Effect of botulinum toxin on inducibility and maintenance of atrial fibrillation in ovine myocardial tissue.

BACKGROUND: Aberrant vagal stimulation may promote the generation and propagation of atrial fibrillation (AF). Researchers have suggested that botulinum toxin (BTX), a neurotoxin that decreases neural vagal stimulation, may decrease the incidence of postoperative AF. The exact electrophysiologic mechanism underlying the observations and histopathologic alterations associated with BTX are unclear. OBJECTIVE: To investigate the electrophysiologic, functional, and histopathologic effects of BTX on fibrillation induction in ovine atria. METHODS: Eight sheep underwent BTX injections into their pulmonary veins, atrial fat pads, and ventricular walls. Electrophysiology with pacing was performed at baseline and 7 days after injection to evaluate the atrial effective refractory period (ERP) and vulnerability to AF with and without vagal stimulation. Echocardiography was performed at baseline and day 7. After euthanasia, histopathologic analysis was performed. RESULTS: Seven sheep completed the study. For both atria, there was significant shortening in the ERP with vagal stimulation versus no stimulation on day 0 but not on day 7. More aggressive pacing was required to induce AF in the left atrium on day 7 than on day 0. Echocardiography on day 7 showed no significant changes in ejection fraction or new wall-motion abnormalities of the left and right ventricle. Histopathologic analysis showed no significant adverse effects. CONCLUSION: The subacute BTX effect reduced the vulnerability of atrial tissue to AF induction and reduced the vagal influence on atrial ERP shortening compared to baseline levels. Direct BTX injection did not cause myocardial dysfunction or histologic adverse effects.

ACCF/AHA/ASE/ASNC/HFSA/HRS/SCAI/SCCT/SCMR/STS 2013 multimodality appropriate use criteria for the detection and risk assessment of stable ischemic heart disease: a report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, American Heart Association, American Society of Echocardiography, American Society of Nuclear Cardiology, Heart Failure Society of America, Heart Rhythm Society, Society for Cardiovascular Angiography and Interventions, Society of Cardiovascular Computed Tomography, Society for Cardiovascular Magnetic Resonance, and Society of Thoracic Surgeons.

The American College of Cardiology Foundation along with key specialty and subspecialty societies, conducted an appropriate use review of common clinical presentations for stable ischemic heart disease (SIHD) to consider use of stress testing and anatomic diagnostic procedures. This document reflects an updating of the prior Appropriate Use Criteria (AUC) published for radionuclide imaging (RNI), stress echocardiography (Echo), calcium scoring, coronary computed tomography angiography (CCTA), stress cardiac magnetic resonance (CMR), and invasive coronary angiography for SIHD. This is in keeping with the commitment to revise and refine the AUC on a frequent basis. A major innovation in this document is the rating of tests side by side for the same indication. The side-by-side rating removes any concerns about differences in indication or interpretation stemming from prior use of separate documents for each test. However, the ratings were explicitly not competitive rankings due to the limited availability of comparative evidence, patient variability, and range of capabilities available in any given local setting. The indications for this review are limited to the detection and risk assessment of SIHD and were drawn from common applications or anticipated uses, as well as from current clinical practice guidelines. Eighty clinical scenarios were developed by a writing committee and scored by a separate rating panel on a scale of 1-9, to designate Appropriate, May Be Appropriate, or Rarely Appropriate use following a modified Delphi process following the recently updated AUC development methodology. The use of some modalities of testing in the initial evaluation of patients with symptoms representing ischemic equivalents, newly diagnosed heart failure, arrhythmias, and syncope was generally found to be Appropriate or May Be Appropriate, except in cases where low pre-test probability or low risk limited the benefit of most testing except exercise electrocardiogram (ECG). Testing for the evaluation of new or worsening symptoms following a prior test or procedure was found to be Appropriate. In addition, testing was found to be Appropriate or May Be Appropriate for patients within 90 days of an abnormal or uncertain prior result. Pre-operative testing was rated Appropriate or May Be Appropriate only for patients who had poor functional capacity and were undergoing vascular or intermediate risk surgery with 1 or more clinical risk factors or an organ transplant. The exercise ECG was suggested as an Appropriate test for cardiac rehabilitation clearance or for exercise prescription purposes. Testing in asymptomatic patients was generally found to be Rarely Appropriate, except for calcium scoring and exercise testing in intermediate and high-risk individuals and either stress or anatomic imaging in higher-risk individuals, which were all rated as May Be Appropriate. All modalities of follow-up testing after a prior test or percutaneous coronary intervention (PCI) within 2 years and within 5 years after coronary artery bypass graft (CABG) in the absence of new symptoms were rated Rarely Appropriate. Pre-operative testing for patients with good functional capacity, prior normal testing within 1 year, or prior to low-risk surgery also were found to be Rarely Appropriate. Imaging for an exercise prescription or prior to the initiation of cardiac rehabilitation was Rarely Appropriate except for cardiac rehabilitation clearance for heart failure patients.

Transthoracic echocardiography of the HeartWare left ventricular assist device.

BACKGROUND: The unique findings on transthoracic echocardiography of the HeartWare left ventricular assist device (LVAD) have not been previously described. METHODS AND RESULTS: HeartWare LVADs were implanted in 19 patients from May 2009 through December 2010; 152 comprehensive transthoracic echocardiograms (TTEs) performed postoperatively on these patients were retrospectively analyzed for device component visualization, inlet cannula/outflow conduit flow velocities, and imaging artifacts. The inlet cannula was adequately visualized in 66% of studies, incompletely visualized in 14%, and not visualized in 20%. Spectral Doppler interrogation of inlet cannula flow velocity was always uninterpretable due to artifact. Standard parasternal long-axis and apical views always included the inlet cannula in the imaging sector, resulting in a prominent "waterfall" color Doppler artifact obscuring the mitral valve. Inclusion of the inlet cannula in the imaging sector also precluded spectral Doppler interrogation of the mitral valve owing to artifact. The outflow conduit was partially visualized and interrogated by spectral Doppler in 68% of studies, and the average measured peak flow velocity was 1.4 m/s (range 1.0-1.9 m/s). CONCLUSIONS: The HeartWare LVAD inlet cannula and outflow conduit are both readily visualized by TTE in a majority of patients. However, significant color and spectral Doppler artifacts occur when the inlet cannula is visualized in the imaging sector, necessitating routine off-axis Doppler interrogation of the mitral valve.

ACCF/SCAI/AATS/AHA/ASE/ASNC/HFSA/HRS/SCCM/SCCT/SCMR/STS 2012 appropriate use criteria for diagnostic catheterization: American College of Cardiology Foundation Appropriate Use Criteria Task Force Society for Cardiovascular Angiography and Interventions American Association for Thoracic Surgery American Heart Association, American Society of Echocardiography American Society of Nuclear Cardiology Heart Failure Society of America Heart Rhythm Society, Society of Critical Care Medicine Society of Cardiovascular Computed Tomography Society for Cardiovascular Magnetic Resonance Society of Thoracic Surgeons.

The American College of Cardiology Foundation, in collaboration with the Society for Cardiovascular Angiography and Interventions and key specialty and subspecialty societies, conducted a review of common clinical scenarios where diagnostic catheterization is frequently considered. The indications (clinical scenarios) were derived from common applications or anticipated uses, as well as from current clinical practice guidelines and results of studies examining the implementation of noninvasive imaging appropriate use criteria. The 166 indications in this document were developed by a diverse writing group and scored by a separate independent technical panel on a scale of 1 to 9, to designate appropriate use (median 7 to 9), uncertain use (median 4 to 6), and inappropriate use (median 1 to 3). Diagnostic catheterization may include several different procedure components. The indications developed focused primarily on 2 aspects of diagnostic catheterization. Many indications focused on the performance of coronary angiography for the detection of coronary artery disease with other procedure components (e.g., hemodynamic measurements, ventriculography) at the discretion of the operator. The majority of the remaining indications focused on hemodynamic measurements to evaluate valvular heart disease, pulmonary hypertension, cardiomyopathy, and other conditions, with the use of coronary angiography at the discretion of the operator. Seventy-five indications were rated as appropriate, 49 were rated as uncertain, and 42 were rated as inappropriate. The appropriate use criteria for diagnostic catheterization have the potential to impact physician decision making, healthcare delivery, and reimbursement policy. Furthermore, recognition of uncertain clinical scenarios facilitates identification of areas that would benefit from future research. © 2012 Wiley Periodicals, Inc.

Transcatheter aortic valve replacement after chest radiation: A propensity-matched analysis.

BACKGROUND: Chest radiation therapy (CRT) for malignant thoracic neoplasms is associated with development of valvular heart disease years later. As previous radiation exposure can complicate surgical treatment, transcatheter aortic valve replacement (TAVR) has emerged as an alternative. However, outcomes data are lacking for TAVR patients with a history of CRT. METHODS: We conducted a retrospective study of all patients who underwent a TAVR procedure at a single institution between September 2012 and November 2018. Among 1341 total patients, 50 had previous CRT. These were propensity-matched in a 1:2 ratio to 100 patients without history of CRT. Thirty-day adverse events were analyzed with generalized estimating equation models. Overall mortality was analyzed with stratified Cox regression modelling. RESULTS: Median clinical follow-up was 24 months (interquartile range [IQR], 12-44 months). There was no difference between CRT and non-CRT patients in overall mortality (hazard ratio [HR] 0.84 [0.37-1.90], P = 0.67), 30-day mortality (HR 3.1 [0.49-20.03], P = 0.23), or 30-day readmission rate (HR 1.0 [0.43-2.31], P = 1). There were no differences in the rates of most adverse events, but patients with CRT history had higher rates of postprocedural respiratory failure (HR 3.63 [1.32-10.02], P = 0.01) and permanent pacemaker implantation (HR 2.84 [1.15-7.01], P = 0.02). CONCLUSIONS: For patients with aortic valve stenosis and previous CRT, TAVR is safe and effective, with outcomes similar to those in the general aortic stenosis population. Patients with history of CRT are more likely to have postprocedural respiratory failure and to require permanent pacemaker implantation.

ACCF/ASE/ACEP/AHA/ASNC/SCAI/SCCT/SCMR 2008 appropriateness criteria for stress echocardiography: a report of the American College of Cardiology Foundation Appropriateness Criteria Task Force, American Society of Echocardiography, American College of Emergency Physicians, American Heart Association, American Society of Nuclear Cardiology, Society for Cardiovascular Angiography and Interventions, Society of Cardiovascular Computed Tomography, and Society for Cardiovascular Magnetic Resonance: endorsed by the Heart Rhythm Society and the Society of Critical Care Medicine.

The American College of Cardiology Foundation (ACCF) and the American Society of Echocardiography (ASE) together with key specialty and subspecialty societies, conducted an appropriateness review for stress echocardiography. The review assessed the risks and benefits of stress echocardiography for several indications or clinical scenarios and scored them on a scale of 1 to 9 (based upon methodology developed by the ACCF to assess imaging appropriateness). The upper range (7 to 9) implies that the test is generally acceptable and is a reasonable approach, and the lower range (1 to 3) implies that the test is generally not acceptable and is not a reasonable approach. The midrange (4 to 6) indicates a clinical scenario for which the indication for a stress echocardiogram is uncertain. The indications for this review were drawn from common applications or anticipated uses, as well as from current clinical practice guidelines. Use of stress echocardiography for risk assessment in patients with coronary artery disease (CAD) was viewed favorably, while routine repeat testing and general screening in certain clinical scenarios were viewed less favorably. It is anticipated that these results will have a significant impact on physician decision making and performance, reimbursement policy, and will help guide future research.

ACCF/ASE/ACEP/AHA/ASNC/SCAI/SCCT/SCMR 2008 Appropriateness Criteria for Stress Echocardiography. A report of the American College of Cardiology Foundation Appropriateness Criteria Task Force, American Society of Echocardiography, American College of Emergency Physicians, American Heart Association, American Society of Nuclear Cardiology, Society for Cardiovascular Angiography and Interventions, Society of Cardiovascular Computed Tomography, and Society for Cardiovascular Magnetic Resonance endorsed by the Heart Rhythm Society and the Society of Critical Care Medicine.

The American College of Cardiology Foundation (ACCF) and the American Society of Echocardiography (ASE) together with key specialty and subspecialty societies, conducted an appropriateness review for stress echocardiography. The review assessed the risks and benefits of stress echocardiography for several indications or clinical scenarios and scored them on a scale of 1 to 9 (based upon methodology developed by the ACCF to assess imaging appropriateness). The upper range (7 to 9) implies that the test is generally acceptable and is a reasonable approach, and the lower range (1 to 3) implies that the test is generally not acceptable and is not a reasonable approach. The midrange (4 to 6) indicates a clinical scenario for which the indication for a stress echocardiogram is uncertain. The indications for this review were drawn from common applications or anticipated uses, as well as from current clinical practice guidelines. Use of stress echocardiography for risk assessment in patients with coronary artery disease (CAD) was viewed favorably, while routine repeat testing and general screening in certain clinical scenarios were viewed less favorably. It is anticipated that these results will have a significant impact on physician decision making and performance, reimbursement policy, and will help guide future research.

Heart failure due to a post-traumatic calcified pericardial hematoma.

Chest-wall trauma can produce bleeding into the pericardium and initiate a process of inflammation, calcification, and scarring that may eventually produce pericardial constriction. Herein, we present an unusual case of a man who experienced chest trauma at age 16 years, and developed heart failure 40 years later secondary to a large, calcified pericardial hematoma. During its prolonged genesis, the pericardial mass became deeply embedded in the myocardium and produced evidence of both constrictive and restrictive cardiomyopathy. Despite attempted surgical resection, the lesion could not be completely removed, nor could its hemodynamic impact be completely resolved.

Contrast echocardiography for right-sided heart conditions: case reports and literature review.

Contrast echocardiography is recognized to be a safe, effective technique for evaluating the endocardial border and left ventricular function in patients who have suboptimal non-contrast echocardiograms. However, its use in diagnosing right-heart conditions is less well established. Herein, we report our experience with the use of contrast echocardiography for diagnosing 3 distinct right-sided heart conditions (hypokinesis of the right ventricular free wall, severe tricuspid regurgitation, and cardiac tamponade) in patients who had suboptimal echocardiograms. Further studies should be done to validate the use of contrast echocardiography for diagnosing right-heart conditions.

Methemoglobinemia in a young man.

In patients who have cyanosis and dyspnea that are unrelated to a cardiopulmonary cause, 1 rare possible diagnosis is methemoglobinemia. This condition is generally asymptomatic, even when the methemoglobin level is as high as 40% of the total hemoglobin value. In the patient described herein, extensive pulmonologic and cardiologic investigations failed to yield the correct diagnosis, which was finally made on the basis of physical findings and arterial blood-gas analysis. Later, a DNA analysis, reported separately by others, showed that the patient's methemoglobinemia was caused by a novel mutation of the cytochrome b5 reductase gene.