Search PubMed⌕ Search

Biomedical subjects

R B Karp

Publications and source records attributed to R B Karp.

At least 73 records · Page 4Linked to original sources
PubMed1983

Treatment of intra-atrial cardiac tumors.

Intracavitary tumors of the atria are rare, generally diagnosed as myxoma, and considered benign. Of 20 such tumors presenting for surgery between Jan 1, 1967, and Jan 1, 1982, sixteen were myxomas: 13 in the left and three in the right atrium. Four additional patients operated on for suspected right atrial myxoma had other lesions: two thrombus (simulating myxoma), one leiomyoma originating in the right iliac vein, and one clear cell adenocarcinoma from the left kidney. One initially benign myxoma underwent malignant transformation. Eighteen hospital survivors were followed up from one month to 134 months (mean, 61 months). All are New York Heart Association class I. We recommend inferior vena cavagram for right-sided lesions. For patients older than 40 years, coronary angiography and appropriate bypass grafting should be performed. Surgery must include resection of all abnormal tissue. Follow-up with echocardiography should continue for five years.

Adenocarcinoma↗
PubMed1983

Surgical treatment of aneurysms of the descending thoracic aorta: an analysis of 85 patients.

We have reviewed our experience with resection of 85 aneurysms of the descending thoracic aorta during a ten-and-one-half year interval ending in June, 1980. There were 39 arteriosclerotic aneurysms, 35 aneurysms associated with chronic aortic dissection, and 11 posttraumatic aneurysms. During repair, a temporary shunt was used in 56 patients (66%), partial (venoarterial) cardiopulmonary bypass (CPB) in 19 patients (22%), and simple aortic cross-clamping in 10 patients (12%). Hospital mortality was 11.8%, and was unrelated to the type of aneurysm or operative method. Spinal cord injury developed in 3 of the 83 patients surviving operation (3.6%), and occurred once with each of the three operative methods. Among the 82 operative survivors without preoperative renal failure, postoperative renal failure requiring hemodialysis occurred in 2 of the 10 patients who had simple aortic cross-clamping (20%), 2 of the 54 who had a shunt (3.7%), and in none of the 18 who underwent partial CPB (p = 0.049). Postoperative renal dysfunction (a rise in the preoperative blood urea nitrogen and creatinine levels of 50% or more) occurred in 27 of the 53 patients (51%) who had preoperative and postoperative determinations. Age, intraoperative hypotension, and the use of simple aortic cross-clamping were significant (p less than 0.05) independent predictors of postoperative renal dysfunction. Intraoperative blood loss and the incidence of reoperation for bleeding did not differ significantly among the three operative methods. We conclude that the aneurysm resection technique and the development of intraoperative hypotension have an important effect on postoperative renal function. Partial CPB may represent the optimal method for preservation of renal function, and may also be the method of choice for elderly patients with preexisting renal dysfunction.

Adult↗
PubMed1983

Value of early postoperative epicardial programmed ventricular stimulation studies after surgery for ventricular tachyarrhythmias.

The value of early postoperative epicardial programmed ventricular stimulation studies after electrophysiologically-directed surgery for ventricular tachyarrhythmia was assessed in 34 patients who underwent epicardial stimulation within 7 to 30 days (mean 9.8) of surgery and were followed up for at least 6 months. The antiarrhythmic operation performed was an endocardial ventriculotomy (full encircling or limited), an endocardial resection, a wall resection or a combination of these procedures. All these interventions were directed by intraoperative mapping during sinus rhythm. Temporary epicardial wire electrodes left at the time of surgery rather than endocardial catheter electrodes were used to perform the pacing. The stimulation protocol included the introduction of up to three ventricular extrastimuli and incremental burst ventricular pacing performed at twice diastolic threshold (9.2 +/- 5.8 mA for the right ventricle and 6.0 +/- 3.5 mA for the left ventricle). A study was considered positive when ventricular tachycardia, defined as 10 or more consecutive ventricular beats, was induced by any pacing modality. Nineteen patients (Group I) had a negative study: after stimulation of both ventricles in 15 patients and of the left ventricle only in 4. Fifteen patients (Group II) had a positive study: after stimulation of the right ventricle in nine patients and of the left ventricle in six. The two groups were comparable with respect to preoperative clinical status, surgical procedures performed and postoperative ejection fraction. No arrhythmic events were observed in Group I during a mean follow-up period of 19.5 months (range 4 to 37), whereas seven arrhythmic events (47% incidence) occurred (p = 0.0008) in Group II during a mean follow-up period of 17.7 months (range 5 to 39).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

Late results after mitral valve replacement with the Björk-Shiley and porcine prostheses.

The late results of isolated mitral valve replacement were retrospectively evaluated in 357 patients receiving a Björk-Shiley (B-S) tilting disc prosthesis and 96 patients receiving a porcine bioprosthesis (PB) (Vascor or Carpentier-Edwards) between March, 1973, and July, 1978. The groups were comparable with regard to age, sex, New York Heart Association functional class, preoperative cardiac rhythm (sinus or atrial fibrillation), left atrial size (normal or enlarged), and presence of thrombus in the left atrium at operation. All of the B-S and 14 of the PB patients received long-term anticoagulant therapy. The median duration of follow-up was 46 months in the B-S group and 32 months in the PB group. At 5 years, survival was 70% for the B-S and 68% for the PB groups (NS). The percentage of patients free of thromboembolic episodes was 77% for the B-S and 78% for the PB groups (NS). Fifty-six percent of the B-S and 49% of the PB patients were alive and free of thromboembolism, complications related to anticoagulant therapy, or other valve-related complications (dehiscence, degeneration, or endocarditis) (NS). The presence of atrial fibrillation, enlarged left atrium, preoperative thromboembolic episodes, and left atrial thrombus had no effect on the incidence of thromboembolic complications with either prosthesis. From this analysis, it appears that the major advantage of the PB over the B-S prosthesis is its use in patients in whom long-term anticoagulation is contraindicated.

Adult↗
PubMed1982

Tricuspid atresia in adults.

Congenital atresia of the tricuspid valve is still uncommon in adult patients. However, increasingly successful palliative surgery in children now has increased its incidence after age 15 years. This investigation updates the clinical features of this disease in adults in light of modern diagnostic and surgical techniques. The data on all 18 adults with tricuspid atresia having angiography after age 15 years at this institution since 1970 were reviewed. The patients' ages ranged up to 45 years; 12 had had previous palliative surgery. Left cineventriculography, particularly biplane, with the long axial view (60 degrees left anterior oblique with cranial angulation) is the most important diagnostic mode and reveals the ventricular and great vessel relations. According to standard classification, 11 patients had type I anatomy (normal great arterial relations), 4 type II (transposed great arteries) and 2 type III ("corrected transposition of the great arteries"). One patient with inverted ventricles could not be classified. Associated additional congenital defects were uncommon. On the basis of these data, a new anatomic classification of tricuspid atresia is given which encompasses all possible atrial-ventricular-great arterial combinations. Seven patients had further surgery after study, including two procedures of the Fontan type (right atrium to pulmonary arterial conduit). Follow-up data on all 18 patients revealed two deaths (one early after operation, one late after study without further surgery). The remaining 16 patients survive 2 to 120 months after study. Four patients had naturally balanced pulmonary and systemic circulations and have survived to ages 21 to 41 years without surgery. Prudent surgical decision based on accurate anatomic diagnosis and the need for optimal effective pulmonary blood flow may result in a relatively optimistic prognosis in adults with this disease.

Adolescent↗
PubMed1982

Surgical treatment in Ebstein's malformation.

Between January, 1967, and July, 1981, 24 patients with Ebstein's malformation underwent surgical repair. Sixteen had tricuspid valve replacement; 8 did not. All interatrial communications were closed. Two patients had plication of atrialized ventricle. Twenty had dysrhythmias; these were surgically treated in 4. Four patients (17%), each with valve replacement, died in the hospital (70% confidence limits, 9-28%); 3 of these were among the 6 patients who were preoperatively in New York Heart Association Functional Class IV. There were 3 late deaths, 1 from noncardiac causes and 2 from persistent tricuspid regurgitation in patients without valve replacement. No late deaths or valve-related complications occurred in the valve replacement group. Dysrhythmias remain a problem, although most patients are symptomatically improved after operation. This experience suggests that good early and late results are obtained with replacement of incompetent tricuspid valves if this is done before advanced symptomatic deterioration, that plication rarely is necessary, and that rhythm disturbances should be recognized and appropriately managed.

Adolescent↗
PubMed1982

Neuronal and adrenomedullary catecholamine release in response to cardiopulmonary bypass in man.

Cardiopulmonary bypass (CPB) alters systemic hemodynamics and affects several biochemical systems involved in cardiovascular regulation. We investigated the changes in levels of circulating epinephrine (E) and norepinephrine (NE) and related them to events during CPB. Twenty-eight patients undergoing various surgical procedures were studied. Plasma E and NE were determined by radioenzymatic assay at eight stages of the operation. A ninefold increase in arterial E (from 75 +/- 13 to 708 +/- 117.3 pg/ml) occurred from prebypass (stage 1) measurements to the end of aortic cross-clamping (stage 4). The values at stage 4 were significantly higher (p less than 0.05) than at all other stages. E decreased rapidly, to 360 +/- 84.3 pg/ml, after myocardial and pulmonary reperfusion (stage 5). Arterial NE increased twofold from stage 1 to stage 4 (from 426 +/- 66.9 to 825 +/- 84.2, p less than 0.05). The increase in NE from initial CPB values (stage 2) to 30 minutes of aortic cross-clamping (stage 3) was associated with an increase in mean blood pressure (r = 0.51, p = 0.02). The peak increases in catecholamines occurred when the heart and lungs were excluded from the circulation, which suggests that either or both contributed to the increase. Because the increase in E was markedly greater than that in NE, the predominant humoral response to CPB appears to be adrenomedullary release of E. This significant increase in catecholamines could jeopardize myocardial protective measures during CPB.

Adrenal Medulla↗
PubMed1982

Simultaneous myocardial revascularization and carotid endarterectomy.

Two methods for performing simultaneous carotid endarterectomy and coronary artery bypass grafting (CABG) were compared in 73 patients. A technique for performing carotid endarterectomy during cardiopulmonary bypass providing hypothermic cerebral protection was used in 37 patients (group 1). The 36 other patients (group 2) underwent carotid endarterectomy immediately before cardiopulmonary bypass was instituted. The mean age, New York Heart Association functional class, ventricular function and extent of carotid disease were similar in the two groups. The proportion of patients with previous myocardial infarction or stroke was higher in group 1 (p less than 0.05). One permanent neurologic deficit (technical error) and one transient neurologic deficit occurred in group 1 and none in group 2 (NS). Twenty-seven patients (37%) had left main disease, compared with an institutional incidence of 14.2% for all coronary operations. Five of seven patients who died early (three in group 1 and four in group 2) had left main disease. No advantage of one method over the other could be demonstrated. Patients with left main coronary artery disease and carotid disease have an increased operative risk.

Aged↗
PubMed1981

Atrial excitability and conduction during rapid atrial pacing.

Using temporary atrial wire electrodes placed at selected atrial sites, rapid atrial pacing at rates of up to 368 beats/min was used to study atrial excitability and conduction in seven patients who underwent open heart surgery. The threshold for atrial pacing was found to be an exponential function of pacing rate (r = 0.55, p less than 0.01), increasing threefold when the fastest pacing rates were compared with the slowest pacing rates (p less than 0.005). Atrial conduction times (measured from pacing to recording sites), prolonged during rapid atrial pacing both for studies conducted before institution of cardiopulmonary bypass (p less than 0.005) and for those done 7 days postoperatively (p less than 0.05). However, prolongation of conduction times always depended on achievement of a critically rapid pacing rate. During rapid atrial pacing, we observed a high incidence of alternans of the atrial electrogram (17 of 42 studies). Thus, human atrial excitability, conduction and electrogram morphology are not constant during pacing at rapid rates. Rather, at rapid pacing rates, there is depression of atrial excitability, prolongation of atrial conduction times and alternation in electrogram morphology. These findings have clinical relevance and theoretical implications for the understanding and treatment of rapid atrial rhythms.

Cardiac Pacing, Artificial↗