Circulation
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Nonpenetrating trauma to the chest can result in cardiac damage that may be overlooked because of associated injuries and the lack of obvious thoracic injury. The clinical diagnosis of important cardiac damage in this setting is difficult. We evaluated noninvasive tests for detecting myocardial damage in 100 patients with severe, nonpenetrating chest trauma. ⋯ ECG abnormalities were noted in 70 patients, and 27 patients had Lown grade 3 or greater dysrhythmias. Fifteen patients died and all had autopsies. The noninvasive abnormalities were nonspecific and did not reflect myocardial contusion that led to clinically important cardiac complications.
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Recent studies have shown that blood flow during closed-chest cardiopulmonary resuscitation (CPR) results primarily from generalized changes in intrathoracic pressure rather than direct compression of the heart. Since ascending aortic and right atrial pressures rise and fall synchronously and to comparable levels during CPR, we hypothesized that the absence of a pressure difference across the coronary vascular bed during CPR precludes coronary blood flow. To test this hypothesis, we compared high-fidelity ascending aortic and right atrial pressures and carotid and coronary blood flow (electromagnetic flowmeters) during closed-chest CPR in 12 fibrillating dogs. ⋯ We conclude that generalized changes in intrathoracic vascular pressures during closed-chest CPR promote carotid but not coronary blood flow. High-compression-force CPR produces small pressure differences across the coronary vascular bed, allowing low levels of coronary flow. However, even high-compression-force CPR is over six times more effective in maintaining carotid flow than coronary flow.
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From August 1974 through April 1981, 23 patients, ages 5 months to 40 years (median 11 years) with corrected transposition of the great arteries (C-TGA), underwent repair of associated intracardiac defects: 20 for ventricular septal defect (VSD), 19 for pulmonary outflow tract obstruction, and five for anatomic tricuspid valve regurgitation. Segmental anatomy was [S,L,L] in 18 or [I,D,D] in 5. Pulmonary outflow tract obstruction was resected in 10 and bypassed with a left ventricle-to-main pulmonary artery conduit in nine patients. ⋯ Eleven of 18 patients with [S,L,L] anatomy had atrioventricular spontaneous or iatrogenic complete block; none of the five patients with [I,D,D] anatomy had atrioventricular block. Pulmonary outflow tract obstruction in [S,L,L] segmental anatomy required conduit interposition in 12 of 14 of our patients to significantly decompress the ventricle. Postoperative development or exacerbation of anatomic tricuspid valve regurgitation occurs in TGA [S,L,L] and may be causally related to surgical complete atrioventricular block.
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The association of coronary artery disease and peripheral vascular disease was studied to determine the influence of coronary artery disease on early and late mortality rates after surgical reconstruction for peripheral occlusive vascular disease and abdominal aortic aneurysm. Between January 1976 and December 1978, 161 consecutive patients underwent surgery for peripheral occlusive vascular disease or abdominal aortic aneurysm. The patients were 35-86 years old (mean 63.3 years). ⋯ The freedom from late cardiac death at 60 months was 71% for the high-risk group (63% patients) and 96% for the low-risk group. The study shows that coronary artery disease is a major determinant of both early and late mortality after arterial reconstruction. The status of the myocardium should be assessed before peripheral vascular surgery, as selective myocardial revascularization may improve survival in these patients.
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Cross-clamping of the descending thoracic aorta for surgical correction of coarctation carries a risk of injury to the spinal cord, which is usually attributed to insufficient blood supply along the spinal arteries. To detect inadvertent interruption of spinal cord perfusion, lumbar pressure was monitored during operation on the aorta in eight patients. One patient incurred ischemic damage of the spinal cord, resulting in paraparesis. ⋯ The pressure increase resulted from expansion of cerebral vessels caused by an acute rise of arterial pressure after clamping, probably aggravated by the administration of a vasodilating drug. During operations in which the circulation of the spinal cord is compromised long enough to cause ischemic damage, the femoral artery and spinal fluid pressures should be monitored. If the pressure difference between femoral artery and lumbar cavity drops to a dangerously low level, a shunting procedure should be performed.