[Andersen syndrome: a particular form of paralysis with cardiac dysrhythmia]. / Le syndrome d'Andersen: une forme particulière de paralysie périodique avec dysrythmie cardiaque.

Andersen syndrome includes a clinical triad with periodic paralysis, cardiac arrhythmia and dysmorphic features most often mild but relevant. It is a potassium channelopathy due to mutation of KCJN2 gene coding for Kir 2.1 protein. We report a familial case with mutation R218W of Kir 2.1 and discuss the main phenotypic and genetic aspects of Andersen syndrome. Muscle manifestations are essentially a periodic paralysis most often of hypokaliemic type. Muscle biopsy reveals tubular aggregates but can be normal as it is shown in the same patient in our kindred. Our proband complained of paralytic attacks since childhood and at adult age she demonstrated a mild permanent deficit of pelvic girdle muscles as it has been described in other types of periodic paralysis after a long duration course. Cardiac manifestations may include in a variable manner a long QT syndrome, premature ventricular contractions, complex ventricular ectopy, polymorphic or bidirectional ventricular tachycardia. Imipramine had a positive effect on arrhythmia in our case. Dysmorphic features are often mild and have to be cautiously looked for as a clue to the diagnosis of Andersen syndrome. They can be easily overlooked if not systematically looked for. Clinical expressivity is variable including in the same family. In our observation, the daughter showed a complete triad, early expressed, which allowed the diagnosis. Her father was late diagnosed on ventricular dysrhytmia but without muscle manifestations and dysmorphic features. Since KCJN2 gene mutation identification, locus heterogeneity of Andersen syndrome was shown. Andersen syndrome kindreds without mutations in KCNJ2 were clinically indistinguishable from KCNJ2-associated subjects. KCNJ2 gene encodes the inward rectifier K+ channel Kir2.1 which plays an important role in maintaining membrane potential and during the terminal phase of cardiac action potential repolarization. Several studies showed a dominant negative effect of the mutation on Kir 2.1 channel function.

[Criteria of localization of the bundle of Kent]. / Critères de localisation des faisceaux de Kent.

The high success rate (> 90%) of radiofrequency ablation of accessory pathways is related to accurate mapping. This determines the site of the accessory pathway and the best target for ablation with the object of reducing the number of applications and the associated morbidity. Analysis of the surface ECG is the first step of localisation of a Kent bundle. Different algorithms may be used based on the correlation between the polarity of the delta wave, of the QRS and the site of the accessory pathway confirmed at surgery or during radiofrequency ablation procedures. Some of the recent algorithms allow localisation of certain postero-septal or sub-epicardial pathways, the ablation of which can only be accomplished via the coronary sinus or one of its branches, or in an abnormally dilated coronary sinus, the so-called diverticulum. A relatively accurate localisation of the accessory pathway from the surface ECG reduces the duration of an ablation procedure and may economise the need for left-sided catheterisation. However, the endocavitary electrogrammes determine the precise target of ablation whether this be the ventricular or atrial pole of the bundle of Kent. The association of the criteria obtained by bipolar and unipolar recordings in sinus rhythm, during pacing or reentrant tachycardia enables accurate localisation in the majority of cases. Ablation of some pathways may be more complex because of their site or the presence of associated congenital or acquired cardiac disease which alters the anatomical or electrical markers. In these cases, the electrical criteria, especially those of the surface ECG may be erroneous and non invasive investigations such as Doppler echocardiography, isotopic ventriculography with phase analysis are most valuable with a positive predictive value of over 90%.

[Quantification of mitral regurgitation by cine-MRI. Comparison with transesophageal echocardiography in 45 patients]. / Quantification des régurgitations mitrales par ciné-IRM. Comparaision avec l'échographie doppler transoesophagienne chez 45 patients.

Cine-MRI demonstrates the presence of mitral regurgitation by a signal void. This study was undertaken to assess the value of this method for quantification of mitral regurgitation in a population not excluding either patients with mitral valve prostheses or those with atrial fibrillation. The subjects included had a mean age of 59 years and were referred for transoesophageal echocardiography, either for assessment of valvular heart disease (38 patients), or for detection of atrial thrombosis before external electrical cardioversion (7 patients). Eight patients had mitral valve prostheses and 19 were in atrial fibrillation. Cine-MRI was performed within 12 days of the transoesophageal echocardiography study with a 1.5 tesla magnet, using a sequence of gradient echo in 3 parallel planes in the 4 chamber view. The regurgitation was quantified by MRI from the extension of the signal void in the left atrium. The transoesophageal Doppler echocardiographic criteria were the width of the regurgitant jet at its origin, the intensity of the regurgitation signal recorded by continuous wave Doppler and the extension of the jet within the left atrium. The quantification by degrees 1 to 4 did not differ by more than 1 degree between the 2 techniques in 43 of the 45 patients. Out of 4 left atrial thrombus detected by transoesophageal echocardiography, only 1 was visible by MRI. The authors concluded that quantification of mitral regurgitation by cine-MRI provides similar results to those obtained by transoesophageal echocardiography and that the correlation remains valid in cases of atrial fibrillation. However, Doppler echocardiography provides further valuable information for the clinician.

Cochlear implantation in a pacemaker patient.

The authors present their experience with cochlear implantation in a 22-year-old patient who had a cardiac pacemaker because of complete atrioventricular block. The question of compatibility between the cochlear implant (multichannel Digisonic DX10AE) and the pacemaker (Biotronik Nanos-01AE) was raised. After consulting the two manufacturers regarding the risk of electrical interference, the authors decided to program the pacemaker in a locked mode (VOO) and then perform cochlear implantation. When the cochlear implant was switched on for the first time, electrocardiograms were obtained to ensure that the two devices were compatible. Absolutely no interference was detected. After a 3-year follow-up, cochlear implant performance remains excellent.

Assessment of aortic regurgitation severity by magnetic resonance imaging of the thoracic aorta.

A new method of assessing the severity of aortic regurgitation severity by magnetic resonance imaging has been developed. Two groups were studied: 20 controls (age = 58 +/- 19 years) without valvular aortic disease, and 24 patients (age = 62 +/- 13 years) with chronic aortic insufficiency evaluated by magnetic resonance and aortic root cineangiography within 1 week of each other. A magnetic resonance sequence (TR = 35 ms/TE = 12 ms/flip angle = 20 degrees/magnet = 1.5 T) was acquired in a plane containing the thoracic aorta. A transverse saturation band 30 mm wide was positioned 30-40 mm above the aortic valve. Aortic insufficiency was graded; the importance of end-diastolic retrograde movement in the saturation band in the descending aorta was noted. Magnetic resonance was also compared to Doppler echocardiography in 20 patients. In the controls, we found that retrograde blood flow was absent (18/20) or mild (2/20). In contrast, the presence of marked retrograde movement in a saturation band across the thoracic aorta was always associated with severe aortic regurgitation (angiographic grade III or IV). This rapid method (imaging time less than 20 min) can be applied in most patients with aortic regurgitation and is likely to be helpful when echocardiography is not possible or gives inconclusive results.

Thallium perfusion and myocardial hypertrophy in transplanted heart recipients with normal or near-normal coronary arteriograms.

In patients with hypertrophic cardiomyopathy or systemic hypertension, exercise thallium perfusion defects have been observed but without significant angiographic stenoses. Hypertension and myocardial hypertrophy are common in transplanted heart recipients, and the aim of this study was to determine if exercise thallium scintigraphy false-positives are frequent in transplanted heart recipients. Thirty-four transplanted heart recipients were evaluated by exercise thallium single emission computed tomography and subsequently had a normal or near normal coronary arteriogram. At the time of the exercise, the patients (28 men and six women) had a mean age of 48.9 +/- 12 years and 29 had been previously treated for systemic hypertension. The mean duration between transplantation and the exercise test was 31.6 +/- 13 months. In all patients left ventricular mass was obtained by echocardiography within 3 months of thallium 201 SPECT and was > or = 130 g.m-2 in nine males and > or = 110 g.m-2 in four females. M-mode septal + posterior end-diastolic thickness was > 23 mm in 14 patients, all of whom had been previously treated for systemic hypertension. These patients were older and endured a longer period during which the heart was kept cold but ischaemic before being grafted ('cold ischaemia') but a shorter exercise duration than patients without left ventricular hypertrophy. During exercise testing, 26 of 34 patients achieved at least 80% of their maximal predicted heart rate and two developed significant ECG changes.(ABSTRACT TRUNCATED AT 250 WORDS)

[Prognostic value of thallium-201 myocardial scintigraphy in patients with hypertension, suspected of coronary disease]. / Valeur pronostique de la scintigraphie myocardique au thallium 201 chez l'hypertendu suspect de maladie coronaire.

This study was undertaken to determine the prognostic value of exercise myocardial scintigraphy in hypertension patients suspected of coronary disease. One hundred and thirty six hypertension patients (mean age: 59) suspected of coronary disease were monitored for 46 months after thallium 201 exercise myocardial scintigraphy (tomographic mode). Prognostic factors analysed were clinical (typical nature of pain, exercise blood pressure), electrocardiographic (presence of repolarisation abnormalities in resting ECG), ergometric (electrically positive test) and scintigraphic (existence or not of transitory hypofixation). Events sought were: death of coronary origin, non-fatal myocardial infarction, aorto-coronary bypass and coronary angioplasty. One-way analysis showed that the existence of transitory hypofixation by scintigraphy, positive exercise electrocardiogram and typical angina pain enabled the prediction of coronary events. Thus 14 of 36 patients (39%) with transitory or combined hypofixation had a coronary event as against 7 of the 100 patients without transitory hypofixation. Only the existence of transitory hypofixation retained a prognostic value for coronary events by multivariate analysis (relative risk = 5.4, p = 0.001). It was also found that the prognosis was good when scintigraphy did not reveal transitory hypofixation while exercise testing was positive (2 coronary events/27 patients). It is concluded that, despite the possibility of "false positives", linked in particular to myocardial hypertrophy, myocardial scintigraphy offers better prediction of coronary events in hypertension patients that other clinical or electrocardiographic parameters.

[Left ventricular involvement in mucoviscidosis after 2 years of age]. / L'atteinte ventriculaire gauche des mucoviscidoses après l'âge de 2 ans.

BACKGROUND: The cardiac involvement in cystic fibrosis includes the rare cardiomyopathy seen in infants and changes in left ventricular performance in older children. POPULATION AND METHODS: 67 patients, 6 to 34 months-old (mean: 16.7), 37 male and 30 female, with cystic fibrosis, were studied. Their Shwachman score was < 70. None showed any clinical manifestations of left ventricular insufficiency, but 6 patients had right ventricular insufficiency. Echocardiography was performed on 58 patients; it showed dilation of the right ventricle in 32 of them. Left ventricular perfusion was studied with thallium 201 tomoscintigraphy and left ventricular ejection fraction with 99mTc ventriculography. RESULTS: The left ventricular ejection fraction was < 45% in 17 patients and scintigraphy showed hypofixation in 6 of them. In contrast, only 4 of the 50 patients with left ventricular ejection fraction > 45% had thallium hypofixation. CONCLUSIONS: Resting perfusion abnormalities are more frequent in patients with a low left ventricular ejection fraction. These perfusion abnormalities suggest that myocardial fibrosis complicates the advanced stages of cystic fibrosis.

[New developments of antiplatelet drugs]. / Nouveaux développements des médicaments antiplaquettaires.

A better knowledge of platelet activation mechanisms has made it possible to develop antiplatelet agents that are capable of inhibiting primary haemostasis at very precise levels. Many of these agents block the synthesis or receptor of an hemostasis I agonist. Thus, the thromboxane A2 receptor can be blocked, or its synthesis can be interrupted, by thromboxane synthetase inhibitors, by cyclooxygenase inhibitors, or by omega 3 fatty acids which are competitive inhibitors. Inhibitors of thrombin (hirudin), PAF acether and serotonin (ketanserin) also are available. Other antiplatelet agents secreted by endothelial cells act as haemostasis I antagonists by elevating platelet cAMP or cGMP levels (prostacyclins and analogues, nitrate derivatives). Monoclonal antibodies and RGD peptides directly inhibit the glycoproteins that are responsible for platelet adhesion or aggregation, but their users are faced with problems of cost and route of administration. Of all these new antiplatelet agents, only ticlopidine, which has an imperfectly known mode of action, has proved effective in multiple situations, but its use is limited by its side-effects.

Atrioventricular nodal conduction and refractoriness following abrupt changes in cycle length.

The properties of the atrioventricular (AV) nodal conduction and effective refractory period in man are generally evaluated at a constant basic cycle length (CL) and, in most cases, they demonstrate an inverse relationship to the drive cycle. The response of AV node to abrupt change in CL is less defined. We therefore studied the effects of abrupt changes in CL on AV nodal conduction time and refractoriness in 18 patients. AV nodal conduction time, and effective and functional refractory periods were measured during: (1) a constant long CL, (2) a constant short CL, and (3) after an abrupt increase in CL just prior to the introduction of extrastimuli. In 10 of the 18 patients a constant long CL of 600 ms, a constant short CL of 400 ms and a sudden short-to-long change in CL (400 to 600 ms) were tested. AV nodal conduction times (A2H2) were measured at the shortest and longest comparable A1A2 intervals. The mean value of the shortest A2H2 intervals for constant CL of 600 ms was 144 +/- 18 ms; for a constant CL of 400 ms it was 162 +/- 17 ms; after a sudden short-to-long change in CL (400 to 600 ms) it was 142 +/- 14 ms. The mean value of the longest A2H2 intervals at a constant CL of 600 ms was 185 +/- 18 ms; at a constant CL of 400 ms it was 236 +/- 26 ms (p less than 0.01) and after a short-to-long change in CL (400 to 600 ms) 199 +/- 21 ms. AV nodal effective refractory periods measured at the same three CLs had mean values of 279 +/- 13 ms; 300 +/- 15 ms and 294 +/- 13 ms, respectively. Similar results were obtained when other CLs such as 700 to 900, 500 to 900, and 400 to 700 ms were tested. The data suggest that after abrupt short-to-long changes in CL, AV nodal function curves shift from long constant CL toward short constant CL as the coupling intervals decrease, indicating a cumulative pattern. Although the return to baseline conduction time after the fast basic rate is known to be slow, the limitation of this effect to the very early premature beat in the human has not been reported previously.

[Cardiomuscular lysosomal glycogenosis in adults without known enzyme deficiency. A cause of familial myocardiopathy and lysosomal glycogen overload with normal acid maltase]. / Glycogénose lysosomiale cardio-musculaire de l'adulte sans déficit enzymatique connu. Cause de myocardiopathie familiale et surcharge lysosomiale en glycogène avec maltase acide normale.

An unusual form of familial myocardiopathy is reported. The disease affected siblings entering adulthood and presented as subclinical skeletal muscle and patent cardiac muscle lesions. Quadriceps muscle biopsy performed in a young man who subsequently died of cardial failure revealed excessive lysosomal glycogen storage, as in type II glycogenosis, but biochemistry showed normal enzymatic activity. In a sister with hypertrophic myocardiopathy only leucocytes were examined; they also showed normal enzymatic activity. Other clinical manifestations of this form of familial myocardiopathy are hypoglycaemia and moderate skeletal muscle involvement. At histology, the image is that of Pompe's disease, but the acid maltase level is normal. The condition seems to be transmitted as an autosomal dominant trait.

The spatial distribution of late ventricular potentials.

Body surface potential mapping (BSPM) was used to study the spatial distribution of late ventricular potentials. In a group of 15 normals and 21 patients with documented ventricular tachycardia (VT), BSPM performed with 63 averaged and high-pass filtered ECG leads (LP-BSPM) showed that late potentials have a mostly dipolar distribution and that they can be reasonably well detected with only three orthogonal leads. In a group of 17 VT patients who also had BSPM performed during induced VT (VT-BSPM), six patients had LP-BSPM similar to one of the VT-BSPM, suggesting that the locations and orientations of both types of sources are similar. In a group of 12 VT patients who had epi-endo VT mapping at surgery, LP-BSPM showed close extrema (reflecting antero-apical delay) for patients with anterior or apical VT sites, suggesting that VT originates in delayed regions. BSPM thus provides useful information about the detection and significance of late potentials.

Efficacy and safety of intravenous and oral diltiazem for Wolff-Parkinson-White syndrome.

The electrophysiologic effects and safety of diltiazem administered either intravenously or orally were studied in 14 patients with Wolff-Parkinson-White syndrome during orthodromic reentrant tachycardia and atrial fibrillation (AF). Anterograde and retrograde effective refractory periods of the accessory pathway did not change significantly from baseline during either i.v. or oral administration. Administration by either route prevented induction of sustained reentrant tachycardia in 8 patients. In 6 patients, the reentrant tachycardia was either nonsustained (2 patients) or sustained at much slower rates than the baseline rates (mean +/- standard deviation, baseline, 290 +/- 41 ms; i.v., 355 +/- 40 ms [p less than 0.001]; and oral, 377 +/- 33 ms [p less than 0.001]). In these patients anterograde atrioventricular conduction was prolonged significantly from the mean baseline value of 163 +/- 36 ms to 212 +/- 35 ms with i.v. administration (p less than 0.005) and 225 +/- 33 ms with oral administration (p less than 0.005). Retrograde conduction via the accessory pathway did not change significantly after administration of diltiazem. The shortest preexcited RR intervals during AF were significantly reduced during i.v. but not during oral administration: control, 327 +/- 47 ms; i.v., 270 +/- 28 ms (p less than 0.001); and oral, 323 +/- 44 ms (difference not significant). In 5 patients AF was sustained for a mean of 20 minutes after i.v. and for 12 minutes after oral administration (p less than 0.20), compared with a baseline mean value of 0.83 minute.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of autonomic nervous system modulation on retrograde atrioventricular nodal conduction in the human heart.

Although the influence of the autonomic nervous system on anterograde atrioventricular nodal conduction is well established, its effect on retrograde atrioventricular nodal conduction has not been examined systematically. Since retrograde atrioventricular nodal conduction in subjects with normal anterograde conduction may vary from intact retrograde conduction to complete retrograde block when assessed during ventricular pacing, in this study patients with (a) intact retrograde atrioventricular nodal conduction (group 1) were studied during parasympathetic (vagal) stimulation by carotid sinus pressure and during sympathetic inhibition (propranolol 0.2 mg.kg-1 intravenously) and (b) retrograde atrioventricular nodal block (group 2) were studied during vagal blockade (atropine 0.04 mg.kg-1 intravenously) and during sympathetic stimulation (isoproterenol 1-4 micrograms.min-1 infusion). In both groups changes in sinus cycle length and anterograde atrioventricular nodal conduction were measured. In group 1 vagal stimulation by carotid sinus pressure in 20 patients caused the cycle length at which retrograde atrioventricular nodal block was induced to be significantly lengthened from a mean(SD) of 375(59) to 451(51) ms in six patients; caused complete retrograde block in 10 patients; and had no effect in four patients. Sympathetic inhibition by propranolol in another 15 patients delayed the onset of pacing induced retrograde atrioventricular nodal block from a mean(SD) of 340(60) to 418(80) ms in 11 patients; caused complete retrograde atrioventricular nodal block in three patients; and had no effect in one patient. In group 2 vagal blockade by atropine caused a 1:1 retrograde response during ventricular pacing up to a mean(SD) cycle length of 470(135) ms in six out of eight patients. The infusion of isoproterenol caused the retrograde atrioventricular nodal block to be abolished and 1:1 conduction to be resumed up to a ventricular pacing mean(SD) cycle length of 364(57) ms in six out of eight patients. It is concluded that (a) the autonomic nervous system modulates retrograde atrioventricular nodal conduction in a similar manner to its anterograde counterpart and (b) that since retrograde atrioventricular nodal conduction was reversible after the administration of either atropine or isoproterenol retrograde atrioventricular nodal block may be dynamic (physiological) rather than fixed (anatomical) in nature.

Characterization of the spatial distribution of late ventricular potentials by body surface mapping in patients with ventricular tachycardia.

Low-level activity at the end of the QRS complex was analyzed from 63 thoracic leads in 15 normal subjects and in 21 patients with ventricular tachycardia (VT). The latter had old myocardial infarction and no conduction disturbances and had not been receiving antiarrhythmic drugs. In both normal subjects and patients with VT, isopotential maps of the time-averaged and filtered (25 Hz high-pass) electrocardiograms during the terminal portion of the QRS were dipolar, i.e., they showed single positive and negative regions. For patients with VT, the extrema were either distant, with one over the precordial area and the other over the back, or close together in the precordial region. In 10 patients, maps recorded after administration of antiarrhythmic drugs remained the same while QRS duration was prolonged. In six patients, maps recorded before antiarrhythmic surgery showed distant extrema for septal or posterobasal VT sites of origin and close extrema for anterior or posteroapical sites. Generally, QRS duration was reduced and maps were modified after surgery. Late potentials can be well detected with only three orthogonal leads because their distributions are dipolar, but maps provide additional information about their distribution, which may be related to conduction delay sites and possibly to VT sites of origin. Sources near the torso surface would produce close extrema, whereas deeper sources would produce distant extrema.

[Total or partial electrical interruption of the atrioventricular pathway. Evaluation of clinical results and indications]. / Interruption électrique totale ou partielle de la voie auriculo-ventriculaire. Appréciation des résultats cliniques et des indications.

After checking on the efficacy and innocuity of catheter ablation of the His bundle in an experimental study in the sheep, 22 patients with supraventricular tachycardia resistant to an average of 5.5 +/- 1.7 antiarrhythmic drugs per patient underwent this procedure. The most common arrhythmias were atrial fibrillation or flutter (poorly tolerated in 14 cases), and reciprocating tachycardia (8 cases, including 3 with accessory atrioventricular pathways). In 3 of the 5 patients with intranodal tachycardia, an initial attempt was made to modify one of the two AV nodal conduction pathways. Although complete atrioventricular block was obtained in all patients, atrioventricular conduction returned in 15 patients between the 30th minute and 4th day after the procedure. A second attempt at His bundle ablation was carried out in 9 patients. During follow-up ranging from 1 to 38 months, complete or an advanced degree of atrioventricular block persisted in 5 patients, the other patients being in sinus rhythm (12 cases) or slow atrial fibrillation (2 cases). The remaining patient who was in complete atrioventricular block died of septicaemia 2 months after the procedure. The clinical results were evaluated by electrophysiological investigation, exercise testing and Holter monitoring. There were 15 satisfactory clinical results (83.3 p. 100) and 3 poor results. This series shows that interruption or modification of the normal atrioventricular conduction pathway may be performed at low risk and with good results in a high percentage of cases. It is a valuable therapeutic option in patients with supraventricular tachycardia resistant to antiarrhythmic therapy.

[Treatment of recurrent ventricular tachycardia with hydroquinidine. Evaluation of its efficacy with electrophysiological technics]. / Traitement des tachycardies ventriculaires récidivantes par l'hydroquinidine. Appréciation de l'efficacité par les techniques électrophysiologiques.

Electrophysiological investigations were used to test the efficacy of dihydroquinidine chlorhydrate (600 or 1 200 mg/day) in a prospective study of 18 patients with recurrent ventricular tachycardia documented by electrocardiography. These patients did not respond to an average of 3.1 +/- antiarrhythmic drugs, including amiodarone in 12 patients. Hydroquinidine was well tolerated in 17 patients but had to be withdrawn in 1 patient because of hypotension. The effect of hydroquinidine on ventricular tachycardia induced by programmed pacing was evaluated after a 48 to 72 hours treatment, 3 to 5 hours after the last dose. After hydroquinidine it was not possible to induce ventricular tachycardia in 10 patients (58.8%). In the other 7 patients, it was possible to induce a ventricular tachycardia under treatment. In one case, hydroquinidine aggravated the arrhythmia as the induced tachycardia had a shorter cycle. In the other patients, hydroquinidine lengthened the tachycardia cycle by an average of 94 +/- 79 ms. The right ventricular refractory period increased cycle by 44 +/- 23 ms. Long-term hydroquinidine was prescribed for 7 patients, twice in association with amiodarone. Relapse was observed in 2 patients, 1 and 5 months after the onset of treatment. Five patients were well controlled by the treatment. The results of this study demonstrate the efficacy of hydroquinidine for the prevention of tachycardia induced by stimulation and underline its value in the treatment of sustained, recurrent ventricular tachycardia. This study illustrates the illustrates the importance of electrophysiological techniques for the identification of patients likely to benefit from a given antiarrhythmic treatment.