Eric H.C. Yu

American Society of Echocardiography Consensus Statement on the Clinical Applications of Ultrasonic Contrast Agents in Echocardiography

UNLABELLED ACCREDITATION STATEMENT: The American Society of Echocardiography (ASE) is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. The ASE designates this educational activity for a maximum of 1 AMA PRA Category 1 Credit.trade mark Physicians should only claim credit commensurate with the extent of their participation in the activity. The American Registry of Diagnostic Medical Sonographers and Cardiovascular Credentialing International recognize the ASEs certificates and have agreed to honor the credit hours toward their registry requirements for sonographers. The ASE is committed to resolving all conflict-of-interest issues, and its mandate is to retain only those speakers with financial interests that can be reconciled with the goals and educational integrity of the educational program. Disclosure of faculty and commercial support sponsor relationships, if any, have been indicated. TARGET AUDIENCE This activity is designed for all cardiovascular physicians, cardiac sonographers, and nurses with a primary interest and knowledge base in the field of echocardiography; in addition, residents, researchers, clinicians, sonographers, and other medical professionals having a specific interest in contrast echocardiography may be included. OBJECTIVES Upon completing this activity, participants will be able to: 1. Demonstrate an increased knowledge of the applications for contrast echocardiography and their impact on cardiac diagnosis. 2. Differentiate the available ultrasound contrast agents and ultrasound equipment imaging features to optimize their use. 3. Recognize the indications, benefits, and safety of ultrasound contrast agents, acknowledging the recent labeling changes by the US Food and Drug Administration (FDA) regarding contrast agent use and safety information. 4. Identify specific patient populations that represent potential candidates for the use of contrast agents, to enable cost-effective clinical diagnosis. 5. Incorporate effective teamwork strategies for the implementation of contrast agents in the echocardiography laboratory and establish guidelines for contrast use. 6. Use contrast enhancement for endocardial border delineation and left ventricular opacification in rest and stress echocardiography and unique patient care environments in which echocardiographic image acquisition is frequently challenging, including intensive care units (ICUs) and emergency departments. 7. Effectively use contrast echocardiography for the diagnosis of intracardiac and extracardiac abnormalities, including the identification of complications of acute myocardial infarction. 8. Assess the common pitfalls in contrast imaging and use stepwise, guideline-based contrast equipment setup and contrast agent administration techniques to optimize image acquisition.

Mitral regurgitation in hypertrophic obstructive cardiomyopathy: relationship to obstruction and relief with myectomy

OBJECTIVES This study examined: 1) the impact of myectomy on postoperative mitral regurgitation (MR) and 2) the association between the severity of MR and the left ventricular outflow tract (LVOT) gradient. BACKGROUND For patients with hypertrophic obstructive cardiomyopathy (HOCM) and MR, controversy exists as to whether myectomy alone is sufficient in eliminating MR. Furthermore, the relationship between the degree of MR and the LVOT peak gradient has not been well defined. METHODS We performed pre- and postoperative transthoracic as well as intraoperative transesophageal studies in 104 consecutive patients with HOCM undergoing septal myectomy. Left ventricular outflow tract gradient and the nature of MR were assessed. RESULTS In the 93 patients without independent mitral valve disease, a relationship was observed between MR severity and the LVOT gradient. Left ventricular outflow tract gradient (mean +/- standard deviation) for trivial, mild, moderate and severe MR were: 23.2+/-19.1, 43.8+/-25.4, 70.1+/-21.0 and 104+/-21.0 mm Hg (p < 0.001). Early postoperative, MR was absent or trivial in 80%, mild in 19% and moderate in 1%. None of these patients required additional mitral valve surgery. For patients with independent mitral valve disease (n = 11), five required mitral valve surgery as well as myectomy. The remainder had significant reductions in the degree of MR with myectomy alone. CONCLUSIONS For patients with HOCM and MR not due to independent mitral valve disease, myectomy significantly reduced the degree of MR, without requirement for additional mitral valve surgery. In these patients the severity of MR was directly related to the magnitude of the LVOT gradient.

Muscle Sympathetic Nerve Activity During Wakefulness in Heart Failure Patients With and Without Sleep Apnea

Sympathetic activation and sleep apnea are present in most patients with symptomatic systolic heart failure (HF). Acutely, obstructive and central apneas increase muscle sympathetic activity (MSNA) during sleep by eliciting recurrent hypoxia, hypercapnia, and arousal. In obstructive sleep apnea patients with normal systolic function, this increase persists after waking. Whether coexisting sleep apnea augments daytime MSNA in HF is unknown. We tested the hypothesis that its presence exerts additive effects on MSNA during wakefulness. Overnight sleep studies and morning MSNA recordings were performed on 60 subjects with ejection fraction <45%. Of these, 43 had an apnea-hypopnea index ≥15 per hour. Subjects with and subjects without sleep apnea were similar for age, ejection fraction, HF etiology, body mass index, blood pressure, and heart rate. Daytime MSNA was significantly higher in those with sleep apnea (76±2 versus 63±4 bursts per 100 heartbeats [mean±SEM], P=0.005; 58±2 versus 50±3 bursts/min, P=0.037), irrespective of its etiology (the mean difference for central sleep apnea was 17 bursts per 100 heartbeats; n=14; P=0.006; and for obstructive sleep apnea, 11 bursts per 100 heartbeats; n=29; P=0.032). In a subgroup (n=8), treatment of obstructive sleep apnea lowered MSNA by 12 bursts per 100 heartbeats (P=0.003). Convergence of independent excitatory influences of HF and sleep apnea on central sympathetic neurons results in higher MSNA during wakefulness in HF patients with coexisting sleep apnea. This additional stimulus to central sympathetic outflow may accelerate the progression of HF; its attenuation by treatment of sleep apnea represents a novel nonpharmacological opportunity.

A population-based study of cardiac morbidity among Hodgkin lymphoma patients with preexisting heart disease.

The risk of cardiac hospitalization (CH) in Hodgkin lymphoma (HL) patients with preexisting heart disease was evaluated. Patients with HL were identified from a population-based registry (N = 3964). Data were abstracted from records of a randomly selected subcohort (N = 1096). A population-based registry was used to identify CH. Factors associated with CH and the incidence of CH after HL were estimated with competing risk models. Preexisting heart disease was the strongest predictor of posttreatment CH (hazard ratio = 3.98, P < .001) and significantly modified (P = .01) the effect of treatment on the risk of CH. Among patients with preexisting heart disease, treatment with mediastinal radiation therapy plus doxorubicin-based chemotherapy was associated with a 10-year incidence of CH more than 20% higher than treatment with chemotherapy alone. There is a high risk of CH after mediastinal radiation therapy plus doxorubicin-based chemotherapy among patients with preexisting heart disease; this is an important consideration when weighing treatment options, and in the follow-up of these patients.

2010 Canadian Cardiovascular Society/Canadian Society of Echocardiography Guidelines for Training and Maintenance of Competency in Adult Echocardiography

Guidelines for the provision of echocardiography in Canada were jointly developed and published by the Canadian Cardiovascular Society and the Canadian Society of Echocardiography in 2005. Since their publication, recognition of the importance of echocardiography to patient care has increased, along with the use of focused, point-of-care echocardiography by physicians of diverse clinical backgrounds and variable training. New guidelines for physician training and maintenance of competence in adult echocardiography were required to ensure that physicians providing either focused, point-of-care echocardiography or comprehensive echocardiography are appropriately trained and proficient in their use of echocardiography. In addition, revision of the guidelines was required to address technological advances and the desire to standardize echocardiography training across the country to facilitate the national recognition of a physicians expertise in echocardiography. This paper summarizes the new Guidelines for Physician Training and Maintenance of Competency in Adult Echocardiography, which are considerably more comprehensive than earlier guidelines and address many important issues not previously covered. These guidelines provide a blueprint for physician training despite different clinical backgrounds and help standardize physician training and training programs across the country. Adherence to the guidelines will ensure that physicians providing echocardiography have acquired sufficient expertise required for their specific practice. The document will also provide a framework for other national societies to standardize their training programs in echocardiography and will provide a benchmark by which competency in adult echocardiography may be measured.

Contrast echocardiography in Canada: Canadian Cardiovascular Society/Canadian Society of Echocardiography position paper

As an adjunct to transthoracic, transesophageal and stress echocardiography, contrast echocardiography (CE) improves the diagnostic accuracy of technically suboptimal studies when used in conjunction with harmonic imaging. Intravenous ultrasound contrast agents are indicated for left ventricular (LV) opacification and improvement of LV endocardial border delineation in patients with suboptimal acoustic windows. Demonstrated benefits of CE include improvement in the accuracy of LV measurements, regional wall motion assessment, evaluation of noncompaction cardiomyopathy, thrombus detection, Doppler signal enhancement and conjunctive use with stress echocardiography. Studies have shown the value of CE in the assessment and quantification of myocardial perfusion, and recent clinical trials have suggested a role for contrast perfusion imaging in the stratification of patients with suspected coronary artery disease. While it adds some time and cost to the echocardiographic study, CE frequently obviates the need for additional specialized, expensive and less accessible cardiac investigations, and allows for prompt and optimal subsequent patient management. Despite its proven advantages, CE is presently underused in Canada, and this situation will, unfortunately, not improve until several barriers to its use are overcome. Resolving these important hurdles is vital to the future of CE and to its eventual implementation into clinical practice of promising contrast-based diagnostic and therapeutic applications, including the assessment of perfusion by myocardial CE.

Echocardiographic Detection of Cardiac Dysfunction in Childhood Cancer Survivors: How Long Is Screening Required?

Childhood cancer survivors treated with anthracycline chemotherapy are at an increased risk of long‐term cardiac toxicity, and guidelines recommend that exposed survivors undergo echocardiography every 1–5 years. However, it is unclear whether survivors should undergo echocardiographic screening indefinitely, or if a period of echocardiographic stability indicates that screening is no longer necessary. The objective of this study was to evaluate the outcomes of echocardiographic screening to aid in the refinement of existing guidelines.

Electrocardiographic Interpretation Skills of Cardiology Residents: Are They Competent?

Achieving competency at electrocardiogram (ECG) interpretation among cardiology subspecialty residents has traditionally focused on interpreting a target number of ECGs during training. However, there is little evidence to support this approach. Further, there are no data documenting the competency of ECG interpretation skills among cardiology residents, who become de facto the gold standard in their practice communities. We tested 29 Cardiology residents from all 3 years in a large training program using a set of 20 ECGs collected from a community cardiology practice over a 1-month period. Residents interpreted half of the ECGs using a standard analytic framework, and half using their own approach. Residents were scored on the number of correct and incorrect diagnoses listed. Overall diagnostic accuracy was 58%. Of 6 potentially life-threatening diagnoses, residents missed 36% (123 of 348) including hyperkalemia (81%), long QT (52%), complete heart block (35%), and ventricular tachycardia (19%). Residents provided additional inappropriate diagnoses on 238 ECGs (41%). Diagnostic accuracy was similar between ECGs interpreted using an analytic framework vs ECGs interpreted without an analytic framework (59% vs 58%; F(1,1333) = 0.26; P = 0.61). Cardiology resident proficiency at ECG interpretation is suboptimal. Despite the use of an analytic framework, there remain significant deficiencies in ECG interpretation among Cardiology residents. A more systematic method of addressing these important learning gaps is urgently needed.

Contrast echocardiography: Putting things into perspective - a Canadian Cardiovascular Society/Canadian Society of Echocardiography joint commentary

In a recently published Canadian Cardiovascular Society/Canadian Society of Echocardiography Position Paper on Contrast Echocardiography in Canada, we reviewed the clinical diagnostic utility of ultrasound contrast agents (UCAs) in echocardiography (1). These agents are approved in Canada for left ventricular (LV) opacifi-cation in suboptimal echocardiograms to enhance endocardial borders and ventricular chambers, and assess regional wall motion. Despite improvements in the quality of echocardiographic imaging, an estimated 5% to 10% of rest echocardiograms and 20% to 30% of stress echocardiograms remain suboptimal (2–4). The use of UCAs improves diagnostic accuracy and contributes to a cost-effective pattern of care (3). In previous clinical studies, UCAs have been shown to be safe and effective in numerous circumstances such as improving the accuracy of qualitative assessment of global LV systolic function as well as quantitative assessment of LV volumes and ejection fraction, improving the accuracy and interobserver agreement of LV regional wall motion evaluation, increasing the reproducibility and interobserver agreement in stress echocardiography interpretation, and helping to define specific anomalies (myocardial rupture, pseudoaneurysms, intracardiac thrombi, aortic dissection, LV noncompaction, apical hypertrophic cardiomyopathy, etc) (1). UCAs enhance Doppler signals and have been used during transesophageal echocardiography for left atrial appendage thrombus detection and assessment of aortic dissection (1).