Chest Pain Evaluation: Diagnostic Testing.

Chest pain/discomfort (CP) is a common symptom and can be a diagnostic dilemma for many clinicians. The misdiagnosis of an acute or progressive chronic cardiac etiology may carry a significant risk of morbidity and mortality. This review summarizes the different options and modalities for establishing the diagnosis and severity of coronary artery disease. An effective test selection algorithm should be individually tailored to each patient to maximize diagnostic accuracy in a timely fashion, determine short- and long-term prognosis, and permit implementation of evidence-based treatments in a cost-effective manner. Through collaboration, a decision algorithm was developed (www.chowmd.ca/cadtesting) that could be adopted widely into clinical practice.

La douleur ou la gêne thoracique sont des symptômes fréquents qui peuvent poser un dilemme diagnostique pour de nombreux médecins. Les erreurs de diagnostic d'une cause aiguë ou chronique progressive d'origine cardiaque peuvent d'ailleurs entraîner un risque considérable de morbidité et de mortalité. La présente synthèse porte sur les différentes options et modalités d'établissement du diagnostic et de la gravité d'une coronaropathie. Un algorithme efficace pour le choix des tests doit être adapté à chaque patient afin de maximiser l'exactitude diagnostique dans les plus brefs délais, de déterminer le pronostic à court et à long terme, et de permettre une mise en œuvre de traitements fondés sur des données probantes tout en tenant compte des coûts. Un algorithme décisionnel a donc été conjointement mis au point (www.chowmd.ca/cadtesting) et pourrait être largement adopté dans la pratique clinique.

Long COVID-19: A Primer for Cardiovascular Health Professionals, on Behalf of the CCS Rapid Response Team.

It is now widely recognized that COVID-19 illness can be associated with significant intermediate and potentially longer-term physical limitations. The term, "long COVID-19" is used to define any patient with persistent symptoms after acute COVID-19 infection (ie, after 4 weeks). It is postulated that cardiac injury might be linked to symptoms that persist after resolution of acute infection, as part of this syndrome. The Canadian Cardiovascular Society Rapid Response Team has generated this document to provide guidance to health care providers on the optimal management of patients with suspected cardiac complications of long COVID-19.

Cardiovascular Care Delivery During the Second Wave of COVID-19 in Canada.

Hospitals and ambulatory facilities significantly reduced cardiac care delivery in response to the first wave of the COVID-19 pandemic. The deferral of elective cardiovascular procedures led to a marked reduction in health care delivery with a significant impact on optimal cardiovascular care. International and Canadian data have reported dramatically increased wait times for diagnostic tests and cardiovascular procedures, as well as associated increased cardiovascular morbidity and mortality. In the wake of the demonstrated ability to rapidly create critical care and hospital ward capacity, we advocate a different approach during the second and possible subsequent COVID-19 pandemic waves. We suggest an approach, informed by local data and experience, that balances the need for an expected rise in demand for health care resources to ensure appropriate COVID-19 surge capacity with continued delivery of essential cardiovascular care. Incorporating cardiovascular care leaders into pandemic planning and operations will help health care systems minimise cardiac care delivery disruptions while maintaining critical care and hospital ward surge capacity and continuing measures to reduce transmission risk in health care settings. Specific recommendations targeting the main pillars of cardiovascular care are presented: ambulatory, inpatient, procedural, diagnostic, surgical, and rehabilitation.

Validation of two-dimensional methods for left atrial volume measurement: a comparison of echocardiography with cardiac computed tomography.

BACKGROUND: Left atrial volume (LAVol) is an important predictor of cardiovascular outcomes. Different formulas are applied to calculate LAVol using two-dimensional transthoracic echocardiography (2DTTE) with variable reference values. The objective of the study was to evaluate the accuracy of methods to calculate LAVol by 2DTTE or cardiac computed tomography (CT). METHODS AND RESULTS: Overall 177 consecutive patients who underwent both a 2DTTE and retrospective electrocardiogram (ECG)-gated coronary CT angiography (CTA) within 15 days were included for this study. LA volume measurements were calculated by 2DTTE and 2DCT using the biplane area-length, biplane Simpson's, prolate-ellipsoid-1 and prolate-ellipsoid-2 methods. These results were compared with those measured by CT using a volumetric method. There was very good correlation between the CT and echocardiographic measures for LAVol, but significant underestimation of the echocardiographic methods when compared to the reference standard (33.5%, 39.1%, 48.1%, and 53.2% for the biplane area-length, biplane Simpson's, prolate-ellipsoid-1, and prolate-ellipsoid-2 methods, respectively). The biplane area-length method using 2DTTE had the closest volume estimation of all echocardiographic methods to the reference standard (67.6 ± 25.5 mL vs. 106 ± 35.5 mL, r = 0.712). Similarly, the biplane area-length method using CT most accurately predicted LAVol (103.3 ± 36.0 mL, r = 0.965). CONCLUSIONS: Compared to CT, 2DTTE provides reasonable assessment of LAVol, although all measurement methods underestimate LAVol. For both 2DTTE and CT, the biplane area-length method appears to provide the most accurate 2D estimate of LAVol.

Measuring coronary artery calcification using positron emission tomography-computed tomography attenuation correction images.

AIMS: Cardiac computed tomography (CT) measured coronary artery calcium (CAC-CT) is a well-validated and accurate tool for estimating atherosclerotic burden and prognosis. Computed tomography attenuation correction (ACCT) obtained during cardiac positron emission tomography (PET) has been used to visually estimate CAC; however, quantification using a non-gated ACCT images has not been described. We sought to understand the relationship between CAC measured using cardiac computed tomography (CT) and CAC using ACCT images obtained during cardiac PET perfusion imaging. METHODS AND RESULTS: Patients with both CAC-CT and cardiac PET within 6 months of each other were identified. CAC-CT images were scored using the Agatston scoring method, while ACCT images were scored using different attenuation thresholds for calcium. CAC-CT and ACCT scores were compared. Between August 2007 and October 2010, 91 patients were included in the analysis. Interobserver reliability was excellent at all thresholds of detection tested. Pearson correlation was strongest between CAC-CT and ACCT at 50 HU threshold of detection (ACCT(50)). Implementing CAC categories (0, 1-100, 101-400, >400), there was a high degree of agreement between observers as well as between CAC-CT and ACCT(50). Correlation was best for lower CAC scores; however, as CAC-CT increased, ACCT(50) underestimated CAC. CONCLUSION: Quantifying CAC using ACCT images appears to be feasible and accurate. In a single cardiac PET examination, information regarding perfusion, LV function, flow quantification, and CAC can be obtained without additional radiation.

Infective endocarditis presenting as ST-elevation myocardial infarction: an angiographic diagnosis.

While systemic embolic events occur with relative frequency in infective endocarditis (IE), coronary embolization remains an uncommon cause of ST elevation myocardial infarction. Herein we report a case of ventricular fibrillation and anterior ST elevation myocardial infarction occurring in a patient initially presenting with septic shock. Angiography proved diagnostic for IE of a native bicuspid aortic valve complicated by root abscess and left anterior descending artery occlusion. Histologic examination of the embolectomy specimen from the left anterior descending artery confirmed the presence of thrombus and bacteria. The present case highlights difficulties in identifying and managing patients with coronary embolism of vegetations from IE.

Determining patient prognosis using computed tomography coronary angiography.

In addition to demonstrating luminal narrowings, cardiac computed tomography angiography (CTA) has the ability to detect nonstenotic plaque, vessel wall calcification and can assess left ventricular function. CTA prognostic studies have considered these components individually and in combination to produce novel risk factor scores to help predict clinical outcomes. In this article, we will consider the utility of CTA to predict clinical risk by considering the evidence for luminal stenosis, plaque scores, plaque descriptors and models combining these elements. We will also discuss some of the emerging applications of CTA that will likely provide future prognostic data in coronary artery disease patients. Although initially described as an anatomical investigation to determine the presence of coronary disease, CTA is being explored as a tool for functional imaging and may soon provide a noninvasive technique of anatomical and functional assessment previously only possible by invasive methods.

Established and emerging dose reduction methods in cardiac computed tomography.

Cardiac computed tomography (CT) is a non-invasive modality that is commonly used as an alternative to invasive coronary angiography for the investigation of coronary artery disease. The enthusiasm for this technology has been tempered by a growing appreciation of the potential risks of malignancy associated with the use of ionising radiation. In the spirit of minimizing patient risk, the medical profession and industry have worked hard to developed methods and protocols to reduce patient radiation exposure while maintaining excellent diagnostic accuracy. A complete understanding of radiation reduction techniques will allow clinicians to reduce patient risk while providing an important diagnostic service. This review will consider the established and emerging techniques that may be adopted to reduce patient absorbed doses from x-ray CT. By modifying (1) x-ray tube output, (2) imaging time (scan duration), (3) imaging distance (scan length) and (4) the appropriate use of shielding, clinicians will be able to adhere to the 'as low as reasonably achievable (ALARA)' principle.

Changes in the activity of a CpG neuron after the reinforcement of an operantly conditioned behavior in Lymnaea.

We have previously shown that the aerial respiratory behavior of the mollusk Lymnaea stagnalis can be operantly conditioned, and the central pattern generating (CPG) neurons underlying this behavior have been identified. As neural correlates of operant conditioning remain poorly defined in both vertebrates and invertebrates, we have used the Lymnaea respiratory CPG to investigate neuronal changes associated with the change in behavior after conditioning. After operant conditioning of the intact animals, semi-intact preparations were dissected, so that changes in the respiratory behavior (pneumostome openings) and underlying activity of the identified CPG neuron, right pedal dorsal 1 (RPeD1), could be monitored simultaneously. RPeD1 was studied because it initiates the rhythmic activity of the CPG and receives chemo-sensory input from the pneumostome area. Pneumostome openings and RPeD1 activity were monitored both before and after a reinforcing training stimulus applied to the open pneumostome of operantly conditioned and yoked control preparations. After presentation of the reinforcing stimulus, there was a significant reduction in both breathing behavior and RPeD1 activity in operant preparations but not in yoked and naïve controls. Furthermore these changes were only significant in the subgroup of operantly conditioned animals described as good learners and not in poor learners. These data strongly suggest that changes in RPeD1 activity may underlie the behavioral changes associated with the reinforcement of operant conditioning of the respiratory behavior.