Modeling Diagnostic Expertise in Cases of Irreducible Uncertainty: The Decision-Aligned Response Model.

PURPOSE: Assessing expertise using psychometric models usually yields a measure of ability that is difficult to generalize to the complexity of diagnoses in clinical practice. However, using an item response modeling framework, it is possible to create a decision-aligned response model that captures a clinician's decision-making behavior on a continuous scale that fully represents competing diagnostic possibilities. In this proof-of-concept study, the authors demonstrate the necessary statistical conceptualization of this model using a specific electrocardiogram (ECG) example. METHOD: The authors collected a range of ECGs with elevated ST segments due to either ST-elevation myocardial infarction (STEMI) or pericarditis. Based on pilot data, 20 ECGs were chosen to represent a continuum from "definitely STEMI" to "definitely pericarditis," including intermediate cases in which the diagnosis was intentionally unclear. Emergency medicine and cardiology physicians rated these ECGs on a 5-point scale ("definitely STEMI" to "definitely pericarditis"). The authors analyzed these ratings using a graded response model showing the degree to which each participant could separate the ECGs along the diagnostic continuum. The authors compared these metrics with the discharge diagnoses noted on chart review. RESULTS: Thirty-seven participants rated the ECGs. As desired, the ECGs represented a range of phenotypes, including cases where participants were uncertain in their diagnosis. The response model showed that participants varied both in their propensity to diagnose one condition over another and in where they placed the thresholds between the 5 diagnostic categories. The most capable participants were able to meaningfully use all categories, with precise thresholds between categories. CONCLUSIONS: The authors present a decision-aligned response model that demonstrates the confusability of a particular ECG and the skill with which a clinician can distinguish 2 diagnoses along a continuum of confusability. These results have broad implications for testing and for learning to manage uncertainty in diagnosis.

Native mitral valve staphylococcus endocarditis with a very unusual complication: Ruptured posterior mitral valve leaflet aneurysm.

Infective endocarditis (IE) is a life-threatening disease associated with in-hospital mortality of nearly one in five cases. IE can destroy valvular tissue, which may rarely progress to aneurysm formation, most commonly at the anterior leaflet in instances of mitral valve involvement. We present a remarkable case of a patient with IE and a rare complication of a ruptured aneurysm of the posterior leaflet of the mitral valve. Two- and Three-dimensional transesophageal echocardiography, intra-operative videography, and histopathologic analysis revealed disruption at this unusual location-at the junction of the P2 and P3 scallops, surrounded by an annular abscess.

Importance Ranking of Electrocardiogram Rhythms: A Primer for Curriculum Development.

INTRODUCTION: Electrocardiogram interpretation is an essential skill for emergency and critical care nurses and physicians. There remains a gap in standardized curricula and evaluation strategies used to achieve and assess competence in electrocardiogram interpretation. The purpose of this study was to develop an importance ranking of the 120 American Heart Association electrocardiogram diagnostic labels with interdisciplinary perspectives to inform curriculum development. METHODS: Data for this mixed methods study were collected through focus groups and individual semi-structured interviews. A card sort was used to assign relative importance scores to all 120 American Heart Association electrocardiogram diagnostic labels. Thematic analysis was used for qualitative data on participants' rationale for the rankings. RESULTS: The 18 participants included 6 emergency and critical care registered nurses, 5 cardiologists, and 7 emergency medicine physicians. The 5 diagnoses chosen as the most important by all disciplines were ventricular tachycardia, ventricular fibrillation, atrial fibrillation, complete heart block, and normal electrocardiogram. The "top 20" diagnoses by each discipline were also reported. Qualitative thematic content analysis revealed that participants from all 3 disciplines identified skill in electrocardiogram interpretation as clinically imperative and acknowledged the importance of recognizing normal, life threatening, and time-sensitive electrocardiogram rhythms. Additional qualitative themes, identified by individual disciplines, were reported. DISCUSSION: This mixed-methods approach provided valuable interdisciplinary perspectives concerning electrocardiogram curriculum case selection and prioritization. Study findings can provide a foundation for emergency and critical care educators to create local ECG educational programs. Further work is recommended to validate the list amongst a larger population of emergency and critical care frontline nurses and physicians.

Aortic root thrombus complicated by left main coronary artery occlusion visualized by 3D echocardiography in a patient with continuous-flow left ventricular assist device.

Aortic root thrombus is an uncommon complication of continuous-flow left ventricular assist devices (LVAD). We present the case of a 71-year-old man with ischemic cardiomyopathy who underwent destination therapy HeartMate II LVAD placement. Eighteen months later, he presented with a cerebrovascular accident followed by myocardial infarction. Transesophageal echocardiography revealed an aortic root thrombus spanning the left and noncoronary cusps and obliterating the left main coronary artery. We discuss the incidence, risk factors, and management of aortic root thrombus in LVAD patients. To our knowledge, this is the first report of three-dimensional echocardiography used to characterize an LVAD-associated aortic root thrombus.

Giant Cell Myocarditis: Not Always a Presentation of Cardiogenic Shock.

Giant cell myocarditis is a rare and often fatal disease. The most obvious presentation often described in the literature is one of rapid hemodynamic deterioration due to cardiogenic shock necessitating urgent consideration of mechanical circulatory support and heart transplantation. We present the case of a 60-year-old man whose initial presentation was consistent with myopericarditis but who went on to develop a rapid decline in left ventricular systolic function without overt hemodynamic compromise or dramatic symptomatology. Giant cell myocarditis was confirmed via endomyocardial biopsy. Combined immunosuppression with corticosteroids and calcineurin inhibitor resulted in resolution of symptoms and sustained recovery of left ventricular function one year later. Our case highlights that giant cell myocarditis does not always present with cardiogenic shock and should be considered in the evaluation of new onset cardiomyopathy of uncertain etiology as a timely diagnosis has distinct clinical implications on management and prognosis.

Endovascular repair of contained abdominal aortic aneurysm rupture with aortocaval fistula presenting with high-output heart failure.

Aortocava fistula is a rare condition ranging from 0.22% to 6% of all ruptured aortic aneurysms. Recognition and diagnosis of this entity can often be difficult and requires heightened clinical suspicion to ensure that prompt surgical management leads to a favorable outcome. We herein describe the diagnosis and the technical points of successful endovascular management of aortocaval fistula in the setting of a ruptured abdominal aortic aneurysm.

Normal intima-media thickness on carotid ultrasound reliably excludes an ischemic cause of cardiomyopathy.

BACKGROUND: Coronary artery disease (CAD) is the most common cause of left ventricular systolic dysfunction (LVSD). Patients with ischemia as the cause of LVSD may warrant revascularization. Angiography is the most accurate method of CAD diagnosis but is invasive, expensive, and associated with some risk. Noninvasive imaging for CAD often involves expensive equipment, radiation exposure, medication, and/or contrast administration. Carotid ultrasound with measurement of intima-media thickness (IMT) is safe and inexpensive. Carotid IMT is well correlated with the presence of CAD. We assessed the accuracy of carotid ultrasound for identification of CAD as a potential etiology of LVSD. METHODS: Patients with LVSD (ejection fraction < or =40%) of uncertain etiology referred for angiography underwent carotid ultrasound. Patients with history of myocardial infarction were excluded. Two experienced cardiologists blinded to CAD status determined common carotid artery (CCA) IMT and plaque. Significant CAD was defined as > or =50% stenosis of any major artery. Ischemic LVSD was defined as (1) left main and/or proximal left anterior descending coronary artery > or =75% or (2) > or =2 major arteries with > or =75% stenosis. RESULTS: Mean ejection fraction was 27% +/- 10% in 150 patients. Significant CAD was found in 64 (42.7%) and ischemic LVSD in 40 (26.7%). Carotid plaque was seen in 95 (63.3%). Mean CCA IMT was > or =0.9 mm in 69 (46.0%). The combination of mean CCA IMT <0.9 mm and no plaque had negative predictive value for ischemic LVSD of 98%. CONCLUSIONS: Carotid ultrasound with IMT measurement is a valuable screening tool for excluding an ischemic etiology of LVSD when CAD is suspected.

Total anomalous pulmonary venous connection in an adult: comprehensive multimodality evaluation.

An unusual case of total anomalous pulmonary venous connection surviving to adulthood without surgical correction is presented. Transthoracic echocardiography first led to this diagnosis and magnetic resonance imaging refined the anatomic diagnosis leading to successful surgical correction.

Rare flow pattern in a patient with cor triatriatum.

Doppler echocardiography demonstrated a rare flow pattern due to cor triatriatum that is also present in subvalvular or supravalvular mitral stenosis: a forward gradient, in both systole and diastole.

Localized pericardial hematoma presenting with acute hypoxemia.

Localized pericardial hematomas after cardiac surgery may have atypical clinical presentations due to regional alterations in cardiac function and hemodynamics. We report a case of extravascular thrombus that compressed the main pulmonary artery and produced acute hypoxemia due to right-to-left shunting across a patent foramen ovale. We review the pathophysiology leading to this finding and the echocardiographic studies that established the diagnosis.

Saphenous vein graft aneurysm masquerading as a right atrial mass.

We report a case of a large saphenous vein graft (SVG) aneurysm masquerading as a right atrial mass on transesophageal echocardiogram. Cardiac magnetic resonance angiography reliably made a diagnosis of SVG aneurysm extrinsically compressing right atrium. This case illustrates the importance of using combined imaging modalities for the diagnosis and management of cardiac masses.

The a-dip of aortic regurgitation.

Echocardiography has become the diagnostic technique of choice for delineating the intracardiac hemodynamics in a host of pathophysiologic states. Pressures and flows can be estimated or measured with enough accuracy to allow for clinical decision-making. We present a case with an unusual Doppler echocardiographic finding and discuss its derivation.

Bilateral pulmonary artery compression and obstruction by tumor: diagnosis by unusual Doppler flow patterns.

Pulmonary artery obstruction may be caused by tumor within or external to the arteries. Presented here is a patient with life-threatening compromise in pulmonary flow that was caused by a pulmonary neoplasm. The Doppler echocardiogram showed subtotal narrowing of the right pulmonary artery and total occlusion of the left pulmonary artery. In addition, the beneficial effects of chemotherapy were documented by Doppler.

Effect of treatment on the incidence of stroke and other emboli in 519 patients with severe thoracic aortic plaque.

Severe aortic plaques seen on transesophageal echocardiography (TEE) are a high-risk cause of stroke and peripheral embolization. Evidence to guide therapy is lacking. Retrospective information was obtained regarding the occurrence of embolic events (stroke, transient ischemic attacks, or peripheral emboli) in 519 patients with severe thoracic aortic plaque seen on TEE since 1988. Treatment with statins, warfarin, or antiplatelet medications was noted. Treatment was not randomized. In a matched-paired analysis, each patient taking each class of therapy was matched for age, gender, previous embolic event, hypertension, diabetes, congestive failure, and atrial fibrillation to someone not taking that medication. Multivariate analysis was also performed. An embolic event occurred in 111 patients (21%). Multivariate analysis showed that statin use was independently protective against recurrent events (p = 0.0001). Matched analysis also showed a protective effect of statins (p = 0.0004; absolute risk reduction 17%, relative risk reduction 59%, number needed to treat [n = 6]). No protective effect was found for warfarin or antiplatelet drugs. The odds ratio for embolic events was 0.3 (95% confidence interval [CI] 0.2 to 0.6) for statin therapy, 0.7 (95% CI 0.4 to 1.2) for warfarin, and 1.4 (95% CI 0.8 to 2.4) for antiplatelet agents. Thus, there is a protective effect of statin therapy, and no significant benefit of warfarin or antiplatelet drugs on the incidence of stroke and other embolic events in patients with severe thoracic aortic plaque on TEE.

The risk of the development of aortic stenosis in patients with "benign" aortic valve thickening.

BACKGROUND: Aortic valve thickening (AVT) without aortic stenosis (AS) is common and was often considered benign. However, it has recently been found to be associated with increased morbidity and mortality. It is unknown whether patients with AVT are at risk for the development of AS. METHODS: Our echocardiography database from 1987 to 1993 was searched for cases of AVT with at least 1 year of echocardiographic follow-up. The risk of the development of AS was compared in patients with and without AVT. RESULTS: There were 2131 patients with AVT and at least 1 year of echocardiographic follow-up. Aortic stenosis developed in 338 patients (15.9%) (mild, 10.5%; moderate, 2.9%; and severe, 2.5%). Multivariate analysis, including age, left ventricular hypertrophy, and mitral annular calcification, revealed that only mitral annular calcification was independently and significantly associated with progression to AS. CONCLUSIONS: Aortic valve thickening without stenosis is common, and it may progress to significant AS. It is possible that this development of AS may be responsible for some of the increased morbidity and mortality in patients with AVT.

Quantification of left-to-right shunt in patent ductus arteriosus with the PISA method.

Direct Doppler echocardiographic calculation of shunt flow in patent ductus arteriosus (PDA) may be difficult because the orifice area is not well visualized. We used proximal isovelocity surface area (PISA) method to calculate the effective shunt orifice area and the shunt volume in a patient with PDA. The PISA calculation correlated well with shunt estimation by echocardiographic volumetric methods and by oximetry.

Transesophageal Echocardiography in the Evaluation of Aortic Trauma.

Transesophageal echocardiography (TEE) is superior to other imaging techniques for the diagnosis of aortic trauma. It can accurately, rapidly, and safely diagnose life-threatening conditions such as aortic rupture, pseudoaneurysm, traumatic aortic dissection, and intramural hematoma. TEE is useful for the diagnosis and prevention of iatrogenic aortic trauma induced by cardiovascular surgery, intraaortic procedures, and cardiopulmonary resuscitation. (ECHOCARDIOGRAPHY, Volume 13, March 1996)