Myocardial viability assessed by dobutamine echocardiography in acute myocardial infarction after successful primary coronary angioplasty.

Dobutamine echocardiography (5 and 10 microg/kg/ min) was performed in 40 patients 4 +/- 1 days after acute myocardial infarction reperfused by primary coronary angioplasty. The left ventricle was divided into 11 segments. Reversible myocardial dysfunction was indicated by a decrease in at least 2 grades in the total segmental score. Follow-up echocardiography was performed 2 months later. Contractile reserve was documented in 18 patients with dobutamine echocardiography (45%). Sensitivity, specificity, positive, and negative predictive value of dobutamine echocardiography in predicting improvement in contractile function at follow-up were 82%, 83%, 78%, and 86%, respectively. Negative predictive value was high in all dyssynergic segments (86%). Positive predictive value was higher in hypokinetic than in akinetic segments (73% vs 21%; p <0.05). Recovery of wall motion at follow-up was statistically associated with higher left ventricular ejection fraction (p <0.04), collateral blood flow before reperfusion (p = 0.007), and dobutamine responsiveness (p = 0.0001), and was more frequently observed in hypokinetic than in akinetic segments (p <0.05). Thus, low-dose dobutamine echocardiography accurately predicts the extent of irreversibly damaged myocardium early after successful direct coronary angioplasty in acute myocardial infarction.

[Atrioventricular nodal tachycardia]. / Les tachycardies jonctionnelles.

The atrioventricular junction consists of the atrioventricular node and the bundle of His up to its division. All tachycardias arising in these structures or which depend on these structures for their sustenance are called "junctional". There are four main types. The first three correspond to reciprocating rhythms, nodal tachycardia, tachycardias using an accessory pathway with unidirectional retrograde conduction, and chronic reciprocating atrioventricular nodal tachycardia. All varieties of reciprocating atrioventricular nodal tachycardia have been well studied and their diagnosis is possible from the standard surface electrocardiogram from the position and morphology of the P' wave. They are accessible to radical treatment by radiofrequency ablation of the slow pathway or accessory pathway, when present. The definitive treatment of ectopic atrioventricular nodal tachycardia is not yet established and has to be considered case by case, this form of arrhythmia being rare.

[Electrocardiography of atrioventricular block]. / L'électrocardiogramme des blocs auriculo-ventriculaires.

A functional physiological block protects the ventricles from the risks of excessively rapid atrial rhythms. Pathological AVB is classified in three degrees according to whether the ventricular excitation is delayed, intermittent or absent. The site of AVB can be accurately determined by endocavitary electrophysiological studies but can also be estimated from the surface electrocardiographic recordings. fundamental research has questioned the sle responsibility of conduction defects in Wenckebach and paroxysmal blocks: they suggest the presence of abnormalities of excitability in pathological zones.

[Ventricular tachycardia in children]. / Les tachycardies ventriculaires de l'enfant.

Ventricular tachycardia (VT) in children is different to that observed in the adult because ischemic heart disease is exceptionally rare in this age group. The arrhythmia sometimes presents with cardiac failure or loss of consciousness. VT complicates the outcome of operated Tetralogy of Fallot, arrhythmogenic right ventricular dysplasia and some cardiac tumours. Cardiomyopathies are also a cause of VT but it must be noted that ventricular dysfunction may be the result of a prolonged arrhythmia and will disappear after return to sinus rhythm. Many cases of childhood VT occur without any patent cardiac disease even after extensive investigations. Some are benign with a good prognosis, such as salvoes of VT or sustained attacks of so-called ventricular Bouveret. Others carry a more reserved prognosis and require active treatment. Incessant tachycardia of the newborn is difficult to stop may be cured without sequellae. Torsades de pointes is sometimes iatrogenic complicating congenitally long QT syndromes with or without deafness or familial nature, and which may be likened to adrenergic VT. Amiodarone and betablockers are the best antiarrhythmic agents. Investigations with a diagnostic or therapeutic objective are easier in older children but these techniques, whilst not being systematic, do not exclude the very young children. Ablation techniques progress and the limited indications of surgery and implantable defibrillators have to be considered case by case.

[Surgery for arrhythmias]. / Chirurgie des arythmies.

The role of surgery in the treatment of cardiac arrhythmias has been marginalized in recent years with the rise in eminence of radiofrequency current ablation especially in the Wolff-Parkinson-White syndrome and nodal reentrant tachycardia. The indications of antiarrhythmia surgery for ventricular arrhythmias have become standardised. The unquestioned efficacy of the surgical techniques proposed (endarterectomy or cryosurgery with or without peroperative mapping) should not be associated with unacceptable mortality rates as when left ventricular function is too poor, implantation of a defibrillator is always possible. In the domain of atrial fibrillation, the interventions proposed (corridor or maze procedures) do not have the foundations that the follow-up of a sufficient number of cases would confer but they have the merit, especially the latter, of taking the underlying physiopathological mechanisms into consideration.

[Arrhythmia due to mitral valve prolapse]. / Les arythmies du prolapsus valvulaire mitral.

Mitral valve prolapse (MVP) a common condition easily recognised by echocardiography with, however, strict criteria to avoid diagnosis by excess, may be complicated by arrhythmias. Two very different situations oppose severe decompensated mitral regurgitation due to myxoid dystrophy and quasi-asymptomatic MVP with a good prognosis and a low risk of complications. The important question is therefore to detect risk criteria of sudden death in patients with few symptoms. Unfortunately, no isolated factor or association of factors resolves this problem in a given patient. However, it is usually young women without severe mitral regurgitation but with thickened valves and, sometimes, a long QT interval, who are involved. Programmed ventricular stimulation and the detection of later ventricular potentials do not seem to be useful in the present state of our knowledge.

[Transient entrainment of tachycardia]. / L'entraînement transitoire des tachycardies.

Transient entrainment of tachycardia by pacing at a faster rate corresponds to its acceleration with return to sinus rhythm either when the pacing is interrupted or when the pacing rate is slowed. It conforms to strict criteria detectable either on the surface electrocardiogramme (constant fusion, progressive fusion, change of morphology before termination of a tachycardia) or on selective endocavitary recording when entrainment is hidden. The phenomenon described by Waldo in 1977 in atrial flutter is found in all reentrant tachycardias. It is currently being studied in ventricular tachycardia. The electrophysiological concept is useful because it facilitates the understanding of the mode of termination of tachycardia by stimulation and the localisation of zones for destruction during ablation.

[Our experience with bioprostheses in French Polynesia. A follow-up study from 1975 to 1988]. / L'expérience des bioprothèses en Polynésie française. Suivi de 1975 à 1988.

French Polynesia has unique social, cultural and geographic features. The prevalence of acute rheumatic fever (ARF) of 1.2 % population justified the health authorities' classification of this endemic as "major, severe, and prioritary" in 1984. Seventy per cent of patients with ARF develop cardiac sequellae which require surgery in 25 per cent of cases. Bioprostheses were considered from 1975 as the ideal valve replacement for these young, often undisciplined patients with no facilities for haemostatic control. Reoperation for valve degeneration has been increasingly frequent since 1982 and poses an acute problem leading to this statistic study and to a reflection as to the value of continuing to use this type of valve in this population. Analysis of 178 Polynesians with one or more cardiac bioprostheses in 1988, totalling 221 valves with a mean follow-up of 55 months, shows an actuarial survival rate excluding operative mortality of 86.7 +/- 3 % at 5 years (93.8 +/- 2.5 % in patients under 25 years of age, p = 0.001). Fifty-two patients (29 %) have been reoperated with a probability of being free of reoperation at 5 years of 70.1 +/- 4.2% (85.2 +/- 3.9 % in patients over 25 years of age and 43.8 +/- 7.8 % in patients under the age of 25, p = 0.002). The authors discuss the alternative of bioprostheses in this population : mechanical valves with anti-coagulant or anti-aggregant therapy, frozen aortic homografts, mitral valvuloplasty.

[Traumatic tricuspid insufficiency. Apropos of 2 cases]. / Insuffisance tricuspide traumatique. A propos de 2 observations.

The authors report two cases of tricuspid regurgitation by a ruptured anterior papillary muscle secondary to non-penetrating thoracic trauma. In the presence of suggestive clinical and electrocardiographic abnormalities (systolic murmur, right heart failure, right bundle branch block), echocardiography confirmed the tricuspid regurgitation, showed its mechanism and excluded any other intracardiac lesions. Tricuspid annuloplasty was performed in both cases because of the persistence of failure or degradation of the patient's clinical condition. Peroperative echocardiography was used to judge the quality of the surgical repair in both cases. Traumatic tricuspid regurgitation is a rare condition and the diagnosis is often delayed. Echocardiography is the investigation of choice and guides treatment which is essentially valvular repair in symptomatic patients.

[Value of the superior trans-septal approach in mitral valve replacements]. / Intérêt de la voie trans-septale supérieure dans les remplacements valvulaires mitraux.

Mitral valve exposure is widely improved by the superior-transseptal approach (STS). The diffusion of this technique has been restricted because of the possibility of detrimental effects of sino-atrial arrhythmias, especially in patients in sinus rhythm preoperatively. Between April 1991 and December 1992, we performed mitral valve replacement (MVR) on 55 patients by an STS approach. The mean age was 57.7 +/- 11.3 years (38-75 years). 21 were reoperations and 1 patient had been operated twice. The procedure consisted in 10 MVR with a bioprosthetic valve and 45 with a mechanical valve. Associated procedures were 5 tricuspid annuloplasties, 13 aortic valve replacements, 1 tricuspid valve replacement, 4 CABG, and 1 aneurysm resection. Overall hospital mortality was 9.1 +/- 3.8% (5/55). Mortality for isolated MVR was 6.2 +/- 4.2% (2/32). 51% (28/55) were in sinus rhythm (SR) preoperatively, 43% (12/28) of them had never presented atrial fibrillation. Postoperatively among those 28 patients in SR, 20 remained in SR, 7 were in atrial fibrillation, and 1 in atrial flutter. 3.6% (2/55) needed transient electrosystolic pacing for very slow atrial fibrillation 20% (11/55) have presented a transient sino-atrial dysfunction; None of these rhythmic events had any adverse effect. Finally, the very good visibility and accessibility are the major advantages of this approach, especially in mitro-tricuspid combined procedures, in small left atrium and repeat surgery. As sino-atrial arrhythmias are transient, we think this approach can be routinely employed in MVR.