Experimental demonstration and observation of a plasmon wave occuring at a GaAs-Au-GaN interface.

Integration of surface plasmon structures using semiconductor materials is limited due to the difficulties encountered in maintaining the resonance conditions upon packaging. We propose here a technology process allowing us to bond two semiconductors, such as gallium nitride (GaN) and gallium arsenide (GaAs), through a thin metal layer. This solution allows the excitation of a surface plasmon wave in an integrated classical Kretschmann configuration. The Letter presents various metal bonding conditions employed for Au deposited on both GaN/sapphire and GaAs substrates aiming at semiconductor-metal-semiconductor interfaces transparent at telecom wavelengths. The process conditions for the bondings are optimized using Ti/Au (3 nm/30 nm) layers on each of the wafers to be bonded under an applied pressure of 500 mbar at a low temperature of 250°C.

Apical hypertrophic cardiomyopathy: clinical and metabolic studies.

Among the hypertrophic non-obstructive cardiomyopathies, a particular group of patients with concentric apical hypertrophy can be described. We studied seven patients (five men and two women) who underwent heart catheterization because they had giant negative T waves in the precordial leads. M-mode and two-dimensional echocardiograms revealed no obstruction within the outflow tract of the ventricle. Coronary angiography was normal in all cases. None of these patients demonstrated any significant peak systolic pressure gradient in the outflow tract. A characteristic spade-like configuration (concentric apical hypertrophy) was observed in the right anterior oblique ventriculogram at end diastole. The apical thickness reached 17.2 +/- 0.85 mm and was significantly greater than mid-anterior wall thickness (9.8 +/- 2.14 mm). In five cases, atrial pacing with coronary arterial and venous lactate sampling revealed abnormalities in myocardial metabolism. With a mean follow up of 43 months, three patients remain asymptomatic and one had heart failure. ECG abnormalities were unchanged and echocardiograms showed an increase of the septal and posterior wall thickness, suggesting a transformation in concentric diffuse hypertrophic cardiomyopathy.

[Hemodynamic and coronary effects of methylergometrin]. / Effets hémodynamiques et coronaires de la méthylergométrine.

The methylergometrine test (ME) was performed during coronary angiography in 43 patients either by a single injection of 0,4 mg (34 cases) or by fractioned doses every 5 minutes of 0,1 mg, 0,2 mg, 0,3 mg, 0,4 mg (total 1 mg) (9 cases). Opacification of the coronary arteries was performed 1, 3 and 5 minutes after each injection; left ventricular pressures were recorded with a Millar catheter-tip transducer. The heart rate and first derivative of left ventricular pressure did not vary significantly after the 0,4 mg single dose ME. Left ventricular end systolic pressure rose by 11 p. 100 (p less than 0,001) and left ventricular end diastolic pressure from 18,3 to 23,1 mmHg (p less than 0,001). Myocardial oxygen consumption assessed by the TTI rose from 2873 +/- 896 to 3083 +/- 788 mmHg.s-1 .min (p less than 0,01), but myocardial contractility as assessed by the V max fell from 1,68 +/- 0,40 to 1,58 +/- 0,35 s-1 (p less than 0,001). The reduction in the calibre of the coronary lumen was identical after the single 0,4 mg dose and the 1 mg fractioned doses. In the later case, 50 p. 100 of the maximal response was observed after the first injection of 0,1 mg. After the single dose of 0,4 g ME the reduction in coronary lumen was very rapid over the first 3 minutes. Prolonged observation up to the 10th minute (7 patients) showed slight aggravation of the vasoconstriction between the 5th and 10th minutes, justifying an injection of a nitrate derivative before discontinuing surveillance. The vasoconstriction induced by ME seems to be within the physiological limits of vasoconstriction. The maximal overall decrease of the coronary diameter was 12,3 +/- 7,8 p. 100 and never exceeded 20 p. 100. There was a significant difference in the response of atheromatous patients in whom the vasoconstriction was greater in the presence of resting angina than in the absence of resting angina (16,4 +/- 8,7 p. 100 compared to 9,7 +/- 6,4 p. 100, p less than 0,01).

Detrimental effect of propranolol in patients with coronary arterial spasm countered by combination with diltiazem.

This study determines, with quantitative variables, if propranolol is detrimental in patients with documented coronary arterial spasm and if this drug can be used in combination with calcium antagonists. Eleven patients with documented coronary spasm were entered prospectively in a study with 4 phases of 2 days each: (1) control, (2) diltiazem or propranolol (mean 225 +/- 75 mg/day), (3) propranolol or diltiazem (360 mg/day), (4) propranolol and diltiazem. The effects of the drugs were assessed by the detection of ischemic electrocardiographic episodes (24-hour electrocardiographic monitoring) and provocative tests with ergonovine. During the period of treatment with propranolol, the number and the duration of attacks increased and provocative tests had positive results in all patients. Diltiazem completely abolished spontaneous episodes, but 6 of 11 patients remained sensitive to the administration of ergonovine. The association of the 2 drugs led to a disappearance of ischemic episodes. In conclusion, propranolol is ineffective in patients with coronary artery spasm. It can be used in combination with diltiazem, but without any advantage over diltiazem alone.

The provocation of coronary arterial spasm in patients with recent transmural myocardial infarction.

Provocative tests for coronary spasm were performed in a group of 131 patients (124 men and 7 women) with recent (less than 6 weeks) transmural myocardial infarction. Coronary arteriography was performed 27 +/- 9 days after the onset of the infarction. The provocative test was performed using a single IV bolus of 0.4 mg of ergometrine. Aortic pressure, ECG and arteriograms of the two coronary vessels were repeated 3 and 5 min later. Provoked spasm was observed in 27 (21%) of the patients. In 13 (48%) the coronary spasm occurred in a vessel presumed to be responsible for the myocardial infarction, while it was observed in coronary artery unrelated to the area of the infarct in 14 (52% of the cases with spasm). Thus, this study demonstrates a high degree of reactivity of the coronary tree of patients with recent transmural myocardial infarction suggesting the likelihood of a role for spasm in the infarction process and offering some explanation for subsequent recurrent ischemic events.

[Coronary artery spasm. Apropos of 165 cases]. / Le spasme artériel coronaire. A propos de 165 observations.

This study comprised 165 cases of coronary artery spasm (147 men and 18 women) with an average age of 49,2 years (range 27 to 73 years). Smoking was a particularly significant risk factor. Symptoms were usually of recent onset (80%) and dominated by attacks of angina pectoris either at rest alone or associated with angina of effort. 14% of cases of spasm were observed during acute myocardial infarction. Some cases presented with syncope due to cardiac arrhytmias. The basal electrocardiogramme was normal in 53% of cases. Exercise stress testing may be normal (30/65 cases) or positive (ST depression recorded in 26/65 cases). In 5 cases, ST elevation was observed. Left ventricular function was usually normal: 115 patients (70%) had organic atherosclerotic lesions, with 1, 2 and 3 vessel disease in 40%, 18% and 22% respectively. Spasm was spontaneous in 24,2% of cases but most commonly provoked by ergometrine. Criteria of spasm only applied to focal spasm and exclused catheter--induced spasm. The most common site of spasm was the right coronary artery (50,3% of cases), followed by the left anterior descending (31% of cases) and left circumflex (10,3% of cases). The outcome of these 165 cases depended on the therapeutic options (surgical treatment in 48 cases). The medium term results were generally good with a low mortality rate and follow up showed that the calcium antagonists provided effective prophylaxis against recurrence of spasm.

[Right ventricular dysplasia: Uhl's disease. Echocardiography and tomodensitometry study. Apropos of a case in an adult]. / Dysplasie du ventricule droit: maladie de Uhl. Etude échocardiographique et tomodensitométrique. A propos d'une observation chez l'adulte.

The author discusses Uhl's disease in a 60 year old patient as indicated by right ventricular insuficiency without troubles of the ventricular rhythm. Echocardiography revealed the distinctive symptoms of this illness (dilation of the right cavities, diastolic opening of the pulmonary valve, delayed closing of the tricuspid valve) emphasizing its diagnostic value. The contribution of tomodensitometry is considered.

[Incidence of induced coronary artery spasm in recent acute transmural myocardial infarction]. / Fréquence du spasme artériel coronaire provoqué au cours de l'infarctus du myocarde aigu transmural récent.

A number of studies have suggested that coronary spasm may play a role in the genesis of myocardial infarction. We carried out a provocation test with 0,4 mg intravenous methylergometrine in 131 patients undergoing routine coronary angiography at least 6 weeks after transmural myocardial infarction. The 124 men and 7 women of equal mean age of 49,6 years underwent the investigation on average 27 +/- 9 days after the date of onset of myocardial infarction. Seventy four patients had anterior infarcts (antero septal, anterior, apical), 55 had inferior infarcts (inferior, diaphragmatic and true posterior) and 2 had lateral wall infarcts. Thirty two patients with anterior infarcts (45 p. cent) had a single vessel disease of the left anterior descending artery, 19 had double vessel disease (25 p. cent), 16 had triple vessel disease (21,6 p. cent). During the provocation test with methylergometrine, 13 patients (17,6 p. cent) developed a spasm, 6 on the left anterior descending, 6 on the right coronary and 1 on the left circumflex artery. The patients with insignificant coronary lesions (7 cases) did not develop focal spasm. Twenty seven patients with inferior infarcts (49 p. cent) had single vessel disease, 19 had double vessel disease (34,6 p. cent) and 9 patients had triple vessel disease (16,4 p. cent). The provocation test induced spasm in 14 of the 55 patients (25,5 p. cent). The spasm was localised on the right on the right coronary artery in 9 cases, on the left circumflex in 3 cases and the left anterior descending artery in 2 cases. Therefore, in the whole population studied, 27/131 patients (21 p. cent) developed focal spasm after methylergometrine. In 13 cases, the spasm was observed in the coronary artery presumed to be responsible for the infarct, and in 14 cases on a vessel which did not correspond to the infarcted territory. Resting angina preceded myocardial infarction in only 6 of these 27 patients. This study does not confirm that coronary spasm was the cause of myocardial infarction. It does show the presence of a certain degree of reactivity of the coronary vessels after recent myocardial infarction. Half of the cases of spasm occurred on the vessel presumed responsible for the infarct but the other cases occurred in another zone, which suggests the possibility of post-infarction angina or even a recurrent myocardial infarction. This would be an indication for prophylactic treatment with calcium antagonist drugs.

[Strategy of the treatment of vasospastic angina pectoris]. / Stratégie du traitement de l'angine de poitrine vasospastique.

The strategy of treatment in vasospastic angina is mainly based on the results of coronary angiography. In a series of 165 patients with coronary spasm documented by angiography, 51 patients (31 per cent) had angiographically normal arteries and 69 per cent had organic atherosclerotic lesions. Patients with fixed atherosclerotic lesions were divided in two subgroups depending on whether the lesions were operable. The first subgroup (47 cases) comprised patients with operable lesions and coronary spasm. They underwent aorto-coronary bypass associated with a procedure to prevent spasm (plexectomy) (40 cases). Depending on the site of the lesions, some patients with operable lesions may benefit from coronary angioplasty followed by treatment with calcium antagonist drugs. Patients in the second subgroup (67 cases) with inoperable fixed atherosclerotic lesions were treated with calcium antagonists. Betablockers, which may be considered in organic coronary artery disease, are theoretically contra-indicated because of the vasospastic factor. The remaining patients with "angiographically normal" vessels (51 cases) were treated with nitrate derivatives and calcium antagonists. Treatment should be directed to the suppression of the clinical symptoms and, above all, of ECG signs of ischemia as proved by repeated Holter monitoring. The clinical course may also be assessed by repeated provocation tests. Results may depend on the doses and their timing during the 24 hour period. Duration of treatment in patients with angiographically normal vessels has not yet been established. Isolated cardiac denervation may be indicated in these patients who fail to respond to medical treatment (8 cases).

What is the role of the coronary circulation in congestive heart failure?

Manifestations of congestive heart failure are frequently observed in patients with coronary disease. However, they may be predominant in patients who have sustained prior myocardial infarction, in whom left ventricular aneurysm or papillary muscle dysfunction may induce left ventricular dysfunction. A small group of patients can develop severe cardiac insufficiency and pump failure on the basis of diffuse occlusive coronary artery disease. Heart failure can also be induced by congenital coronary abnormalities and in congestive cardiomyopathy some previous studies have suggested a decrease of coronary blood flow per unit of myocardial mass. Moreover, coronary artery disease can be associated and worsened congestive heart failure can result from other causes (e.g. valvular disease). However, congestive heart failure per se can also disturb coronary circulation as a result of changes in subendocardial myocardial perfusion or metabolism.

Coronary hemodynamics following intravenous or intracoronary injection of diltiazem in man.

We measured coronary sinus blood flow by continuous thermodilution technique and aortic pressure after administration of diltiazem to 23 patients with coronary artery disease. In one group of patients (n = 12) the drug was infused at a rate of 0.15 mg/kg during 2 min followed by an infusion of 0.05 mg/kg during 8 min. Heart rate was unchanged except at 5 min when it decreased slightly. Aortic pressure was significantly (p less than 0.01) decreased, while coronary sinus flow increased slightly and transiently. A second group of patients (n = 5) received an intracoronary injection of 0.15 mg/kg of diltiazem into the left coronary artery. In a third group of patients (n = 7) 0.05 mg/kg of diltiazem was injected into the left coronary artery. In both these two groups the drug induced a marked increase of coronary sinus flow and a decrease of aortic pressure, while myocardial oxygen consumption was unchanged. This effect was dose related, since the rise in coronary flow was 47% with an injection of 0.15 mg/kg but only 23% with a dose of 0.05 mg-kg. These changes were short-lasting with values returning to normal within 10 min after the injection. We conclude that diltiazem is a potent dilator of coronary arteries.

[Treatment of a severe coronary artery spasm, refractory to complete denervation of the heart (autotransplantation)]. / Traitement d'un spasme artériel coronaire sévère, réfractaire par dénervation complète du coeur (autotransplantation).

The case reported is that of a 49 year old man with very severe Prinzmetal angina due to spasm of the left circumflex artery. Despite intensive medical treatment he continued to suffer frequent attacks with atrioventricular block. As plexectomy was not possible in this case, complete cardiac denervation was performed. After surgery, he had no further attacks and continuous ECG monitoring showed no ischemic phenomena. Nevertheless, a stress test was still able to induce spasm of the same artery which was painless but associated with ECG changes. Eighteen months postoperatively, resting angina recurred with positive stress tests giving painful attacks. Four hypotheses are discussed: 1) the local factor was very important, with a zone of hyperactivity on the left circumflex artery, 2) one of the mechanisms of coronary artery spasm could be the nervous stimulation of this zone, 3) this zone was insensitive to nervous stimulation after autotransplantation but remained sensitive to methylergometrine, 4) the recurrence of resting angina and painful symptoms on stress testing suggests the possibility of reinnervation of the heart, as has been shown after cardiac transplantation, the autonomic nervous system does not play the role generally attributed to it in the genesis of spasm.

Frequency of provoked coronary arterial spasm in 1089 consecutive patients undergoing coronary arteriography.

We established the incidence of coronary artery spasm provoked by 0.4 mg of methergine in 1089 consecutive patients undergoing coronary angiography. The test was performed after routine coronary arteriography. Subjects included patients with angina, both typical and atypical, patients who had recently had myocardial infarction and patients with either valvular disease or congestive cardiomyopathy. Patients with spontaneous spasm, left main narrowing or severe three-vessel disease were excluded. One hundred thirty-four patients experienced focal spasm. Focal spasm was uncommon in patients with atypical precordial pain (1.2%), angina of effort (4.3%), valvular disease (1.95%) or cardiomyopathy (0%). It occurred most often in patients with angina at rest and less often in patients with angina both at rest and induced by exercise. Spasm was provoked in 20% of patients with recent transmural infarction, but in only 6.2% of patients studied later after infarction. Spasm was superimposed on fixed atherosclerotic lesions in 60% of the patients. No serious complications were encountered. Although the patients who underwent provocation tests in this study are not representative of all patients with coronary artery disease, spasm occurred in 20% of patients who experienced a coronary event and in 15% of patients who complained of chest pain.

[Surgical treatment of Prinzmetal's angina pectoris by plexectomy associated with aortocoronary bypass. Apropos of 56 cases]. / Traitement chirurgical de l'angine de poitrine de Prinzmetal par plexectomie associée au pontage aorto-coronaire. A propos de 56 observations.

The results of coronary bypass surgery are generally not as good in Prinzmetal angina as in classical angina pectoris. The percentage of myocardial infarction, recurrent angina and death is much higher. One reason for these failures could be the persistence of coronary spasm. In order to prevent this, denervation of the pre-supra and retro aortic nerve plexuses was carried out in 56 patients (54 male, 2 female) with Prinzmetal angina and operable coronary arterial lesions. Forty patients had documented coronary spasm mainly of the left anterior descending (20 cases) or the right coronary artery (13 cases). Surgery consisted of cardiac denervation associated with direct myocardial revascularisation by implantation of I (37 cases), 2 (13 cases) or 3 (6 cases) aorto coronary bypass grafts. Two deaths were observed in the perioperative period (one low output syndrome and one severe arrhythmia) and one myocardial infarction in the postoperative period. Of the 54 survivors, 49 are asymptomatic and 2 have recurrent spontaneous angina. Exercise electrocardiography in 44 patients was negative in 40 cases. Continuous electrocardiographic recordings (Holter method) in 33 patients was negative for ischemia and of 25 bypass grafts controlled, 24 were patent. Seventy five methylergometrine provocation tests were performed: only 2 were positive, both in patients with recurrent attacks. Therefore, with respect to the total numbers of recurrent angina (2), post operative infarction (I), peri and post operative deaths (3), the percentage of poor results was only 10,7 p. 100, almost three times lower than in previously reported series. In conclusion, we can say that the association of cardiac denervation with coronary bypass surgery significantly improves the percentage of good results (89,3 p. 100 of patients presenting with Prinzmetal angina).

[Hemodynamic and coronary effects of isosorbide dinitrate: comparison of intravenous and intracoronary injection]. / Effets hémodynamiques et coronaires du dinitrate d'isosorbide: comparaison entre les voies d'injection intracoronaire et intraveineuse.

The hemodynamic and coronary effects of a single dose of 3 mg of isosorbide dinitrate (ISD) were studied in 26 patients after intra-coronary (17 cases) and intravenous injection (9 cases). The study was carried out after opacification of the coronary arteries and a 0,4 mg ergometrine test. The radiological contrast and ergometrine increased left ventricular end diastolic (10,4 +/- 0,89 mm Hg to 22,5 +/- 1,88 mm Hg) and systolic pressures (131,4 +/- 4,8 mm Hg to 158,7 +/- 5,8 mm Hg) without changing V max. After ergometrine, the diameter of the coronary vessels decreased by 8,8%. After ISD, these pressures fell significantly from the 10th second; the lowest pressure after ISD was related to the initial pressure at the end of the ergometrine test (systolic pressure Y = 0,68 X + 6,39, R = 0,89, p less than 0,001) ( end diastolic pressure : Y = 0,36 X + 0,17, R = 0,68 , p less than 0,01). Moderate transient tachycardia was probably a reflex reaction. The increase in V max, maximal after 1 to 2 minutes, seemed to have a different mechanism. The global effect is to decrease myocardial oxygen consumption as reflected by the fall in the tension - time - index (3083 +/- 2,13 to 2330 +/- 184 mm Hg . sec-1 . min . The diameter of the coronary vessels rose by 26% with respect to the smallest diameter observed after ergometrine. The intracoronary and intrafemoral venous injection gave identical hemodynamic and coronary changes from the first minute. The effects were maximal between 2 and 4 minutes and continued after 10 minutes. The only difference was a more rapid decrease in systolic pressure after intrafemoral administration. Dilatation occurred before the hemodynamic effects after intracoronary injection, which is an argument for using intracoronary ISD in the treatment of spasm induced by ergometrine.