The digital journey: 25 years of digital development in electrophysiology from an Europace perspective.

AIMS: Over the past 25 years there has been a substantial development in the field of digital electrophysiology (EP) and in parallel a substantial increase in publications on digital cardiology.In this celebratory paper, we provide an overview of the digital field by highlighting publications from the field focusing on the EP Europace journal. RESULTS: In this journey across the past quarter of a century we follow the development of digital tools commonly used in the clinic spanning from the initiation of digital clinics through the early days of telemonitoring, to wearables, mobile applications, and the use of fully virtual clinics. We then provide a chronicle of the field of artificial intelligence, a regulatory perspective, and at the end of our journey provide a future outlook for digital EP. CONCLUSION: Over the past 25 years Europace has published a substantial number of papers on digital EP, with a marked expansion in digital publications in recent years.

On the use of partitioning for scheduling of surgeries in the inpatient surgical department.

In hospitals, the efficient planning of the operating rooms (ORs) is difficult due to the uncertainty inherent to surgical services. This is especially true for the inpatient surgical department where complex and long surgeries are often performed along with surgeries on emergency patients. This paper aims to improve the scheduling of the inpatient department by partitioning the elective surgeries into the more predictable surgeries (MPS) group and the less predictable surgeries (LPS) group, based on surgery duration variability, and by scheduling each of the two surgery groups in different ORs. Through a simulation study that comprehensively investigates the impact of the partitioning on different performance measures under various environmental settings, we report important findings and insights. First, partitioning can effectively shorten the waiting times of elective patients for both MPS and LPS groups, but the option should be allowed to reassign patients from the MPS or LPS ORs to the other ORs when needed. Meanwhile, partitioning sometimes slightly increases the elective cancellation rate. Second, the ability to use the available capacity of the ORs as much as possible is key to reducing elective waiting times. Third, partitioning might slightly worsen the waiting times of emergency patients, while the slightly negative impact on emergency patients decreases when the number of ORs is higher. Fourth, the beneficial impact of partitioning on elective patients increases with an increased patient demand. Last, for the settings considered in this study there was no benefit in partitioning the elective patients into more than two groups.

Translating Data From an Electronic Prescribing and Medicines Administration System Into Knowledge: Application to Doctor-Nurse Time Discrepancy in Antibiotic Ordering and Administration.

BACKGROUND: Electronic Prescribing and Medicines Administration (EPMA) systems are being widely implemented to facilitate medication safety improvement. However, translating the resulting big data into actionable knowledge has received relatively little attention. OBJECTIVE: The objective of this study was to use routinely collected EPMA data in the study of exact time discrepancy between physicians' order and nurses' administration of systemic antibiotics. We evaluated first and follow-up dose administration and dose intervals and examined multifactorial determinants in ordering and administration explaining potential discrepancy. METHODS: We conducted an observational study of electronic health records for all medical patient stays with antibiotic treatment from January to June 2018 (n=4392) in a large Belgian tertiary care hospital. Using an EPMA system with Barcode Medication Administration, we calculated time discrepancy between order and administration of first doses (n=6233), follow-up doses (n=87 960), and dose intervals. Multiple logistic regression analysis estimated the association between time discrepancy and various determinants in ordering and administration. RESULTS: Time discrepancy between physician order and nurse administration was <30 minutes for 48.7% of first doses and 61.7% of follow-up doses, with large variation across primary diagnoses. Greater dose intervals, oral versus intravenous administration, and order diversion from regular nurse administration rounds showed strongest association with less timely administration. CONCLUSIONS: EPMA systems show huge potential to generate actionable knowledge. Concerning antibiotic treatment, having physicians' orders coincide with regular nurse administration rounds whenever clinically appropriate, further taking contextual factors into account, could potentially improve antibiotic administration timeliness.

Due time driven surgery scheduling.

In many hospitals there are patients who receive surgery later than what is medically indicated. In one of Europe's largest hospitals, the University Hospital Leuven, this is the case for approximately every third patient. Serving patients late cannot always be avoided as a highly utilized OR department will sometimes suffer capacity shortage, occasionally leading to unavoidable delays in patient care. Nevertheless, serving patients late is a problem as it exposes them to an increased health risk and hence should be avoided whenever possible. In order to improve the current situation, the delay in patient scheduling had to be quantified and the responsible mechanism, the scheduling process, had to be better understood. Drawing from this understanding, we implemented and tested realistic patient scheduling methods in a discrete event simulation model. We found that it is important to model non-elective arrivals and to include elective rescheduling decisions made on surgery day itself. Rescheduling ensures that OR related performance measures, such as overtime, will only loosely depend on the chosen patient scheduling method. We also found that capacity considerations should guide actions performed before the surgery day such as patient scheduling and patient replanning. This is the case as those scheduling strategies that ensure that OR capacity is efficiently used will also result in a high number of patients served within their medically indicated time limit. An efficient use of OR capacity can be achieved, for instance, by serving patients first come, first served. As applying first come, first served might not always be possible in a real setting, we found it is important to allow for patient replanning.

Development of a set of measurable outcome indicators for Flemish patients with inflammatory bowel disease.

OBJECTIVE: Uniform and standardised quality measurement allows care assessment and improvement. Following a pragmatic consensus method we aimed to agree on a selection of measurable quality indicators that can be used to assess, benchmark and gradually improve inflammatory bowel disease (IBD) care in Flanders. METHODS: Of 49 structures, 135 processes and 37 outcome indicators identified through literature, 58 were preselected and reformulated into measurable outcome indicators by four IBD physicians. A larger expert group scored the 58 indicators on a 10-point importance scale twice, endorsed by patient and expert perspectives in between rounds. Additional items could be suggested. A final selection and subset of indicators with room for improvement were agreed upon during a consensus meeting. RESULTS: Fifty indicators received an importance score of 7 or higher by ≥80% of the participants (seven IBD nurses, one abdominal surgeon, one chief medical officer and 31 IBD physicians including two paediatricians). Eight indicators scored highly important by 60-80%, two indicators reintroduced by patients and one newly suggested, were discussed during the consensus meeting. Among 26 participants, eight indicators were agreed to be added to the final selection. Of the 58 selected items, 19 were retained in the improvement subset, related to patient-reported outcomes, use of hospital services and survival, patient characteristics, monitoring of disease activity and remission, endoscopy guidelines, infection prevention, steroid and other medication use. CONCLUSION: Fifty-eight indicators were selected to assess IBD care in Flanders and a subset of 19 for use in clinical practice to steer quality improvement initiatives.

Imaging in population science: cardiovascular magnetic resonance in 100,000 participants of UK Biobank - rationale, challenges and approaches.

UK Biobank is a prospective cohort study with 500,000 participants aged 40 to 69. Recently an enhanced imaging study received funding. Cardiovascular magnetic resonance (CMR) will be part of a multi-organ, multi-modality imaging visit in 3-4 dedicated UK Biobank imaging centres that will acquire and store imaging data from 100,000 participants (subject to successful piloting). In each of UK Biobank's dedicated bespoke imaging centres, it is proposed that 15-20 participants will undergo a 2 to 3 hour visit per day, seven days a week over a period of 5-6 years. The imaging modalities will include brain MRI at 3 Tesla, CMR and abdominal MRI at 1.5 Tesla, carotid ultrasound and DEXA scans using carefully selected protocols. We reviewed the rationale, challenges and proposed approaches for concise phenotyping using CMR on such a large scale. Here, we discuss the benefits of this imaging study and review existing and planned population based cardiovascular imaging in prospective cohort studies. We will evaluate the CMR protocol, feasibility, process optimisation and costs. Procedures for incidental findings, quality control and data processing and analysis are also presented. As is the case for all other data in the UK Biobank resource, this database of images and related information will be made available through UK Biobank's Access Procedures to researchers (irrespective of their country of origin and whether they are academic or commercial) for health-related research that is in the public interest.

Artificial intelligence in medical device software and high-risk medical devices - a review of definitions, expert recommendations and regulatory initiatives.

INTRODUCTION: Artificial intelligence (AI) encompasses a wide range of algorithms with risks when used to support decisions about diagnosis or treatment, so professional and regulatory bodies are recommending how they should be managed. AREAS COVERED: AI systems may qualify as standalone medical device software (MDSW) or be embedded within a medical device. Within the European Union (EU) AI software must undergo a conformity assessment procedure to be approved as a medical device. The draft EU Regulation on AI proposes rules that will apply across industry sectors, while for devices the Medical Device Regulation also applies. In the CORE-MD project (Coordinating Research and Evidence for Medical Devices), we have surveyed definitions and summarize initiatives made by professional consensus groups, regulators, and standardization bodies. EXPERT OPINION: The level of clinical evidence required should be determined according to each application and to legal and methodological factors that contribute to risk, including accountability, transparency, and interpretability. EU guidance for MDSW based on international recommendations does not yet describe the clinical evidence needed for medical AI software. Regulators, notified bodies, manufacturers, clinicians and patients would all benefit from common standards for the clinical evaluation of high-risk AI applications and transparency of their evidence and performance.

Wearable technology and the cardiovascular system: the future of patient assessment.

The past decade has seen a dramatic rise in consumer technologies able to monitor a variety of cardiovascular parameters. Such devices initially recorded markers of exercise, but now include physiological and health-care focused measurements. The public are keen to adopt these devices in the belief that they are useful to identify and monitor cardiovascular disease. Clinicians are therefore often presented with health app data accompanied by a diverse range of concerns and queries. Herein, we assess whether these devices are accurate, their outputs validated, and whether they are suitable for professionals to make management decisions. We review underpinning methods and technologies and explore the evidence supporting the use of these devices as diagnostic and monitoring tools in hypertension, arrhythmia, heart failure, coronary artery disease, pulmonary hypertension, and valvular heart disease. Used correctly, they might improve health care and support research.

Reallocation of operating room capacity using the due-time model.

BACKGROUND: Demand for surgical treatment is rising while operating room (OR) resources are limited. Requests for more resources therefore can only be partly met by repartitioning the existing sparse resources. OBJECTIVE: Our goal is to define a method to allocate OR block times among surgical disciplines in such a way that patients can be treated within an acceptable time after the need for surgery is established. In this paper, we introduce and explore the potential of the concept of the individual patient deviation from the optimal due time (DT) as a potential driver for OR (re-) allocation. STUDY DESIGN AND SETTING: Using retrospective data for abdominal and gynecologic surgery, we analyzed DT deviation and 3 additional modifiers. From this analysis, a reallocation of OR time to the different (sub-) specialties was calculated using a simple model. RESULTS: The results show the capability of measuring and visualizing relative overcapacity versus undercapacity of OR resources with respect to this patient-centered metric of DT. The reallocation results from the model show a potentially significant shift between programs. CONCLUSIONS: We propose the "due-time" concept as a valid measure to quantify OR resource use. The use of a DT-based model provides a transparent, acceptable system for regular reallocation of OR times between and within specialties.

A new electric method for non-invasive continuous monitoring of stroke volume and ventricular volume-time curves.

BACKGROUND: In this paper a new non-invasive, operator-free, continuous ventricular stroke volume monitoring device (Hemodynamic Cardiac Profiler, HCP) is presented, that measures the average stroke volume (SV) for each period of 20 seconds, as well as ventricular volume-time curves for each cardiac cycle, using a new electric method (Ventricular Field Recognition) with six independent electrode pairs distributed over the frontal thoracic skin. In contrast to existing non-invasive electric methods, our method does not use the algorithms of impedance or bioreactance cardiography. Instead, our method is based on specific 2D spatial patterns on the thoracic skin, representing the distribution, over the thorax, of changes in the applied current field caused by cardiac volume changes during the cardiac cycle. Since total heart volume variation during the cardiac cycle is a poor indicator for ventricular stroke volume, our HCP separates atrial filling effects from ventricular filling effects, and retrieves the volume changes of only the ventricles. METHODS: ex-vivo experiments on a post-mortem human heart have been performed to measure the effects of increasing the blood volume inside the ventricles in isolation, leaving the atrial volume invariant (which can not be done in-vivo). These effects have been measured as a specific 2D pattern of voltage changes on the thoracic skin. Furthermore, a working prototype of the HCP has been developed that uses these ex-vivo results in an algorithm to decompose voltage changes, that were measured in-vivo by the HCP on the thoracic skin of a human volunteer, into an atrial component and a ventricular component, in almost real-time (with a delay of maximally 39 seconds). The HCP prototype has been tested in-vivo on 7 human volunteers, using G-suit inflation and deflation to provoke stroke volume changes, and LVot Doppler as a reference technique. RESULTS: The ex-vivo measurements showed that ventricular filling caused a pattern over the thorax quite distinct from that of atrial filling. The in-vivo tests of the HCP with LVot Doppler resulted in a Pearson's correlation of R = 0.892, and Bland-Altman plotting of SV yielded a mean bias of -1.6 ml and 2SD =14.8 ml. CONCLUSIONS: The results indicate that the HCP was able to track the changes in ventricular stroke volume reliably. Furthermore, the HCP produced ventricular volume-time curves that were consistent with the literature, and may be a diagnostic tool as well.

Cost-Minimization Analysis for Cardiac Revascularization in 12 Health Care Systems Based on the EuroCMR/SPINS Registries.

OBJECTIVES: The aim of this study was to compare the costs of a noninvasive cardiac magnetic resonance (CMR)-guided strategy versus 2 invasive strategies with and without fractional flow reserve (FFR). BACKGROUND: Coronary artery disease (CAD) is a major contributor to the public health burden. Stress perfusion CMR has excellent accuracy to detect CAD. International guidelines recommend as a first step noninvasive testing of patients in stable condition with known or suspected CAD. However, nonadherence in routine clinical practice is high. METHODS: In the EuroCMR (European Cardiovascular Magnetic Resonance) registry (n = 3,647, 59 centers, 18 countries) and the U.S.-based SPINS (Stress-CMR Perfusion Imaging in the United States) registry (n = 2,349, 13 centers, 11 states), costs were calculated for 12 health care systems (8 in Europe, the United States, 2 in Latin America, and 1 in Asia). Costs included diagnostic examinations (CMR and x-ray coronary angiography [CXA] with and without FFR), revascularizations, and complications during 1-year follow-up. Seven subgroup analyses covered low- to high-risk cohorts. Patients with ischemia-positive CMR underwent CXA and revascularization at the treating physician's discretion (CMR+CXA strategy). In the hypothetical invasive CXA+FFR strategy, costs were calculated for initial CXA and FFR in vessels with ≥50% stenoses, assuming the same proportion of revascularizations and complications as with the CMR+CXA strategy and FFR-positive rates as given in the published research. In the CXA-only strategy, costs included CXA and revascularizations of ≥50% stenoses. RESULTS: Consistent cost savings were observed for the CMR+CXA strategy compared with the CXA+FFR strategy in all 12 health care systems, ranging from 42% ± 20% and 52% ± 15% in low-risk EuroCMR and SPINS patients with atypical chest pain, respectively, to 31% ± 16% in high-risk SPINS patients with known CAD (P < 0.0001 vs 0 in all groups). Cost savings were even higher compared with CXA only, at 63% ± 11%, 73% ± 6%, and 52% ± 9%, respectively (P < 0.0001 vs 0 in all groups). CONCLUSIONS: In 12 health care systems, a CMR+CXA strategy yielded consistent moderate to high cost savings compared with a hypothetical CXA+FFR strategy over the entire spectrum of risk. Cost savings were consistently high compared with CXA only for all risk groups.

Left-ventricular shape determines intramyocardial mechanical heterogeneity.

Left-ventricular remodeling is considered to be an important mechanism of disease progression leading to mechanical dysfunction of the heart. However, the interaction between the physiological changes in the remodeling process and the associated mechanical dysfunction is still poorly understood. Clinically, it has been observed that the left ventricle often undergoes large shape changes, but the importance of left-ventricular shape as a contributing factor to alterations in mechanical function has not been clearly determined. Therefore, the interaction between left-ventricular shape and systolic mechanical function was examined in a computational finite-element study. Hereto, finite-element models were constructed with varying shapes, ranging from an elongated ellipsoid to a sphere. A realistic transmural gradient in fiber orientation was considered. The passive myocardium was described by an incompressible hyperelastic material law with transverse isotropic symmetry. Activation was governed by the eikonal-diffusion equation. Contraction was incorporated using a Hill model. For each shape, simulations were performed in which passive filling was followed by isovolumic contraction and ejection. It was found that the intramyocardial distributions of fiber stress, strain, and stroke work density were shape dependent. Ejection performance was reduced with increasing sphericity, which was regionally related to a reduction in the active fiber stress development, fiber shortening, and stroke work in the midwall and subepicardial region at the midheight level in the left-ventricular wall. Based on these results, we conclude that a significant interaction exists between left-ventricular shape and regional myofiber mechanics, but the importance for left-ventricular remodeling requires further investigation.

In-vivo validation of a new non-invasive continuous ventricular stroke volume monitoring system in an animal model.

INTRODUCTION: Recently, a non-invasive, continuous ventricular stroke volume monitoring system using skin electrodes has been developed. In contrast to impedance-based methods, the new technique (ventricular field recognition) enables measurement of changes in ventricular volume. A prototype using this new method was built (the hemologic cardiac profiler, HCP) and validated against a reference method in a pig model during variations in cardiac output. METHODS: In six Dalland pigs, cardiac output was simultaneously measured with the HCP (CO-HCP), and an invasive ultrasonic flow-probe around the ascending aorta (CO-FP). Variations in CO were achieved by change in ventricular loading conditions, cardiac pacing, and dobutamine administration. Data were analysed according to Bland-Altman analysis and Pearson's correlation. RESULTS: Pearson's correlation between the CO-HCP and the CO-FP was r = 0.978. Bland-Altman analysis showed a bias of - 0.114 L/minute, and a variability of the bias (2 standard deviations, 2SD) of 0.55 L/minute. CONCLUSIONS: The results of the present study demonstrate that CO-HCP is comparable to CO-FP in an animal model of cardiac output measurements during a wide variation of CO. Therefore, the HCP has the potential to become a clinical applicable cardiac output monitor.

Impact of myocardial haemorrhage on left ventricular function and remodelling in patients with reperfused acute myocardial infarction.

AIMS: Myocardial haemorrhage is a common complication following reperfusion of ST-segment-elevation acute myocardial infarction (MI). Although its presence is clearly related to infarct size, at present it is unknown whether post-reperfusion haemorrhage affects left ventricular (LV) remodelling. Magnetic resonance imaging (MRI) can be used to identify MI, myocardial haemorrhage, and microvascular obstruction (MVO), as well as measure LV volumes, function, and mass. METHODS AND RESULTS: Ninety-eight patients (14 females, 84 males, mean age: 57.7 years) with MI reperfused with percutaneous coronary intervention (PCI) were studied within the first week (1W) and at 4 months (4M) after the event. T2-weighted MRI was used to differentiate between haemorrhagic (i.e. hypointense core) and non-haemorrhagic infarcts (i.e. hyperintense core). Microvascular obstruction and infarct size were determined on contrast-enhanced MRI, whereas cine MRI was used to quantify LV volumes, mass, and function. Twenty-four patients (25%) presented with a haemorrhagic MI. In the acute phase, the presence of myocardial haemorrhage was related to larger infarct size and infarct transmurality, lower LV ejection fraction, and lower systolic wall thickening in the infarcted myocardium (all P-values <0.001). At 4M, a significant improvement in LV ejection fraction in patients with non-haemorrhagic MI was seen (baseline: 49.3 +/- 7.9% vs. 4M: 52.9 +/- 8.1%; P < 0.01). Left ventricular ejection fraction did, however, not improve in patients with haemorrhagic MI (baseline: 42.8 +/- 6.5% vs. 4M: 41.9 +/- 8.5%; P = 0.68). Multivariate analysis showed myocardial haemorrhage to be an independent predictor of adverse LV remodelling at 4M (defined as an increase in LV end-systolic volume). This pattern was independent of the initial infarct size. CONCLUSION: Myocardial haemorrhage, the presence of which can easily be detected with T2-weighted MRI, is a frequent complication after successful myocardial reperfusion and an independent predictor of adverse LV remodelling regardless of the initial infarct size.

Determination of regional ejection fraction in patients with myocardial infarction by using merged late gadolinium enhancement and cine MR: feasibility study.

PURPOSE: To quantify regional ejection fraction (EF) in patients with myocardial infarction (MI) by using merged late gadolinium enhancement (LGE) and cine magnetic resonance (MR) imaging, and compare this method with the standardized 17-segment American Heart Association approach. MATERIALS AND METHODS: After institutional review board approval and informed consent, 15 MI patients (14 men, one woman; mean age, 63 years +/- 10 [standard deviation]) were studied at 1 week and at 4 months after MI. Short-axis LGE MR information was used to quantify infarct size, and to divide the left ventricle (LV) on short-axis cine MR images in infarct, periinfarct, and remote regions by using a fixed-center method, yielding information on regional volumes, regional EFs, systolic wall thickening (SWT), and systolic wall motion (SWM). This approach was compared with a floating-center approach and the 17-segment approach. RESULTS: Mean infarct size (normalized to LV mass) was 25% +/- 14 at 1 week and 16% +/- 8 at 4 months (P < .001). At 4 months, LV EF significantly improved (mean, 47.9% +/- 5.9 vs 50.9% +/- 6.6, P = .031), matching an improvement of regional EF (mean, 17.1% +/- 11.5 vs 24.6% +/- 13.1, P = .005) and SWM (mean, 3.2 mm +/- 1.7 vs 3.9 mm +/- 2.1, P = .027) in the infarcted myocardium. No significant changes in regional EF, SWT, or SWM occurred in the remote myocardium. Regional EF estimates correlated well with SWT and SWM (both r = 0.92, P < .001). The floating-center method invariably underestimated regional EF (mean, -20.8% +/- 7.6; 95% confidence interval: -23.7%, -17.9%), especially with increasing infarct size. By using the 17-segment approach, no functional improvement was shown in the infarcted myocardium. CONCLUSION: Assessment of regional ventricular performance (regional EF) in well-defined areas (eg, infarcted and remote myocardium) is feasible by using merged LGE and cine MR imaging.

Full or pressure limited reperfusion of an acute myocardial infarct results in a different wall thickness and deformation of the distal myocardium--implications for clinical reperfusion strategies.

AIM: The study aim was to determine the sequence of changes in both wall thickness and function in 'at risk' myocardium (using M-mode and radial strain/strain-rate imaging) induced by reperfusion of an acute transmural infarction, and to relate these changes to the presence or absence of a pressure-limiting stenosis in the infarct related epicardial vessel. METHODS: Eighteen closed-chest pigs were randomized into two groups (each with nine animals). In Group I, 4 weeks prior to induction of an acute transmural infarct, a copper coated stent was implanted in the proximal circumflex artery (Cx) to create a coronary artery stenosis of between 30 and 95% lumen diameter. At 4 weeks, the stenotic Cx vessel was occluded for 90 min by inflation of a PTCA balloon placed proximal to the stenosis to produce an acute transmural infarction. In Group II (the control group), 90 min Cx occlusion was performed in a normal vessel. In both groups the resulting acute transmural infarction was reperfused after 90 min by removing the PTCA balloon. For both groups, cardiac ultrasound data, including strain/strain-rate imaging, were collected at all stages of the investigation for subsequent offline analysis. RESULTS: In both groups, acute reperfusion (TIMI flow 3 or 2), immediately increased infarct zone end-diastolic wall thickness due to the development of oedema. The acute increase in wall thickness was significantly higher in the non-stenotic animals as compared to the ones with a residual stenosis. Neither of the groups showed any tendency to normalize deformation (strain) during the reperfusion period. CONCLUSION: In this experimental study, the measurement of end-diastolic wall thickness was a simple and non-invasive tool to monitor acute infarct reperfusion. It also provided information on the presence of a flow limiting stenosis in the infarct related artery after restoration of the flow. The deformation of the myocardium remained impaired during early reperfusion, whether reflow was at full pressure or low pressure due to a residual stenosis in the infarct related artery.

Non-invasive measurement of volume-time curves in patients with mitral regurgitation and in healthy volunteers, using a new operator-independent screening tool.

Left ventricular volume-time curves (VTCs) provide hemodynamic data, and may help clinical decision making. The generation of VTCs using echocardiography, however, is time-consuming and prone to inter-operator variability. In this study, we used a new non-invasive, operator-independent technique, the hemodynamic cardiac profiler (HCP), to generate VTCs. The HCP, which uses a low-intensity, patient-safe, high-frequency applied AC current, and 12 standard ECG electrodes attached on the thorax in a pre-defined pattern, was applied to five young healthy volunteers, five older healthy volunteers, and five patients with severe mitral regurgitation. From the VTCs generated by the HCP, the presence or absence of an isovolumetric contraction phase (ICP) was assessed, as well as the left ventricular ejection time (LVET), time of the pre-ejection period (tPEP), and ratio of the volumes of the early (E) and late (A) diastolic filling (E V/A V ratio), and compared to 2D transthoracic echocardiography (2D TTE) at rest. The reproducibility by two different operators showed good results (RMS = 5.2%). For intra-patient measurement RMS was 2.8%. Both LVET and the E V/A V ratio showed a strong significant correlation between HCP and 2D TTE derived parameters (p < 0.05). For tPEP, the correlation was still weak (p = 0.32). In all five patients with mitral regurgitation, the ICP was absent in the VTC from the HCP, whereas it was present in the 10 healthy volunteers, which is in accordance with pathophysiology. We conclude that the HCP seems to be a method for reproducible VTC generation, and may become a useful early screening tool for cardiac dysfunction in the future.

Experimental assessment of a new research tool for the estimation of two-dimensional myocardial strain.

One-dimensional strain imaging has been shown to be angle dependent. To address this problem, a new methodology, 2D-strain, has become available. The aim of this study was to validate this methodology in an in vivo set-up against sonomicrometry. In five open chest sheep, ultrasound gray-scale images were acquired of the inferolateral wall from two different angles. The longitudinal and radial strain components were simultaneously extracted using the novel 2D-strain methodology. The extracted values were compared with sonomicrometry using Bland-Altman statistics and correlation coefficients. A good agreement was found for the longitudinal strain component, while, for the radial strain estimates, the accuracy was less. 2D-strain is a fast and accurate tool to assess longitudinal strain from apical views. Further improvements are needed for the method to be sufficiently accurate in estimating the deformation perpendicular or close to perpendicular to the ultrasound beam.

Visualization of ventricular thrombi with contrast-enhanced magnetic resonance imaging in patients with ischemic heart disease.

BACKGROUND: Ventricular thrombus formation is a frequent and potentially dangerous complication in patients with ischemic heart disease. Although transthoracic echocardiography (TTE) is generally used as diagnostic technique, we explored the role of contrast-enhanced (CE)-MRI to detect ventricular thrombi. METHODS AND RESULTS: In 57 patients with acute myocardial infarction, chronic myocardial infarction, or ischemic cardiomyopathy, MRI was performed to evaluate ventricular function (CINE-MRI) and to depict presence of myocardial necrosis and/or scarring and no-reflow areas (CE-MRI). All studies were analyzed for concomitant ventricular thrombi. CE-MRI depicted 12 mural thrombi (3.1+/-2.9 cm3), located in left ventricular (LV) apex or adherent to anteroseptum, presenting as black, well-defined structures surrounded by bright contrast-enhanced blood. Thrombus formation on CE-MRI was related to larger end-diastolic volumes; lower ejection fractions; the region of delayed enhancement and lowest wall motion score, especially in left anterior descending coronary artery territory; and LV aneurysm formation. On CINE-MRI, thrombi were found in 6 patients. Nonvisualized thrombi were usually small (mean size 1.2+/-0.7 cm3). TTE depicted thrombi in 5. Nonvisualized lesions were most frequently located in LV apex and had a larger size than nonvisualized lesions on CINE-MRI (3.0+/-3.2 cm3). In 3 patients with suspected apical thrombus on TTE, MRI was normal. CONCLUSIONS: CE-MRI is not only an excellent technique to depict myocardial necrosis and scar tissue in patients with ischemic heart disease, but this study also suggests a better identification of LV thrombi than with presently used clinical imaging modalities, such as TTE.