Biomedical subjects
Publications and source records attributed to P Besse.
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Intravenous trinitroglycerine (IV TNT) was used in 17 patients with myocardial pre-infarction syndrome defined by the presence of prolonged spontaneous attacks of attacks of angina, with electrocardiographic changes, persisting despite medical treatment with beta-blockers and oral nitrite derivatives. Seven patients had chronic angina, 7 had angina of recent onset and 3 patients had early post-infarction angina. IV TNT was used for 3 to 11 days at a mean dose of 40 micrograms/mn in 11 patients and 8 micrograms/mn in 6 patients. In the latter, cardiac output and pulmonary pressures were measured. IV TNT made it possible to decrease or stop angina attacks in all the patients except one. There was no significant variation in heart rate and mean blood pressure fell by 8 mmHg (p < 0.001). Cardiac index was maintained despite a fall in capillary pressure of 4.1 mmHg (p < 0.01). Coronary arteriography was performed in 16 cases, with circulatory assistance in 4 patients. Thirteen patients were treated by surgical revascularisation, with two operative deaths. IV TNT appeared to be effective and well tolerated treatment in these particularly severe forms of unstable angina.
The direct action of nitrate derivatives on myocardial contractility is not fully understood. The effects of Glyceryl Trinitrate (1 mM/L.) and Sodium Nitro prussiate (3 X 10(-5) M/L.) on papillary muscle were studied during 30 minutes hypoxia followed by 60 minutes reoxygenation: Both conditions were analysed every 5 minutes: 1. Contractility was assessed by maximal shortening velocity with no load (Vmax), maximal isometric force (PF), number of active cross-bridges and peak time (TPF), a characteristic of the period of activity. 2. Relaxation was assessed by the relaxation velocity (V relax) and the 1/2 relaxation time (THR). The two nitrate derivatives had the same effects: during anoxia, a notable reduction of the maximal force was observed; myocardial depression continued during the first 15 minutes of reoxygenation. After the 30th minute of investigation all parameters increased significantly (107-110 p. 100, p less than 0,01); TPF and THR returned to normal. A positive inotropic effect and improvement of the relaxation phase were observed at the end of reoxygenation. This effect is not attributed to improved segmental performance especially as it occurred at dosages close to those used in therapeutics.
The action of dysopyramide was studied in 13 patients, 11 with ventricular and 2 with supraventricular arrhythmias. The drug was given parenterally at first and then by mouth. The patients were monitored with an arrhythmia counter and the plasma levels of disopyramide measured throughout the treatment period. The plasma level was stable at about 4 micrograms/ml during the different phases. Toxic levels of 10 microgram/ml were observed in 1 patient in renal failure. The antiarrhythmic action was very effective (70% success), especially on the ventricular arrhythmias. Two of the four patients who failed to respond to treatment had low, non-therapeutic plasma levels. The dosage should be adapted with respect to the patient's weight and renal function.
The haemodynamic changes caused by intravenous mexiletine were studied in 12 patients. Initially the drug was given rapidly at the rate of 3 mg/kg/min for 10 minutes and then slowly at a rate of 0,06 mg/kg/min for 30 minutes. The plasma Mexiletine level measured after 20 minutes was used to divide the series of patients into two groups: in Group A the level was over 0,7 g/ml (0,961 +/- 0,109 microgram/ml) whilst in Group B the level was only 0,547 +/- 0,101 microgram/ml. The mean aortic pressure, heart rate and left ventricular end diastolic volume did not vary significantly in the two groups. The left ventricular end diastolic pressure rose, and the cardiac index and the ejection fraction fell in Group A. The indices of left ventricular contractility fell in all patients of the start of the injection. This depression only persisted to the end of the injection in Group A. Mexiteline did not cause significant changes in post extrasystolic potentialisation in the 5 cases in which this phenomenon was studied.
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A case of atrioventricular block (AVB) complicating hypertrophic obstructive cardiomyopathy is reported and analysed with respect to the results of cardiac catheterisation. The installation of 2nd degree AVB was associated with an increase of the intraventricular pressure gradient from 36 to 128 mmHg. This aggravation was related to the lenghtening of diastole which lowered the aortic diastolic pressure and allowed a more forceful ventricular contraction with a reduction in the calibre of the intraventricular stenosis. The sudden lenghtening of diastole also led to an increased contractility of the following systole. In complete AVB the increased gradient was related to a reduction in ventricular volume secondary to the loss of atrial systole. The 33 mmHg pressure gradient disappeared when spontaneous atrial systole or an atrial systole provoked by sequential atrioventricular pacing preceded ventricular contraction. Sequential atrioventricular pacing would seem to be the most appropriate pacing technique in hypertrophic obstructive cardiomyopathy complicated by complete AVB.
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The clinical significance and mechanism for changes in the axis of the QRS complex during attacks of angina pectoris (excluding cases of Prinzmetal's angina) are unknown. Previous work has suggested that left anterior hemiblock under these circumstances is a sign of unstable angina indicating a lesion in the anterior descending artery. Two cases with left anterior hemiblock associated with frequent attacks of angina have been the subject of careful study. In case one, atrial stimulation tests showed that the left axis deviation was not related to tachycardia. It only occurred when atrial stimulation was carried out for long enough to induce myocardial ischaemia as witnessed by precordial pain and disorders of repolarisation. In case two, the left anterior hemiblock came on at first at the same time as the attacks of angina, and then became permanent. Bypass graft of the anterior descending artery restored the QRS axis to normal, and corrected the repolarisation disorders which were of ischaemic origin. These findings argue in favour of an ischaemic origin of this conduction defect. Unlike ischaemia of the left anterosuperior subbranch, anterior left hemiblock is indicative of extensive ischaemia of the anterior wall of the left ventricle relative to an obstruction in the anterior descending artery or in the main trunk of the left coronary artery.
The cardiac function of 37 cases of ventricular dyskinesia were studied by cineangiography. The amplitude and speed of contraction of the contracting parts was evaluated as well as the volume of the akinetic zone. A score of coronary artery obstruction was made for those patients who underwent coronary arteriography. All the patients had resection of their aneurysm. Four patients died in the immediate post-operative period. Six patients developed a temporary low output state requiring circulatory assistance. Twenty-seven patients were operated on successfully without posing any haemodynamic problem. Good immediate and late post-operative results were associated with an ejection fraction of the contracting part greated than 0,40, a dyskinetic area less than 40% and a coronary artery obstruction index of less than 6. Resection of the aneurysm, sometimes associated with aorto-coronary bypass grafting (5 cases), led to a marked improvement in heart failure and/or disappearance of ventricular arrhythmias.
We have studied the fate of 49 patients with stenosis of the trunk of the left coronary artery of more than 50%. The follow-up period extends from 1,5 years to 5 years (with a mean of 33.83 +/- 13.55 months). The clinical picture was not characteristic. Unstable angina was found in 59% of cases. The exercice test (29 patients) was positive in 100%, with a mean depression of 3.3 mm. Stenosis of the trunk, which is rarely an isolated condition (8% of cases), is usually associated with disorders of the other main coronary vessels. Twenty six patients underwent surgery. Thirteen patients who were operable were treated medically. The performance of the left ventricle and the degree of involvement of the coronary arteries were comparable in these two groups. Seven inoperable patients were treated medically. Actuarial survival curves show a significant difference (p less than 0.01) in survival after two years between the operated cases (88%), the operable cases treated medically (60%), and the inoperable cases (57%). The decreased mortality of the operated cases corresponds also with a greater functional capacity in the survivors compared with that of the cases treated medically.
Left ventricular function was studied in 15 patients with rapidly progressive Duchenne de Boulogne muscular dystrophy. Only one patient had a previous history of cardiac failure. All patients had typical electrocardiographical changes. Haemodynamic and angiographic investigation was performed in all patients. Three groups of patients were distinguished according to angiographic criteria : group I comprising 7 normal patients. group II comprising 4 "intermediary" patients, and group III of 4 patients with hypokinetic cardiomyopathy. Segmental ventricular dyskinesis was observed in 6 patients. Mitral incompetence was present in 2 cases and mitral valve prolpse in 1 case. All patients had a normal resting cardiac index. Patients in group II and III had end diastolic left ventricular pressures greater than 15 mmHg. An intravenous angiotensin test was performed in 4 patients from groups I and II. Impaired left ventricular function was demonstrated in patients thought to be normal in the basal state. Finally, myocardial involvement in this group of patients runs a parallel course to the duration and severity of the peripheral muscular disease.
Twenty-two hypertensive patients with normal coronary arteriograms underwent a complete study of left ventricular performance. The patients were classified into three groups according to the findings on X-ray and ECG investigation: group I--ECG normal, X-ray normal (6 cases); group II--ECG showed left atrial hypertrophy, X-ray normal (7 cases); group III-ECG showed left ventricular hypertrophy, X-ray showed cardiac dilatation (9 cases). The results of this study were as follows:--cardiac ouptut was lowered in groups II and III;--end-diastolic volume was lowered in group II and raised in group III;--LVEDP was raised in groups II and III;--V max and VEC max were lower in groups II and III than in group I;--left ventricular compliance was diminished in groups I and II. Myocardial rigidity of the left ventricle was similar in the three groups. Hypertensive heart disease is therefore characterised by early changes in compliance of the left ventricle. These are associated with geometrical changes in the ventricle: disturbance of the volume/mass ratio of the left ventricle. These findings have therapeutic implications for the importance of beta-blockers.
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The haemodynamic action of I-V Cordarone have been studied in 20 subjects over a 15 minute period. Over the 15 minute period we studied variations in left pulmonary and ventricular pressures, in cardiac output, and in the paramaters of contraction VEC max, V max and Taylor's index. At a dose of 5 mg/kg there is a fall in peripheral resistance (1274 +/- 232 to 915 dynes/s/cm-5), and the measurements of contraction hardly vary. At a dose of 10 mg/kg, after an initial increase in output and a fall in peripheral resistance there occurs, after 4 minutes, an increase in left ventricular end-diastolic pressure (from 6 +/- 2 to 13 +/- 4 mmHg, P less than 0.01), and a lowering of contractility (VEC max reduced from 49.7 +/- 12.4 to 27.1 +/- 3.8, P less than 0.001). We have shown that the first phase of this response is due to the solvent (Tween 80), while the fall in contractility is due to the amiodarone. Doses above 10 mg/kg must be used with care, and only if there is no evidence of impaired cardiac function.
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A fragment of septum was removed for biopsy in 11 patients with obstructive cardiomyopathy who were undergoing surgery. Electron microscopi revealed an increase in the numbers of mitochondria, deposits of glycogen, and deforming fibrosis. As far as the components of muscle fibres are concerned, both lysis and synthesis of neosarcomeres are to be found, together with abnormalities of the Z band and disorientation of the myofibrils. The number and severity of these abnormalities were found to vary from patient to patient and also in different sections. Although these features are virtually constant in cases of obstructive cardiomyopathy, they are not specific for this condition; they are also found in cases of non-obstructive hypertrophic cardiomyopathy.