Circulation
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The age-associated decline in aerobic exercise capacity is partially reversible by endurance exercise training. Moderate-intensity endurance exercise training increases aerobic exercise capacity mediated, in part, by improvement of stroke volume and left ventricular performance in older men. The present study was designed to characterize the nature of cardiovascular adaptations to strenuous endurance exercise of long duration and to delineate the mechanisms underlying increased stroke volume and cardiac output in highly trained older endurance athletes. ⋯ Cardiac adaptations in older endurance trained men are characterized by volume-overload left ventricular hypertrophy and enhancement of left ventricular systolic performance at peak exercise. These adaptive responses contribute to enhanced stroke volume at peak exercise in older endurance trained men.
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Pressure-volume relations have been established as useful measures of left ventricular (LV) performance. Application of these methods to the intraoperative setting have been limited because of difficulties acquiring LV volume data. Transesophageal echocardiographic automated border detection can measure LV cross-sectional area as an index of volume, which can be coupled with pressure data to construct pressure-area loops on-line. The purpose of this study was to evaluate intraoperative LV performance in patients undergoing coronary bypass surgery before and immediately after cardiopulmonary bypass using on-line pressure-area relations. ⋯ Intraoperative pressure-area loops may be acquired and displayed on-line using transesophageal echocardiographic automated border detection and readily analyzed in a manner similar to pressure-volume loops. LV performance was depressed immediately after cardiopulmonary bypass compared with before. On-line pressure-area relations may be clinically useful to assess LV performance in patients undergoing cardiac surgery in whom load and contractility may be expected to vary rapidly.
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We report an unusual type of residual interventricular communication in patients with conotruncal malformations in which the aorta is completely or partly aligned with the right ventricle (RV). Interventricular communications after surgical repair usually result from additional defects, patch dehiscence, or incomplete closure and lie in the septal plane. However, after a right ventricular aorta is baffled to the left ventricle, the ventricular septal defect (VSD) patch and RV free wall form part of the systemic outflow tract. This "neo-left ventricular" outflow tract may provide a location for residual interventricular communications out of the septal plane. ⋯ "Intramural" residual interventricular defects are difficult to diagnose by all modalities. Umbrella placement may reduce the left-to-right shunt. Successful surgical closure may require removal and reattachment of the anterior portion of the patch.
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Case Reports
The role of transesophageal echocardiography in identifying anomalous coronary arteries.
The study objective was to evaluate the role of transesophageal echocardiography in identifying the origin of anomalous coronary arteries and confirming their course in relation to the great vessels. The diagnosis of coronary anomalies is made by angiography. The anomalous left main artery with a course between the pulmonary artery and the aorta has been associated with myocardial infarction and sudden death. The course of these anomalous coronary arteries is difficult to demonstrate by angiography alone. ⋯ Transesophageal echocardiography is a useful noninvasive test for diagnosing anomalous origin of the coronary arteries. Furthermore, it is a valuable adjunct to angiography in demonstrating the abnormal course of the left main coronary artery interposed between the aorta and the pulmonary artery, a potentially life-threatening entity.
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Verapamil-sensitive, idiopathic left ventricular tachycardia (ILVT) with right bundle branch block configuration and left-axis deviation has been suggested to originate from the left posterior fascicle. The purpose of this study was to determine how frequently potentials generated by the Purkinje fiber network (P potential) can be recorded preceding ventricular activation, and the role of the P potential in guiding radiofrequency catheter ablation. ⋯ These findings support the hypothesis that ILVT originates from the Purkinje network of the left posterior fascicle. A P potential can be recorded at the posteroapical left ventricular septum during ILVT, and ablation is successful at the site recording the earliest P potential. Pace mapping with similar QRS is not specific due to capture of the Purkinje fiber network at a site remote from the origin of the tachycardia.