Biomedical subjects
Publications and source records attributed to P Defaye.
We report a case of inadvertent transarterial permanent pacing of the left ventricule that was not diagnosed on routine chest radiography or ECG. The malposition was diagnosed because of the rupture of the mitral valve cordage 2 months after pacemaker implantation. We emphasize the radiographic appearance of this rare malposition.
Non-invasive quantification of mitral regurgitation remains a clinical problem. The aim of this study was to assess a new methodology of Doppler echocardiographic assessment of the mitral regurgitant fraction. The study included 60 patients (average age 61 years) in sinus rhythm with mitral regurgitation. The cardiac output was measured by Doppler echocardiography at four sites: the aortic, pulmonary and mitral rings and at the tips of the mitral leaflets by a method previously validated and published. Using the average of the aortic and pulmonary cardiac outputs on the hand and the mitral cardiac output on the other, it was possible to calculate the regurgitant fraction: (mean mitral flow-mean aortic/pulmonary flow)/mean mitral flow. This was correlated with the Sellers angiographic grades of regurgitation. The results confirm this validated procedure: the correlation of aortic and pulmonary flows was good: r = 0.94. This also held true for mitral flow at the two sites: r = 0.96. The correlation between the Doppler echocardiographic regurgitant fraction and the angiographic estimation of the severity of mitral regurgitation was good: r = 0.89. There was a statistically significant difference between the Doppler echocardiographic regurgitant fractions corresponding to Sellers Grades I, II and III mitral regurgitation (p = 0.0001). This study shows that Doppler echocardiographic measurements of blood flow at different orifices of the heart applied to the quantification of mitral regurgitation is a reliable method, the use of which, with strict methodological criteria, may be proposed in everyday clinical practice.
One of the main advantages of Doppler echocardiography is the possibility of non-invasive measurement of blood flow at each valvular orifice. This method enables quantification of valvular regurgitation, the measurement of Qp/Qs in cardiac disease with atrial or ventricular shunts, and the interpretation of gradients and functional surface areas in valvular stenosis or prosthesis with respect to the underlying haemodynamics. In each of these application, the measurement of pulmonary blood flow is valuable as the reference blood flow, and even indispensible in cases of shunts. The authors' objective was to study the feasibility and accuracy of pulmonary flow measurement in 100 consecutive patients (40 women and 60 men, average age 56.7 +/- 17.5 years) with cardiac disease (82%) or healthy hearts (18%). A grading from A to D was accorded depending on the technical difficulty of the examination, each grade having three degrees: 1) difficulty of recording and poor quality Doppler spectrum, 2) difficulty of measuring orifice diameter by 2D echocardiography, 3) necessity of analysis of color coded anterograde flow to measure the pulmonary valvular orifice. Grade A was distributed to easily recordable measurements with no difficulty; grade B for measurements with one difficulty; grade C for measurements with 2 difficulties and grade D for investigations judged to be impossible or unreliable (3/3 criteria). The feasibility of measurement of the cardiac output at the pulmonary orifice was 88% (A:55%, B:25%, C:8%). The correlation between the pulmonary flow and reference measurements at the aortic and/or mitral valve and/or mitral annulus was 0.96. The average difference between the pulmonary and reference flow was 51 +/- 273 cc/min.(ABSTRACT TRUNCATED AT 250 WORDS)
Fainting (short loss of consciousness) is a frequent reason for a consultation in a general practitioner's or cardiologist's office. Four main causes are recognized commonly: cardial with auriculo-ventricular block and arrhythmias, vascular in particular vaso-vagal syncopes, neurologic and other causes. In 38 to 47% of the patients no etiology is found: these are syncopal attacks of unknown origin. The first diagnostic step comprises noninvasive investigations. A 24-hour recording of the ECG or a 'long strip' improve the diagnostic rate by 10%. They are particularly useful for sick sinus syndromes. The head-up tilt-test has been developed recently. It is very useful for detection of vagovasal syncope and permits to understand the pathophysiology and the therapeutic consequences of these disorders. This test plays a particular role for the diagnosis of syncopes of unknown causes and shows in 24 to 75% of the cases pathologic results. Patients at high risk for ventricular arrhythmia can be recognized by ECG with high amplification. Doppler investigation of the neck vessels, however, seems to be of low diagnostic value in syncopes. Invasive measures are the last line resort. Electrophysiologic studies provide criteria that are well defined. They are useful for detection of ventricular dysrhythmias and conduction disorders. This latter approach is reserved to patients with negative noninvasive tests and in particular with cardiopathy. The approach to syncope and the power of noninvasive and invasive tests is thus well established. However, in a certain number of patients the cause for fainting is not disclosed. Fortunately mortality is low in this particular group.
The aim of this study was evaluation of mid-term results, with a mean follow-up of 23 months (range: 6 months to 6 years), in 449 patients undergoing 500 consecutive angioplasty procedures before 1989. All of these 449 patients underwent primary angioplasty, and not dilatation after restenosis. Data processing of information, based upon a questionnaire filled out by the patient's own cardiologist, enabled 100 per cent follow-up. In these patients with a mean age of 56 (range: 32-83), angioplasty was single in 93 per cent of cases. The indication was unstable angina (45%), following a myocardial infarction (44%) or, more rarely, stable angina (10%). The anterior interventricular was dilated more often than the right coronary and circumflex (56%, 31% and 22% respectively). The cardiac survival rate of 41 months was 94.3 per cent, 78 per cent of patients not having experienced any serious coronary events at the time of last available information. 65 (sixty five) per cent of patients were asymptomatic and the Thallium stress test was normal in 67 per cent of them. Angina recurred in 17 per cent of patients, twice as often in women (p < 0.02). 14 (fourteen) per cent had undergone a bypass procedure and 14 per cent had been redilated. Comparisons by the Kaplan-Meier method showed less good results after the age of 57: higher mortality (p < 0.01), more frequent recurrences of angina (p < 0.05), more frequent aorto-coronary bypasses (p < 0.001). Aorto-coronary bypasses were commoner after dilatation of the anterior interventricular (p < 0.005), after multiple dilatations (p < 0.03) or after unstable angina (p < 0.05).
The measurement of cardiac output by the Doppler-echocardiography method is of considerable interest since, in contrast to other available techniques, it offers the possibility of the measurement of output at each valve orifice, thus providing a quantitative approach to valve regurgitation. The 4 basic data items required are: the surface area of the valve orifice, trans-valvular Doppler velocity spectrum, duration of ejection and of filling, and heart rate. A large number of studies have analysed the various investigation techniques and have shown their excellent correlation with reference invasive methods. In the light of experience acquired in our Echocardiography Laboratory, we recommend, in accordance with data from the literature, the exclusive use of pulsed Doppler and measurement of valve orifices by two-dimensional imaging at the point of insertion of the aortic and sigmoid cusps as well as at the mitral ring. A simplified method for the measurement of mitral surface area on the basis of TM records is suggested.
Measurement by Doppler-echocardiography of blood flow rates has the advantage over techniques for the measurement of cardiac output of determining the latter for each valve orifice, and of opening up an approach to the quantification of aortic and mitral regurgitation. This prospective study involving 103 subjects free of any valve leak showed the absence of an significant difference between aortic, pulmonary and mitral ring flow rates in a given individual. Correlations between results obtained at the three measurement sites were: r = 0.92 between aorta and pulmonary artery, r = 0.90 between aorta and mitral ring and r = 0.90 between pulmonary artery and mitral ring. These results support the validation of this technique and would justify its use in the evaluation, quantification and monitoring of mitral and aortic valve leaks.
The measurement of cardiac output at the extremity of the mitral cusps, by Doppler-echocardiography, is of fundamental value, in particular for the evaluation of valve regurgitation. However, it comes up against a theoretical difficulty resulting from constant variation in the surface area of this orifice during diastole. After reviewing the main measurement methods available in the literature, a simplified method based upon the diameter of the ring and calculation of a mean diastolic intercusp distance by TM is suggested. Evaluation of this technique in 101 patients free of valve of leak showed its feasibility to be close to 100% and the correlation with aortic (r = 0.90), pulmonary (r = 0.91) and mitral ring (r = 0.88) outputs was entirely satisfactory. Our method would thus seem to be a good compromise between digitalised integration methods for the measurement of mitral surface area--optimal but complex--and the aim of simplification compatible with routine clinical use.
Various methods are available today for the quantification of regurgitation by transthoracic Doppler. The present review deals with their respective usefulness in tricuspid insufficiency (TI). Despite their contribution in the domain of mitral and aortic insufficiency, precise quantification methods remain of very limited value regarding the tricuspid orifice, and this because of practical difficulties of application. Evaluations of the severity of TI is based, essentially, on a semiquantitative approach. Cartography of the regurgitation stream, by colour Doppler, is the chief method, despite its limitations which are clearly emphasised by the effects of the contrast test. The discovery, by pulsed Doppler, of laminar systolic flow is a sign of capital importance. It is indicative of massive TI and of particular anatomical and hemodynamic conditions, but it is uncommon. Systolic reversal of flow in the inferior vena cava is a good sign of severity but lacks specificity. In contrast, measurement of maximum velocities of TI, while essential for the evaluation of pulmonary pressures, is of no value in terms of the quantification of regurgitation. Transthoracic Doppler data must be taken together with those of transthoracic echocardiography, the esophageal approach offering nothing special, being essentially useful in lesion evaluation. The quantification of TI, by transthoracic Doppler, has derived only very little benefit from the current orientation of Doppler methods.
Although global mortality in the year following myocardial infarction is about 10%, this figure varies from less than 1% to more than 50% in some very high risk cases. The principal objective of clinical evaluation during the acute phase is to establish a prognosis and propose a rational strategy for myocardial revascularisation (by bypass grafting or angioplasty) in patients with a poor prognosis. An essential feature of this evaluation is to reduce health care costs and hospital stay to a minimum. Coronary angiography is the only investigation which allows assessment of the coronary circulation and is probably the best method of evaluating global and regional left ventricular function, two essential prognostic factors: on the other hand, it does not provide information about the presence of residual ischaemia or persistent myocardial viability in the infarcted territory. Some very high risk patients should undergo systematic coronary angiography to determine the possibilities for myocardial revascularisation: early post-infarction angina, left ventricular failure, chronic angina, elderly but valid patients... The indications of coronary angiography should also extend to patients with non-Q wave infarction, to young patients with myocardial infarction on thrombolysed infarcts: results of coronary angiography should then be compared with those of standard exercise stress testing. It is only in other situations, concerning a minority of patients, in which two attitudes may be considered: the first, to perform coronary angiography very early (within 24-48 hours of admission) allowing early discharge from hospital of many cases, completed later by standard exercise stress testing: any revascularisation procedure is considered at that time and requires a second hospital admission. The second attitude consists in performing coronary angiography between the 7th and 10th day only if some paraclinical changes are present: exercise stress testing then has an essential role; to improve its negative predictive value for absence of long-term coronary events it should be associated with radionuclide investigation of myocardial perfusion (thallium, MIBI) or with an evaluation or residual myocardial viability (labelled fatty acids, cyclotron). This attitude also allows early identification of "good candidates" for myocardial revascularisation.