Biomedical subjects
M Gueron
Publications and source records attributed to M Gueron.
Spontaneous regression of isolated stenosis of the left main coronary artery.
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Anomalous origin of the posterior descending artery from the obtuse marginal.
We describe a patient with an unusual coronary anatomic variant in which the obtuse marginal gives rise to the posterior descending artery. The angiographic features and clinical recognition of this anomaly are reviewed.
Echocardiographic and radionuclide angiographic observations following scorpion envenomation by Leiurus quinquestriatus.
The echocardiographic and radionuclide angiographic abnormalities in children after scorpion envenomation with L. quinquestriatus, were evaluated. Five children were severely hypertensive, one of them in respiratory failure and another had pulmonary edema. The results revealed poor global contractility 12-15 hr after the sting in three patients. The radionuclide angiograms also revealed poor contractility with low ejection fraction. There was enzymatic evidence of myocardial damage. The changes observed in the echocardiograms and radionuclide angiograms were attributed to catecholamine induced myocardial ischemia. The abnormalities observed suggest that systolic dysfunction plays a role in the pathogenesis of heart failure in scorpion envenomation, in addition to a decrease of left ventricular compliance and increased impedance to left ventricular emptying. The beneficial effects of nifedipine in hypertension and other cardiovascular manifestations justify the routine use of afterload reduction in children with cardiovascular manifestations after scorpion envenomation.
Vasodilators and calcium blocking agents as treatment of cardiovascular manifestations of human scorpion envenomation.
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Improved left ventricular function in myocardial infarction following intravenous thrombolytic therapy with acylated plasminogen activator.
Forty-six patients with acute myocardial infarction (MI) were treated within three hours of the onset of chest pain with an intravenous bolus (IV) of 30 units of anisolated plasminogen activator streptokinase complex (APSAC). Reperfusion was detected in 31 patients (67%) by clinical, electrocardiographic, and enzymatic criteria. The mean time elapsed between the onset of the chest pain to thrombolytic therapy was 114 +/- 53 minutes. Left ventricular ejection fraction (LVEF) was significantly better in patients with anterior and inferior myocardial infarction who had successful reperfusion, as compared with those who did not (48.8 +/- 13.0 vs 35.3 +/- 10.9, p less than 0.05 and 59.7 +/- 12.6 vs 47.9 +/- 15.3, p less than 0.05, respectively). The rate of reocclusion within three weeks was 22%. The overall one-year mortality was 4%. There were no serious adverse reactions following the thrombolytic treatment. Thus bolus IV injection of 30 units of APSAC is both safe and effective in preserving left ventricular function when given early in the course of acute myocardial infarction.
Vasodilators and hypertensive encephalopathy following scorpion envenomation in children.
Twenty-three children were admitted to a pediatric intensive care unit for scorpion envenomation with severe hypertension. The hypertension responded to analgesics and sedatives in 15 (65 percent) of the 23. The remaining eight children required specific antihypertensive therapy, and their condition promptly responded to intravenous hydralazine and sublingual nifedipine; rebound hypertension was observed in one. Hypertension is a frequent complication of a scorpion's sting in children, and specific antihypertensive therapy is indicated in severe cases. Hydralazine and nifedipine are effective and safe in such instances.
Asymptomatic or mildly symptomatic effort-induced myocardial ischemia: plasma beta-endorphin and effect of naloxone.
The hypothesis that endogenous opioids may be involved in reduced exercise-induced ischemic pain or in silent ischemia was tested. Fifteen male patients with coronary artery disease were tested in a randomized, double-blind crossover study. After a preliminary screening effort test they were divided into two groups: the first group of nine patients received an i.m. injection of naloxone 0.4 mg, or saline as placebo, and the second group, comprising six patients, received 4 mg naloxone or saline i.v. Effort testing was performed at weekly intervals on an ergometric bicycle, following the Bruce protocol. ECG, heart rate, blood pressure and pain perception were monitored continually. Blood was sampled through an indwelling venous catheter for beta-endorphin determination before, at the peak of, and 10-20 min following exercise. ST depression, heart rate, blood pressure and the double product were similar after naloxone and following saline administration. Beta-endorphin concentrations in plasma were significantly increased following exercise in the second group of patients. The increase in beta-endorphin concentration was larger when the patients were pretreated with naloxone (4 mg) than with placebo. However, chest pain was not significantly altered by either dose of naloxone.
[Cough associated with captopril and enalapril].
Persistent dry cough is not a known adverse reaction of captopril and enalapril. We present 5 patients with persistent dry cough severe enough to warrant withdrawal of the drug, which resulted in rapid and complete recovery. Challenge with the drugs induced recurrence of cough. The pathogenesis of the reaction is unknown, but possible mediators include bradykinin and prostaglandins.
[Long-term follow-up of prosthetic heart valves].
257 patients underwent single or double heart valve replacement between 1964-1986. In 141 (55%) after isolated mitral valve replacement, operative mortality was 14.8% and after 5, 10, 15 and 20 years, actuarial survival was 84%, 70%, 59% and 44%, respectively. In 70 who underwent isolated aortic valve replacement, operative mortality was 7.1% and after 5, 10, 15 and 20 years, actuarial survival was 85%, 85%, 72% and 72%. In 46 who underwent combined aortic and mitral replacement, operative mortality was 4.3% and after 5, 10 and 15 years, actuarial survival was 78%, 71% and 71%.
Gastrointestinal bleeding in calcific aortic stenosis.
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Follow-up of isolated mitral valve prosthesis, 1964-86.
We review the data of 141 patients who underwent mitral valve replacement between 1964 and 1986. In the majority of patients, a tilting disk or a Cage ball prosthesis was implanted. Overall operative mortality was 14.8%, and 120 patients who were followed for a mean period of 4.5 +/- 2 years (540 patient years) showed a late mortality (greater than 30 days postoperatively) of 20.8%. The actuarial survival was 84% at 5 years and 44% at 20 years. Most of the late deaths were cardiac related, with sudden death as the leading cause. The incidence of prosthetic valve-related complications--thromboembolism, bacterial endocarditis and warfarin-related hemorrhage--were higher than in other series; however, long-term survival was comparable. Delay in advising mitral valve surgery is the probable cause of some of the results observed in this series.
Follow-up of isolated aortic valve prosthesis, 1964-86.
Between May 1964 and November 1986, 70 patients underwent aortic valve replacement with (20%) or without (80%) additional surgical procedures. Most of the prosthetic devices were Starr-Edwards models and Björk-Shiley and Sorin tilting disks. Long-term follow-up (305 patient years) was assessed in 65 patients who survived the operation. Actuarial survival was 85 +/- 2% at 5 years and 72 +/- 6% at 20 years. The linearized rate of deaths occurring greater than 30 days postoperatively was 3.6% per patient year; sudden death was the most frequent cause of death. Preoperative functional capacity class significantly influenced the immediate outcome of surgery. Although the incidence of prosthetic valve-related complications was higher than in previous studies, survival rates were comparable.
Atypical ventricular tachycardia and alternating Osborn waves induced by spontaneous mild hypothermia.
A one-month-old infant developed atypical ventricular tachycardia, complete right bundle branch black, and alternating 2:1 Osborn waves during spontaneous mild hypothermia; 10 h after rewarming, the electrocardiogram was normal.
Respiratory failure in children following envenomation by the scorpion Leiurus quinquestriatus: hemodynamic and neurological aspects.
Nine children, hospitalized for severe respiratory failure following scorpion envenomation, were a part of a group of 61 youngsters and infants admitted to the Pediatric Intensive Care Unit of the Soroka Medical Center, Beer-Sheva during the years 1983-87 because of scorpion venom intoxication. Four out of the nine had cardiogenic shock, three had severe systemic hypertension and one had severe airway obstruction. All nine patients had central nervous system manifestations, including lethargy, confusion and agitation (three cases), and markedly reduced level of consciousness (six cases). Hemodynamic studies performed in two patients showed 'high pressure' (cardiogenic) pulmonary edema. Seven patients recovered completely, one died and another one was left severely handicapped. Hydralazine i.v. showed a remarkable effect on the systemic blood pressure and central nervous system disturbances in addition to mechanical ventilation. Based on our own experience and previous clinical and experimental studies, the possible pathogenetic mechanisms underlying the respiratory and central nervous system dysfunction following scorpion sting are discussed.
Coronary angiography in a patient with mirror-image heart ("situs inversus").
A right-sided heart associated with mirror-image atrial arrangement (situs inversus) is a rare condition. The incidence of coronary arterial disease in this setting is probably similar to that in the general population. Description of coronary angiography in this condition is very rare. We have recently catheterized such a patient. The necessary approach to coronary angiography is emphasized.
Cor pulmonale due to adenoidal or tonsillar hypertrophy or both in children. Noninvasive diagnosis and follow-up.
Four children, aged 1 to 3 1/2, were first seen with cor pulmonale, pulmonary edema and severe respiratory distress due to chronic upper airway obstruction secondary to adenoidal or tonsillar hypertrophy or both. Arterial blood gas values, electrocardiograms and chest x-ray films were compatible with cor pulmonale. Echocardiography (four cases) and radionuclide angiography (two cases) showed severe right ventricular and right atrial dilation with reduced right ventricular ejection fraction. Following surgery, all four children improved; their echocardiographic and radionuclide findings returned to normal. Cardiac catheterization, traditionally performed in such cases, was unnecessary. The diagnosis and follow-up of this syndrome are adequately performed noninvasively.
Chest thump terminating atrioventricular nodal reentry tachycardia.
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