Use of troponin assay 99th percentile as the decision level for myocardial infarction diagnosis.

Background: The Universal Definition of Myocardial Infarction recommends the 99th percentile concentration of cardiac troponin in a normal reference population as part of the decision threshold to diagnose type 1 spontaneous myocardial infarction. Adoption of this recommendation in contemporary worldwide practice is not well known.

Methods: We performed a cohort study of 276 hospital laboratories in 31 countries participating in the National Heart, Lung, and Blood Institute-sponsored International Study of Comparative Health Effectiveness with Medical and Invasive Approaches trial.

Long-Term Follow-Up of Outcomes With F-18-Fluorodeoxyglucose Positron Emission Tomography Imaging-Assisted Management of Patients With Severe Left Ventricular Dysfunction Secondary to Coronary Disease.

Background: Whether viability imaging can impact long-term patient outcomes is uncertain. The PARR-2 study (Positron Emission Tomography and Recovery Following Revascularization) showed a nonsignificant trend toward improved outcomes at 1 year using an F-18-fluorodeoxyglucose positron emission tomography (PET)-assisted strategy in patients with suspected ischemic cardiomyopathy. When patients adhered to F-18-fluorodeoxyglucose PET recommendations, outcome benefit was observed.

Does FDG PET-assisted management of patients with left ventricular dysfunction improve quality of life? A substudy of the PARR-2 trial.

Background: Patients with left ventricular dysfunction whose management is directed by F-18-fluorodeoxyglucose (FDG) positron emission tomography (PET) imaging may have a quality of life (QOL) benefit over standard care.

Methods: Among 430 patients randomized in the PET and Recovery Following Revascularization (PARR)-2 trial to FDG PET-assisted management vs standard, QOL scores were obtained using the European Quality of Life-5 Dimensions (EQ-5D) in 427 patients at baseline (FDG PET n = 216; standard n = 211) and 355 patients at 12-month follow-up (FDG PET n = 184; standard n = 171). EQ-5D scores between FDG PET and standard arms were compared using mixed model repeated measures (MMRM).

Non-invasive assessment of functionally relevant coronary artery stenoses with quantitative CT perfusion: preliminary clinical experiences.

Objectives: We developed a quantitative Dynamic Contrast-Enhanced CT (DCE-CT) technique for measuring Myocardial Perfusion Reserve (MPR) and Volume Reserve (MVR) and studied their relationship with coronary stenosis.

Methods: Twenty-six patients with Coronary Artery Disease (CAD) were recruited. Degree of stenosis in each coronary artery was classified from catheter-based angiograms as Non-Stenosed (NS, angiographically normal or mildly irregular), Moderately Stenosed (MS, 50-80% reduction in luminal diameter), Severely Stenosed (SS, >80%) and SS with Collaterals (SSC).

Increasing benefit from revascularization is associated with increasing amounts of myocardial hibernation: a substudy of the PARR-2 trial.

Objectives: We sought to determine: 1) whether F-18-fluorodeoxyglucose (FDG) positron emission tomography (PET) parameters identify high-risk patients who gain benefit from revascularization; 2) whether there is a cut point for such benefit; and 3) predictors of outcome in patients with severe left ventricular (LV) dysfunction due to coronary artery disease.

Background: Patients with ischemic LV dysfunction might benefit from revascularization but not without risk. The FDG PET imaging can detect viable myocardium that recovers after revascularization.

F-18-fluorodeoxyglucose positron emission tomography imaging-assisted management of patients with severe left ventricular dysfunction and suspected coronary disease: a randomized, controlled trial (PARR-2).

Objectives: We conducted a randomized trial to assess the effectiveness of F-18-fluorodeoxyglucose (FDG) positron emission tomography (PET)-assisted management in patients with severe ventricular dysfunction and suspected coronary disease.

Background: Such patients may benefit from revascularization, but have significant perioperative morbidity and mortality. F-18-fluorodeoxyglucose PET can detect viable myocardium that might recover after revascularization.

Prolonged strenuous exercise alters the cardiovascular response to dobutamine stimulation in male athletes.

Prolonged strenuous exercise has been associated with transient impairment in left ventricular (LV) systolic and diastolic function that has been termed 'cardiac fatigue'. It has been postulated that cardiac beta-adrenoreceptor desensitization may play a central role; however, data are limited. Accordingly, we assessed the cardiovascular response to progressive dobutamine stimulation after prolonged strenuous exercise (2 km swim, 90 km bike, 21 km run).

Blood volume expansion and cardiorespiratory function: effects of training modality.

Purpose: To evaluate the effects of different modalities of aerobic (i.e., interval (INT) and continuous (CONT)) training on cardiorespiratory function and the importance of training-induced blood volume (BV) expansion on aerobic power and LV function.

Arteriovenous fistula-associated high-output cardiac failure: a review of mechanisms.

High-output cardiac failure can be a rare complication of high-output arteriovenous fistula. The authors present a case in which a hemodialysis patient with a high-flow arteriovenous fistula has cardiac failure that improves with fistula closure. The hemodynamic effects of a fistula are reviewed, and the hemodialysis literature regarding high-output cardiac failure is summarized.

Evaluation of outcome and cost-effectiveness using an FDG PET-guided approach to management of patients with coronary disease and severe left ventricular dysfunction (PARR-2): rationale, design, and methods.

Patients with severe ventricular dysfunction and coronary disease have high morbidity and mortality. They may benefit from revascularization but have significant perioperative morbidity and mortality. Positron emission tomography (PET) imaging with F-18-fluorodeoxyglucose (FDG) can detect viable myocardium that may recover from revascularization in such patients.

Myocardial response to incremental exercise in endurance-trained athletes: influence of heart rate, contractility and the Frank-Starling effect.

Recent evidence indicates that endurance-trained athletes are able to increase their stroke volume (SV) throughout incremental upright exercise, probably due to a progressively greater effect of the Frank-Starling mechanism. This is contrary to the widely held belief that SV reaches a plateau at a submaximal heart rate (irrespective of fitness level), owing to a limitation in the time for diastolic filling. The purpose of this investigation was to evaluate whether endurance-trained athletes rely on a progressively greater effect of the Frank-Starling mechanism throughout incremental exercise.

Resistance training and cardiac hypertrophy: unravelling the training effect.

Resistance training (RT) is a popular method of conditioning to enhance sport performance as well as an effective form of exercise to attenuate the age-mediated decline in muscle strength and mass. Although the benefits of RT on skeletal muscle morphology and function are well established, its effect on left ventricular (LV) morphology remains equivocal. Some investigations have found that RT is associated with an obligatory increase in LV wall thickness and mass with minimal alteration in LV internal cavity dimension, an effect called concentric hypertrophy.

Effects of exercise training in patients with heart failure: the Exercise Rehabilitation Trial (EXERT).

Background: The purpose of this study was to examine the effects of exercise training on functional capacity in patients with heart failure.

Methods: One hundred eighty-one patients in New York Heart Association class I to III, with ejection fraction <40% and 6-minute walk distance <500 meters, were recruited into a randomized, controlled, single-blind trial comparing 3 months of supervised training, then 9 months of home-based training with usual care.

Results: There was a significant increase in 6-minute walk distance at 3 and 12 months but no between-group differences.