Low-frequency stimulation of the hippocampus following fear extinction impairs both restoration of rapid eye movement sleep and retrieval of extinction memory.

Post-learning rapid eye movement (REM) sleep deprivation has often been shown to impair hippocampal functioning, which results in deficit in retrieval of some types of memory. However, it remains to be determined whether post-learning alteration of hippocampal functioning affects, in turn, REM sleep. Recent studies have shown that both post-extinction REM sleep deprivation and post-extinction application of hippocampal low-frequency stimulation (LFS) impair memory of fear extinction, indicating possible bidirectional interactions between hippocampal functioning and REM sleep. To analyze the potential effect of post-extinction alteration of hippocampal functioning on REM sleep, rats were implanted with stimulating electrodes in the dorsal hippocampus for post-extinction LFS. Sleep was recorded before (two sessions, 1 day apart) and after conditioning (five tone and eyelid-shock pairings), and following extinction training (25 tone-alone presentations) for 6 h per session. Fear conditioning reduced time spent in REM sleep, which was restored with fear extinction. Hippocampal LFS, applied immediately following extinction training, abolished the restorative effect of fear extinction on REM sleep and impaired extinction retrieval. These data extend previous findings and suggest bidirectional interactions between hippocampal functioning and REM sleep for successful extinction retrieval.

[C. Walton Lillehei and the epic of open heart surgery]. / C. Walton Lillehei et l'épopée de la chirurgie à coeur ouvert.

C. Walton Lillehei (1918-1999) from the Surgery Department of the University of Minnesota in Minneapolis (MN, USA), was the precursor of open heart surgery. He successively introduced heart-lung machine, intracardiac repairs, pacemaker, and mechanical cardiac valves.

Influence of post-surgery time after cardiac transplantation on exercise responses.

Influence of post-surgery time after cardiac transplantation on exercise responses. Med. Sci. Sports Exerc., Vol. 28, No. 2, pp. 171-175, 1996. To test the hypothesis that exercise response changes with time after cardiac transplantation, we investigated the cardiorespiratory responses of nine orthotopic heart transplant patients (52.4 +/- 2 yr) during graded exercise tests (30 W.3 min-1) done at 1, 3, 6, 9 and 12 months post-surgery. At peak exercise, 1) oxygen uptake per kg of body weight (VO2), minute ventilation (VE) and oxygen pulse (O2 pulse) did not change significantly between 1 and 12 months postsurgery; 2) transplanted heart rate (HRt) and delta heart rate (peak exercise heart rate--resting heart rate) increased significantly over time (P < 0.01; P < 0.05) with a marked increase between 1 and 3 months (P < 0.05); and (3) a significant negative correlation existed between O2 pulse and HRt (r = -0.36, P < 0.05), whereas no correlation was found between delta heart rate and delta VO2 (peak exercise VO2- resting VO2, l.min-1). During submaximal exercise, HRt increased significantly over time (P < 0.001); VO2, VE, and O2 pulse showed no significant change; and the VO2-HRt relationship shifted toward higher values of HRt. We conclude that, in the absence of formal physical training, the exercise response of denervated transplanted heart increases in relation to post-surgery time but does not affect oxygen uptake at submaximal and peak levels of exercise.

Long term follow up of 292 patients after valve replacement with the Omnicarbon prosthetic valve.

In a prospective study, 292 consecutive patients received 336 Omnicarbon cardiac valves from September 1984 through September 1992 at the Montpellier University Hospital. There were 153 aortic (52%), 95 mitral (33%) and 44 double (15%) mitral and aortic replacements. Mean age was 58 years; 57% were male. Total follow up was 1,383 patient-years, with a maximum of nine and a mean of 4.87 years. Early mortality was 2.75% overall. Late mortality occurred at a rate of 1.9%/patient-year. Nine-year probability of freedom from mortality (including early mortality) was 85.0% +/- 2.6% overall. There were no cases of structural failure. Thromboembolic events occurred in nine patients, producing a linearized rate of 0.7%/patient-year. Hemorrhage associated with anticoagulant therapy occurred at a rate of 0.8%/patient-year. Therefore, the combined rate of thromboembolic/hemorrhagic events was 1.5%/patient-year. Cumulative overall freedom from thromboembolism and hemorrhage was 91.5% +/- 1.9% at nine years; it was 86.2% +/- 4.3% after mitral and 95.1% +/- 2.0% after aortic valve replacement. Hemolytic anemia was not observed. Endocarditis occurred eight times (0.6%/patient-year), and there were seven cases of perivalvular lead (0.5%/patient-year). At the end of the follow up, 86% of the patients were in NYHA class I. It is concluded that clinical results over a nine-year period are excellent with the Omnicarbon prosthesis.

Surgical treatment of extracranial internal carotid artery aneurysm.

Aneurysms of the extracranial internal carotid artery are rare but can be responsible for severe complications such as rupture, thrombosis, or embolism. Between 1961 and 1985 we operated on 38 aneurysms of the extracranial internal carotid artery in 35 patients, 22 males and 13 females, whose ages ranged from 6 to 73 years. The underlying causes of aneurysm included atherosclerosis (12 cases), fibromuscular dysplasia (eight cases), a congenital defect (five cases), infection (one case), and trauma (six cases); in six cases aneurysm was secondary to spontaneous dissection. Signs of cerebral ischemia were present in 26 (74%) patients and a cervical mass was found in six. The aneurysm was proximal (i.e., below the angle of the mandible) in 16 patients and distal (i.e., above the angle of the mandible) in 22. After resection of the aneurysm, arterial continuity was restored in 37 patients by resection and grafting (12 cases), resection and anastomosis (11 cases), or arteriorrhaphy (14 cases). One death occurred 13 days after operation due to myocardial infarction. Two patients experienced a reversible neurologic event. Transient paresis of cranial nerves was observed in eight patients. During a follow-up period that ranged from 6 to 30 years, four patients were lost to follow-up and 25 patients remained asymptomatic. Three patients had asymptomatic thrombosis of the carotid artery detected at follow-up investigations. The potential risks of cerebral ischemia and rupture and the satisfactory long-term results achieved with surgery are strong arguments in favor of surgical treatment for aneurysms of the extracranial internal carotid artery.

[Floating thrombus in the right atrium and severe pulmonary embolism. Value of intravenous thrombolysis]. / Thrombus flottant de l'oreillette droite et embolie pulmonaire grave. Intérêt de la thrombolyse intraveineuse.

Mobile right atrial thrombi carry a high risk of pulmonary embolism which may be massive and are a medical emergency. Although surgery is commonly indicated, treatment with intravenous thrombolytics is an alternative and was successful in 4 out of 6 cases reported by the authors. Six patients, admitted for severe pulmonary embolism confirmed by pulmonary scintigraphy (6 cases) and by angiography (2 cases), underwent echocardiography which demonstrated a mobile right atrial thrombus. One patient was operated as an emergency and died immediately afterwards. Another, treated with heparin because of contraindications to surgery and thrombolysis had a recurrent fatal pulmonary embolism. In the other four cases, intravenous thrombolytic therapy was started immediately after echocardiography with 250,000 IU of streptokinase in 30 minutes, followed by 100,000 IU per hour for 48 to 72 hours associated with heparin 300 to 500 IU/kg/day. The biological efficacy of the treatment was confirmed in all cases (fibrinogen < 1 milligram; TCA > 60 s). A clinical improvement with improved blood gases was rapidly obtained in all 4 cases. The thrombus had totally disappeared at control echocardiography 8 to 12 hours after the initial examination. There were no complications, in particular no haemorrhages. After 6 months' follow-up, the outcome was good with oral anticoagulants (4 cases) associated with implantation of a caval filter in 1 case. Thrombolysis seems to be an effective alternative to surgery as there four cases demonstrate.

False aneurysm of the ascending aorta following aortic valve replacement.

False aneurysm of the ascending aorta is a rare and life-threatening complication of open heart surgery, usually occurring late after operation. Echocardiography, especially transesophageal echocardiography, is a non-invasive method of examination which can be very helpful in its diagnosis. Deep hypothermia and circulatory arrest allow a bloodless field during surgery and provide an adequate patient protection. Infection is a very well known predisposing factor, but cystic medial necrosis of the aortic wall also seems to play a role in this complication. We report three cases, two of them had cystic medial necrosis and the presence of infection could be proved in none.

Adult coronary aneurysms related to Kawasaki disease.

Kawasaki disease (KD) is an acute illness encountered in infancy and childhood. Cardiovascular complications of this syndrome are recognized as being part of the adult coronary artery disease population. Reported herein is the surgical treatment of multiple coronary artery aneurysms, severe stenotic lesions and thrombotic involvement of the coronary arterial tree that could be ascribed to childhood KD in two adult patients with no risk factors for atherosclerotic heart disease. Surgical management of such patients reveals safe and provides satisfactory quality of life.

Mediastinitis in heart transplant recipients: successful treatment by closed local irrigation.

Following cardiac transplantation bacterial mediastinitis is a severe early complication. Between March 1986 and September 1993, cardiac transplant operations were performed in 101 patients, of whom six developed purulent mediastinitis. Treatment consisted of surgical débridement, closed local irrigation, drainage and systemic antibiotics. No patient died as a result of bacterial mediastinitis. Low cardiac output and requirements for resternotomy for bleeding and prolonged artificial ventilation were significantly higher in the group with sternal infection. In contrast, since January 1991 the dose of corticosteroid was decreased from 5 mg/kg per day to 1.5 mg/kg per day beginning on the first day after operation. A total of 51 heart transplant operations have been subsequently performed without sign of mediastinal infection.

Fibromuscular dysplasia of the internal carotid artery: long-term surgical results.

Fifty-eight patients underwent 72 operations for symptomatic fibromuscular dysplasia (FMD) between 1970 and 1986. There were 35 females and 23 males aged between 36 and 76 years (average 56). Among the 72 operated on lesions (11 bilateral) FMD stenotic lesions (string of beads, tubular, focal) were isolated (32) or associated with elongation (tortuosity, coiling, kink) in 24 cases, FDM aneurysms (7), and dissecting pseudoaneurysms (9). The surgical techniques included graduated or balloon intra-luminal dilatation either isolated (29) or associated with resection-anastomosis (35), saphenous graft (4) and reconstructive aneurysmorrhaphy (4). Bifurcation endarterectomy was combined in 14 patients. There was no hospital death. There were 2 neurologic deficits after operation (1 transient) and 12 transient nervous disorders due to dissection near the base of the skull required in one third of the cases. The follow-up period extends from 6 to 22 years. Five patients were lost to follow-up. Out of the 53 remaining patients, 44 (83%) are living and asymptomatic. Nine patients died: 4 from myocardial infarction, 3 from cancer, 2 from neurologic disease. Three late successful reoperations were observed: 1 aneurysm formation following graduated dilatation, 2 anastomotic stenosis. Surgical intraluminal dilatation either isolated or combined with reconstructive techniques is a safe and durable operation relieving symptoms. The benefits of repair are long lasting and should be offered to patients with symptomatic FMD carotid lesions. The medical management of asymptomatic cases allows to study the natural history of the disease whose causes are not so far fully known.

Heart transplantation for terminal congestive heart failure in an acromegalic patient.

Dilated hypokinetic cardiomyopathy in an acromegalic patient is an uncommon event. Specific hormonal therapy with octreotide (a somatostatin analogue) is now recognized as able to improve cardiac failure. A case of worsening of cardiac function under such a therapy is described in this report. Octreotide was finally discontinued and a cardiac transplantation performed. Soon after surgery, treatment with octreotide was started again and no other adverse reaction was noticed. Furthermore, no deleterious or synergistic interaction between the somatostatin analogue and cyclosporine A was detected. A pharmacological hypothesis is given to explain the inability of octreotide to counteract cardiac failure. The patient died 6 months after surgery probably because of an acute episode of arrhythmia.

Doppler echocardiographic evaluation of the Omnicarbon cardiac valve prostheses.

Comprehensive 2 D/Doppler examination of 98 patients (mean age 56), implanted between September 1984 and February 1991, with normally functioning aortic (n = 49) and mitral (n = 49) Omnicarbon valves (OC) were analyzed in order to characterize the normal hemodynamic profiles of the OC valves. The mean time from implantation was 36.4 months (range 6 to 78). The following parameters were assessed (average of 5 measurements): peak transvalvular velocity (peak V), peak instantaneous gradient (peak G), mean transvalvular gradient (mean G), effective aortic valve area (ef Va), modified aortic valve area (m Va), aortic permeability index (PI), mitral valve area (Mit Va). Doppler data were correlated to prosthetic sizes (ranging from 21-29 mm for aortic OC and from 23-31 mm for mitral OC). The study establishes normal Doppler hemodynamics for each size (especially in aortic position) of OC valves and shows excellent performance. Significant correlations between peak G, mean G, Pl, and prosthetic aortic valve size (AS) were moderate. By contrast there were strong relationships between AS and ef Va (r = 0.56, p < 0.001) or mVa (r = 0.55, p < 0.001). These data should be helpful to identify OC prosthetic dysfunction.

[Dilated cardiomyopathy in acromegaly worsening under octreotide treatment. Apropos of a case]. / Cardiomyopathie dilatée au cours d'une acromégalie aggravée sous octréotide. A propos d'un cas.

Dilated cardiomyopathy associated with acromegaly is rare, but may improve with octreotide, a somatostatin analogue. The authors give the first description here of paradoxical worsening in cardiac function during such treatment, with the onset of episodes of acute decompensation following each attempt at starting treatment. Thus worsening was confirmed objectively by a challenge test with octreotide: increased dyspnea, fall in shortening fraction and in echocardiographic cardiac output (of 17 to 14% and 4 to 3 l/min respectively), a decrease in isotopic ejection fraction from 15 to 6% and this in parallel with efficacy regarding hormone levels of GH and IGF1 and a reduction in tumour size by CT scan. No further episode of decompensation occurred after treatment was stopped permanently. The patient underwent a transplant 3 months later. Suppression of the positive inotropic effect of GH by octreotide, associated with an increase in peripheral resistance is suggested. A negative inotropic effect of this hormonal analogue on too advanced a case of heart disease is also a possibility.

Superior mesenteric arteriovenous fistula after ileal resection.

Postoperative superior mesenteric arteriovenous fistula is very rare. We report the case of a 55-year-old woman in whom the discovery of an abdominal bruit led to the diagnosis of superior mesenteric arteriovenous fistula seven years after ileal resection. The clinical and pathophysiological aspects, as well as the therapeutic modalities, of this rare lesion are reviewed.

Dissecting aneurysms of the ascending aorta occurring late after aortic valve replacement.

In 4 patients who had undergone aortic valve replacement, a dissection of the ascending aorta appeared between 7 and 16 years later (mean 12 years). This is a rare complication, occurring in less than one percent of cases. Three cases of aortic regurgitation and one of aortic stenosis developed, and 3 of the cases had dilatation of the ascending aorta and hypertension. The symptoms of dissection were accompanied by signs of either the superior vena caval syndrome or compression of the pulmonary artery. The diagnosis was confirmed by echography and by CT scan. Despite the advances made in the surgery of dissection the prognosis was serious, and 2 of the 4 patients died. Avoidance of this complication depends on replacement of the ascending aorta (composite tube or supracoronary graft according to the involvement of the sinuses of Valsalva) as soon as the diameter of aorta exceeds 55 mm. In cases of moderate dilatation (45-50 mm), systemic reinforcement with Dacron mesh has been shown to have long-term effectiveness.