Chirurgie cardiaque chez le nouveau-né et le nourrisson

During the past five years, 127 newborn infants with marked anoxia, severe cardiac failure or respiratory problems secondary to a cardiac lesion were operated upon at l''Hôpital Ste-Justine, Montreal, Quebec.Infants in cardiorespiratory distress from a cardiac lesion for which the surgical treatment is well established, such as complicated coarctation of the aorta, were either cured or improved in 78% of cases. The fatal outcome following medical treatment of patients suffering from lesions for which the surgical treatment is not yet well established, e.g. interruption of the aortic arch, led us to operate upon these infants with the hope of salvaging some of them despite the high surgical risk.The decision to operate was usually based on clinical grounds; however, cine-angiocardiography was at times required to establish the exact diagnosis. Light anesthesia was essential to the success of the operation. Postoperative care was facilitated by a team of nurses well experienced in the treatment of newborn subjects with heart lesions. Fluids were administered in a minimum quantity of 700 c.c./m.² for 24 hours, and potassium was the only electrolyte added to the replacement fluids. Respiratory problems were reduced to a minimum by active physiotherapy. However, intubation with aspiration of tracheobronchial secretions was carried out when necessary.     

Scintigraphie cardiaque à la 123I-métaiodobenzylguanidine et cardiomyopathies : « le retour »: (Insuffisance cardiaque et scintigraphie à la 123I-MIBG)

Congestive heart failure is a often associated with an impairment of sympathetic nervous system, i.e., global hyperactivity and regional impairment of adrenergic system. Cardiac 123I-métaiodobenzylguanidine (MIBG) scintigraphy is a radionuclide technique which can explore the presynaptic adrenergic function. Cardiac fixation of MIBG is decreased in congestive heart failure, reflecting a reduction of norepinephrine uptake by the myocardial presynaptic ending nerves. The impairment of presynaptic function is early and actually involved in the pathogenesis of cardiac failure. Cardiac MIBG scintigraphy is a useful tool to explore the myocardial adrenergic stores in patients with congestive heart failure.     

Asynchronisme cardiaque chez le sujet à QRS fin. Étude par échocardiographie Doppler tissulaire

ObjectiveTo assess the prevalence of different types of cardiac dyssynchrony by pulsed Doppler ultrasound and Doppler tissue in patients with narrow QRS with or without left ventricular systolic dysfunction.MethodologyProspective, cross-sectional survey at the Institute of Cardiology of Abidjan, from January to April 2012, in subjects with narrow QRS. Group 1: patients with dilated cardiomyopathy with severe left ventricular dysfunction (left ventricular end diastolic diameter greater than 60 mm and/or 30 mm/m² and ejection fraction less than 35% NYHA stage IV). Group 2: normal subjects with normal echocardiography. All patients underwent an evaluation including tissue Doppler search for different types of dyssynchrony (atrioventricular, interventricular and left intraventricular).ResultsPatients in group 1 were significantly older (51.5 ± 15.8 vs. 35.8 ± 7.8, P = 0.03), with larger left ventricular diameters and significantly higher pulmonary systolic pressure. The prevalence of different types of dyssynchrony in group 1 were: atrioventricular dyssynchrony 43.7%, interventricular dyssynchrony 37.5%, left ventricular dyssynchrony 65.6%. Group 2: atrioventricular dyssynchrony 0%, interventricular dyssynchrony 0%, left ventricular dyssynchrony 35%.ConclusionA large proportion of patients with left ventricular systolic dysfunction and narrow QRS have cardiac dyssynchrony and left ventricular dyssynchrony can be found in healthy patients. This raises the problem of the specificity of Doppler ultrasound criteria using cardiac tissue Doppler to assess cardiac dyssynchrony.     

Le BNP dans l’exploration de l’insuffisance cardiaque et le syndrome coronarien aigu

Le BNP, ou “Brain Natriuretic Peptide”, initialement mis en évidence au niveau de l’encéphale de porc, est aujourd’hui renommé “B-type natriuretic peptide” en raison de l’origine myocardique chez l’homme. Sa synthèse, principalement réalisée au niveau du ventricule gauche, à partir d’une pro-hormone, le Pro-BNP, est liée à l’état d’étirement de la paroi ventriculaire.     

Effets immédiats du dimenhydrinate sur la contraction utérine e le rythme cardiaque foetal durant le travail.

The effects of intravenous administration of 100 mg of dimenhydrinate (Gravol) were studied in 20 patients during active spontaneous labour. The uterine activity and the fetal heart rate were monitored by an invasive technique. After administration of the medication the uterine activity increases significantly, and in 20% of the cases decelerations in the fetal heart rate of the hypoxic type occurred. Because of its unpredictable effects, this drug should be used with care during labour.     

Communication interventriculaire avec défaillance cardiaque chez le nouveau-né et le nourrisson: Evaluation du traitement médical

Twenty-seven infants with ventricular septal defects and in cardiac failure were followed regularly under medical treatment for an average period of 17 months. The diagnosis was proved in all cases by cardiac catheterization.At the end of the follow-up period, the patients could be classified as follows: Sixteen patients showed no change in their cardiovascular status, and six had signs of pulmonary infundibular stenosis. One child had died from bronchopneumonia. Another was classified as having probable functional closure of the defect. Finally, three other children, because of failure of medical treatment, underwent banding of the pulmonary artery. One died during the operation.It is concluded that the great majority of patients with ventricular septal defects and cardiac failure can be carried successfully under medical management until the age at which corrective surgery is feasible. Palliative procedures which in themselves carry a fairly high mortality risk should be used only as a last resort.     

Amélioration de l’estimation du rythme cardiaque fœtal en utilisant les signaux Doppler directionnels et YIN

Techniques dedicated to the fetal heart rate detection identify the patterns that repeat themselves over the time. The heart rate estimation is algorithmically similar to the estimation of the fundamental frequency (pitch) of voice signals. The new YIN technique introduced for the estimation of the fundamental frequency is applied to fetal heart rate estimation from the directional Doppler signals. We compare the performances in terms of probability of detection and accuracy of the estimation of the technique YIN with those of the cross-correlation, implemented in the Oxford SONICAID? monitors. A better detection probability and accuracy of estimation of fetal heart rate was obtained in case of YIN.     

Comparaison des taux de BNP et NT-proBNP chez des patients insuffisants rénaux pour prévenir l’insuffisance cardiaque

Background

The aim of the study was to compare the performances of BNP and NT-proBNP for diagnosing heart failure (HF) in a population of patients with high incidence of chronic renal insufficiency (CRI, plasma creatinine > 1.5 mg/dl).

Patients and methods

Ninety-eight patients were included in this study. BNP and NT-proBNP determinations were performed by an immunofluorescent assay (Biosite®) and by an electrochemiluminescence sandwich immuno assay (Roche Diagnostic®), respectively.

Results and discussion

BNP and NTproBNP level are correlated in CRI and non CRI. Both assays are useful to rule out CRI pts suspected of HF. However, in renal failure pts, higher decision limits should be used for improving the positive predictive value of the assays.     

Profil évolutif de la dénervation cardiaque sympathique dans l’amylose héréditaire à transthyrétine

IntroductionCardiac amyloidosis is a rare disease with poor prognosis, requiring an early diagnosis. I123-MIBG plays an important role in early evaluation of sympathetic cardiac innervation, which is decreased due to amyloid infiltration. The aim of this study was to assess the temporal evolution of cardiac denervation in patients with hereditary amyloidosis, particularly the rate of progression and regional abnormalities; and to identify progression markers.MethodsForty-six patients were included. All of them were carriers of a TTR mutation or received domino liver transplantation, and underwent at least two evaluations of cardiac innervation with MIBG, between February 2011 and February 2018. Progression of cardiac denervation was determined by comparing the H/M ratio at first and final assessment. Regional abnormalities were evaluated using the perfusion/innervation mismatch on a 17 segments model. Logistic regression analysis was used to identify predictors of progression.ResultsTwenty-two patients were stable and 24 were progressive. The mean delay between two MIBG scans was 3.2 ± 1.3 years. Late H/M decreased by 3.9%/year in progressive group, and tended to accelerate after symptoms onset (− 1.4 ± 5.4 vs − 0.49 ± 2.9, P = 0.03). Regional abnormalities were initally located in the infero-latéral segments and extended to the inferior and lateral walls at final assessment. LVEF (OR: 0.90, P = 0.003) and initiation of amyloidosis targeted treatment (OR = 5,35, P = 0.003) were independent predictors of sympathetic denervation progression.ConclusionProgression of myocardial sympathetic denervation in hereditary amyloidosis is slow, but accelerates after symptoms onset. LVEF and treatment are potential progression markers. Regional abnormalities are mainly located in the inferolateral segments and tend to extend at the borders of the denervated area.     

Intérêt de la tomoscintigraphie cardiaque à la 123I-mIBG couplée à la perfusion myocardique dans le diagnostic de l’atrophie multisystématisée

ObjectiveThe aim of this prospective study is to assess the pertinence of using ¹²³I-mIBG myocardial tomoscintigraphy coupled with perfusion scintigraphy as a diagnostic tool, to discriminate between multiple system atrophy (MSA) and idiopathic Parkinson's disease (PD) at first guided by clinical data and L-DOPA tests.Material and methodsForty patients, aged from 43 to 78 years (median 62 years) with Parkinson's syndrome were studied. Nineteen had a diagnosis of PD (criteria of brain bank) and 21 AMS (Gibbs criteria). All were given test to acute L-DOPA. Chest-centered planar imaging (128 × 128 matrix, 5 minutes of duration) is performed at 1 hour and 4 hours after injection of 220 MBq of ¹²³I-mIBG, in addition a non-synchronised tomoscintigraphy (64 × 64 matrix, 32 images of 50 seconds , zoom 1.45) was performed after the 4th hour and 15 minutes after injection of 200 to 400 MBq of ^99mTc-tetrofosmin. Besides neurological data, the parameters retained for comparison purposes with ¹²³I-mIBG cardiac tomoscintigraphy were patients’ age, duration of disease and L-DOPA test results. Two regions of interest (ROI) identical in size and in shape are used for ¹²³I-mIBG uptake quantifications (H/M and washout [Wo]). The first one was placed in projection of mediastinum (M) and the other one in projection of heart (H).ResultsWe found an overall decreased uptake of the myocardial ¹²³I-mIBG without perfusion abnormality in 15 of 19 patients with PD and 11 among them were L-DOPA sensitive (L-DOPA test greater than 30%). Normal tracer uptake with ¹²³I-mIBG associated with an almost quite normal perfusion was seen in 15 of 21 patients with MSA and they were little or not L-DOPA sensitive (L-DOPA test less than 30%). Therefore, 10 discordant cases (25%) between cardiac scintigraphy and clinical evolution of disease with also discordant L-DOPA tests were observed. In the PD group, quantification of data enhanced the diagnostic decision with low heart to mediastinum ratio (H/M) (1.32 ± 0.15 at the early stage and 1.25 ± 0.13 at the later stage). In the MSA group, the uptake of ¹²³I-mIBG (1.66 ± 0.43 at the early stage and 1.72 ± 0.42 at the later stage) was comparable to literature data, however, with significant inter-individual variations. The association of data of scintigraphy with L-DOPA test allows to improve sensitivity in 84% and specificity in 90.5%.ConclusionOur prospective study of 40 cases shows the relevance of cardiac sympathetic postganglionic imaging with ¹²³I-mIBG coupled with myocardial perfusion scintigraphy to discriminate between MSA and PD with a higher sensitivity (71.4%) compared to the test with L-DOPA but a lower specificity (78.9%) than the L-DOPA. The difficulty of diagnosis is firstly linked to damage occurring to both the pre- and postganglionic sympathetic systems in patients with MSA and secondly to the integrity of the sympathetic nerve endings in patients with PD. However, the association of data of scintigraphy with L-DOPA test show a significant improvement of sensibility (84%).