[Plasma homocysteine is not a predictive factor of restenosis after coronary angioplasty]. / Le dosage plasmatique de l'homocystéine n'est pas un facteur prédictif de resténose après angioplastie coronaire.

Hyper-homocysteinaemia is a cardiovascular risk factor. In parallel, anatomopathological studies of post-angioplasty coronary restenosis show histological appearances similar to those observed in patients with severe hyper-homocysteinaemia. Based on these histological observations, the authors tried to assess the predictive value of raised plasma homocysteine levels for coronary restenosis after angioplasty. Two hundred and twenty-two patients treated by coronary angioplasty were followed up clinically for 6 months. Thallium 201 myocardial scintigraphy was performed in 179 patients and coronary angiography in 74 patients. Seventy-nine patients had coronary restenosis diagnosed by coronary angiography in 55 cases, by myocardial scintigraphy in 23 cases and strongly suspected clinically in only one patient. No significant differences in homocysteine levels were observed between patients with multiple restenosis or requiring revascularisation, and those without restenosis and not requiring revascularisation. Plasma homocysteine does not therefore seem to be a predictive factor of post-angioplasty coronary restenosis.

[MRI quantification of regional variations of left ventricular parietal stress in normal subjects]. / Quantification par imagerie par résonance magnétique des variations régionales de la contrainte pariétale du ventricule gauche chez le sujet normal.

The object of this study was to analyse regional variations in end systolic left ventricular wall stress in normal subjects using three-dimensional magnetic resonance imaging (MRI) with excellent spatial resolution. Eight to 12 contiguous short axis sections of the left ventricle were acquired from the apex to the base in apnoea with a rapid echo-gradient sequence in 15 healthy volunteers. The end systolic wall stress was calculated by three methods: Grossman's formula (CR) using the wall thickness and radius of curvature, Janz's formula (CS) using the surfaces, and a three-dimensional approach (C3D) providing a precise calculation of the radius of curvature. The values of wall stress obtained by CS and CR were lower (p < 0.001) at the apex (3.2 and 3.3 10(3) newton/m2 respectively) than at the base (6.9 and 7.1 10(3) newton/m2). There was no difference between the base and apex with the C3D method (8.0 and 9.0 10(3) newton/m2 respectively, NS). The same results were observed at the inferior, lateral, anterior and septal segments with an increase at the base using the CS and CR formulae, the C3D remaining homogeneous in the left ventricle except for the interventricular septum. The lateral wall stress was significantly lower with respect to the interventricular septum in all sections from the apex to the base, irrespective of the method of calculation used. The differences in regional wall stress from the base to the apex reported in healthy subjects seem to be related to an underestimation of left ventricular wall thickness and an underestimation of the radius of curvature rather than to a physiological phenomenon.

Regional assessment of wall curvature and wall stress in left ventricle with magnetic resonance imaging.

Left ventricular functional abnormalities are associated with regional increases of wall stress and modifications of wall curvature. This study describes the integration of the short-axis and long-axis wall curvatures for determining peak systolic wall stress. Quantification was realized with cine magnetic resonance imaging (MRI) from the location of the endocardial and epicardial borders of the left ventricle on pairs of consecutive short-axis sections. Fifteen normal volunteers were subjected to cine MRI, and different methods of calculating peak systolic wall stress were compared. A short-axis analysis showed a 55 +/- 13% increase of the circumferential mean of the peak systolic wall stress between apical and basal sections. Regarding the curvature, no significant increase of wall stress was observed except on the septal wall (31 +/- 18%). Short-axis studies proved to be insufficient for determining the regional variations of left ventricular wall stress and for providing normal reference values for the location of abnormal regions in patients.

Three-dimensional coronary artery MR imaging using prospective real-time respiratory navigator and linear phase shift processing: comparison with conventional coronary angiography.

Respiratory gating with navigator echo is a recent technique to detect diaphragm position in 3D magnetic resonance (MR) coronary angiography. The purpose of our study was to image proximal coronary arteries and to detect significant stenoses in patients with coronary artery diseases and to compare with contrast enhanced angiography results. Twenty patients with coronary artery diseases who were referred for conventional angiography underwent magnetic resonance angiography (MRA). Three-dimensional gradient echo volumes were acquired using cardiac and respiratory gating and fat suppression. Using reformatted oblique planes and maximum intensity projection technique, visualization coronary segments and detection of significant coronary stenoses were made. Eighty-three coronary segments were analyzed. The sensitivity and specificity were 65% and 93%, respectively. The corresponding positive and negative predictive values were 69% and 91%. This study shows the ability to image correctly coronary arteries and to identify proximal stenoses, but image quality need to be improved for an efficiency detection of coronary artery stenoses in clinical practice.

[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...).

Noninvasive assessment of the infarct-related coronary artery blood flow velocity using phase-contrast magnetic resonance imaging after coronary angioplasty.

This study assesses infarct-related coronary artery blood flow velocity using phase-contrast magnetic resonance imaging (MRI) in patients with reperfused acute myocardial infarction (AMI) and compares these results with flow measurements obtained nonsimultaneously by intracoronary Doppler ultrasound. MRI examination was performed in 17 patients with AMI within 1 to 4 days (mean 2.5 days) after direct or rescue coronary angioplasty using a 0.014-in Doppler guidewire. MRI was performed on a 1.5-T clinical imager. The fast gradient echo segmented k-space phase-contrast pulse sequence was employed during breath-hold. The MRI and Doppler parameters of average peak velocity and maximum peak velocity were measured. Mean phase contrast MRI average peak velocity was 13.3+/-10.7 cm/s, and mean phase-contrast MRI maximum peak velocity was 27+/-16.6 cm/s. Mean Doppler average peak velocity was 17.1+/-5.1 cm/s, and mean Doppler maximum peak velocity was 35.5+/-10.1 cm/s. At the same anatomic levels, phase-contrast MRI average peak velocity correlated significantly to Doppler average peak velocity (r = 0.52; p<0.006) and Doppler maximum peak velocity (r = 0.42; p<0.03). Phase-contrast MRI velocity measurements were correlated with the same heterogeneity of Thrombolysis In Myocardial Infarction 3 flow velocity observed during Doppler examination. Thus, by comparing phase-contrast MRI with invasive intracoronary Doppler flow measurements, the measured MRI values showed significant correlation with Doppler data. Phase-contrast MRI has the potential to noninvasively quantify coronary flow velocity and to evaluate quality of reperfusion in patients with AMI after reperfused therapy.

Cerebral hemodynamics during carotid massage in patients with carotid sinus syndrome.

The effect of cardioinhibition and/or vasodepression on cerebral hemodynamics assessed by transcranial Doppler has been investigated during carotid massage in 11 patients (62-87 years, mean age 72) with carotid sinus syndrome. The patients were tested in the OOO mode (n = 11) with six tested in the DDD mode. Carotid massage in the OOO mode decreased mean arterial pressure by 44% (P < 0.01) and mean cerebral blood flow velocity by 50% (P < 0.01). Although not significant, cerebrovascular resistance increased transiently by 17% during massage, then decreased by 31% upon recovery. Carotid massage in the DDD mode decreased arterial pressure by 30% (P < 0.01), cerebral blood velocity by 23% (P < 0.01), and resistance by 15% (P < 0.05). The decreased cerebral perfusion induced by cardioinhibition and/or vasodepression results from the delayed onset of cerebral autoregulation. Pacing in the DDD mode temporarily assists the critical period preceding the onset of cerebral autoregulation that plays a key role in preventing the deleterious effects of vasodepression.

Experimental validation of an automated edge-detection method for a simultaneous determination of the endocardial and epicardial borders in short-axis cardiac MR images: application in normal volunteers.

The goal of this study was to put together several techniques of image segmentation to provide a reliable assessment of the left ventricular mass with short-axis cardiac MR images. No initial manual input was required for this process based on region growing, gradient detection, and adaptive thresholding. A comparison between actual mass and automatic assessment was implemented with 9 minipigs that underwent spin-echo MR imaging. Fifteen normal volunteers were studied with a fast-gradient-echo sequence. The automatic segmentation was then controlled by three trained observers. Actual mass and automatic segmentation were strongly correlated (r = .97 with P < .01). For normal volunteers, the standard error of estimation of the automatic assessment (12 g) compared well with the average myocardial mass (120 +/- 30 g) and the interobserver reproducibility of the manual assessment (9 g). These results allow the application of this method to the quantification of the left ventricular function and mass in clinical practice.

[Measurement of the left ventricular mass using MRI with automatic determination of the endocardial and epicardial contours]. / Mesure de la masse ventriculaire gauche en IRM par détermination automatique des contours endocardiques et épicardiques.

This study describes a method of automatic border detection of the left ventricular endocardium and epicardium associating three methods of segmentation (increase of region, border detection and adaptive threshold), applicable to the evaluation of ventricular mass and volume by magnetic resonance imaging. Despite slight underestimation, the spin-echo sequence used in 9 small pigs provided a value of left ventricular mass close to that observed ex vivo (r = 0.97, SEE = 6.05 g). Clinical validation using a rapid gradient-echo sequence was undertaken and compared with manual border detection carried out by three independent, trained operators. The study population included healthy subjects and patients with global or segmental left ventricular dysfunction with or without ventricular deformation. The correlations between automatic and manual detection were satisfactory both for calculation of left ventricular mass (r = 0.93, SEE = 13 g) and measurement of surfaces (r = 0.91, SEE = 1.4 cm2). The concordance of the two methods was confirmed by the Bland and Altman test. Cardiac magnetic resonance imaging may provide accurate and reproducible measurements of left ventricular mass within acceptable acquisition and image processing times for routine use. Although the clinical value of such a method is accepted both for establishing the prognosis and guiding management, studies of the cost/efficacy ratio should be undertaken to situate magnetic resonance imaging with respect to other non-invasive techniques of investigation of left ventricular function.

[Plasma noradrenaline and the prognosis of chronic cardiac failure: a multicenter study]. / Importance de la noradrénaline plasmatique pour l'évaluation pronostique de l'insuffisance cardiaque chronique. Etude multicentrique.

Plasma noradrenaline is little used in evaluating the prognosis of cardiac failure because of the theoretical necessity of interrupting treatment for a few days before blood sampling. The present study reevaluated the prognostic value of this parameter with blood sampling performed during treatment and then 48 hours after withdrawal of treatment in 192 patients with chronic stable cardiac failure at an advanced stage (64% of patients in Classes III or IV with an average ejection fraction of 28.5 +/- 13.5%). During follow-up (average 43 months) there were 51 deaths and 17 transplants. None of the patients were lost to follow-up. Univariate analysis of 52 variable observers during the initial phase of evaluation found in decreasing order of predictive value for death plasma noradrenaline levels before and after withdrawal of treatment for 48 hours. Serum sodium, age, systolic mean and diastolic pulmonary artery pressures. In multivariate analysis: noradrenaline with or without withdrawal of treatment, hyponatraemia and systolic pulmonary artery pressure. Actuarial survival curves distinguished the following parameters: noradrenaline levels became predictive at concentrations of over 210 pg/mL and there was a significant difference in survival with respect to 4 levels of serum noradrenaline (with or without treatment) > 300 pg/mL, 300 to 600 pg/mL and > 900 pg/mL. This serum noradrenaline measured without withdrawal of treatment (especially angiotensin converting enzyme inhibitors) is a powerful predictor of mortality, carrying a progressively poorer prognosis as the concentration increases.

Simultaneous and correlated detection of endocardial and epicardial borders on short-axis MR images for the measurement of left ventricular mass.

A method was developed for fast, reproducible assessment of left ventricular mass with detection of the endocardial and epicardial borders. The method makes use of short-axis magnetic resonance (MR) imaging in conjunction with an integrated segmentation approach that includes region growing, edge detection, and adaptive thresholding. The mass of the left ventricle in nine Yucatan minipigs was measured ex vivo and compared with the mass as determined in vivo with both full automated segmentation and an interactive process involving two trained observers. The test sample consisted of 59 sections obtained during diastole. There was good correlation between actual mass and both automatically and manually assessed mass. Linear regression analysis showed that the difference between ex vivo measurement and automatic mass assessment (standard error of estimation [SEE] = 5 g) was similar to interobserver variability in interactive mass assessment (SEE = 4 g). Mass assessment with short-axis MR imaging and an integrated segmentation approach does not require location of the ventricular cavity and allows precise delineation of the endocardial and epicardial borders. The results of this experimental study are encouraging for the potential use of this technique in clinical cardiac functional analyses.

[Value of MRI with injection of gadolinium in the diagnosis of mitral ring abscess. Apropos of a case]. / Apport de I'IRM avec injection de gadolinium dans le diagnostic d'abcès de l'anneau mitral. A propos d'une observation.

Transoesophageal echocardiography is the investigation of choice for the diagnosis of valvular vegetations in infectious endocarditis but the diagnosis of an associated ring abscess is sometimes difficult especially in patients with valvular prostheses or calcifications which are in important source of artefacts. The authors report a case of mitral annular abscess confirmed at surgery and comment on the diagnostic and prognostic value of cardiac MRI. MRI showed an abnormal cavity directly related to the mitral annulus and separated from the left ventricle by a low intensity signal which increased after injection of gadolinium suggesting an inflammatory origin and therefore arising from the abscess. The cavity was heterogeneous in T1 associating zones of low intensity with high intensity signals increasing in T2 on the second echo (thrombus and necrosis). Cine-MRI showed non communication between the abscess cavity and the left ventricle or atrium.

[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.

[Is the presence of right ventricular high intensity signals sufficient for the diagnosis of right ventricular dysplasia?]. / La présence d'hypersignaux ventriculaires droits est-elle suffisante pour le diagnostic de dysplasie ventriculaire droite?

The aim of this study was to assess "morphological" MRI data (spin-echo) compared with cine-MRI in 10 patients with documented right ventricular dysplasia and 10 normal controls. Data was acquired with a 0.5 Tesla superconductor magnet associating sequences of spin-echo and gradient echo (cine-MRI). An abnormal high intensity signal was observed in spin-echo in 9 out of the 10 patients. They were present on the anterior and sub-tricuspid walls of the right ventricle (8/10) and in the pulmonary infundibulum (8/10). A dyskinetic zone corresponding to the abnormal signals was detected in 8 patients. In the control group, only one subject had an abnormal high intensity signal and no dyskinesis could be detected. The association of high intensity signals and dyskinesis would seem to be very specific of right ventricular dysplasia. On the other hand, a high intensity signal alone may be observed in apparently normal subjects and would seem to be less specific.

[Value of thyroidectomy in amiodarone-induced hyperthyroidism. Apropos of 3 cases]. / Intérêt de la thyroïdectomie dans les hyperthyroïdies induites par l'amiodarone. A propos de 3 cas.

Amiodarone-induced hyperthyroidism in a relatively rare complication of long-term treatment with this molecule. It usually carries a good prognosis with regression being the rule after withdrawal of the drug although lethal forms have been reported. Conventional medical therapy (synthetic antithyroid drugs, steroids, betablockers) used in severe forms, is not always effective. In addition, amiodarone may be essential for the treatment of life-threatening, poorly tolerated arrhythmias, refractory to other forms of treatment. The authors report the cases of three patients treated with amiodarone for malignant arrhythmias who developed severe hyperthyroidism resistant to medical therapy and who were treated by total thyroidectomy. Surgery was followed by rapid resolution of the thyrotoxicosis without significant complications and immediate represcription of amiodarone. Thyroidectomy therefore seems a simple solution for amiodarone-induced hyperthyroidism allowing very rapid resolution of the hyperthyroidism and the possibility of immediate represcription of amiodarone.

[Increase of sialic acid concentration in the plasma of patients with coronary disease]. / Augmentation de la concentration d'acide sialique dans le plasma de malades atteints de coronaropathies.

OBJECTIVES: Plasma levels of sialic acid are elevated in patients with coronary heart disease. We evaluated the specificity of this increase and attempted to correlate it with the severity of coronary lesions. METHODS: Total plasma sialic acid levels measured in 60 control subjects were compared with that in 135 patients with heart disease requiring coronarography. RESULTS: Plasma levels of sialic acid were significantly higher in patients (664 +/- 146 mg/l) than in controls (584 +/- 100 mg/l). In the group of patients, sialic acid level was only increased in those with coronary lesions - infarcts (738 +/- 166 mg/l) and angina (664 +/- 121 mg/l) - but was not raised above normal levels in those with other heart diseases (cardiomyopathy, valve failure, etc.). There was a positive correlation (p < 0.001) between raised sialic acid level and the severity of the coronary lesions as measured on coronarography. CONCLUSIONS: The elevated level of sialic acid in patients with coronary heart disease could be related to disorders in cell adhesion.

Radionuclide angiography and magnetic resonance imaging: complementary non-invasive methods in the diagnosis of constrictive pericarditis.

Constrictive pericarditis presents with a suggestive clinical picture, and its diagnosis is based on a haemodynamic pattern revealing impaired ventricular filling. In this study of 15 patients with pure isolated constrictive pericarditis, we attempted to evaluate the diagnostic value of two non-invasive methods not usually employed in this indication: radionuclide angiography (RNA) and magnetic resonance imaging (MRI). Whilst RNA permits analysis of the functional pattern of the global and segmental left ventricular filling impairment, MRI allows measurement of the thickness of the pericardium. RNA revealed increased early diastolic filling as evidenced by a shorter one-third filling time (TF1/3; P<0.0001 with respect to a normal population), a higher peak filling rate (PFR; P<0.01) and its early occurrence (P<0.001), increased one-third and mid diastolic filling fractions (P<0.01), and the ratio of the PFR over the peak ejection rate (P<0.01). During late diastole, the atrial filling fraction decreased (NS). The patients with constrictive pericarditis also showed a decrease in the physiological filling asynchrony, as assessed by segmental evaluations. Seven patients underwent MRI. The pericardium was thickened in all the patients, varying from 6 to 14 mm (normal: 2.5+/-0.7 mm), without any systolo-diastolic variation. Pericardial thickening appeared as a dark low-intensity signal band, demonstrating the fibrocalcific nature of the pericardial contents. Sagittal and coronal cross-sections were particularly well-suited to show the non-uniformity of the pericardial thickening. These results indicate that RNA and MRI are complementary non-invasive methods, and can provide the functional and anatomical information required for the diagnosis of constrictive pericarditis.

[Electrophysiological study for the diagnosis and prognosis of syncope of unknown origin]. / Exploration électrophysiologique pour le diagnostic et le pronostic des syncopes de cause indéterminée.

OBJECTIVE: To evaluate, on the basis of long-term outcome, the value of electrophysiologic exploration for determining the cause of syncope of unknown origin after clinical examination and standard laboratory tests. METHODS: In 1985 and 1986, 109 consecutive patients with syncope of unknown origin underwent electrophysiologic exploration. The patients were divided into two groups. Baseline electrocardiogram was abnormal in 59 patients: cardiopathy (32%), ischemia (17%). In 44 of these patients, electrophysiologic exploration revealed major abnormalities requiring treatment (Group 1). No aetiology could be defined in 65 patients (Group 2). Patients were followed for 37 +/- 11 months. Three were lost to follow-up and 106 were retained for analysis. RESULTS: Morbidity and mortality were 25% and 16% respectively at the end of follow-up. Two sudden deaths were recorded, both in Group 1. Total mortality was greater in Group 1 (10 vs 6) so electrophysiologic exploration had defined a population at lower risk of sudden death and overall mortality. Relapse of syncope was observed in 27 patients (25% and 26% in Groups 1 and 2 respectively) due to rhythm disorders in 8, vasodepression in 1 and unknown origin in 18. CONCLUSION: The rate of recurrent syncope suggests these patients should have a second work-up in order to diagnose initially false negatives. Relapse raises the problem of electrophysiologic abnormalities and multifactorial mechanisms causing syncope of unknown origin.

[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.