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Biomedical subjects

N T Kouchoukos

Publications and source records attributed to N T Kouchoukos.

At least 163 records · Page 9Linked to original sources
PubMed1978

Characterization of atrial fibrillation in man: studies following open heart surgery.

The nature of localized atrial activation during atrial fibrillation was characterized in 34 patients following open heart surgery. Bipolar atrial electrograms (AEG) recorded in each patient with atrial fibrillation exhibited a myriad of sizes, shapes, polarities, amplitudes, and beat-to-beat intervals. On the basis of the AEG morphology and the nature of its baseline, we have classified the recordings into four Types. Type I was characterized by discrete AEG complexes separated by an isoelectric baseline free of perturbation, Type II by discrete AEG complexes but with perturbations of the baseline between complexes, Type III by AEGs which failed to demonstrate either discrete complexes or isoelectric intervals, and Type IV in which AEGs of Type III alternated with periods characteristic of Type I and/or Type II. In 22 patients, the AEGs were recorded a second time, and in 11 of these patients the type of atrial fibrillation changed between the first and second recording period. An atrial flutter-fibrillation pattern in the ECG was associated with a relatively ordered atrial activation pattern and a relatively slow atrial rate. Human atrial fibrillation is not an electrophysiologically homogeneous process when compared among different patients or ad seriatim in the same patient.

Adult↗
PubMed1978

Surgical implications of pulmonary hypertension in congenital heart disease.

The effects of pulmonary vascular disease on the results of surgical closure of single large ventricular septal defects are reviewed. Hospital mortality in infants was not affected by the presence of preoperative pulmonary vascular disease. The late results were clearly related to age at operation, preoperative pulmonary vascular resistance, and pulmonary artery pressure. Probability of event analysis allows selection of the optimal age for elective repair of large ventricular septal defects.

Child, Preschool↗
PubMed1978

Left ventricular aneurysmectomy in patients with single vs multivessel coronary artery disease.

To identify clinical syndromes benefiting from post-myocardial infarction (MI) left ventricular (LV) aneurysmectomy, 145 consecutively operated patients were followed a mean of 23 +/- 2 months postoperatively. Of the 145 patients, 49% had single-vessel (SV) coronary artery disease (CAD) (> or = 70% stenosis), 49% had multivessel (MV) CAD, and 2% (3 patients) had an unknown extent of CAD. Patients with SV-CAD and MV-CAD had similar distributions of age, sex, aneurysm location, LV end-diastolic pressure, LV ejection fraction, and scar size. In the SV-CAD group, the major operative indication was incapacitating heart failure (CHF), whereas in the MV-CAD group, the major operative indication was angina, often in combination with CHF. Coronary bypass grafting was done in 17/71 (24%) of SV-CAD and 64/71 (90%) of MV-CAD. Acute (30-day) postoperative survival was 89% (129/145) overall, and long-term survival 73%. Throughout the follow-up period, survival was similar in SV-CAD and MV-CAD. At follow-up, 89% of all survivors had CHF symptoms of functional Class II severity or less, and 97% of survivors had angina of Class II severity or less. Improvement in angina was most striking in the multivessel group whose angina had been more severe preoperatively. Thus, in patients undergoing LV aneurysmectomy and concomitant coronary revascularization: 1) SV-CAD is common; 2) SV-CAD has predominantly CHF preoperatively and usually relief of CHF postoperatively; 3) MV-CAD has both angina and CHF preoperatively, with symptomatic relief of both postoperatively; and 4) preoperative CAD extent does not influence survival.

Coronary Artery Bypass↗
PubMed1978

Changes in left ventricular segmental wall motion following randomization to medicine or surgery in patients with unstable angina.

Twenty-six patients with unstable angina pectoris had biplane left ventricular (LV) angiograms and coronary arteriograms (CAGs) initially and at a median of 1 year following randomization to medical (15 patients) or surgical 11 patients) therapy. Left ventricular segmental wall motion was analyzed by a digital computer yielding segmental ejection fraction for 10 zones along the LV perimeter. Baseline and follow-up CAGs were analyzed simultaneously by one observer, and changes in LV segmental coronary perfusion were estimated. Left ventricular angiograms were analyzed separately from CAGs and independently of knowledge of changes in estimated segmental coronary perfusion. Left ventricular segmental wall motion was more frequently improved in surgical patients than in medical patients. Furthermore, in surgical patients there was a significant correlation between changes in LV segmental wall motion and perfusion to LV segments supplied by the left anterior descending coronary artery, whereas no such correlation for any segment was found in the medical group. Thus, this prospective randomized study suggests that, in patients with unstable angina, coronary revascularization may significantly improve LV segmental wall motion compared to medically treated patients. In the surgical group, improvement in LV wall motion relates to improvement in coronary perfusion to the segments supplied by the left anterior descending artery.

Adult↗
PubMed1978

Long-term patency of saphenous veins for coronary bypass grafting.

The patency of 871 aortocoronary saphenous vein grafts in 438 patients was evaluated for a mean (+/- SEM) of 12.1 +/- 0.3 months after operation. Second studies were performed in 62 patients (134 grafts) at a mean of 42 +/- 1.3 months postoperatively (range, 13 to 61 months). The 1-year patency rate was 79.4% and increased from 76% for 546 grafts placed in 1970-1973 (Period I) to 85% for 325 grafts in 1974-1976 (period II) (P = 0.001). Overall patency was highest (82%) for grafts to the anterior descending system and lowest (76%) for the right system. These patency rates also increased between periods I and II from 79 to 88% (P < 0.05) for the anterior descending and 72 to 83% (P < 0.05) for the right system. For 47 right coronary arteries having associated distal manual endarterectomy, the graft patency rate was 62% vs 78% for those not endarterectomized (P < 0.05). Of 116 grafts patent at the initial study, five were occluded at the second study, a late failure rate of 3.7% and a mean annual attrition rate of 1.7% between 12 and 42 months after operation. High-grade (> 50%) stenoses were present in three of the five grafts at initial study. Development of late stenosis was observed in two grafts (1.7%). These data document improved 1-year patency rates for grafts in period II and a low incidence of late failure and development of late stenosis for up to 61 months following operation. Continued use of saphenous vein grafts to all three coronary arterial systems appears justified.

Adult↗
PubMed1978

Use of temporarily placed epicardial atrial wire electrodes for the diagnosis and treatment of cardiac arrhythmias following open-heart surgery.

We retrospectively assessed our experience with the use of bipolar atrial epicardial electrodes in 70 consecutive patients following open-heart surgery. These patients, representing 1 month's experience on one of our cardiac surgical services, are a random sample of our total experience with more than 6.000 patients in whom we have routinely placed such electrodes. The atrial wire electrodes were used diagnostically and/or therapeutically in 57 patients a total of 139 times. In only 13 patients were the atrial wires not used for any reason. Atrial electrograms were recorded 63 times in 34 patients, 41 times to establish a diagnosis of an arrhythmia and 22 times to confirm the diagnosis of an arrhythmia originally suspected from interpretation of a standard or monitor electrocardiogram (ECG). Atrial pacing was used to treat abnormalities of rhythm or conduction or both in 75 instances in 49 of the 70 patients. Because of their great utility in the diagnosis and treatment of arrhythmias, we conclude that routine placement of atrial wire electrodes at the time of operation is indicated regardless of the nature of the open-heart procedure or the preoperative rhythm.

Arrhythmias, Cardiac↗
PubMed1977

Changes in working status of patients following coronary bypass surgery.

Coronary artery bypass surgery has gained a major role in the management of ischemic heart disease. Relief of symptoms is often the primary goal for these surgical procedures while other effects relating to rehabilitation of such patients have been neglected. To determine change in work status as a result of operation, job status and hours worked before and after surgery were analyzed in 350 patients who had coronary artery bypass grafting procedures. Overall, there was no improvement in return to work or hours worked after surgery. Hours worked before surgery, relief of symptoms, severity of disease, number of bypass grafts placed, and level of education all related substantially to a change in work capacity. It appears that if the potential for enhanced productivity is to be realized, rehabilitative measures must be intensified following coronary artery surgery.

Angina Pectoris↗
PubMed1977

Afterload reduction and cardiac ouptut in infants early after intracardiac surgery.

Sixteen infants less than 18 months old were studied within 3 hours of intracardiac surgery. Initial mean arterial pressure and systemic vascular resistance levels were higher than normal in each infant (99 +/- 17.2 mm Hg and 48 +/- 18.1 units'm2', respectively [mean +/- standard deviation]); cardiac index was low (1.9 +/- 0.48 liters'min-1-2) and mean left and right atrial pressures were 11.4 +/- 2.39 and 12.5 +/- 3.10 mm Hg, respectively. Mean pulmonary arterial pressure was 29 mm Hg; pulmonary vascular resistance was 8.6 units'm2'. When nitroprusside was infused to reduce mean arterial pressure to about normal, cardiac index increased 17 percent and mean left and right atrial pressures decreased 25 and 22 percent, respectively. Mean pulmonary arterial pressure decreased 31 percent. When atrial pressures returned to initial values after infusion of blood with continued infusion of nitroprusside, cardiac index increased another 24 percent. When administration of nitroprusside was discontinued, cardiac index decreased to 116 percent of the initial value and mean atrial pressure increased to 90 percent of the initial value. The study demonstrated the favorable effect on cardiac output of vasodilator therapy in combination with blood volume expansion in hypertensive infants early after intracardiac surgery. An empirical equation interrelating atrial and arterial pressures and cardiac index was derived from the data.

Blood Pressure↗
PubMed1977

Replacement of the ascending aorta and aortic valve with a composite graft: results in 25 patients.

Our experience with combined replacement of the ascending aorta and aortic valve with a composite prosthetic valve-Dacron tube graft in 25 patients from September, 1974, to December, 1976, is reviewed. The technique involves suture of the composite graft to the aortic annulus, to the aortic tissue surrounding the coronary ostia, and to the distal ascending aorta, closing the aortic wall over the graft before discontinuing cardiopulmonary bypass. Annuloaortic ectasia was the most common indication for operation (15 patients). Perfusion of the coronary arteries was used in the first 15 patients. In the remaining 20, internal and external myocardial cooling with one period of ischemic arrest (average, 67 minutes) was used. There was 1 hospital death (4%), and there have been 3 late deaths (12%) in the 27-month follow-up period. This technique appears to be applicable to most types of aneurysmal disease of the proximal ascending aorta associated with aortic valve incompetence. All aneurysmal tissue from the aortic annulus to the innominate artery is excluded, bleeding through the graft is eliminated, operative time is reduced, and the late results have been satisfactory to date.

Adult↗
PubMed1977

Triple-valve replacement: an analysis of eight years' experience.

The total experience with combined aortic, mitral, and tricuspid valve replacement in 38 patients during an eight-year period ending in December, 1974, is reviewed. The hospital mortality was 23.7% (9 patients) and was influenced by the preoperative New York Heart Association Functional Class: 18%(5 of 28 patients) in Class III and 40%(4 of 10) in Class IV. Intraoperative myocardial injury was the other important factor affecting hospital mortality. The majority of late deaths were related to cardiac causes. The five-year survival was 53% (20 patients) for the entire group and 62% (17 patients) for the Class III patients. At latest follow-up (mean, 44 months), 22 (76%) of the hospital survivors had improved by at least one functional class. It appears that surgical intervention before patients reach Class IV status should give better early and long-term results. Our current indications for tricuspid valve replacement as opposed to repair are presented.

Adult↗