Cardiac Window Research Articles

Esophageal rupture diagnosed with bedside ultrasound

A 69-year-old man presented to the emergency department with hematemesis, hypotension, tachycardia, and hypothermia. The emergency physician performed a bedside ultrasound of the chest, heart, and abdomen. The heart was unable to be visualized in the parasternal, apical, or subxiphoid windows, and free fluid and particulate matter were visualized in the chest and abdomen. The inability to visualize the heart in the normal cardiac windows suggested a diagnosis of pneumopericardium. Based upon the patient's presenting symptoms and ultrasound findings, an esophageal perforation was suspected. Esophageal perforation is a medical emergency. Deterioration and death due to sepsis can occur within hours of presentation [6]. Although there is a great deal of literature discussing the diagnosis of esophageal perforation by chest radiograph, computed tomography (CT), and esophagography, there are no articles on the role of ultrasound. Esophageal perforation may result in the communication of air between the esophagus and pericardium and the leakage of gastric contents into the chest and peritoneal cavity. The presence of air in the pericardial sac results in nonvisualization of the heart on ultrasound. Fluid in the chest and abdomen may be visualized in the posterior upper abdominal windows. Although these ultrasound findings alone are not entirely specific for esophageal perforation, when coupled with a high index of suspicion due to the patient presentation, ultrasound can be one of the most portable, readily available, low-cost, and minimally invasive techniques to make the diagnosis of esophageal perforation.

Is pocket ultrasound ready for prime time?

Th e recent trial by Biais and colleagues adds to a growing body of literature supporting point-of-care ultrasound in the critical care setting [1]. Th e authors demonstrate that, in the hands of two expert users, a newer pocket-sized device was comparable with conventional ultrasound machines for several key echocardiographic parameters. Clearly in the right hands, the Vscan™ (GE Healthcare, Wauwatosa, WI, USA) is a promising tool, but we must be cautious not to extra polate these data to non-expert users. Th e novelty and convenience of pocket ultrasound should not distract from the requirement for proper training in medical school or for postgraduate medical education [2]. Th e emphasis must be on adequate training in a defi ned skill set within the scope of practice for a given specialist before pocket ultrasound becomes a management tool at the bedside. Furthermore, the device’s limitations must also be delineated. Th e Vscan™ has a single-phased array transducer, which is suitable for cardiac and abdominal windows, but the absence of a linear probe limits the use of this device for ultrasound-guided vascular access. For instance, in the medical ICU setting, the Vscan™ has great potential to guide bedside procedures such as thoracentesis and paracentesis but at this time is not appropriate to aid in central line placement. Th e authors do not directly bring cost into their discussion, but an advantage of the pocket device is that it retails at nearly one-quarter of the price of the comparison machine used in their trial. Th ese various ben efi ts and limitations must be taken into consideration when determining whether the Vscan™ is cost-eff ective for a given clinical setting.

Low‐dose cardio‐respiratory phase‐correlated cone‐beam micro‐CT of small animals

Micro-CT imaging of animal hearts typically requires a double gating procedure because scans during a breath-hold are not possible due to the long scan times and the high respiratory rates, Simultaneous respiratory and cardiac gating can either be done prospectively or retrospectively. True five-dimensional information can be either retrieved with retrospective gating or with prospective gating if several prospective gates are acquired. In any case, the amount of information available to reconstruct one volume for a given respiratory and cardiac phase is orders of magnitud lower than the total amount of information acquired. For example, the reconstruction of a volume from a 10% wide respiratory and a 20% wide cardiac window uses only 2% of the data acquired. Achieving a similar image quality as a nongated scan would therefore require to increase the amount of data and thereby the dose to the animal by up to a factor of 50. To achieve the goal of low-dose phase-correlated (LDPC) imaging, the authors propose to use a highly efficient combination of slightly modified existing algorithms. In particular, the authors developed a variant of the McKinnon-Bates image reconstruction algorithm and combined it with bilateral filtering in up to five dimensions to significantly reduce image noise without impairing spatial or temporal resolution. The preliminary results indicate that the proposed LDPC reconstruction method typically reduces image noise by a factor of up to 6 (e.g., from 170 to 30 HU), while the dose values lie in a range from 60 to 500 mGy. Compared to other publications that apply 250-1800 mGy for the same task [C. T. Badea et al., "4D micro-CT of the mouse heart," Mol. Imaging 4(2), 110-116 (2005); M. Drangova et al., "Fast retrospectively gated quantitative four-dimensional (4D) cardiac micro computed tomography imaging of free-breathing mice," Invest. Radiol. 42(2), 85-94 (2007); S. H. Bartling et al., "Retrospective motion gating in small animal CT of mice and rats," Invest. Radiol. 42(10), 704-714 (2007)], the authors' LDPC approach therefore achieves a more than tenfold dose usage improvement. The LDPC reconstruction method improves phase-correlated imaging from highly undersampled data. Artifacts caused by sparse angular sampling are removed and the image noise is decreased, while spatial and temporal resolution are preserved. Thus, the administered dose per animal can be decreased allowing for long-term studies with reduced metabolic inference.

Spontaneous Closure of a Ventricular Septal Defect in a Horse

Spontaneous Closure of a Ventricular Septal Defect in a Horse

Erectile dysfunction and coronary artery disease: the cardiac window opens

International Journal of Clinical PracticeVolume 63, Issue 8 p. 1119-1119 Erectile dysfunction and coronary artery disease: the cardiac window opens G Jackson, G Jackson EditorSearch for more papers by this author G Jackson, G Jackson EditorSearch for more papers by this author First published: 13 July 2009 https://doi.org/10.1111/j.1742-1241.2009.02144.xCitations: 1Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL No abstract is available for this article.Citing Literature Volume63, Issue8August 2009Pages 1119-1119 RelatedInformation

Directed bedside transthoracic echocardiography: preferred cardiac window for left ventricular ejection fraction estimation in critically ill patients

Bedside transthoracic echocardiography (TTE) performed by emergency physicians (EPs) is valuable in the rapid assessment and treatment of critically ill patients. We sought to determine the preferred cardiac window for left ventricular ejection fraction (LVEF) estimation by EP sonographers in a critically ill patient population. Prospective investigator-blinded study of focused bedside TTE in a convenience sample of surgical intensive care patients. Investigators were faculty, fellows, or residents from an academic emergency medicine department. Five standard cardiac views were performed: parasternal long axis (PSLA), parasternal short axis (PSSA), subxiphoid 4-chamber, subxiphoid short axis, and apical 4-chamber (AFC). LVEF was determined using at least 1 cardiac view. Investigators rated their preference for each cardiac view on a 5-point Likert scale. A total of 70 studies were performed on 70 patients during a 6-month period. Users rated the PSLA as the most useful view for estimation of LVEF (mean 4.23; 95% confidence interval, 3.95-4.51). Pairwise comparisons of cardiac ultrasound views revealed PSLA was preferred over all other views (P < .05) except PSSA (P = .23). Complete 5 view examinations were not achieved in all patients (PSLA in 98%, PSSA in 96%, apical 4-chamber in 74%, subxiphoid 4-chamber in 35%, and subxiphoid short axis in 18%). Interobserver correlation of LVEF estimation was good (r = 0.86, r2 = 0.74, P < .0001). Parasternal long axis and PSSA are the preferred echocardiographic windows for EP estimation of LVEF using focused bedside TTE in critical care patients. This may be an important consideration in patients who often have physical barriers to optimal echocardiographic evaluation, are relatively immobile, and have unstable conditions requiring rapid assessment and intervention.

Positioning of the univent tube with bronchial blocker without fibreoptic bronchoscopy

The postoperative monitoring and treatment of the patient undergoing aortic valve replacement is a complex challenge. Echocardiography is the only method which provides dynamic and real-time bedside imaging of the heart. Focused assessed transthoracic echocardiography has been shown to provide a usable window for cardiac imaging in a mixed ICU population. The aim of this study was to evaluate the feasibility of perioperative imaging of the heart and pleura according to the focused assessed transthoracic echocardiography protocol in patients scheduled for aortic valve replacement.Thirty-five adult patients scheduled for aortic valve replacement were followed perioperatively with focused assessed transthoracic echocardiography examinations. A Vivid-7 echo-machine and a 2.5 MHz matrix transducer with second-harmonic imaging were used for data acquisition. The image quality for the cardiac window was graded 1-5 (1 = no image, 2 = poor and unusable image quality, 3 = usable image quality, 4 = good image quality and 5 = perfect image quality). A score >or=3 equalled an image quality judged to be of sufficient quality to be interpreted and thereby to contribute to clinical decision-making.All patients had at least one usable window preoperatively. At least one usable window was obtained in 88% of patients on the first postoperative day, and in 97% at discharge. The image quality changed over time, with the poorest quality being observed on the first postoperative day. The apical view with the patient in the left lateral position provided the best cardiac window on all occasions. The presence of drains did not significantly affect the achievability of a satisfactory examination. The number of patients with pleural effusion was relatively high. On the first postoperative day, 10 subjects had unilateral and one subject had bilateral pleural effusions. At discharge, 14 patients had unilateral and four patients had bilateral effusions.We conclude that the image quality of the heart and pleura, according to the focused assessed transthoracic echocardiography concept, is sufficient to undergo interpretation and thereby contribute to the perioperative clinical decision-making in patients with aortic stenosis.

358: Echocardiographic View Preference in Bedside Estimation of Ejection Fraction by Clinicians in Critical Care Patients

To determine the preferred cardiac window for ejection fraction (EF) estimation by and emergency medicine (EM) and critical care physicians and to determine the accuracy of measured EF versus formal echocardiography assessment.

A computer model study of the ventricular fibrillation vulnerable window: sensitivity to regional conduction depressions.

The cardiac vulnerable window is typically defined to be that portion of the cardiac cycle during which ectopic stimuli can induce ventricular fibrillation (VF). We have used cardiac electrophysiological computer modeling to investigate how the size and shape of the cardiac vulnerable window is affected by regional conduction velocity depressions (RCVDs), as might be found in ischemia. Computer simulations were performed on a three-dimensional finite-state, discrete-element model of the ventricles of a dog heart, with simulated RCVDs of 0% (normal) to 100% (infarcted) isolated to the apical region of this heart. Using a programmed electrical stimulation protocol, vulnerability was quantified as the number of ectopic stimuli necessary to induce VF. We observed a nonlinear and nonmonotonic relation between increases in RCVD and the vulnerability of the heart to ectopic stimuli. The size and shape of the vulnerable window remained stable through RCVDs of 30%, expanded rapidly thereafter through RCVDs of 90%, and then contracted significantly at the RCVD of 100%. These increases in vulnerability were manifest as both a lowering of the overall stimulus thresholds necessary for fibrillation (window "deepening"), and an increase in the fraction of the cardiac cycle susceptible to these ectopic stimuli (window "widening"). In all cases of induced VF, the mechanism of induction was through reentry facilitated by temporary functional block. Moreover, the ability to form such a block--and thus the likelihood of subsequent VF--was enhanced as the RCVD increased. Taken together, these results demonstrate the complex relation between vulnerability and RCVD and, at the very least, suggest that the entire shape of the vulnerable window, rather than just its minimum threshold, is important when determining a heart's electrical stability. These conclusions are supported by results obtained from an experimental study--which utilized a similar programmed stimulation protocol--of normal and ischemic canine hearts.

Diagnostic accuracy of two-dimensional echocardiography for detection of left atrial thrombus in patients with mitral stenosis.

Two-dimensional echocardiograms of 56 patients with mitral stenosis, who subsequently underwent operation, were analyzed to evaluate the accuracy for the detection of left atrial thrombi. From left parasternal, apical, and subcostal cardiac windows, multiple planes (including standard planes and their derived scanning planes) were assessed for the presence or absence of mass echoes in the left atrium. The results showed 63% sensitivity, 95% specificity, 87% positive predictive value, 84% negative predictive value, and 83% overall diagnostic accuracy. Most of the false-negative cases had their thrombi confined to the left atrial appendage. We conclude that in patients with mitral stenosis, two-dimensional echocardiography is promising for the diagnosis of left atrial thrombi, particularly when they locate or extend to the main left atrial cavity (not confined to atrial appendage).

Myocardial high energy phosphate metabolism in closed chest dog: creation of an animal model.

A chronic closed chest dog model was developed to study myocardial metabolism with NMR spectroscopy. Cardiac windows were surgically created in 10 dogs by removal of two ribs and accompanying skeletal muscle. Marlex mesh was sewn between the two exposed ribs, and fascia and skin were closed. 31P spectra were obtained using a surface coil placed into the surgically created pouch and using routine NMR pulsing techniques.

Diagnostic ultrasound imaging in domestic animals: Two-dimensional and M-mode echocardiography.

Two-dimensional (linear scanning) and M-mode echocardiography in normal cattle, horses, goats and dogs were examined to obtain fundamental information for clinical application. The cardiac window, which allows penetration of the ultrasound beam, was defined in the left and right 3rd and 4th intercostal spaces near the olecranon in cattle, goats and dogs, and in the area above the olecranon of the 4th and 5th spaces in horses. It was possible to identify the cardiac valves, cavities and walls, and to observe their configuration and motion by both methods. In particular, in cattle and horses, using real time two-dimensional imaging, in spite of the impossibility of observing the short-axis view due to ribs, it was relatively easy to visualize the morphology and movement of the intracardiac structures, and it was easy to choose the location and direction of the probe for M-mode imaging. However, obtaining the typical M-mode echotardiograms of cardiac valves was not as easy as that of the ventricles, especially in cows, in which the ossa cordis seemed to have an effect on imaging of the mitral and aortic valves. After observing the two-dimensional long-axis echocardiogram from the cardiac window of each structure, manipulation of the probe according to the tomogram readily produced the M-mode tracing of the target structure.

Technique for dual transducer echocardiography.

Circuitry for simultaneous recording from dual transducers on a single echocardiogram is presented. The technique may be used to compare the motion pattern and time intervals of separate intracardiac structures. The technique may be difficult, is limited by the size of the cardiac window, and may be most useful for research purposes.

Staphylococcal Pericarditis in a Patient with Systemic Lupus Erythematosus

A patient with systemic lupus erythematosus developed spiking fevers, which were controlled by parenteral steroids, and, later, pericardial friction rub. Staphylococcal pericarditis was diagnosed by periocardiocentesis; no pathogenic organisms were found in blood or sputum. The infection did not respond to methicillin, and irrigation with Dakin's solution through a cardiac window was required to cure the pericarditis.