Sullivan Hj

Topography of cardiac ganglia in the adult human heart

Published descriptions of the topography of cardiac ganglia in the human heart are limited and present conflicting results. This study was carried out to determine the distribution of cardiac ganglia in adult human hearts and to address these conflicts. Hearts obtained from autopsies and heart transplant procedures were sectioned, stained, and examined. Results indicate that the largest populations of cardiac ganglia are near the sinoatrial and atrioventricular nodes. Smaller collections of ganglia exist on the superior left atrial surface, the interatrial septum, and the atrial appendage-atrial junctions. Ganglia also exist at the base of the great vessels and the base of the ventricles. The right atrial free wall, atrial appendages, trunk of the great vessels, and most of the ventricular myocardium are devoid of cardiac ganglia. These findings suggest modifications to surgical procedures involving incisions through regions concentrated with ganglia to minimize arrhythmias and related complications. Repairs of septal defects, valvular procedures, and congenital reconstructions, such as the Senning and Fontan operations, involve incisions through areas densely populated with cardiac ganglia. The current standard procedure for orthotopic heart transplantation severs cardiac ganglia and their projections to nodal and muscular tissue. One modification of the current heart transplantation procedure, involving bicaval anastomosis, preserves atrial anatomy and the cardiac ganglia. Preservation of cardiac ganglia within the donor heart may provide additional neuronal substrate for intracardiac processing and targets for regenerating nerve fibers to the donor heart.

Myocardial metabolism and adaptation during extreme hemodilution in humans after coronary revascularization

ObjectiveThis study was designed to evaluate the oxygen transport adjustments and myocardial metabolic adaptation that occurs with different levels of hemodilution during normothermia after cardiopulmonary bypass. DesignProspective, nonrandomized study. SettingOperating room in a university hospital. PatientsEight patients with ejection fractions (>40%) undergoing elective coronary artery bypass grafting. MethodsBefore the institution of cardiopulmonary bypass, blood was withdrawn from patients to a target hematocrit of 15%. After coronary artery bypass grafting, a catheter was inserted directly into the coronary sinus. After the patients were rewarmed to 37°C, they were weaned from cardiopulmonary bypass. Hemodynamic indices were measured, as well as measurements of myocardial oxygen consumption (Vo2) and myocardial metabolism (lactate extraction and coronary sinus hypoxanthine). Measurements were made at three different hematocrit values: 15%, 20%, and 25%. Hematocrit was increased by autologous blood transfusion. Measurements and Main ResultsThe three levels of hemodilution (hematocrit: 17.4 ±PT 3.4%; 23.0 ±PT 3.7%; 27.8 ±PT 4.8%) were significantly different from baseline (hematocrit 37 ±PT 2.6%; p <.05). Oxygen delivery, which increased with autologous transfusion, exceeded 350 mL/min/m2 at each level of dilution. The myocardial Vo2 increased significantly after autologous transfusion compared with the most dilute condition (7.0 ±PT 3.7 mL/min at hematocrit 17.4% vs. 11.2 ±PT 4.8 mL/min at hematocrit 23.0% and 12.4 ±PT 4.0 mL/min at hematocrit 27.8%). This transfusion-induced increase was also true of myocardial oxygen extraction. Lactate extraction and hypoxanthine release were normal and unchanged at each level of hemodilution. Systemic oxygen extraction ratio increased with hemodilution and decreased with autologous transfusion. ConclusionsHemodilution to a hematocrit of approximately 15% is tolerated in anesthetized humans after coronary artery bypass surgery. There was no evidence of myocardial ischemia, as demonstrated by absence of S-T depression on the electrocardiogram, lactate extraction, or hypoxanthine release. In selected patients, postoperative transfusion may be based on systemic physiologic end-points, such as oxygen extraction ratio, rather than set hematocrit values.

Qualitative evaluation of coronary flow during anesthetic induction using thallium-201 perfusion scans.

Qualitative distribution of coronary flow using thallium-201 perfusion scans immediately postintubation was studied in 22 patients scheduled for elective coronary artery bypass surgery. Ten patients received a thiopental (4 mg/kg) and halothane induction. Twelve patients received a fentanyl (100 μg/kg) induction. Baseline thallium-201 perfusion scans were performed 24 h prior to surgery. These scans were compared with the scans performed postintubation. A thallium-positive scan was accepted as evidence of relative hypo-perfusion. Baseline hemodynamic and ECG data were obtained prior to induction of anesthesia. These data were compared with the data obtained postintubation. Ten patients developed postintubation thallium-perfusion scan defects (thallium-positive scan), even though there was no statistical difference between their baseline hemodynamics and hemodynamics at the time of intubation. There was no difference in the incidence of thallium-positive scans between those patients anesthetized by fentanyl and those patients anesthetized with thiopental-halothane. The authors conclude that relative hypoperfusion, and possibly ischemia, occurred in 45% of patients studied, despite stable hemodynamics, and that the incidence of these events was the same with two different anesthetic techniques.

Infection of a ventricular aneurysm and cardiac mural thrombus. Survival after surgical resection

Infections of cardiac mural thrombi are rare, and because antemortem diagnosis is difficult and antibiotic therapy alone ineffective, the associated mortality has been significant. A patient with gram-negative bacillary infection of a mural thrombus is described. Gallium 67 citrate isotope scanning and two-dimensional echocardiography were helpful adjuncts in establishing the diagnosis. Surgical resection of the infected myocardial tissue and prolonged antimicrobial therapy were necessary for cure.

Surgical correction of truncus arteriosus in infancy

An 8 week old infant with severe heart failure from type 1 truncus arteriosus underwent successful corrective surgery employing the Rastelli procedure with use of deep hypothermia and total circulatory arrest. Postoperative hemodynamic studies showed complete closure of the septal defect, disappearance of truncal stenosis, but presence of mild porcine valve stenosis. This procedure is possible even in very small subjects and is preferable to palliative pulmonary arterial banding.