[Vasovagal syncope: the value of tilt-table testing in the evaluation of loss of consciousness]

Syncope, an eminently frequent syndrome, has multiple and varied causes. Its diagnosis is important in view of the poor prognosis of cardiac syncopes and also of the morbidity and discomfort associated with the other etiologies. Unfortunately, the cause eludes us in half the patients so that a clear prognosis and effective therapy can be given to only a few patients. Tilt-table testing, alone or with isoproterenol, is now considered as a noninvasive, sensitive and specific method for identifying patients predisposed to vaso-vagal syncope, a major cause of syncope of unknown origin. Tilt-table testing also helps in tracking many pathologies contributing to syncopes. In the absence of a universal treatment of vasovagal syncope, tilt-table testing has revealed itself as a contributory guide to the best possible treatment.

Clinical usefulness of biplane transesophageal echocardiography

The clinical usefulness of biplane color Doppler transesophageal echocardiography is illustrated by the results obtained in 300 successive examinations. The additional contribution of the newer longitudinal plane was judged significant or major in 64% of the cases. The method was useful mainly for intraoperative examinations, assessment of native valvular disease, prosthetic valve evaluation, search for tumors, and assessment of endocarditis, congenital heart disease, and aortic disease. In contrast, the longitudinal plane option was not contributory in 68% of the cases of thromboembolism. Typically, the technique aided in the evaluation of mitral valve insufficiency and the detection of paraprosthetic leaks. Lesions located at the level of the ascending aorta, the left and right ventricular outflow tracts, and the interatrial septum were also visualized best. The limitations of the method were negligible and the duration of the examination was not significantly increased in comparison to the monoplane method. When available, biplane transesophageal echocardiography seems to be preferred in most clinical settings.

Perioperative mapping of parahisian accessory pathways

In 1989, two patients were operated for deep septal "parahisian" pathways in our institution. Three different mapping techniques were used. (1) Epicardial activation mapping with a belt of 21 bipolar electrodes positioned around the heart. This belt was positioned either on the atrial or on the ventricular side of the atrioventricular annulus in order to localize both the atrial and the ventricular insertion of the bypass tract. (2) Right intra-atrial activation mapping on the normothermic beating heart with a bipolar hand-held probe. (3) Right intra-atrial cryomapping at 0 degrees C. The "parahisian" pathways are remote from the epicardium and the pattern of epicardial activation is different from that of the free-wall pathways. Case 1: The electrophysiological study showed a concealed anteroseptal bypass tract. The peroperative atrial epicardial mapping during orthodromic tachycardia (OT) showed simultaneous activation of the posteroseptal area and of the basis of the right appendage. Right intra-atrial mapping during OT showed an anteroseptal "parahisian" pathway. Case 2: The ECG and electrophysiological study showed a right posterior pathway. The first site of epicardial ventricular activation during atrial stimulation was the right posterior area, 30 ms after the onset of the delta wave. The first site of epicardial atrial activation during OT was the posteroseptal area. The right intra-atrial mapping showed a posteroseptal "parahisian" bypass tract. This localization was confirmed with cryomapping.

CONCLUSIONS

Some patterns of epicardial mapping may suggest the presence of a deep septal "parahisian" bypass tract: retrograde atrial activation at different sites (mimicking activation among multiple pathways); delay between the delta wave and the first epicardial electrogram. Right intra-atrial activation and cryomapping are useful to confirm the diagnosis.

[Localization of the accessory pathway and surgical treatment in Wolf-Parkinson White syndrome]

The accessory bypass tracts are responsible for many episodes of supraventricular arrhythmias in man. The Wolff-Parkinson-White syndrome is the best example. These arrhythmias can be refractory to the medical treatment and are sometimes lethal. Different techniques can be used to destroy these pathways. The surgical dissection is the most widely accepted technique. The accessory pathways are made of working muscle and are neither visible, nor palpable by the surgeon. The electrical properties of these pathways are used to localize them. These techniques are either non-invasive or invasive. The non-invasive techniques consist of the careful analysis of the surface electrocardiogram in sinus rhythm and during tachycardia. The invasive techniques consist of a pre-operative electrophysiological study and intra-operative mapping. The electrophysiological study consists of the introduction of multiples catheters inside the heart through peripheral veins. The intra-operative mapping consists of measurements done on the surface or inside the heart after the chest has been open. After precise localization of the areas of insertion of these abnormal tracts the surgeon proceeds with the dissection, starting either on the epicardial or on the endocardial side of the heart. The surgical results are excellent and there are only few complications. These techniques were used to operate six patients presenting with the Wolff-Parkinson-White syndrome.

The spectrum of mitral regurgitation in idiopathic mitral valve prolapse: a color Doppler study

To characterize the spectrum of mitral regurgitation in mitral valve prolapse, one hundred patients were studied by color Doppler flow mapping. The findings were correlated with the clinical presentation and with the possible complications. Mitral regurgitation was absent in 46 patients, mild in 26 patients, moderate in 18 patients and severe in 10 patients. The jet orientation was central in 15 patients, antero-medial in 13 patients and postero-lateral in 26 patients. The regurgitation was early systolic in 7 patients, late systolic in 20 patients and holosystolic in 27 patients. A good agreement was observed between the color flow patterns and the presence, timing and radiation of a murmur. Systolic clicks were not predictors of the presence or the severity of regurgitation. The grade of mitral regurgitation was positively correlated with, age, left heart enlargement and valvular redundancy. No sex difference was observed. The prevalence of serious arrhythmias or cerebral ischemic events was not significantly increased when a regurgitation was present.

[Left ventricular function in obstructive chronic bronchopneumopathy]

Left ventricular (LV) function was studied, using echocardiography, radionuclide angiography and right catheterization, in 20 patients (mean age 60.9 +/- 1.5 years) with severe stable chronic obstructive pulmonary disease (COPD) and without known heart disease. The diagnosis of LV failure, suspected on clinical grounds in 8 of these patients, was confirmed by raised pulmonary capillary wedge pressure (PCWP) in only one patient. Nineteen subjects had normal PCWP and LV ejection fraction (LVEF) values, radionuclide LVEF and end diastolic LV dimension being the most powerful discriminators between the single abnormal patient and the others. Echocardiograms of sufficient quality were obtained in 11 out of the 19 normal patients and constantly showed LV dimensions in the lowest part of the normal range. The stroke volume index (SVI) - cardiac output being measured by thermodilution - was found to be decreased in 9 of 14 patients with normal LVEF values. We conclude that in patients with severe COPD (1) LV failure is quite unfrequent and the empirical use of digitalis should not be recommended, (2) radionuclide angiography is the most useful procedure for routine evaluation of LV function and (3) a decreased SVI is frequently found in patients with a small LV cavity and a normal LVEF, suggesting some degree of diastolic dysfunction of the left ventricle.

Predictors of the variation of the ejection fraction during exercise in patients with and without coronary heart disease

The aim of this study was to determine the factors influencing the different response of the ejection fraction (EF) of the left ventricle at exercise observed in patients with and without significant coronary heart disease. We have studied 98 patients referred for coronary angiography (82 men, 16 women), of whom 49 patients had a previous myocardial infarction and 71 patients had significant coronary heart disease. Exercise testing was performed and combined with a cardiac blood pool imaging at equilibrium. The variation of the EF between rest and peak exercise (delta EF) was measured. Twelve clinical, exercise-related, isotopic, and coronary arteriographic variables were examined in a linear univariate and statistical analysis. In the univariate regression, seven variables were significant regressors on the delta EF. In the multivariate regression, only four variables were significant regressors on the delta EF. Three independent predictors were found: the rate-pressure product, the ST depression, and the occurrence of a previous myocardial infarction. These three independent predictors reflect the myocardial functional reserve.

Late prosthetic valve endocarditis: review of 19 cases and treatment

Eighteen out of 1606 patients treated by valve replacement between January 1971 to June 1979 were admitted in Brugmann University Hospital for late prosthetic valve endocarditis. Of the 19 episodes (one patient had two distinct episodes four years apart), nine (group I) were treated medically and 10 (group II) by combined medical and surgical therapy. The infective organism was Staphylococcus epidermidis in two-thirds of our cases. Two cases in group I (22.2%) were long-term survivors. In group II, all 10 patients survived reoperation. There were four late deaths; six patients (60%) were still alive 1.8 to 4.4 years later (mean survival three years). Prompt prosthetic valve replacement is recommended in the presence of systemic emboli, evolving murmurs, uncontrolled sepsis or congestive heart failures (especially if the infective organism is a fungus or a staphylococcus), in late prosthetic valve endocarditis.

Effect of sotalol on haemodynamics and renin-angiotensin-aldosterone system in hypertensive patients

1. Twenty-three hypertensive patients were treated by sotalol, a pure beta-adrenergic receptor blocking agent. The drug produced a significant decrease of blood pressure in nineteen patients. 2. On average, cardiac index decreased but not significantly; heart rate decreased and stroke index increased significantly. Total peripheral resistance varied in both directions. 3. Sotalol determined a fall in plasma renin concentration (only significant in the high-renin group), a fall in plasma angiotensin II concentration and in urinary excretion rate of aldosterone accompanied by a rise in plasma potassium concentration. 4. The fall of blood pressure was not correlated with the decreases of renin and angiotensin II concentrations or excretion rate of aldosterone. However, in the placebo period plasma angiotensin II concentration was significantly correlated with total peripheral resistance; during sotalol treatment the variations of these two parameters seemed also to be correlated. 5. There was a poor correlation between decreases of cardiac output and of blood pressure; it was impossible to foresee the magnitude of the lowering of the blood pressure from the initial cardiac index. 6. The association of a diuretic with sotalol enhanced the hypotensive effect of the beta-receptor blocking drug, without significant increase of plasma renin and angiotensin II concentrations.