[Transesophageal echocardiography: a new view of the heart]. / L'échocardiographie transoesophagienne: une nouvelle vision du coeur.

Transoesophageal echocardiography is a simple technique which is now the object of a growing and well-deserved interest, due to the wealth of information it provides. This examination does not supersede the conventional transthoracic echocardiography, but it completes it by supplying more accurate data, especially in difficult clinical cases, such as mitral valve pathology, cardiac valve prostheses, intracardiac thrombosis, aortic dissection and septal abnormalities.

[Thrombosis of mechanical heart valve prosthesis. Value of transesophageal echocardiography in the study of mitral valve prosthesis]. / Thrombose de prothèse valvulaire mécanique. Intérêt de l'échocardiographie transoesophagienne dans l'étude des prothèses mitrales.

Forty-three consecutive patients with mechanical valve prostheses underwent transthoracic and transoesophageal echocardiography for suspected thrombolic prosthetic valve dysfunction. The results of these investigations were compared with those of cineradiography and the clinical outcome. The diagnosis of thrombosis was retained in 11 of the 43 patients (10 mitral and 1 aortic valve prostheses). The transthoracic Doppler echo was clearly abnormal in 6 of the 11 cases. Transoesophageal echo was of essential value in all cases but one, showing abnormal movement of the mobile element and/or a paraprosthetic thrombus. The cineradiography gave false negative results in 6 cases. In conclusion, these cases underline the undeniable value of transoesophageal echocardiography in occlusive or non-occlusive thrombosis of a mitral valve prosthesis. This investigation should be undertaken whenever there is the least suspicion of thrombosis of the prosthesis.

[Cardiac echo-Doppler in the diagnosis and surveillance of the course of acute endocarditis]. / Apport de l'écho Doppler cardiaque dans le diagnostic et la surveillance évolutive des endocardites aiguës.

Infectious endocarditis is still currently a problem. Its frequency is not decreasing and new etiologies have developed, which are often responsible for acute endocarditis, resistant to hospital bacteria. The cardiac Doppler has a role in the positive diagnosis of endocarditis, especially on native valves. This examination permits an accurate evaluation of valvular and perivalvular lesions (abscess, mycotic aneurysms) and their repercussions on the ventricle. Studies in this last decade, have emphasized that the presence of vegetations is a factor of gravity. The Doppler permits an "active" monitoring in high risk forms: endocarditis of the aortic orifice, endocarditis with perivalvular abscess, endocarditis occurring on a prosthetic valve.

[Acute aortic insufficiency. Diagnostic and prognostic value of cardiac ultrasonic Doppler]. / Insuffisance aortique aiguë. Intérêt diagnostique et pronostique de l'écho Doppler cardiaque.

Although infrequent, acute aortic insufficiency must be identified at an early stage. The clinical picture is often deceptive. Ultrasonic cardiography and cardiac Doppler represent, today, a diagnostic technique of choice which specify the mechanism of the acute valve leakage, the condition of the ascending aorta and the repercussions on the left ventricle.

Pacing-induced alternate Wenckebach periods: incidence and clinical significance.

Alternate Wenckebach periods have been defined as episodes of 2:1 atrioventricular (AV) block in which conducted P waves exhibit progressive PR prolongation until two or three successively blocked P waves. Ocurrence of this phenomenon during atrial pacing has been established. Thirty-six patients were studied and right atrial pacing was achieved at increasing rates up to 350 beats/min in order to induce alternate Wenckebach periods. His bundle recordings were obtained in every patient. The patients were subdivided into three groups according to the AV nodal conduction time (AH interval): normal AH (75-130 ms) was present in 17 patients, short AH (70 ms) in 13 patients and prolonged AH (130 ms) in eight patients. Alternate Wenckebach periods were observed in 29 patients (80.5%). In every patient alternate Wenckebach periods occurred at the AV node level. Atrial pacing failed to induce alternate Wenckebach periods in seven patients, six of whom belonged to the short AH group. In four patients 3:1 block never appeared because of block at the atrial level. Two patients presented 2:1 and 3:1 infrahissian block without significant AH prolongation. The remaining patient developed atrial fibrillation. Alternate Wenckebach periods were observed in six of nine patients after intravenous atropine. This study suggests: 1. pacing-induced alternate Wenckebach periods at the AV node level are a physiologic phenomenon; and 2. total or partial bypass (or accelerated AV conduction) atrial refractoriness or vulnerability or block at a lower level may prevent its occurrence.