[Tolerance of treatment with nitrate derivatives]. / Echappement au traitement par les dérivés nitrés.

Tolerance to treatment with nitrate derivatives, suspected for many years and often ignored in everyday clinical practice, has recently been the subject of much study. Although the phenomenon has been clearly demonstrated in patients on long-term therapy, it seems to vary from patient to patient, with the underlying pathology and the galenic form of nitrate used. The mechanism of tolerance to nitrates is multifactorial, related on the one hand to depletion of sulfhydryl groups in the body and on the other to activation of the sympathetic and renin-angiotensin systems. The administration of sulfhydryl groups in the form of N-acetylcysteine partially restores the effects of nitrates in some patients.

[Localized dilatation of the bronchi. A misunderstood etiology of coronaro-bronchial fistula]. / Dilatation des bronches localisée. Etiologie méconnue de fistule coronaro-bronchique.

The authors report the case of a coronary to bronchial artery anastomosis secondary to focal bronchiectasis. The diagnosis was made after finding large retroatrial vessels on coronary arteriography. A pulmonary steal syndrome, frequently reported in this condition in the literature, was not present in that particular case. The diagnosis of a coronary to bronchial artery anastomosis should alert the physician to possible underlying cardiac disease (Tetralogy of Fallot, supravalvular aortic stenosis, severe coronary artery disease). A bronchopulmonary etiology (chronic obstructive airways disease, multiple bullae, bronchiectasis) is less commonly found as the presentation is often atypical.

[Traumatic tricuspid insufficiency. 5 cases]. / L'insuffisance tricuspide traumatique. 5 observations.

Five men (mean age 39 years) were followed up for 6 to 60 months for tricuspid valve regurgitation caused by a front-to-back injury (in a car in four cases, in an aircraft in one case). The time elapsed between the accident and the signal symptoms varied from 28 days to 20 years. The condition was diagnosed on clinical data (stage 2) and on the results of echocardiography and cardiac catheterization. Four patients were operated upon and provided with a bioprosthetic valve. The post-operative period was marked by resolutive atrioventricular block in one case and inferior myocardial infarction in one case. Four points ought to be highlighted: 1. The long-term development of dilatation of the annulus, cicatricial fibrosis or altered left ventricular contractility; 2. The usefulness of pulsed Doppler echocardiography for the diagnosis and surgical indications (quantification of the regurgitation, right ventricular kinetics); 3. The adaptation of treatment to the lesion: repair whenever possible, or annuloplasty, or bioprosthetic valve replacement (mechanical valves must be excluded); 4. The time for surgery is difficult to determine in view of the asymptomatic period, which may be very long. The decision to operate is based on clinical, echocardiographic, haemodynamic and dromotropic (complete arrhythmia due to atrial fibrillation) data. This decision must be reached before right ventricular myocardial deterioration sets in.