 0.002) and POD 3 (5.2 ± 3.6 and 2.2 ± 1.3 in the control group, P  = 0.01). There was no significant difference in hospital mortality (13 % in the control group and 25 % in the optimized group). Haemodynamic optimization based on volumetric and flow PiCCO-derived parameters was associated with a less favorable postoperative outcome compared with a conventional GDT protocol during emergency surgery.
Outcomes of anatomical vs. functional testing for coronary artery disease
The development of coronary artery disease (CAD) is a major, final common pathway in heart disease worldwide. With a rise in stress testing and increased scrutiny on cost-effectiveness and radiation exposure in medical imaging, a focus on the relative merits of anatomic versus functional characterization of CAD has emerged. In this context, coronary computed tomography angiography (CCTA) is a noninvasive alternative to functional testing as a first-line test for CAD detection but is complimentary in its nature. Here, we discuss the design, results, and implications of the PROMISE trial, a randomized comparative effectiveness study of 10,003 patients across 193 sites in the United States and Canada comparing the prognostic and diagnostic power of CCTA and standard stress testing. Specifically, we discuss the safety (e. g., contrast, radiation exposure) of CCTA versus functional testing in CAD, the need for improved selection for noninvasive testing, the frequency of downstream testing after anatomic or functional imaging, the use of imaging results in clinical management, and novel modalities of CAD risk determination using CCTA. PROMISE demonstrated that in a real-world, low-to-intermediate risk patient population referred to noninvasive testing for CAD, both CCTA and functional testing approaches have similar clinical, economic, and safety-based outcomes. We conclude with open questions in CAD imaging, specifically as they pertain to the utilization of CCTA.
Mathematical modeling of cardiac function to evaluate clinical cases in adults and children
Time-varying elastance models can simulate only the pressure and volume signals in the heart chambers while the diagnosis of clinical cases and evaluation of different treatment techniques require more information. In this study, an extended model utilizing the geometric dimensions of the heart chambers was developed to describe the cardiac function. The new cardiac model was evaluated by simulating a healthy and dilated cardiomyopathy (DCM) condition for adults and children. The left ventricular ejection fraction, end-diastolic volume, end-diastolic diameter and diastolic sphericity index were 53.60%, 125 mL, 5.08 cm and 1.82 in the healthy adult cardiovascular system model and 23.70%, 173 mL, 6.60 cm and 1.40 in the DCM adult cardiovascular system model. In the healthy child cardiovascular system model, the left ventricular ejection fraction, end-diastolic volume, end-diastolic diameter and diastolic sphericity index were 59.70%, 92 mL, 4.10 cm and 2.26 respectively and 30.70%, 125 mL, 4.94 cm and 1.87 in the DCM child cardiovascular system model. The developed cardiovascular system model simulates the hemodynamic variables and clinical diagnostic indicators within the physiological range for healthy and DCM conditions proving the feasibility of this new model to evaluate clinical cases in adults and children.