Publications by authors named "William F Armstrong"

Article Synopsis
  • Exercise echocardiography is vital for evaluating the right ventricle and pulmonary circulation, but there's a need for clearer understanding of normal ranges and disease-specific variations.
  • The study involved 2,228 participants including healthy individuals, athletes, and patients with different heart and lung conditions, who underwent echocardiography at rest and during exercise.
  • Key findings indicate that certain measurements can predict increased mortality risk, highlighting significant differences in responses to exercise between healthy subjects and various patient groups.
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Exercise Doppler echocardiography (EDE) is a well-validated tool in ischemic and valvular heart diseases. However, its use in the assessment of the right heart and pulmonary circulation unit (RH-PCU) is limited. The aim of this study is to assess the semi-recumbent bicycle EDE feasibility for the evaluation of RH-PCU in a large multi-center population, from healthy individuals and elite athletes to patients with overt or at risk of developing pulmonary hypertension (PH).

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Purpose: This study was a quality-control study of resting and exercise Doppler echocardiography (EDE) variables measured by 19 echocardiography laboratories with proven experience participating in the RIGHT Heart International NETwork.

Methods: All participating investigators reported the requested variables from ten randomly selected exercise stress tests. Intraclass correlation coefficients (ICC) were calculated to evaluate the inter-observer agreement with the core laboratory.

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The Right Heart International Network is a multicenter international study aiming to prospectively collect exercise Doppler echocardiography tests of the right heart pulmonary circulation unit (RHPCU) in large cohorts of healthy subjects, elite athletes, and individuals at risk of or with overt pulmonary hypertension. It is going to provide standardization of exercise stress echocardiography of RHPCU and explore the full physiopathologic response.

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The cardiopulmonary vascular system represents a key determinant of prognosis in several cardiorespiratory diseases. Although right heart catheterization is considered the gold standard for assessing pulmonary hemodynamics, a comprehensive noninvasive evaluation including left and right ventricular reserve and function and cardiopulmonary interactions remains highly attractive. Stress echocardiography is crucial in the evaluation of many cardiac conditions, typically coronary artery disease but also heart failure and valvular heart disease.

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Article Synopsis
  • The study aimed to find out if lower left ventricular systolic function (LVEF) increases the risk of postoperative complications during noncardiac surgeries.
  • Analyzing data from 1,692 patients who had preoperative echocardiograms, the research found that postoperative infections were the most common complications, with respiratory and renal issues being less frequent.
  • The results indicated that lower preoperative LVEF is linked to a higher chance of postoperative infections and renal complications but not respiratory ones, suggesting the importance of LVEF assessment before surgery.
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Involvement of the cardiovascular system in patients with end-stage liver disease (ESLD) is well recognized and may be seen in several scenarios in adult liver transplantation (LT) candidates. The hemodynamic effects of ESLD may result in apparent heart disease, or in some instances may mask cardiac disease. Alternatively, cardiac disease can occasionally be the underlying etiology of ESLD.

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Background: Transesophageal echocardiography (TEE) is the standard for evaluating cardioembolic sources of stroke, although many strokes remain cryptogenic after TEE. Cardiac magnetic resonance (CMR) imaging may have advantages over TEE. We performed a prospective pilot study comparing CMR to TEE after stroke to assist in planning future definitive studies.

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Background: Frequent idiopathic premature ventricular complexes (PVC) are associated with a reversible form of cardiomyopathy. The effect of frequent PVCs on left ventricular function has not been evaluated in post-infarction patients.

Objective: This study sought to evaluate the value of post-infarction PVC ablation and possible determinants of a reversible cardiomyopathy.

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Stress echocardiography was initially developed in 1979 and has seen substantial success in the evaluation of patients with known or suspected coronary artery disease. It has proven applicable to clinical questions of diagnosis, prognosis and follow-up. It has been heavily dependent on technologic advancements, initially digital capturing for side-by-side visualization and, more recently, developments in detailed methods of evaluating myocardial mechanics and contrast echocardiography for perfusion.

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High mechanical index (MI) echocardiography with contrast agent has been shown to induce Evans blue staining of cardiomyocytes, seen 1 d after exposure, in addition to contraction band necrosis, seen immediately after exposure. This research examined the roles of necrosis vs. apoptosis in these bioeffects.

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Background: There are no randomized, controlled trial data to support the benefit of beta-blockers in patients with asymptomatic left ventricular systolic dysfunction. We investigated whether beta-blocker therapy ameliorates left ventricular remodeling in asymptomatic patients with left ventricular systolic dysfunction.

Method And Results: Patients with left ventricular ejection fraction <40%, mild left ventricular dilation, and no symptoms of heart failure (New York Heart Association class I) were randomly assigned to receive extended-release metoprolol succinate (Toprol-XL, AstraZeneca) 200 mg or 50 mg or placebo for 12 months.

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Background: Acute type A aortic dissection (AAD) remains a highly lethal entity for which emergent surgical correction is standard care. Prior studies have identified specific clinical findings as being predictive of outcome. The prognostic significance of specific findings on imaging studies is less well described.

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Objectives: The aim of this research was to evaluate the potential for myocardial contrast echocardiography (MCE) to provoke microscale bioeffects in a canine model.

Background: Myocardial contrast echocardiography induces bioeffects in rat hearts, but translation of such results to larger animal models is uncertain.

Methods: Dogs were anesthetized and prepared for open- (n = 22) or closed- (n = 6) chest MCE.

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Purpose: To detect specific cardiomyocyte injury induced by myocardial contrast material-enhanced echocardiography (ie, myocardial contrast echocardiography) in rats and to ascertain the influences of contrast material dose and ultrasound exposure on this injury.

Materials And Methods: All animal procedures were approved by the university committee for the use and care of animals. Myocardial contrast echocardiography with 1:4 electrocardiographic (ECG) triggering was performed at 1.

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Myocardial contrast echocardiography (MCE) can induce bioeffects in rat hearts by local activation of the contrast agent gas bodies. This study was designed to examine the influence of agent delivery mode on the magnitude of cardiomyocyte injury. A total of 69 hairless rats were anesthetized and mounted vertically in a water bath.

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Stress echocardiography is commonly employed for the clinical management of known or suspected coronary artery disease. This review discusses the accuracy of the technique, which is equivalent to that of competing imaging techniques, as well as its overall role in patient management. The utilization of stress echocardiographic modalities in clinical presentations, such as chest pain, congestive heart failure, and valvular heart disease, and preoperative risk assessment, as well as determining myocardial viability, are discussed.

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Background: During cardiac resynchronization therapy (CRT), cardiac performance is dependent on an optimized atrioventricular delay (AVD). However, the optimal AVD at different heart rates has not been defined yet during CRT.

Method: The effects of an increase in heart rate by pacing or physical exercise on optimal AVD were studied in 36 patients with biventricular pacemakers/defibrillators.

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Background: Myocardial contrast echocardiography (MCE) has been shown to have a potential for apparently reversible side effects related to the interaction of ultrasound with the contrast microbubbles, including premature ventricular contractions and microvascular leakage. We investigated the potential for high-dose MCE to induce histologically definable microlesions.

Methods: Myocardial contrast echocardiography with 1:4 end-systolic triggering was performed at 1.

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Microvascular permeabilization, petechial hemorrhage and premature ventricular contractions (PVCs) have been demonstrated in an in vivo rat model of myocardial contrast echocardiography (MCE). The purpose of this study was to compare these effects for three US Food and Drug Administration (FDA)-approved ultrasound (US) contrast agents (US CA): Optison, Definity and Imagent. Evans blue dye, an indicator of microvascular permeability, and a contrast agent were injected IV in anesthetized rats suspended in a water bath to mimic scanning depths seen in clinical echocardiology.

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