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Biomedical subjects

J L Gerry

Publications and source records attributed to J L Gerry.

12 recordsLinked to original sources

Clinical management of the cardiovascular complications of the Marfan syndrome.

The Marfan syndrome is an autosomal dominant disorder of connective tissue with manifestations throughout the body. Diagnosis is based on the cardinal effects on the skeletal, ocular, and cardiovascular systems. Long limbs and digits, thoracic cage deformity, dislocation of the ocular lens, mitral valve prolapse, and dilatation of the aortic root are typical signs. Before recent advances in management, valvular regurgitation and aortic dissection accounted for over 90 percent of deaths, often in the third through fifth decades of life. Echocardiography, introduced nearly 2 decades ago, and the recent enhancements of cardiovascular Doppler techniques have greatly improved the ability of identifying patients with Marfan syndrome and following their clinical courses. Cardiovascular surgery has progressed over the same period to provide Marfan patients relatively safe approaches to repair of the life-threatening complications, and surgery should be offered prophylactically. The ability to intervene effectively in the Marfan syndrome requires a clear understanding of its natural history throughout life. This review discusses the clinical course and current management of the cardiovascular complications of the Marfan syndrome in children, young adults, and women considering pregnancy. These approaches have relevance to valvular and aortic problems found in the general population.

Aortic Aneurysm

Effects of nitroglycerin on regional myocardial ischemia induced by atrial pacing in dogs.

The exact mechanism or mechanisms by which nitroglycerin exerts its beneficial effect on pacing-induced regional myocardial ischemia has not been ellucidated previously. In an open-chest, anesthetized canine preparation a fixed, flow limiting stenosis was applied to the left anterior descending (LAD) coronary artery and heart rate was increased by atrial pacing. Mass spectrometry was used to measure myocardial oxygen (PmO2) and carbon dioxide (PmCO2) tensions. Myocardial blood flow was measured by the radioactive microsphere technique. Application of the stenosis resulted in regional decreases in PmO2 and increases in PmCO2 of greater magnitude in the subendocardial than in the subepicardial layer. Atrial pacing resulted in a further decrease in PmO2 and increase in PmCO2 as well as a reduction in subendocardial blood flow. Nitroglycerin (TNG) infusion reduced mean arterial pressure 20 mm Hg, resulting in a 14 mm Hg reduction in PmCO2 in the more ischemic subendocardial layer (P less than 0.05). Myocardial blood flow decreased in all regions; however, the magnitude of this decrease was less in the ischemic region. Addition of aortic constriction abolished both the afterload and preload lowering effects of nitroglycerin but improved ischemic zone blood flow. These data demonstrate that nitroglycerin reduces the severity of pacing-induced regional myocardial ischemia primarily by reducing the determinants of myocardial oxygen demand. We found that when these effects are counteracted, improvement in myocardial oxygen supply becomes the dominant mechanism.

Animals

Evidence for a flow-independent contribution to the phenomenon of thallium redistribution.

Although thallium-201 is known to redistribute slowly into regions of ischemic myocardium after restoration of blood flow, it is not clear to what extent normalization of flow is an essential requirement for the redistribution process. In a search for a flow-independent component of thallium redistribution, 12 dogs with stenosis of the circumflex coronary artery underwent atrial pacing for either 20 minutes (group I, 6 dogs) or 2 hours (group II, 6 dogs). Radioactive thallium and radioactive microspheres, 7 to 10 mu, were injected after 10 minutes of atrial pacing in both groups. Pacing resulted in a 40 percent reduction in subendocardial blood flow to the circumflex-perfused myocardium in both groups I and II. This relative reduction in flow was maintained at a stable level over the 2 hour pacing period in group II. Thallium activity in the relatively ischemic zone was significantly greater in dogs with 2 hours of pacing (group II) than in those with 10 minutes of pacing (group I). Redistribution of thallium occurred despite the continued presence of reduced flow in circumflex-perfused endocardial tissue. These data suggest that a significant component of thallium redistribution may be flow-independent.

Animals

Predictability of the response to the ergonovine test. Value in the diagnosis of coronary spasm.

Thirty-five patients with atypical chest pain were given ergonovine maleate as a provocative test for coronary spasm. None of the patients had significant coronary atherosclerosis. The patients were divided into two groups based on clinical information available before ergonovine testing. Group 1 patients (n=13) had objective evidence of cardiac disease manifested by episodes of syncope, ventricular tachyarrhythmias, myocardial infarction, or transient ST segment shifts with chest pain. Group 2 patients had chest pain but no objective evidence of cardiac disease. The ergonovine test was positive in 11 of 13 patients in group 1. None of the 22 group 2 patients had a positive response to ergonovine. These data suggest that ergonovine testing does not allow for any more precise recognition of patients with atypical chest pain who have coronary artery spasm than do clinical data alone.

Adult

Clinicopathologic analysis of cardiac dysfunction in 52 patients with sickle cell anemia.

Clinical studies have long suggested the presence of a specific cardiomyopathy in sickle cell anemia secondary to intracoronary thrombosis and subsequent infarction. Fifty-two autopsy patients were studied (48 with SS hemoglobin, 4 with S-C or S-Thal hemoglobin) to ascertain the range of cardiac pathologic abnormalities associated with this disease. The average age was 17 years (range 1 month to 48 years). Renal failure and infection were the most common causes of death; the former was a more common cause in adults than in children. Right and left ventricular hypertrophy and dilatation were the most common abnormal pathologic findings. No evidence of recent or remote myocardial infarction, coronary thrombosis or arteritis was noted in any patient. Eight patients who were studied with postmortem coronary arteriograms exhibited markedly increased coronary arterial caliber with no evidence of atherosclerosis. Seventeen of the 52 patients studied had clinical evidence of congestive heart failure before death. Of these 17 patients, 7 had moderate to severe left ventricular hypertrophy associated with chronic renal failure and hypertension, 2 had right ventricular hypertrophy with organized pulmonary thrombosis, 2 had rheumatic mitral valve disease and 2 died during the second trimester of pregnancy. Two of the 17 patients thought to have pulmonary edema before death in fact had aspiration pneumonia and hemorrhagic pneumonitis, respectively. The data suggest that cardiac dysfunction in sickle cell anemia can usually be explained by the adverse effect of coexisting disease on the diminished cardiac reserve of chronic anemia. The data do not support the concept of a specific "sickle cell cardiomyopathy".

Adolescent

Rupture of the papillary muscle of the tricuspid valve. A complication of cardiopulmonary resuscitation and a rare cause of tricuspid insufficiency.

Rupture of a papillary muscle is a rare occurrence. Two patients are described in whom rupture of a papillary muscle of the tricuspid valve developed after external cardiac massage during cardiopulmonary resuscitation. One of these patients survived briefly with clinical evidence of triscupid regurgitation immediately after resuscitation. Although tricuspid valve papillary muscle rupture has been described as a complication of bacterial endocarditis, chest trauma and myocardial infarction, it is a generally unrecognized complication of external cardia massage. Findings in the two patients reported here suggest that patients with a dilated right ventricle may be more susceptible to this rare complication of cardiopulmonary resuscitation.

Adult

Evaluation of left ventricular function in patients with sickle cell anemia.

The echocardiographic measurements of cardiac chamber dimension, ejection phase indices of left ventricular function and the systolic time intervals of 23 adult patients with sickle cell anemia were compared to those of normal control subjects. Patients with sickle cell anemia had a significantly greater mean left ventricular systolic dimension index, left ventricular diastolic dimension index, left ventricular mass, stroke volume index, interventricular septal width, aortic root index and left atrial index. No significant differences were noted between the mean velocity of circumferential fiber shortening, ejection fraction or systolic time intervals. The anemic population was divided into two groups; one consisting of patients less than 30 years old and the other of patients over 30 years old. There was no significant differences between the ventricular dimensions, velocity of circumferential fiber shortening, ejection fraction and systolic time intervals of the two groups. These data indicate that the chronic volume overload of sickle cell anemia is well tolerated without development of left ventricular dysfunction.

Adolescent

Diphtheroid endocarditis. Report of nine cases and review of the literature.

Diphtheroid endocarditis is a rare disease. A large proportion of the reported cases have occurred in the presence of prosthetic heart valves. Nine previously unreported cases of diphtheroid endocarditis are discussed along with 25 others taken from the literature. Eight out of the nine new cases occurred in patients with artificial heart valves. A high mortality was associated with infections occurring on prosthetic heart valves. Microbiological studies were frequently hampered by poor in vitro growth of the organisms. Resistance to penicillin and cephalothin was common. Erythromycin or penicillin in combination with streptomycin is suggested as a rational initial treatment for diphtheroid endocarditis involving prosthetic heart valves to be used until adequate in vitro antibiotic susceptibility testing is completed. Long-term suppressive therapy is suggested for those patients who are poor surgical candidates and for those patients who relapse after a reasonable course of antibiotic therapy.

Adolescent

Inotropic agents.

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Cardiotonic Agents