ISSN:0009-7322    

出版商:OVID    

年代:1995

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1995

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Key WordsEditorials, genes, mexiletine, long QT syndrome.

ISSN:0009-7322    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Key WordsEditorials, chlamydia, immunohistochemistry, atherosclerosis.

ISSN:0009-7322    

出版商:OVID    

年代:1995

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

BackgroundThe genes for the long QT syndrome (LQTS) linked to chromosomes 3 (LQT3) and 7 (LQT2) were identified as SCN5A, the cardiac Sodium sup + channel gene, and as HERG, a Potassium sup + channel gene. These findings opened the possibility of attempting gene-specific control of ventricular repolarization. We tested the hypothesis that the QT interval would shorten more in LQT3 than in LQT2 patients in response to mexiletine and also in response to increases in heart rate.Methods and ResultsFifteen LQTS patients were studied. Six LQT3 and 7 LQT2 patients were treated with mexiletine, and its effects on QT and QT sub c were measured. Mexiletine significantly shortened the QT interval among LQT3 patients (QTcfrom 535 plus/minus 32 to 445 plus/minus 31 ms, P < .005) but not among LQT2 patients (QTcfrom 530 plus/minus 79 to 503 plus/minus 60 ms, P = NS). LQT3 patients (n = 7) shortened their QT interval in response to increases in heart rate much more than LQT2 patients (n = 4) and also more than 18 healthy control subjects (9.45 plus/minus 3.3 versus 3.95 plus/minus 1.97 and 2.83 plus/minus 1.33, P < .05; data expressed as percent reduction in QT per 100-ms shortening in RR). Among these patients, there is also a trend for LQT2 patients to have syncope or cardiac arrest under emotional or physical stress and for LQT3 patients to have cardiac events either at rest or during sleep.ConclusionsThis is the first study to demonstrate differential responses of LQTS patients to interventions targeted to their specific genetic defect. These findings also suggest that LQT3 patients may be more likely to benefit from Sodium sup + channel blockers and from cardiac pacing because they would be at higher risk of arrhythmia at slow heart rates. Conversely, LQT2 patients may be at higher risk to develop syncope under stressful conditions because of the combined arrhythmogenic effect of catecholamines with the insufficient adaptation of their QT interval when heart rate increases. (Circulation. 1995;92:3381-3386.)Key Wordsgenes, mexiletine, long QT syndrome, death, sudden.

ISSN:0009-7322    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

BackgroundDilated cardiomyopathy, characterized by ventricular dilatation and decreased systolic contraction, is twofold to threefold more common as a cause of heart failure than hypertrophic cardiomyopathy and costs several billion dollars annually. The idiopathic form occurring early in life, with a 75% mortality in 5 years, is a common reason for transplantation. It is estimated that at least 20% of cases are familial.Methods and ResultsA family of 46 members spanning four generations underwent history and physical examinations, echocardiographic analysis, and blood sampling for genotyping. Diagnostic criteria, detected by echocardiography, consisted of ventricular dimension of greater or equal to 2.7 cm/m2with an ejection fraction less or equal to 50% in the absence of other potential causes. DNA from all members was analyzed by polymerase chain reaction for amplification of short tandem-repeat polymorphic markers located every 10 cM throughout the human genome. Assuming a penetrance of 90%, linkage analysis was performed to map the responsible chromosomal locus. Linkage analysis, after 412 markers were analyzed, indicated the locus to be on chromosome 1q32, with a peak multipoint logarithm of the odds score at D1S414 of 6.37.ConclusionsThe locus identified in this study for familial dilated cardiomyopathy, 1q32, is rich in candidate genes, such as MEF-2, renin, and helix loop helix DNA binding protein MYF-4. Identification of the genetic defect could provide insight into the molecular basis for the cardiac dilatory response in both familial and acquired disorders. (Circulation. 1995;92:3387-3389.)Key Wordscardiomyopathy, molecular biology, heart failure, genetics.

ISSN:0009-7322    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

BackgroundThe insertion/deletion (ID) polymorphism of the angiotensin-converting enzyme (ACE) gene has been associated with increased coronary heart disease (CHD), although the mechanism of this association is not apparent. We tested the hypothesis that the deletion allele of the ACE gene is associated with insulin resistance.Methods and ResultsWe related ACE genotype to components of the insulin-resistance syndrome in 103 non-insulin-dependent diabetic (NIDDM) and 533 nondiabetic white subjects. NIDDM subjects with the DD genotype had significantly lower levels of specific insulin (DD 38.6, ID 57.1, and II 87.4 pmol *symbol* L sup -1 by ANOVA, P = .011). Non-insulin-treated subjects with the DD genotype had increased insulin sensitivity by HOMA % (DD 56.4%, II 29.4%, P = .027) and lower levels of des 31,32 proinsulin (DD 3.3, II 7.6 pmol *symbol* L sup -1, P = .012) compared with II subjects. There were no differences in prevalence of CHD or levels of blood pressure, serum lipids, or plasminogen activator inhibitor-1 (PAI-1) activity between the three ACE genotypes. In nondiabetic subjects there were no differences in insulin sensitivity, levels of insulin-like molecules, blood pressure, PAI-1, serum lipids, or CHD prevalence between the three ACE genotypes.ConclusionsWe conclude that increased cardiovascular risk of the DD genotype is not mediated through insulin resistance or abnormalities in fibrinolysis. Conversely, we report an increased sensitivity in NIDDM subjects with the ACE DD genotype. (Circulation. 1995;92:3390-3393.)Key Wordsinsulin resistance, angiotensin, ACE gene, plasminogen activator inhibitor.

ISSN:0009-7322    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

BackgroundA total of 36 fetuses with isolated congenital complete heart block and structurally normal hearts have been seen in the department of fetal echocardiography since 1980. Although the prognosis is good in the majority of cases, those who develop intrauterine cardiac failure have a high mortality. The aim of this study was to investigate the contribution to management of sympathomimetic therapy by comparing two possible agents administered to the mothers.Methods and ResultsThe effect of two sympathomimetic agents, isoprenaline and salbutamol, was compared in three patients with isolated complete heart block. Fetal heart rate and indexes of cardiac function were monitored during therapy. Maternal cardiovascular status was also regularly assessed. Dosage of isoprenaline increased from 1 to 12 micro gram/min, and salbutamol increased from 4 to 64 micro gram/min during the trial. No significant change was detected with isoprenaline therapy, but all fetuses showed an increase in heart rate and improvement in ventricular function with salbutamol. Salbutamol was maintained until delivery in one case with evidence of cardiac failure, with resolution of fetal hydrops. All three delivered in good condition close to term. Two of three required pacing in the neonatal period.ConclusionsWe conclude that salbutamol can be effective in the treatment of fetal complete heart block and should be considered in patients with this condition where there is evidence of deteriorating cardiac function. (Circulation. 1995;92:3394-3396.)Key Wordsheart block, drugs, sympathomimetic, fetus.

ISSN:0009-7322    

出版商:OVID    

年代:1995

数据来源: OVID