The role of papillary muscle resection and mitral valve replacement in the control of refractory ventricular arrhythmia.
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Biomedical subjects
Publications and source records attributed to J H Sanders.
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Controversy exists concerning the most effective method of myocardial protection during coronary artery bypass graft operations. Accordingly, we performed a matched-pair analysis between 25 patients receiving multidose hypothermic potassium crystalloid cardioplegia and 25 other patients receiving cold blood potassium cardioplegia. Patients were matched on the basis of preoperative ejection fraction (EF) and the number of anatomically similar stenotic coronary arteries. The adequacy of myocardial protection was assessed by serial perioperative determinations of radionuclide ventriculography, hemodynamic measurements, analyses of electrocardiograms and serum levels of MB-CK. We found that the level of myocardial protection was similar between unstratified groups. However, when subgroups were selected on the basis of prolonged aortic cross-clamp time (greater than ninety minutes) or impaired preoperative left ventricular function (EF less than 40%), there was a suggestion that cold blood cardioplegia may be advantageous.
A total of 40 patients with drug-refractory, life-threatening cardiac rhythm disturbances--ventricular tachycardia in 23 patients and ventricular fibrillation in 17 patients--underwent extended endocardial resection (EER) of scar tissue. Scarring was due to myocardial infarction in 38 patients, to previous congenital heart operation in 1 patient, and to sarcoidosis of the heart in 1. The EER procedure was directed by epicardial and endocardial mapping data whenever possible, and was usually combined with revascularization, aneurysmectomy, or, in 5 patients, mitral valve replacement. Operative mortality was 10%, incident to poor preoperative ventricular function and hemorrhage secondary to previous cardiac surgical procedures. Thirty-three of the 36 survivors (92%) are free of arrhythmia at follow-up periods ranging from 3 to 36 months (mean, 12.5 months); the arrhythmia in the remaining 3 patients is now drug controlled. Thirty-three patients had postoperative electrophysiological studies, and in 30 (91%), the arrhythmia was no longer inducible. The results of surgical treatment for ventricular tachycardia and ventricular fibrillation were similar. The results also proved satisfactory whether the EER procedure was directed by visual observation or mapping.
The quest for the ideal method of myocardial preservation during coronary artery bypass graft (CABG) surgery continues at a rapid pace. Nevertheless, in the present clinical practice of cardiac surgery, the choice is chiefly between hypothermic intermittent ischemic arrest and hypothermic potassium cardioplegia. This study applies newer technics in radionuclear cardiology, as well as more conventional enzymatic, electrocardiographic, and hemodynamic determinations, to the evaluation of the effectiveness of the previously mentioned modes of myocardial protection. Serial assessments are made preoperatively as well as during the first ten days postoperatively. We find that the perioperative incidence of myocardial damage and changes in left ventricular performance are almost identical using either method in patients with relatively normal preoperative left ventricular performance who do not have severe preoperative refractory ischemia or necrosis.
A blood flow calibration apparatus is described for use with electromagnetic flow probes. It is an automatic gravity-flow system, which provides a constant level and therefore constant flow at any preset rate. On several occasions, the use of this device has helped to determine whether flow probes require simple adjustment, factory repair, or replacement. Using this system, a systematic error in the manufacturer's "precalibration" averaging +22% (range, 9 to 50%) has been discovered, and appropriate corrections have been made. The accuracy of these corrections has been confirmed by a rapid, in vivo method of calibration, which also is described and which can be carried out during the conduct of aortocoronary bypass operation. It is recommended that all groups measuring coronary graft flow become familiar with their electromagnetic flowmeter and probes by means such as those described, in the interest of accurate flow measurement after bypass operation.
Forty patients who recently underwent coronary artery bypass graft (CABG) operations had serial hemodynamic and scintigraphic studies. Multidose hypothermic potassium crystalloid cardioplegia was used for myocardial protection and newer techniques in anesthetic management and perioperative patient care were also employed. The method of equilibrium cardiac gated blood pool (GBP) scintigraphy was used to obtain perioperative changes in global ejection fraction (EF) and regional wall motion (RWM). Ninety percent of patients displayed a decrease in EF 2 hours postoperatively when compared to their preoperative values. This change was also associated with a fall in cardiac index (CI) and left ventricular stroke work index (LVSWI). Twenty-four hours postoperatively, EF and CI recovered to preoperative levels, but LVSWI remained depressed. Seven days postoperatively, global EF had improved to a value greater than the preoperative one (50% +/- 3% versus 57% +/- 4%, p < 0.05). Perioperative changes in RWM followed the same pattern as EF, but recovery in this index of regional contractility was faster than EF, since maximal improvement was observed 24 hours postoperatively. Thus transient left ventricular dysfunction is common immediately after CABG, but recent advances in myocardial protection and perioperative management are associated with short-term increases in regional and global left ventricular function documented by noninvasive GBP imaging.
Six primary nurse practitioners were introduced into a large urban jail health service along with supportive organizational changes. The system's primary care volume capacity doubled. The average cost of each patient visit decreased by about one third. The technical quality of primary care improved continuously during a 3-year period of study while patient outcomes, patient satisfaction levels and overall mortality rates remained unchanged. The inmate suicide rate decreased after the introduction of a psychiatrically directed screening and treatment program, and cardiopulmonary resuscitation (CPR) training for correctional officers. Attribution of the decrease awaits further experience. The nurse practitioners delivered primary care equal in technical quality of care provided by medical subspecialty Fellows. A test of clinical knowledge proved to be a good predictor of the technical quality of care delivered by individual graduate nurse practitioners. One measure of the quality of management of illness episodes in the jail clinic correlated weakly with two measures of patient outcome. The addition of nurse practitioners into a well-organized, well-monitored jail health program was a cost-effective means of expanding the program's patient volume capacity. Screening and referral of inmates with high suicide potential, coupled with CPR training for correctional officers, may have been a factor in reducing the inmate suicide rate.
Thirty patients thought to have an atherosclerotic thoracic aneurysm or chronic aortic dissection were evaluated by computed tomography (CT) and the findings compared with those from conventional radiography, thoracic aortography, and surgery. In all cases, CT defined the lesion and correlated well with angiography. Staging of atherosclerotic aneurysms was possible, and CT also demonstrated the relationship between true and false lumina in aortic dissections; however, aortography was often necessary to differentiate a dissection from an aneurysm or for staging. The relative value of CT and aortography is discussed.
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Changes in left ventricular performance after coronary artery bypass grafting (CABG) have been variable. Earlier studies based on contrast left ventriculography have shown occasional improvement in left ventricular function in patients with unstable angina or abnormal preoperative ventricular performance, but for the most part repeat cardiac catheterization several months after operation has shown no significant changes in global left ventricular contraction. In the past few years, advances in radiopharmaceutical technology have made the characterization of left ventricular wall motion accurate and highly reproducible. Since prognosis in patients with coronary artery disease and survival after CABG have been related to global ejection fraction (EF), we employed prospectively on analysis of short-term and long-term changes in EF after CABG utilizing multidose hypothermic potassium crystalloid cardioplegia as the method of myocardial protection. Concomitantly, newer techniques in anesthesia and perioperative patient management were employed to minimize myocardial damage in these patients. Postoperative scintigraphic evaluation showed a transient (2-hour) depression in left ventricular function, followed by recovery to preoperative levels at 24 hours and significant improvement in EF at 7 days. From 7 days to 8 months postoperatively, there was no further change in resting EF, but there was another significant exercise-induced increase in EF at the long-term examination. Thus, present advances in the multidisciplinary management of patients with coronary artery disease are associated with improvement in resting and exercise-related EF postoperatively.
Imaging of the thoracic aorta without recourse to angiography has great theoretic appeal. We have used computerized tomography (CT) in the initial evaluation of 297 patients with suspected mediastinal disease. Nineteen of this group had important findings related to the thoracic aorta: aortic dissection (six), descending thoracic aortic aneurysm (nine), suspected aortic trauma (three), and suspected false aneurysm at a coarctation repair (one). In all cases, the aorta and related pathology were readily demonstrated by CT, aided by the intravenous infusion of contrast material. In 13 of 15 cases, aortic dissection and aortic aneurysm could be accurately diagnosed. In two instances of ascending aortic dissection, it was not possible to distinguish the false lumen from mural thrombus in an atherosclerotic aneurysm.
One hundred patients, ultimately proved to have chest malignancies, were evaluated prospectively with conventional chest tomography and computed tomography. In 58 patients with primary malignancies, conventional tomograms were more useful in evaluation of the hilus than CT scans. The mediastinum was better assessed by CT. Thus, evaluation of the presence of neoplasia is better accomplished by conventional examination, while extent of disease is best assessed by CT. Thoracotomy for curative resection was not attempted (in the latter cases of this series) based on CT findings of mediastinal involvement. In 42 patients with metastases to the chest, CT scans of the lung parenchyma were more sensitive than whole lung tomography but had little additional impact on patient treatment. Nevertheless, in 18 patients the results of CT or whole lung tomography directly affected patient therapy.
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