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In order to assess the prevalence and prognosis of ventricular arrhythmias in patients with surgical mitral regurgitation, a prospective cooperative study was undertaken in 14 French cardiological centres. Seventy-nine patients (45 men, 34 women, average age 62.8 +/- 12.8 years), who underwent mitral valvuloplasty (44 cases) or valve replacement (35 cases), were included. Three 24 hour Holter recordings were performed before, 15 days and 6 months after surgery. Etiology of mitral disease was dystrophic in 49 patients, degenerative in 11, rheumatic in 10, post-endocarditis in 3 and undetermined in 6. Only 5 patients had a left ventricular ejection fraction < or = 45 %. Complex ventricular arrhythmias (Lown > or = 4) were recorded before surgery in 22 patients (28 %), more often in dystrophic disease (17/49 versus 5/30, p = 0.04). No significant correlation was observed between the ventricular arrhythmias and the other preoperative findings, except for a tendency to an inverse correlation between the left ventricular ejection fraction and the Lown grade. Two patients died in the immediate postoperative period (Lown 1); 1 died of a non-cardiac cause at the 2nd month (Lown 4A). The prevalence of complex arrhythmias was unchanged after surgery (34 % on early Holter and 22% on late Holter recordings) with no difference between valvuloplasty and valve replacement. In conclusion, these results indicate that ventricular arrhythmias do not influence the early and 6 month postoperative prognosis in mitral regurgitation with good left ventricular function.

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.

There are many electrocardiographic changes in sinoatrial block. Only 2nd and 3rd degree blocks can be analysed on surface recordings. However, they manifest themselves by pauses, the descriptions of which are rich and varied. They also vary according to the circumstances of apparition and the escape rhythms which accompany them. Related ECG changes such as chronotropic insufficiency or carotid sinus syndrome have been described. However, their significance is not univocal and only a precise analysis of the ECG recordings allows correct interpretation of the clinical and paraclinical signs and the institution of appropriate therapy.

Mitral valve prolapse (MVP) a common condition easily recognised by echocardiography with, however, strict criteria to avoid diagnosis by excess, may be complicated by arrhythmias. Two very different situations oppose severe decompensated mitral regurgitation due to myxoid dystrophy and quasi-asymptomatic MVP with a good prognosis and a low risk of complications. The important question is therefore to detect risk criteria of sudden death in patients with few symptoms. Unfortunately, no isolated factor or association of factors resolves this problem in a given patient. However, it is usually young women without severe mitral regurgitation but with thickened valves and, sometimes, a long QT interval, who are involved. Programmed ventricular stimulation and the detection of later ventricular potentials do not seem to be useful in the present state of our knowledge.

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.

Ventricular tachycardia (VT) in children is different to that observed in the adult because ischemic heart disease is exceptionally rare in this age group. The arrhythmia sometimes presents with cardiac failure or loss of consciousness. VT complicates the outcome of operated Tetralogy of Fallot, arrhythmogenic right ventricular dysplasia and some cardiac tumours. Cardiomyopathies are also a cause of VT but it must be noted that ventricular dysfunction may be the result of a prolonged arrhythmia and will disappear after return to sinus rhythm. Many cases of childhood VT occur without any patent cardiac disease even after extensive investigations. Some are benign with a good prognosis, such as salvoes of VT or sustained attacks of so-called ventricular Bouveret. Others carry a more reserved prognosis and require active treatment. Incessant tachycardia of the newborn is difficult to stop may be cured without sequellae. Torsades de pointes is sometimes iatrogenic complicating congenitally long QT syndromes with or without deafness or familial nature, and which may be likened to adrenergic VT. Amiodarone and betablockers are the best antiarrhythmic agents. Investigations with a diagnostic or therapeutic objective are easier in older children but these techniques, whilst not being systematic, do not exclude the very young children. Ablation techniques progress and the limited indications of surgery and implantable defibrillators have to be considered case by case.

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.

A functional physiological block protects the ventricles from the risks of excessively rapid atrial rhythms. Pathological AVB is classified in three degrees according to whether the ventricular excitation is delayed, intermittent or absent. The site of AVB can be accurately determined by endocavitary electrophysiological studies but can also be estimated from the surface electrocardiographic recordings. fundamental research has questioned the sle responsibility of conduction defects in Wenckebach and paroxysmal blocks: they suggest the presence of abnormalities of excitability in pathological zones.

The frog's inner ear was studied in vivo by high spatial resolution magnetic resonance imaging at 7 Tesla. The vestibule, the internal acoustic meatus, and the auditory tube have been identified. The large otolithic mass contained in the vestibule showed a virtual absence of magnetic resonance signal probably due to its composition of closely packed otoconia.

The present paper reports the results of the first investigation of the semicircular canals in a living, small animal by means of high spatial resolution magnetic resonance imaging. This procedure is noninvasive and allows identification of the endolymphatic and perilymphatic spaces yielding a morphology quite consistent with direct anatomical examination.

Traumatic atloido-occipital dislocation is usually fatal with immediate cardio-respiratory arrest. The authors report 3 cases of children who survived such a spine injury despite neurological impairment. Clinical and radiological data including Magnetic Resonance Imaging are compared with 18 other cases reported in the literature.

The present paper reports on magnetic resonance imaging (MRI) at high spatial resolution of the brown adipose tissue (BAT) in laboratory rodents, in comparison with light and electron microscopy findings. Our aim was to assess whether MRI correlates with the expected ultrastructural differences between newborn and adult BAT. The study was performed on the cervical and the interscapular BAT deposits by means of a nuclear magnetic resonance (NMR)-spectrometer equipped with a high resolution imaging system. Ultrastructural examination of BAT at different ages showed three different patterns of adipocyte ultrastructure in BAT which were associated with different MRI patterns. In BAT, MRI identifies the prevalent type of adipocyte in the tissue providing information consistent with ultrastructural results. Results presented here show that MRI represents a precise and reliable tool to investigate the morphology of tissues in living animals. The safe, non-invasive MRI technique represents a very useful tool in morphological research.

Morphological distinction between brown and white adipose tissue was obtained in the rat by MRI at 7 Tesla. Both superficial (subcutaneous) and deep (mediastinal) brown fat was visualized; the level of resolution was less than 1 mm. These results show that MRI is a potentially useful tool for studying the biology of brown adipose tissue in the experimental animal and, prospectively, in man.

p-Nitrophenyl pent-1-yl ether was metabolized (65-70%) in the presence of liver microsomes from phenobarbital-treated rats to give the 4-(major), 3-(minor), and 2-hydroxypent-1-yl (minor) derivatives which were characterized by g.l.c.-mass spectrometry; O-dealkylation (reflecting 1-hydroxylation) and 5-hydroxylation did not occur to a significant extent. 5,5,5-Trifluorination of the pent-1-yl group markedly reduced the extent of metabolism (to approximately 10%). p-Nitrophenyl 2,2,2-trifluoroethyl ether was virtually completely resistant to microsomal metabolism under conditions where the ethyl analogue was extensively O-dealkylated.

A study is made in this paper of the prognostic significance of a very low distal index (index 6), revealed by irrigraphy. On the basis of examination of 55 case histories, the patients were divided into two groups A and B as a function of the distal indices at the root of the limb. The amputation rate was very high in both groups, but the prognosis was better in group A where the situation could be improved by restorative surgery at a high level. Analysis of the surgical possibilities has indicated that restorative surgery at a high level is a promising procedure, especially in group A. Surgery at the femoro-popliteal level yielded less satisfactory results because of the often considerable degradation of the arterial bed further downstream. Sympathectomy appears to be a useful supplement to restorative surgery in appropriate cases. The concept of the reduced distal index is also valuable for detecting cases of arteritis which are still well compensated but are in danger of vascular failure (dangerous claudications).

The 4 cases reported here are meant to illustrate the value of colour doppler-echocardiography in the diagnosis of ventricular septal rupture consecutive to an anterior myocardial infarction. With this method, the examination begins with colour doppler ultrasound superimposed on two-dimensional echocardiographic images and is completed by pulsed and continuous wave doppler velocimetry. In all 4 patients an abnormal colour doppler flow was visualized from the outset; it started in the left ventricule and crossed the ventricular septum to enter the right ventricule, thus confirming the diagnosis and locating the septal defect. This abnormal flow was easy to recognize. On the apical "4 cavity" projection it followed a semi-circular anti-clockwise course which occurred at each cardiac cycle. The flow was red at first in presystole at the apex of the left ventricule; it became blue in pre- and middle-systole while traversing the septum, then mosaic-like in middle- or end-systole around the septal defect on the right ventricular side, and finally blue again in pre-diastole within the right ventricle. The blue trans-septal flow persisted at least up to pre-diastole. The diagnosis of septal rupture was confirmed at surgery in 3 cases and at right heart catheterization in 1 case. Colour doppler-echocardiography is a simple, efficient and rapid method, superior to contrast echocardiography or pulsed doppler alone, for direct real-time visualization of the shunt. It makes the septal defect easy to locate, and it avoids invasive exploratory manoeuvres in cases where surgery is contra-indicated and/or when coronary angiography is not mandatory.

In some reptiles, the hemoglobin oxygen affinity is lowered by CO2 and not by the usual phosphate cofactors. To understand the molecular mechanism of this regulation, Caiman crocodylus hemoglobin's primary structure has been determined. The alignment of the 141 residues of the alpha chain as well as the 146 of the beta chain were obtained by classical method of sequence analysis and are compared with some mammalian, avian, amphibian, and fish hemoglobin chains. Furthermore, from these sequences, it is possible to explain the non-interaction of phosphorylated cofactors with the caiman deoxyhemoglobin on the basis of mutations of the amino acids responsible for their fixation on the beta chain. Among these residues only lysine beta 82 is unchanged. In addition a site has been proposed for the fixation of HCO3- which involves ionic bonds with serine beta 1 and glutamic acid beta 144 (Perutz et al. (1981) Nature 291, 682-684) (1).