Vol. 20, No. 10
C. R. Conti, M.D. 827
S. Gupta, MBBS, MRCP, and A. J. Camm, M.D., FRCP 829
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Although common chronic infections have been postulated to play a role in the pathogenesis and progression of coronary heart disease (CHD) and atherosclerosis, no single infectious agent has been proven to be causal. The pathogen, Chlamydia pneumoniae has recently emerged as a possible culprit, based on sero-epidemiologic data, pathologic examinations, animal experiments, and recent pilot studies of antibiotic treatment in patients with established CHD. Final clarification as to whether C. pneumoniae is a true causative agent, an association, or a mere innocent bystander in CHD and atherosclerosis will only come from large-scale antibiotic intervention trials.
U. Ikeda, M.D., and K. Shimada, M.D. 837
Cardiac myocytes express two types of nitric oxide (NO) synthase, eNOS and iNOS. eNOS activity is regulated by the contractile state of the heart, while iNOS expression is induced by cytokines. Nitric oxide induced by cytokines causes negative inotropic and lethal effects on cardiac myocytes. Expression of iNOS in the myocardium is increased in patients with dilated cardiomyopathy with clinical evidence of heart failure. Several neurohumoral factors activated in chronic heart failure augment cardiac iNOS expression and could cause cardiac dysfunction and cell damage.
T. Waszyrowski, M.D., J. D. Kasprzak, M.D., M. Krzeminska-Paku/la, Ph.D., FESC, A. Dziatkowiak, Ph.D., J. Zaslonka, Ph.D. 843
The aim of this 8-year follow-up study was to compare the clinical results of aortic valve replacement with homografts versus mechanical prostheses. Total 8-year mortality observed in the group of 143 patients was 4.9%. Probability of 8-year survival was nonsignificantly higher in the homograft than in the mechanical prosthesis recipients.The most common late complications were ventricular arrhythmia and heart failure. Serious bleeding occurred only in the mechanical valve recipients. Mortality, probability of survival, and hemodynamic improvement at 8-year follow-up after aortic valve replacement are independent of the type of implanted valve. Severe late complications are more common after mechanical valve than after homograft implantation.
Y. Mishiro, M.D., T. Oki, M.D., A. Iuchi, M.D., T. Tabata, M.D., H. Yamada, M.D., K. Manabe, M.D., K. Fukuda, M.D., M. Abe, M.D., Y. Onose, M.D., T. Ishimoto, M.D., S. Ito, M.D. 850
This study was undertaken to evaluate the mechanism of physiologic mitral regurgitation (MR) in young normal subjects using transthoracic echocardiography. In subjects with MR, the left ventricular (LV) diastolic dimension and left atrial systolic dimension were slightly smaller, the ratio of the maximum anteroposterior diameter to the maximum transverse diameter on chest radiography, and the ratio of short- to long-axis diameter of the LV cavity at end diastole determined from two-dimensional short-axis echocardiogram were significantly lower. Thus, "flattening" of the thorax may cause spatial imbalance of the mitral complex and resulting malcoaptation of the valve in young normal subjects with physiologic MR.
S. Jeffery, Ph.D., P.J. Kelling, M.D., C. Badorff, M.B., A. Lukaszyk, M.B., Y.S. Boriskin, Ph.D. J.C. Booth, Ph.D., J. Hodgson, Ph.D., M.J. Davies, FACC, W.J. McKenna, M.D., FACC 857
Estimates of enteroviral-positive tissue in patients with dilated cardiomyopathy (DCM) range from 0 to 50%, but very little sequence information is so far available on those samples that are positive. RNA from biopsy or explant tissues was examined for the presence of enterovirus using reverse transcriptase polymerase chain reaction (PCR). The nucleotide sequences of all positive PCR products were determined by direct sequencing. Positive PCR signals were found in 10% of samples from patients with DCM, and 16% of control tissues. The results do not support a major role for persistent enteroviral infection in DCM.
H. A. Carrasco G., M.D., M. Alarcón, M.D., L. Olmos, M.D., J. Burguera, Ph.D., M. Burguera, Ph.D., A. Dipaolo, M.D., H. R. Carrasco v., M.D. 865
In this study, the possibility that early ultrastructural changes described in myocardial biopsies from patients with chronic Chagas' disease may cause biochemical alterations in the normal pattern of 9 electrolytes, 5 glycoprotein fractions, and 12 enzymes related to cardiac metabolism was investigated. Early release of inorganic phosphorus (p<0.01) and isocitrate dehydrogenase (p<0.01) from the heart and increased activity of serum alkaline phosphatase and aldolase (p<0.05) were found. These biochemical patterns could be applied to the follow-up of patients with Chagas' disease and to the evaluation of the results of future therapies.
P. Syrris, Ph.D., R. Schwartzman, M.D., S. Jeffery, Ph.D., J. C. Kaski, M.D., N. Carter, Ph.D. 870
This study determined the frequency of the apolipoprotein(a) kringle IV 37 Met66*Thr polymorphism in 182 unrelated Caucasian patients with chronic stable angina and in 64 unrelated patients of Afro-Caribbean origin. The results show there is no association between this mutation and either Lp(a) levels or severity of coronary artery disease.
S. Kuroki, M.D., U. Ikeda, M.D., Y. Maeda, M.D., H. Sekiguchi, M.D., K. Shimada, M.D. 873
This paper reports that the DD genotype of the angiotensin-converting enzyme gene is a potent genetic risk factor for organic coronary artery disease, while it confers no appreciable increase in risk of vasospastic angina. Findings also suggest the diversity of the pathogenesis of vascular lesions in these two types of coronary artery disease.
B. F. Waller, M.D., J. D. Clary, P.A.-C, Todd Rohr, P.A.-C 879
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This five-part review focuses on selected nonneoplastic diseases of the aorta and pulmonary trunk. Because many more diseases affect the aorta compared with the pulmonary trunk and right and left main pulmonary arteries, most of this review will be devoted to disorders of the aorta. Part III of this five-part series discusses the etiology of aortic aneurysms and aortitis.
J. J. Glazier, M.D., FRCPI, J. G. McGinnity, M.S., P.A.-C., J. R. Spears, M.D. 885
A 37-year-old man, who had received 3 weeks of antimicrobial therapy for aortic valve endocarditis, presented with an acute anteroseptal wall myocardial infarction. Coronary angiography demonstrated occlusion of the mid left anterior descending artery, thought to have been caused by embolization of a sterile vegetation. Following failure of balloon dilation to achieve vessel patency, this was achieved by placement of an intracoronary stent.
L. Lin, M.D., J. B. Conti, M.D., A. B. Curtis, M.D. 890
Idiopathic left ventricular tachycardia can be treated effectively with verapamil. This paper reports the case of a patient with idiopathic left ventricular tachycardia in whom the arrhythmia was effectively terminated and suppressed with an alternative calcium-channel blocker, diltiazem.
N.A. Herity, M.D., and G.W.N. Dalzell, M.D. 893
A 61-year-old man presented with an acutely ischemic left lower limb. Typical risk factors for embolism were absent. Transthoracic and subsequently transesophageal echocardiography were performed and revealed the unexpected finding of a patent foramen ovale with right- to-left shunting of contrast. Further investigation demonstrated the presence of multiple pulmonary emboli and extensive thrombosis of the deep veins of the left thigh. The classical signs of deep venous thrombosis had been masked by the more dramatic signs of arterial ischemia. In patients with embolic episodes without typical risk factors, transesophageal echocardiography is significantly more sensitive than the transthoracic approach for the detection of intracardiac shunts.
K. Csapo, M.D., L. Voith, M.D., T. Szuk, M.D., I. Edes, M.D., D. J. Kereiakes, M.D. 898
Left ventricular wall rupture after myocardial infarction is a mechanical complication that may result in a pseudoaneurysm. False or pseudoaneurysms were detected in 6 (0.0026%) of 2,600 consecutive patients (4 women, 2 men; mean age 59.4 years) undergoing cardiac catheterization, all of whom had a history of cardiovascular disease, with diagnosis of pseudoaneurysm confirmed by echocardiography. The average time from the occurrence of acute infarction to diagnosis was 37.0 days (range 3-80 days). All patients were in New York Heart Association functional class IV congestive heart failure; in four patients cardiogenic shock was present. Five patients underwent coronary angiography, which demonstrated multivessel disease and occlusion of the infarct-related artery (TIMI 0) without adequate collateral circulation (grade 0-1). Five patients had surgical repair of the false aneurysm, and, in three patients, concomitant coronary bypass grafting was performed. The 2-year mortality rate for all patients was 50%. Early diagnosis of false aneurysm is facilitated by echocardiography, and coronary angiography is required before surgery. Early surgical correction with coronary revascularization is advised.
W. Bruce Fye, M.D. 904