Explosive deep water basalt in the sumisu backarc rift.

Eruption of 1-million-year-old tholeiitic basalt >1800 meters below sea level (>18 megapascals) in a backarc rift behind the Bonin arc produced a scoriaceous breccia similar in some respects to that formed during subaerial eruptions. Explosion of the magma is thought to have produced frothy agglutinate which welded either on the sea floor or in a submarine eruption column. The resulting 135-meter-thick pyroclastic deposit has paleomagnetic inclinations that are random at a scale of <2.5 meters. High magmatic water content, which is about 1.3 percent by weight after vesiculation, contributed to the explosivity.

[Linear insertion of atrioventricular valves (Livav): echocardiographic diagnosis, reliability and prevalence in the general population]. / Insertion linéaire des valves auriculoventriculaires (Ilvav): fiabilité du diagnostic échographique et prévalence dans une population sans trisomie 21.

OBJECTIVES: Assess the reliability of prenatal diagnosis of linear insertion of atrioventricular valves (Livav) by echocardiography as well as estimate Livav's prevalence in a population without Down syndrome. PATIENTS: One hundred and twenty-three fetuses of whom 113 were explored before and after birth and 631 consecutive out-patients explored in cardiopediatric unit. METHODS: Determination of the likehood ratio (LHR+ and LHR-) of Livav prenatal diagnosis. Evaluation of the consistency between pre- and postnatal diagnoses as well as between two observers after birth (Kappa index). Prevalence study according to the presence of Down syndrome, cardiac malformation or others abnormalities. RESULTS: LHR+ value was 6.17 and LHR- value was 0.30 for echographic Livav prenatal diagnosis. Consistency was low between pre- and postnatal diagnoses (Kappa = 0.57) and higher between two observers after birth (Kappa = 0.79). Livav prevalence was 2 to 5% in a population without Down syndrome but 15% when associated with a cardiac malformation. Seventy-eight percent Down syndromes had either Livav or AVSD. CONCLUSION: Livav echographic prenatal diagnosis is difficult, for it generates many false positives. Livav is not specific of Down syndrome and can be found relatively frequently in other subjects.

Optimal right ventricular pacing site in chronically implanted patients: a prospective randomized crossover comparison of apical and outflow tract pacing.

OBJECTIVES: To evaluate the long-term functional and hemodynamic effects of right ventricular outflow tract (RVOT) pacing by comparison with right ventricular apical (RVA) pacing. BACKGROUND: Acute studies have suggested that RVOT pacing could significantly improve cardiac performance in comparison with RVA pacing but no data are available in chronically implanted patients. METHODS: Sixteen patients with chronic atrial tachyarrhythmia and complete AV block were included. Left ventricular ejection fraction (LVEF) was > or =40% in ten and <40% in six. Patients were implanted with a standard DDDR pacemaker connected to two ventricular leads. A screw-in lead was placed at the RVOT and connected to the atrial port. A second lead was positioned at the RVA and connected to the ventricular port. Right ventricular outflow tract and RVA pacing was achieved by programming either the AAIR or the VVIR mode respectively. Four months later patients were randomized so as to undergo either RVOT or RVA pacing for three months according to a blind crossover protocol. Apart from the pacing mode, programming remained unchanged throughout the study. At the end of each period, NYHA class, LVEF, exercise time and maximal oxygen uptake were assessed. RESULTS: No significant difference was observed between the two modes for all the parameters analyzed. These identical results were observed in all patients globally, in patients with LVEF > or =40% as in those with LVEF <40%. CONCLUSIONS: Within the limits of this study, no symptomatic improvement or hemodynamic benefit was noted after three months of RVOT pacing, by comparison with RVA pacing.

Global left ventricular cardiac function: comparison between magnetic resonance imaging, radionuclide angiography, and contrast angiography.

RATIONALE AND OBJECTIVES: Cardiac magnetic resonance imaging (MRI) has been shown to be a robust and noninvasive method to assess left ventricular (LV) cardiac function. This study sought to assess volumes and mass calculated with MRI using fast techniques for acquisition and postprocessing, and to compare results in terms of cost-effectiveness with those of radionuclide angiography (RNA) or contrast angiography (CA). METHODS: Thirty-five patients and 15 healthy volunteers were studied. All patients underwent an MRI examination during the same period that they underwent ventriculography (26 patients) or radiography (25 patients). From 7 to 11 short-axis slices were acquired with a breath-hold fast-gradient echo-segmented sequence from apex to base. Contours were drawn with an automated border detection software. RESULTS: Ejection fraction (EF) correlated well between modalities (r = 0.77, P<0.001, for MRI and RNA; r = 0.72, P< 0.001, for MRI and CA). CONCLUSIONS: Cardiac MRI is a fast and accurate technique for estimation of LV volumes, EF, and mass.

[Use of radionuclide isotopes by cardiologists. Results of a French survey. Study group: "Nuclear Cardiology" of the French Society of Cardiology and the Society of Nuclear Medicine and Biophysics]. / Utilisation des isotopes par les cardiologues. Résultats de l'enquête française. Le groupe de travail "Cardiologie nucléaire" de la Société française de cardiologie et de la Société française de médecine nucléaire et biophysique.

The authors report the results of an enquiry carried out amongst French cardiologists to determine their opinion about radionuclide investigations in cardiological practice. Of the 5,050 cardiologists contacted, 1,431 (28.3%) replied. The cardiologists were attracted by the non-invasive nature (84%) of radionuclide techniques and their complementarity with other methods of investigation (74%) but regretted their cost (55%), their lick of availability in emergencies (35%) and, in general, their difficult of access (30%). Only 38% of the cardiologists who replied used radionuclide investigation on an everyday basis, this being impossible for some because of the distance to the nearest centre with these facilities (on average 32 km but exceeding 50 km in 29% of cases, and the delay before obtaining an appointment (average 13 days) which was often excessive, especially for myocardial scintigraphy (thallium or equivalent). Each cardiologist prescribed an average of 5 myocardial scintigraphies, 3 pulmonary scintigraphies and 2 radioisotopic ventriculography per month. These results seem to be an overestimation; in fact, radionuclide investigations are relatively underemployed, probably more because of the factors cited above than because of lack interest or quality, these latter two points being generally judged positively by the majority of cardiologists. Cardiologists require more from the conclusions of the investigation than a simple description of the images obtained. As with all other investigations that they perform themselves, the interpretation of the results must take the clinical context into consideration and form part of the diagnostic and therapeutic management of the patient.(ABSTRACT TRUNCATED AT 250 WORDS)

[Noninvasive methods in the diagnosis of post-infarction false aneurysm. Apropos of a case]. / Apport des méthodes non sanglantes au diagnostic de faux anévrysme post-infarctus. A propos d'un cas.

A case of post-aneurysm detected by chance in an asymptomatic 41 year old man, 3 months after acute infarction, and managed by surgery is reported. Although the aneurysm was too small to cause chest X-Ray changes, the parietal defect was clearly defined by isotopic angioscintigraphy, CAT scanning and M-mode echocardiography. The features of pseudo-aneurysms on CAT scanning are discussed. The value of M-mode echocardiography is confirmed, it alone giving the precise diagnosis through the demonstration of one dynamic sign: systolic expansion of the aneurysmal pocket on a tracing more suggestive of a localised pericardial effusion than of ventricular aneurysm. Early diagnosis by these non-invasive methods of investigation, requested as a result of some initial clinical abnormality, confirmed by angiography, may benefit some patients as the risk of secondary rupture may be avoided by surgical cure. The rarity of this condition is also under question due to the increasing number of reported cases.

[Relation between serum levels and inotropic effect of digoxin in advanced cardiac failure during long-term treatment]. / Relation taux sérique - effet inotrope de la digoxine dans l'insuffisance cardiaque avancée lors d'un traitement au long cours.

The aim of this study was to determine the relationship of digoxin serum levels to their inotropic effects in advanced cardiac failure during long-term therapy with different dosages. The study was based on the analysis of left ventricular systolic time intervals (STI) measured at 97 follow-up appointments of 20 patients in advanced, stable cardiac failure over an average period of 37 days. The dosage of digoxin was varied at successive consultations so that the serum digoxin levels reached 0.50 ng/ml on at least one occasion. The serum digoxin levels (SD) varied between 0 and 4 ng/ml. Four levels of SD were individualised: A) "control" SD less than 0.25 ng/ml (22 consultations); B) SD: 0.25 to 1 ng/ml (n = 25); C) SD: 1.0 to 2.0 ng/ml (n = 29); D) SD greater than 2 ng/ml (n = 21) including 6 cases with clinical and/or ECG signs of digoxin toxicity. A progressive significant shortening of the electromechanical systolic index (Q-S2 I) was observed up to levels of 2 ng/ml (B and C, -18 ms and -28 ms respectively). The same phenomenon was observed with the ejection time index (ETi) and pre-ejection time index (PETi) (-7 ms and -14 ms; -11 ms and -15 ms respectively) compared to the basal values. At SD greater than 2 ng/ml the reduction remained stable and then started to decrease (positive difference between C and D). These changes were observed in the absence of significant variations of the heart rate. There was a significant linear relationship between the variations of the STI and SD in 15 out of 18 patients (in whom the regression could be calculated, these patients having attended at least 3 appointments). These linear relationships were observed for the Q-S2 i (11-18), the ETi (9-18) and/or PETi (10-18). An unexpected increase in the pre-ejection period was observed in 2 patients. In conclusion, a linear relationship has been shown between SD and inotropic effect which is particularly noticeable at SD levels less than 2 ng/ml. When SD is greater than 2 ng/ml, further increases in SD are associated with smaller variations of the STI. On the other hand, a significant inotropic effect is observed with small doses and SD levels less than 1 ng/ml. This inotropic effect persists unchanged at long-term.

[Recanalization of chronic occlusions and myocardial infarction occurring during reocclusion. Apropos of 2 cases]. / Désobstruction des occlusions chroniques et survenue d'un infarctus lors de la réocclusion. A propos de deux observations.

Although recent techniques have significantly improved the frequency of disobliteration of chronic occlusions, the potential complications in terms of mortality, emergency bypass surgery and myocardial infarction seem as common as in angioplasty of stenosis. Of these complications, the occurrence of infarction during reocclusion at the site of angioplasty has not been described and even been refuted by some authors. We report two cases of acute infarction, one of which was transmural, occurring during late reocclusion after disobliteration of a chronically occluded artery.

[Reciprocal changes in the ST segment in acute inferior myocardial infarction. Value of delay in appearance]. / Modifications en miroir du segment ST dans l'infarctus myocardiques inférieur aigu. Importance du délai d'apparition.

The significance of a "reciprocal" ST depression (ST(-)) in the acute phase of myocardial infarction remains controverted. This may be due to ST(-) not having the same determinants when studied at an early stage (less than 6 hours) or later (greater than 6 hours). The purpose of this study was to find out whether "reciprocal" ST(-) correlates with the same parameters when measured on very early ECG's (before 6 hours) or at a distance from the onset of infarction. The parameters concerned are coronary lesions, extent of the infarction and left ventricular function. ECG was performed in 46 patients with inferior infarct aged from 26 to 70 years (mean 50.8 +/- 9.2 years) between 2-6 h, 6-12 h, 12-24 h and 24-48 h from the beginning of pain. The sum of ST(-) on V1V2V2V4 (V1-4), D1aV1V1 to V6 and L1aV1V5V6, and the sum of ST elevation on L2L3aVf were measured at each period of time. The extent of global and anterior territory hypokinesia, the ejection fraction and the left coronary impairment were evaluated between the 2nd and 4th weeks. At 2-6 hours (a) the sum of ST(-) was greater (though not significantly), and the sum of ST elevation on L2L3aVf was significantly greater (p less than 0.001) when the left anterior descending artery (LAD) was not involved than when it was involved; (b) there was no difference between patients with and without ST depression (on all lead groups) in the degree of left ventricular hypokinesia and ejection fraction value.(ABSTRACT TRUNCATED AT 250 WORDS)

[Right aortic arch with retro-esophageal component. 2 cases]. / Arc aortique droit avec segment rétro-oesophagien. A propos de 2 observations.

Right-sided aortic arch with a retro-oesophageal segment is much rarer than right-sided aortic arch without a retro-oesophageal segment. As opposed to the latter situation which is always associated with congenital heart disease, it is usually an isolated finding. The left subclavian artery arises from a posterior diverticulum and may be stenosed at its origin, giving rise to a systolic murmur as in one of the reported cases, or to a subclavian steal syndrome. The ligamentum arteriosum completes the aortic ring and may give rise to respiratory problems at varying ages and of variable severity, sometimes attributed to asthma. In one of the cases followed up over 15 years chronic respiratory problems and late tracheal lesions were observed. Although the possibility of a double aortic arch may be raised, early surgical treatment is desirable.

[Value of radionuclide ventriculography and magnetic resonance imaging in the diagnosis of constrictive pericarditis]. / Intérêt de la ventriculographie isotopique et de l'imagerie par résonance magnétique dans le diagnostic de péricardite constrictive.

In suggestive clinical presentations, the diagnosis of constrictive pericarditis is confirmed by the haemodynamic findings of impaired ventricular filling (diastole). In this study of 15 patients with pure constrictive pericarditis, the diagnosis value of two non-invasive techniques little used in this indication until now was examined: radionuclide ventriculography (RV) and magnetic resonance imaging (MRI). The RV provides a "functional" diagnosis through the analysis of global and segmental left ventricular filling whilst MRI provides anatomical details of the pericardial thickening. Diastolic dysfunction on RV presented as an increased early diastolic filling time as shown by a shortening of the interval to third filling T1/3R (p < 0.0001), an increased peak diastolic E wave velocity (p < 0.01) and early onset (p < 0.001), increased one third (FR 1/3) and mid (FR 1/2) diastolic filling fractions (p < 0.01) and of the E wave velocity to maximal systolic ejection velocity (S) ration (p < 0.01). The atrial contribution to filling in end diastole decreased (NS). Asynchronous filling, shown by dispersion of the times of onset of segmental early diastolic E peak velocities (delta tE) or of one third diastolic filling delta T1/3R, decreased. Seven patients underwent MRI. Pericardial thickening was present in all patients. The pericardium varied from 6 to 14 mm thick (normal 2.5 +/- 0.7 mm), without any systolo-diastolic variation. The thickening was seen as a dark low intensity signal, indicating the fibro-calcific character of the tissues. Sagittal and coronal views clearly demonstrated the non-uniformity of pericardial thickening.(ABSTRACT TRUNCATED AT 250 WORDS)

[Value of magnetic resonance imaging in cardiac sarcoidosis. Apropos of a case]. / Intérêt de l'imagerie par résonance magnétique dans la sarcoïdose cardique. A propos d'une observation.

The authors report the value of magnetic resonance imaging (MRI) in a case of cardiac sarcoidosis presenting with syncopal ventricular tachycardia (VT). The images were acquired in a monomorphic multiplane echo spin sequence. A 25 millisecond interval was chosen for the weighted T1 sequence. A second weighted T2 sequence using an interval of 70 milliseconds was then performed. The acquisitions were recorded in these planes axial, sagittal and coronal. The thickness of the sections was 8 mm. MRI was useful in locating the exact site and extent of the lesions; this enabled the operators to perform "guided" endomyocardial biopsies. In the weighted T1 sequences, these biopsies showed zones of increased intramyocardial signal density, more pronounced on the second weighted T2 sequences. Moreover, it was possible to follow up the outcome of these lesions with steroid therapy and observe their partial regression. These non-specific appearances may be observed in all inflammatory conditions but, in the context of systemic sarcoidosis, are very suggestive of cardiac involvement. In view of the clinical latency of cardiac sarcoidosis and its poor prognosis, the non-invasive character of MRI should make this a routine investigation in all patients with systemic sarcoidosis.

[Acute intravascular hemolysis after complete occlusion of a patent ductus arteriosus by detachable coils]. / Hémolyse intravasculaire aiguë après occlusion complète d'un canal artériel par coils détachables.

A case of acute intravascular haemolysis after complete occlusion of a patent ductus arteriosus by detachable coils in a 10 months old child is reported. The child had a patent ductus arteriosus, a small secundum atrial defect, mild valvular pulmonary stenosis, and stenosis of branches of the pulmonary artery not diagnosed before closure of the ductus. Haemolysis developed several hours after complete occlusion of the ductus by two detachable coils. The mechanism of the haemolysis was thought to be the presence of metallic spirals in the left pulmonary artery, just beyond stenosis situated at the origin of this artery. Simple balloon dilatation of the left pulmonary artery stenosis resulted in the complete regression of haemolysis.

[Isolated impairement of the regional filling of the left ventricle in the coronary patient with normal systolic function. A study by isotopic ventriculography during rest]. / Altérations isolées du remplissage segmentaire du ventricule gauche chez le coronarien à fonction systolique normale. Etude par ventriculographie isotopique au repos.

The aim of this study was to assess whether resting radionuclide angiography could detect isolated regional left ventricular filling abnormalities due to chronic ischemia. The authors studied global and regional (10 segments) variations of LV volume using an original computerised system in 29 patients with single vessel coronary artery disease and normal systolic function without any other known pathology which could have altered left ventricular filling. Purely diastolic regional wall abnormalities were detected in presumed ischemic territories in over 60% of patients. They were then observed mostly in early rather than late diastole and affected the chronological indices (time to 1/3 LV filling, or to peak early diastolic filling rate) more than those of velocity (peak E or A velocities) or volume (filling fraction at 1/3 and half-diastole or that due to atrial contraction). They suggested delayed relaxation in these regions. These segmental changes are associated with a significant increase in asynchronous filling as judged by the variation in the intervals to peak early diastolic filling (tE) (p less than 0.001) and to one third filling (T 1/3R) (p less than 0.02), in the absence of increased physiological asynchronous contraction. An inversed relationship was observed (p less than 0.01) between the global value of peak early diastolic velocity and the indices of early diastolic asynchronous filling tE (r = -0.48) and T1/3R (r = -0.54). As previously reported, these regional abnormalities are, however, generally too small to cause changes in global diastolic function.

[Cardiac angioscintigraphy at equilibrium coupled with isoproterenol perfusion. Method of diagnosing chronic coronary insufficiency]. / Angioscintigraphie cardiaque à l'équilibre couplée à la perfusion d'isoprotérénol. Méthode diagnostique de l'insuffisance coronaire chronique.

The effects of isoproterenol (IPNA) on global and regional left ventricular wall motion were studied by cardiac angioscintigraphy at equilibrium performed under basal conditions, during IPNA administration (per IPNA) and 10 minutes after (post IPNA) in 50 patients classified by coronary angiography as coronary (C) (n = 37) and non-coronary (NC) patients (n = 13), 5 reference subjects (REF) and 8 non-coronary pathology. The effects were assessed from variations of global LV function and from indices of regional wall function (12 regional ejection fractions - REF). The IPNA perfusion was well tolerated, even in patients with severe coronary lesions. 1. Diagnosis of myocardial dysfunction due to coronary artery disease: it was possible to separate the patients into C and NC groups according to the variations in EF, end systolic (ESV) and REF, especially post IPNA: NC group: per IPNA: 12/13 NC patients showed an increase in EF (+10.7%), a decrease in ESV (-41%) and increased or stable REFs. Post IPNA: 10/13 had raised EF (+4.6%), 9/13 had a reduced ESV (-17.4%) and 10/13 had stable or increased REF. C group: per IPNA: 15/37 C patients showed decreased EF, 12/37 had increased ESV and 15/37 had a decrease in at least two ref greater than or equal to 5%. Post IPNA: 25/37 had decreased EF, 21/37 increased ESV, 34/37 had at least two reduced REFs. These results show that decreased ref post IPNA (sensitivity 91.9%, specificity 66.9%) was a better indicator of coronary artery disease than VEF (sensitivity 68%, specificity 54%), increased ESV (sensitivity 57%, specificity 77%) or ECG changes (sensitivity 54%, p 0.05; specificity 91%, p less than 0.1). 2. Diagnosis of the extent of coronary artery disease: the post IPNA abnormal ref were situated in zones compatible with the coronary lesions: 10/13 single vessel disease (2 false negatives, 1 false localisation); 8/11 double vessel disease (1 false negative, 2 single vessel disease); 5/10 triple vessel disease (2 single vessel and 3 double vessel disease); 2/3 left main stem disease (1 single vessel disease). The study of REF demonstrated at least 2 diseased zones in 15/24 patients with multiple diseased vessels. Independently, the diagnosis of multivessel disease may be suspected by the fall in EF per IPNA (4/13 single vessel cases compared to 11/24 multivessel disease) and, more generally, by the fact that the EF and ZSV per and post IPNA appear more pathological with respect to the reference group when the coronary lesions are most diffuse.(ABSTRACT TRUNCATED AT 400 WORDS)

[Determination of left ventricular volume by cardiac angio-scintigraphy at equilibrium. Comparison with a radiologic method]. / Détermination des volumes ventriculaires gauches par angio-scintigraphie cardiaque à l'équilibre. Confrontation à la méthode radiologique.

Cardiac angioscintigraphy at equilibrium was performed after in vitro red cell labelling in the left anterior oblique and anterior views. A syringe of 10 ml labelled blood was placed on the patient's chest over the left ventricle and in contact with the camera's collimator in the LAO incidence. This syringe plays a dual part: as a direct reference for left ventricular radio-activity and as a marker for measuring the distance between the centre of gravity of the LV and the collimator by Links' method. The correction factor for absorption varies with each individual. An algorithm integrating this data automatically calculates the EDV in millilitres (ml) and the end diastolic and systolic volumes from the ejection fraction (EF) determined by an independent method. The study group was 100 patients (91 men, 9 women; 81 coronary, 11 valvular heart and 8 other diseases) with radiological EDV ranging from 107 to 1 283 ml and radiological EF ranging from 14 to 75 p. 100. A very significant correlation was observed between the radiological and scintigraphic EDV with a regression line close to that of identity: EDVs = 1.05 . EDVR-5 ml (or -3 ml/m2); SD = 48 ml; r = 0.953; p less than or equal to 0.001. The mean deviation between the methods was 35.7 ml (median 24 ml) or 13.7 p. 100 (median 9.4 p. 100) of EDVR. A large discrepancy (over 90 ml or 30 p. 100) was observed in only 7 patients, 4 of whom had severe mitral regurgitation.(ABSTRACT TRUNCATED AT 250 WORDS)

[Corrected transposition of the great vessels in aged adults. Apropos of 2 patients aged 72 and 80]. / Transposition corrigée des gros vaisseaux de l'adulte âgé. A propos de deux patients âgés de 72 et 80 ans.

The authors report two unusual new cases of corrected transposition of the great arteries diagnosed in patients 72 and 80 years of age respectively, presenting with symptoms of cardiac failure of recent onset. Both patients had mild or moderate regurgitation of the systemic atrio-ventricular valve, associated in one case with aortic regurgitation. This association would appear to be fortuitous although already reported in six occasions. The diagnosis was made by echocardiography and confirmed by catheterisation in one case, and by digitised intravenous angiography in the other. These cases are of interest for three reasons: They are very rare: there have been only 20 comparable cases reported in patients over 40 years of age, the eldest being 73. This is probably explained by the high frequency of associated malformations. They illustrate the decisive role of echocardiography in the diagnosis of congenital heart disease, even in the adult. They constitute a "natural experimental model" of a right ventricle submitted to systemic pressures and tend to show that, in the absence of other abnormalities giving rise to an additional pressure or volume overload, the right ventricle is capable of long term adaptation to this situation. These observations indicate a favourable long-term prognosis for children who have undergone "corrective" surgery at atrial level for simple transposition and in whom the right ventricle is required to assume the function of the systemic ventricle for the rest of their life.

[Results of radiofrequency ablation of the atrioventricular junction in patients with refractory atrial arrhythmia and severe impairment of the left ventricular systolic function]. / Résultats de l'ablation de la jonction auriculoventriculaire par radiofréquence chez des patients en arythmie auriculaire réfractaire présentant une altération sévère de la fonction systolique ventriculaire gauche.

Results of radiofrequency ablation of the atrioventricular junction on functional capacity and left ventricular systolic function were assessed in 8 patients (aged 68 +/- 12 years) with refractory atrial fibrillation and severe left ventricular dysfunction, the mean ejection fraction being 31 +/- 11% (range: 20-48%). A clinical, echocardiographic and angioscintigraphic follow-up was performed 24 hours (basal), 3 and 6 months after the procedure. During follow-up, all patients reported the disappearance of palpitations and tiredness, a significant and early regression of effort dyspnoea from average NYHA Class 3.4 +/- 0.7 to 2.2 +/- 0.4 (M3), (p < 0.01), a decrease in end diastolic echocardiographic dimensions (from 57 +/- 10 to 52 +/- 9 mm (M3); p < 0.05) resulting in an increase in fractional shortening from 26 +/- 7% to 34 +/- 6%; p < 0.05. The isotopic EF increased from 31 +/- 11% to 42 +/- 12% (M3) (p < 0.01), and attained 48 +/- 12% (M6). This study shows that controlling the frequency and regularity of cardiac rhythm by ablation of the atrioventricular junction in patients with refractory AF and left ventricular dysfunction results in functional and haemodynamic improvement, especially when there is no apparent underlying cardiac disease. This suggests that this method should be proposed in all patients with refractory atrial fibrillation and left ventricular dysfunction.

[Thallium 201 myocardial scintigraphy and left branch block. Comparative value of exercise test and dipyridamole test]. / Scintigraphie myocardique au thallium 201 et bloc de branche gauche. Intérêt comparé de l'épreuve d'effort et de l'épreuve au dipyridamole.

Stress Thallium 201 myocardial scintigraphy in patients with left bundle branch block often shows reversible septal perfusion defects even in the absence of coronary artery disease. This phenomenon seems more common when the patients have tachycardia. With the working hypothesis that dipyridamole stress testing, which does not greatly increase the heart rate, would be more appropriate than exercise stress testing to unmask coronary artery disease in this condition, the authors compared the results of two Thallium 201 scintigraphies performed after exercise and then after dipyridamole under the same conditions three weeks later, in 67 patients with complete left bundle branch block. Scintigraphy showed one or more reversible perfusion defects in 64/67 patients after exercise but only 32/67 patients after dipyridamole (p < 0.001). There was poor uptake in the septal region in 59 patients (88%) after exercise and in 25 patients (37%) after dipyridamole (p < 0.001). The specificity was evaluated in 23 patients estimated to have no coronary artery disease. If only unequi vocal perfusion defects were considered, the specificity after dipyridamole was higher than that after exercise, increasing from: 35% to 83% for septal defects (p < 0.01); 65% to 96% for anterior wall defects (p < 0.05); 61% to 87% for inferior wall defects (p < 0.05); 57% to 91% for apical defects (p < 0.01); 17% to 83% overall (p < 0.001). Lower values but with a comparable difference were observed when all forms of hypofixation (even minimal) were taken into account.(ABSTRACT TRUNCATED AT 250 WORDS)

[Variations of coronary blood flow measured by intracoronary doppler in the acute phase of myocardial infarction before and after revascularization by angioplasty]. / Variations du flux sanguin coronaire mesuré par doppler intracoronaire à la phase aiguë de l'infarctus du myocarde avant et après revascularisation par angioplastie.

The authors studied the changes in coronary blood flow before, during and after reperfusion by angioplasty of the disease coronary vessel responsible for myocardial infarction using intracoronary Doppler. Forty patients aged 60.2 +/- 15.4 years, admitted for primary myocardial infarction (inferior: 22, anterior: 18) were included. Before reperfusion, the peak velocity of the collateral coronary circulation was 14.8 +/- 8.1 cm/s. The flow was bidirectional, mainly retrograde (N = 32), negative (N = 1) or positive (N = 5). The five Rentrop 0 patients had velocities similar to Rentrop 1, 2 or 3 patients (Rentrop 0: 14.9 +/- 6.4 cm/s; Rentrop 1: 12.3 +/- 9.9 cm/s; Rentrop 2: 15.2 +/- 8.2 cm/s; Rentrop 3: 17.5 +/- 6.3 cm/s). Patients with TIMI 3 reperfusion flow had the highest APV Doppler velocities (average peak velocities during the cardiac cycle) (APV TIMI 3 = 20.2 cm/s versus APV TIMI 1 and 2 = 10.9 cm/s, p = 0.05). After angioplasty, the APV was 18.7 +/- 10.4 cm/s (p < 0.001). Diastolic flow was dominant. Seventeen patients had retrograde systolic flow, 12 had minimal systolic flow and 17 had a steep diastolic deceleration slope. Intracoronary Doppler demonstrates the wide range of coronary flow in TIMI 3 flow patients, both from the morphological and the quantitative points of view, which seems to be independent of the presence of residual stenosis and could be related to abnormalities of the microcirculation. This could allow identification of a subgroup of patients at high risk and candidates for a complementary therapeutic intervention (intra-aortic balloon pumping...).