[Value and limitations of programmed ventricular stimulation]. / Intérêts et limites de la stimulation ventriculaire programmée.

The electrocardiogramme and methods of prolonged ECG recording are sufficient for diagnosing most cardiac arrhythmias. They also provide some prognostic information and allow evaluation and follow-up of treatment. However, in some situations, endocavitary electrophysiological investigations are required when the diagnosis is uncertain, that more prognostic information is required or interventional techniques (endocavitary ablation) are envisaged. The aim of this report is to summarise the value and limitations of programmed ventricular stimulation. Many of its indications have been abandoned in terms of rhythm stratification in the face of more robust parameters, in particular the left ventricular ejection fraction. However, it retains a potential utility in terms of prognosis in arrhythmogenic right ventricular dysplasia, the Brugada syndrome and operated Tetralogy of Fallot. In any event, it is important to remember that studies resulting in diagnostic or therapeutic recommendations were performed with strict protocols of stimulation in selected patients and that these recommendations can only be applied when the evaluation protocols are respected. The indications of programmed ventricular stimulation will increase in the therapeutic field with the development of new techniques of 3D mapping, new systems of catheter guiding which should extend the indications of endocavitary ablation.

[Ventricular extrasystoles]. / Extrasystoles ventriculaires.

Ventricular extrasystoles result from premature excitation of the heart from a site beyond the bifurcation of the bundle of His, at the level of the conductive tissue or myocardial cells. In practice they represent a daily problem for cardiologists due to their frequent occurrence. They can be detected in symptomatic patients and also in asymptomatic subjects, for example during routine health checks. It is therefore important to distinguish benign ventricular extrasystoles from those which are potentially serious, so that a useless or even dangerous treatment is not undertaken and severe anxiety is not caused in patients who have become 'medicalised'. The decision about treatment is only made following electrocardiographic and echographic clinical investigation, with the presence of cardiopathy being one of the major deciding factors.

[Brugada syndrome]. / Syndrome de Brugada.

The Brugada syndrome is characterised clinically by the occurrence of syncope or sudden death due to ventricular arrhythmias in patients with structurally normal hearts and electrocardiographic signs of right bundle branch block and ST elevation in the right precordial leads (V1 to V3). The transmission of the condition is autosomal dominant with variable penetration. Mutations have been identified in a gene coding for the alpha sub-unity of the sodium channel (SCN5A) on chromosome 3 in only 30% of cases. This mutation is responsible for a reduction of the density of the sodium current and explains the aggravation of the electrocardiographic anomalies by antiarrhythmic drugs which block the sodium channels. The prognosis is poor in symptomatic patients and depends on the prevention of sudden death by the implantation of an automatic defibrillator. The therapeutic decision is much more difficult in asymptomatic patients without a family history. The authors propose a decisional algorithm. The management may have to be modified in the months or years to come depending on advances in the understanding of this syndrome.

[The value of repeated determinations of brain natriuretic peptide for the diagnosis of unstable angina]. / Intérêt des dosages répétés du brain natriuretic peptide pour le diagnostic d'angor instable.

The diagnosis of unstable angina (troponine undetectable) is often difficult in the absence of electrocardiographic changes after suggestive chest pains. The object of this study was to analyse the kinetics of Brain Natiuretic Peptide (BNP) during acute coronary syndromes (ACS) without ST elevation. Plasma BNP was measured every 6 hours for 48 hours in 65 patients admitted for suspicion of ACS without ST elevation and without clinical, radiological or echocardiographic signs of left ventricular dysfunction. The results of BNP measurements were masked until the final diagnosis was established on the usual investigations (ECG changes, troponine I values, myocardial scintigraphy, coronary angiography). These investigations identified 3 groups of patients: non-Q wave infarction (group A: 19 patients), unstable angina (group B: 21 patients) and non-coronary chest pain (group C: 25 patients). The peak BNP was significantly higher in groups A (210 +/- 172 pg/ml) and B (152 +/- 159 pg/ml) than in group C (16 +/- 14 pg/ml). However, the BNP was normal or only slightly increased (< 50 pg/ml) in 25% of cases of ACS. Analysis of the kinetics of BNP was much more discriminating: early increase after the pain, peak between the 14th and 24th hours (19th hour on average), followed by a progressive decrease. The kinetics were identical in Groups A and B, contrasting with the flat profile of the curve in group C. A change of > 20 pg/ml in BNP was a better criterion of ACS with a diagnostic accuracy > 90% than increased troponine (group A) or undetectable troponine (group B). The authors conclude that BNP kinetics is a new and reliable diagnostic marker of unstable angina when the usual criteria of ACS are not present (notably a normal ECG and undetectable troponine).

[Bidirectional ventricular tachycardias]. / Tachycardies ventriculaires bidirectionnelles.

Bidirectional tachycardias are rare arrhythmias. Nevertheless in the sixties and seventies these arrhythmias prompted much work relating to their mechanism. Discussions about the supposed supra-ventricular origin of certain bidirectional tachycardias essentially rested on presumptive arguments based on electrocardiographic analysis. All the electrophysiological investigations which could be performed in tachycardia showed a ventricular origin. The current hypotheses concerning the electrophysiological mechanism favour non-unifocal mechanisms as well as a very diverse aetiology: an automatic focus, or the triggered activities being associated with alternating conduction, or re-entry between the left hemibranches. Although the classic context is of excess digitalis with advanced cardiopathy, readily in atrial fibrillation with a poor prognosis as a corollary, the most recent description of catecholergic ventricular tachycardias with the very characteristic appearance of bidirectional tachycardias justifies updating the understanding of these unusual tachycardias.

[Mobile right heart thrombus with minimal pulmonary embolism. A case report]. / Thrombus mobile intracavitaire droit associé à une embolie pulmonaire minime. A propos d'un cas.

The generalisation of the use of transthoracic echocardiography in the investigation of pulmonary embolism leads to the diagnosis of mobile right heart thrombus in about 5% of cases. A review of the literature shows that this association is mainly observed in clinically severe pulmonary embolism. The presence of a mobile right heart thrombus is associated with a poor prognosis and emergency treatment is based on thrombolytic therapy or surgical embolectomy. In minimal or infraclinical pulmonary embolism, the finding of a mobile right heart thrombus is rare and there is no consensus about its treatment. The authors report the case of a 61 year old man admitted to hospital for bilateral deep vein thrombosis with no symptoms of pulmonary embolism in whom investigations revealed a mobile right heart thrombus with minimal pulmonary embolism. The outcome was favourable with progressive resolution of the right heart thrombus with oral anticoagulation after three weeks of heparin therapy.

[Localization of isolated atrial involvement of cardiac sarcoidosis]. / Localisation auriculaire isolée d'une sarcoïdose cardiaque. A propos d'un cas.

The authors report the first case of cardiac sarcoidosis involving only the interatrial septum and the atrioventricular node in a 30 year old man with known lymph node sarcoidosis. The diagnosis was suspected after the finding of an apparently innocent 1st degree atrioventricular block and confirmed by transoesophageal echocardiography and by IMATRON computerised tomography. Isolated atrial involvement of sarcoidosis is rare in the absence of any left ventricular disease. This explains the negative findings at transthoracic echocardiography and radio-isotopic investigations usually recommended for diagnosing cardiac sarcoidosis.

[Legionella myopericarditis]. / Myopéricardite à Legionella.

Cardiac involvement in legionella infection is rare but it is the most common extra-pulmonary complication. It usually takes the form of pericarditis, but a case of legionella myoparicarditis with global left ventricular hypokinesia on echocardiography has been described. The authors report a case of myopericarditis with massive pulmonary oedema and respiratory distress which regressed clinically and on echocardiography with reduction in chamber dilatation and complete recovery of left ventricular function. Legionellosis was confirmed on serology. The infection was probably contracted during a previous hospital admission, therefore, probably a nosocomial infection. Following the description of this case, a review of the literature is proposed.