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Biomedical subjects

J C Farcot

Publications and source records attributed to J C Farcot.

50 records · Page 3Linked to original sources

Two dimensional echocardiographic visualization of ventricular septal rupture after acute anterior myocardial infarction.

In three consecutive cases of ventricular septal rupture after acute anterior myocardial infarction, wide angle two dimensional echocardiography readily visualized the septal defect, permitting the defect to be localized and its size estimated. In addition, negative contrast echoventriculography identified a left to right shunt at the ventricular level. The echocardiographic findings were corroborated by cardiac catheterization data in all patients, by perioperative examination in two and by postmortem findings in one patient. Postoperative echocardiographic studies afforded demonstration of the patch closing the defect. In patients with acute myocardial infarction associated with the sudden appearance of a systolic murmur, two dimensional echocardiography should be performed promptly in order to guide the diagnosis and management of these critically ill patients. In some patients with severe cardiogenic shock, in whom a favorable prognosis depends on rapid treatment, two dimensional echocardiography may allow the patient to be taken to surgery immediately without further study.

Aged↗

New catheter-pump system for diastolic synchronized coronary sinus retroperfusion.

Coronary retroperfusion with the object of delivering oxygenated blood to the ischemic myocardium might be defined as the process of withdrawing blood from a systemic artery and reinjecting it into the coronary sinus. A diastolic synchronized retroperfusion catheter-pump system is presented and feasibility of achieving retrograde infusion of arterial blood was tested. An autoinflatable bladder catheter was specially designed to compartmentalize the coronary sinus at onset of diastole and insure unidirectional retrograde infusion of arterial blood. Bladder deflation at onset of systole allowed coronary venous drainage. Actuation of the retroperfusion bladder catheter was obtained from an electropneumatic console triggered by the electrocardiogram. In vitro and animal studies indicate that this system converted the natural (steady) arteriovenous shunt flow into an artificially pulsed shunt flow, with maximal positive flow in diastole and trivial negative flow in systole but did not alter absolute magnitude of shunt flow. Thus, diastolic synchronized retroperfusion of arterial blood through the coronary sinus may provide temporary protection from acute myocardial ischemia.

Animals↗

Regional left ventricular function assessed by contrast angiography in acute myocardial infarction.

The relationship of segmental left ventricular (LV) wall motion abnormalities to LV function 2-6 days after acute transmural myocardial infarction (MI) was investigated in 45 patients by quantitative contrast ventriculography. Patients were divided into four classes according to the MIRU criteria. Segmental wall motion was assessed by determining the percentage of systolic shortening (deltaS) along nine hemiaxes and the extent of akinetic or dyskinetic abnormally contracting segments (% ACS) expressed as a percentage of end-diastolic perimeter. When compared with that in 17 normal control-subjects, the LV end-diastolic volume was increased only in patients in class III and class IV; the LV end-systolic volume increased progressively from normal through class IV. Ejection fraction had a negative linear correlation with %ACS (r = 0.97). The size of ACS was larger in anterior (34 +/- 14%) than in inferior MIs (23 +/- 7%), resulting in greater LV dysfunction. However, for a comparable size of ACS, infarct location alone did not influence LV function parameters. In the noninfarcted zone, deltaS was increased when the size of ACS was less than 25% and reduced when the size of ACS was greater than 25%. Thus, the size of ACS is a major determinant of LV dysfunction in acute MI. The compensatory mechanisms operate either through an augmented mechanical function of residual myocardium when the infarct is small, or through the Frank-Starling mechanism when the infarct is large.

Angiocardiography↗

[Pericardial effusions (85 cases): radiological aspects (author's transl)].

A radiological study of 85 patients with acute pericarditis and effusion included a group of 35 cases observed before the introduction of ultrasonography and a second group of 50 patients in whom the presence of pericarditis had been confirmed by this investigation. The most important conclusions established were the following: --Absence of radiological signs in 55% of cases (group 1 : 46%, group 2 : 60%); normal heart size in 54% (group 1) and 78% (group 2), and increased size in 34% (group 1) and 20% (group 2). --Hilar manifestations (overlapping and obscuring of the left hilar region) in 26% of cases with a clear predominence of the left forms (14 out of 22). The cardiomegaly was not significant in 28% (group 1) and 14% (group 2). --The high frequency of pericarditis with a normal heart size has to be emphasized. The diagnostic value of hilar manifestations is also mentioned; the sign of left hilar overlapping is described in greater detail. --An overall comparison between the two groups shows, more particularly, the equal importance of left hilar manifestations for the radiological diagnosis of pericarditis. In a general way, it would appear that these hilar signs are the only elements which enable objective diagnosis of pericardial effusions on standard films.

Acute Disease↗

Synchronized retroperfusion of coronary veins for circulatory support of jeopardized ischemic myocardium.

A retroperfusion system was developed that augments retrograde delivery of arterial blood into an acutely ischemic myocardial region during diastole and facilitates coronary venous drainage in systole. An electrocardiogram-synchronized, gas-actuated bladder pump propels retroperfusate through an autoinflatable balloon catheter whose tip is placed within the regional coronary vein that drains the ischemic myocardium. Experiments were performed in 26 closed chest dogs with 4 hour intracoronary balloon occlusion of the proximal left anterior descending coronary artery. An untreated control series consisted of 13 dogs; the remaining 13 dogs were treated with retroperfusion, which was initiated after the first hour of acute coronary occlusion. Synchronized retroperfusion resulted in a significant 37 +/- 10 per cent (mean +/- standard error of the mean) decrease in left ventricular end-diastolic pressure from 11 +/- 2 to 5 +/- 21 mm Hg, a 20 +/- 4 percent decrease in peak systolic pressure (140 +/- 7 to 110 +/- 6 mm Hg) and a 25 +/- 6 percent reduction in systemic vascular resistance (3,880 +/- 340 to 2,380 +/- 300 dynes sec cm-5). Ischemic region intracoronary S-T segment elevation decreased 40 +/- 15 percent, and potassium loss was reduced 92 +/- 22 percent. Partial pressure of oxygen measured distal to the coronary occlusion decreased 36 +/- 2 percent, suggesting oxygen delivery to and extraction by the jeopardized ischemic myocardium. Ventriculography in four dogs revealed an increase in left ventricular ejection fraction and reversal of ischemic segment dyskinesia by synchronized retroperfusion. A nitro-blue tetrazolium study of 10 excised hearts indicated that 3 hours of synchronized retroperfusion significantly reduced the size of ischemic injury to 3.3 +/- 2 percent of the left ventricle (versus 16.2 +/- 5 percent in the untreated control group). In addition, retroperfusion appeared to correct ischemic arrhythmias. The experimental data suggest that this treatment is capable of improving cardiac function and salvaging jeopardized myocardium. Clinical application is envisioned as a prompt temporary emergency support for acute and profound ischemic dysfunction not readily treatable by other interventions.

Animals↗

[Moderate aortic incompetence due to traumatic rupture of a cusp].

The authors recall a case of moderate aortic incompetence caused by traumatic rupture of an aortic cusp occurring in a man of 36 years of age. Anatomical lesions of the aortic valve usually lead to severe incompetence for which surgical treatment is required. In this case, the lesion was well tolerated from the clinical and haemodynamic points of view, and surgery was not required; this tolerance has extended into the mid term. The authors emphasise the importance of echocardiography in the diagnosis of disturbance of an aortic valve, and also in following up the progress of the subsequent aortic incompetence.

Adult↗

Derangements of myocardial metabolism preceding onset of ventricular fibrilliation after coronary occlusion.

To determine alterations in myocardial metabolism and and hemodynamics that occur within the first 30 minutes after coronary arterial occlusion, before the onset of ventricular fibrillation, measurements were compared in two series of dogs. Series A, 90 dogs that did not manifest ventricular fibrillation after coronary occlusion, were considered a control group. Series B consisted of 28 dogs that had ventricular fibrillation within 30 minutes after occlusion. All had similar comprehensive measurements completed preceding the onset of ventricular fibrillation. The animals in series B (subseuqnt fibrillation) had significantly higher heart rates before and after coronary occlusion. In this series cardiac metabolism of the occluded segment judged by transmyocardial lactate extraction, potassium balance, sodium/potassium ratio and blood pH because grossly more abnormal after coronary occlusion than in series A. In 5 animals whose measurements were obtained within 5 minutes of the onset of ventricular fibrillation, a sudden massive lactate production, potassium loss and increased acidosis of the occluded portion supervened minutes before the onset of the fatal arrhythmia. Animals with ventricular fibrillation had higher intracoronary S-T segment elevation that persisted until the onset of ventricular fibrillation. Measurements of abnormal hemodynamic function (left ventricular end-diastolic pressure, peak systolic pressure and first derivative of left ventricular pressure [DP/dt]) were not associated with an increased incidence of ventricular fibrillation. The study indicates that animals that manifest ventricular fibrillation within 30 minutes after coronary occlusion have higher preocclusion heart rates, a more severe metabolic disorder of the coronary occluded segment and more persistent intracoronary S-T segment elevation compared with animals that do not manifest ventricular fibrillation.

Animals↗

Do risk factor interventions prevent or reverse arteriosclerosis?

We have attempted to summarize the current controversies regarding risk factors and preventive measures for control of arteriosclerosis and coronary heart disease. Recognizing that the genesis and development of the disease process are extremely complex and the basic knowledge is limited, it is not likely that conclusive answers to questions will be forthcoming soon which will provide more effective preventive or therapeutic measures. It might be desirable to institute educational and control program aimed at curtailing, at a young age, known AS risk factors such as heavy smoking, particularly if the family history indicates severe risk. Few will question the normal approaches to the treatment of complications of coronary heart disease by control of hypertension, elevated cholesterol, and smoking. However, great caution must be exercised when trying to institute large scale modifications in prevailing life patterns, particularly when based on indefinite risk factor studies and in the face of potentially profound and frequently unknown consequences. The unknowns of atherosclerotic heart disease risk factors, coupled with uncertainties and even doubts about protracted and expensive population studies, lead us to propose an emphasis on alternate selective approaches. We strongly believe that fundamental to progress in the field of arteriosclerosis is an amplification of preventive research efforts with stronger attention focused upon influencing the atherosclerotic processes within the arterial wall. But, more immediately, we urge systematic gathering and careful evaluation of patient data in particular population subsets which exhibit and accelerated mode of arteriosclerosis. Comparative studies of patients, particularly twins, families, and ethnic populations with redilection to early or accelerated arteriosclerosis may be extremely rewarding. Our repeated review of the enormous literature suggests that worldwide collaboration is needed to perfect more meaningful protocols as well as to correlate and critically evaluate existing data provided by population studies of this insidious disease process which represents an evermounting burden to society.

Adult↗

Significance of S-T segment elevations in acute myocardial ischemia. Evaluation with intracoronary electrode technique.

A method is described for measuring intracoronary S-T segment elevations in the closed chest, a technique that appears to provide more reliable measurements of myocardial ischemia. Electrodes were inserted through intracoronary balloon catheters that were placed within a coronary artery and its adjoining vein both proximal and at several points distal to a coronary occlusion. Intracoronary arterial and adjacent venous electrocardiograms produced equivalent tracings. The intracoronary S-T segment elevations after coronary occlusion resembled those recorded from the epicardial surface but were free of artifacts noted in open chest studies. Study of progressive alterations of the intracoronary S-T segment after proximal occlusion of the left anterior descending coronary artery in 18 closed chest dogs revealed a peak segment elevation of 3.2 +/- 0.6 mv within 5 minutes, followed within 2 to 3 hours by spontaneous reduction by more than 40% of the S-T elevation over the occluded zone. In 44% of these animals, the S-T elevation decreased spontaneously to less than 1 mv, and in 22% it decreased to the preocclusion control level within 2 hours of occlusion. This spontaneous decrease in S-T elevation was frequently followed by a secondary increase and then S-T segment fluctuations. Reperfusion of the left anterior descending coronary artery after 30 to 60 minutes of occlusion generally led to a prompt reduction in S-T elevation. In some cases S-T elevations persisted up to 14 hours of occlusion, were reduced after reperfusion and exhibited a renewed pronounced increase after subsequent reocclusion of the left anterior descending coronary artery. During the 1st hour after occlusion, the early S-T segment elevation followed by spontaneous reduction reduction generally corresponded temporally with the derangements in myocardial lactate extraction and potassium loss. However, after 1 hour of occlusion no clear-cut correlation could be established between S-T fluctuations and changes in hemodynamic or myocardial metabolic measurements. We conclude that the new closed chest intracoronary electrocardiographic S-T technique might be of use for monitoring the early ischemic myocardial derangements and to assess benefits or drawbacks of treatment in both the experimental animal and man. Correspondence of S-T segment elevation with lactate and potassium alterations in the coronary-occluded region in the 1st hour after occlusion indicates that S-T segment elevation might represent an index of early myocardial ischemia. The spontaneous S-T changes that follow coronary occlusion must be taken into consideration when investigators utilize S-T segment modification as a sign of effectiveness of treatment.

Acute Disease↗

Regional and global myocardial effects of intravenous and sublingual nitroglycerin treatment after experimental acute coronary occlusion.

The consequences of sublingual and intravenous nitroglycerin treatment after acute coronary occlusion were studied in 18 closed chest dogs. Intravenous (0.1 mg/min) or sublingual (0.4 mg/15 min) nitroglycerin therapy was instituted 1 hour after occlusion and the effects were observed over a period of 2 hours. Hemodynamics and global and regional cardiac function were measured in both the coronary occluded and nonoccluded segments of the left ventricle before and during coronary occlusion, and after administration of nitroglycerin. A similar nine dog control series was used to establish the significance of the measured effects of nitroglycerin. Intravenous nitroglycerin therapy after 1 hour of occlusion resulted in a marked increase in heart rate (37 +/- 12 [mean +/- standard error of the mean] percent), reduction of systolic blood pressure (9 +/- 3%), decrease in left ventricular end-diastolic and end-systolic volumes (32 +/- 5% and 34 +/- 5%), increase in coronary sinus flow (64 +/- 24%) and decrease in left ventricular stroke work (29 +/- 8%). Sublingually administered nitroglycerin produced similar trends but much less pronounced effects. However, intravenous or sublingual administration of nitroglycerin provided no improvement or caused further deterioration in ischemic region lactate extraction and potassium loss. The left ventricular ejection fraction, which was severly depressed after 1 hour of occlusion, changed minimally after administration of nitroglycerin, and there was no evidence of any correction of regional left ventricular akinesia or dyskinesia. Whereas mean systemic vascular resistance changed minimally as a result of nitroglycerin therapy, it increased 19 +/- 8% during a corresponding period of an untreated coronary occlusion series suggesting that nitroglycerin prevented an anticipated increase. Postocclusion S-T segment elevation in the electrocardiogram persisted after treatment. Our data corroborated that nitroglycerin reduced left ventricular volumes and increased coronary sinus flow; however, these improvements were accompanied by persisting metabolic and mechanical derangements in the ischemic region.

Animals↗

Methylprednisolone treatment in acute myocardial infarction. Effect on regional and global myocardial function.

The effects of methylprednisolong treatment on acute myocardial ischemia were studied in nine closed chest dogs. After 1 hour of proximal occlusion of the left anterior descending coronary artery, an intravenous bolus injection (50 mg/kg body weight) of methylprednisolone was administered and its effects studied during an additional 2 hours of occlusion. After 2 hours of treatment the following significant mean alterations from levels after 1 hour of occlusion were noted: an increase of 16.7% in heart rate and decreases of 23% in left ventricular end-diastolic pressure, 32% in stroke volume, 14% in cardiac output and 37% in stroke work. Peak systolic pressure, maximal rate of rise of left ventricular pressure (dP/dt), left ventricular end-diastolic volume, systemic vascular resistance and coronary sinus blood flow changed less than 10%. Ejection fraction and regional cardiac wall motion were not improved. Metabolic dysfunction of the coronary-occluded myocardium, revealed by regional lactate as well as potassium derangements, persisted throughout the 2 hour treatment period. Comparison of these results with equivalent data from an untreated series of nine dogs with 3 hours of occlusion demonstrated no improvement in the treated series. Methylprednistone failed to restore regional cardiac metabolic and mechanical function, and treatment was associated with a further rise in S-T segment elevations. Administration of methylprednisolone after 1 hour of proximal left anterior descending coronary occlusion apparently does not reverse cardiac dysfunction in the first 2 hours of treatment.

Acute Disease↗