摘要:

Endocardial catheter mapping of the right atrium during sinus rhythm and programmed atrial stimulation were performed in 50 patients with sick sinus syndrome to investigate the relationship between abnormal atrial electrograms recorded during sinus rhythm and some determinants of the atrial vulnerability such as repetitive atrial firing and fragmented atrial activity elicited by single extrastimulus. The patients were divided into 2 groups on the basis of the presence (Group I) or absence (Group II) of abnormal atrial electrograms recorded during sinus rhythm. In Group I (N= 32), repetitive atrial firing was induced in 23 (72%) patients, and in Group II (N= 18) in 6 (33%) patients; p less than 0.01. The repetitive atrial firing zone was 41 ± 37 ms in Group I and 12 ± 18 ms in Group II; p less than 0.001. Fragmented atrial activity was induced in 30 (94%) patients from Group I, and in 8 (44%) patients from Group II; p less than 0.0001. The fragmented atrial activity zone was 47 ± 42 ms in Group I and 14 ± 19 ms in Group II; p less than 0.0001. The atrial electrogram width at the premature beat (A2; p < 0.02) and the maximum A2/A1 ratio (p < 0.002) were 178 ± 53 ms and 196% ±40%, respectively in Group I, and 141 ±36 ms and 159% ± 30%, respectively in Group II. Atrial fibrillation was induced in 13 (41%) patients from Group I, and in 1 (6%) patient from Group II (p < 0.01). These data suggest a significantly greater vulnerability of the atrial muscle to atrial fibrillation in patients with sick sinus syndrome who possess abnormal atrial electrograms than in those who do not.

ISSN:0002-9629    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Thrombocytosis is a cause of falsely elevated serum potassium concentrations, and phosphorus concentrations may be similarly distorted. Because plasma concentrations are not affected, the difference between the serum and plasma concentrations detects spurious elevations. The authors, in this study, sought to determine the degree of correlation between thrombocytosis and false elevations in serum potassium and phosphorus concentrations. Ninety-one general, medical/surgical patients with elevated platelet counts were identified by laboratory reports. Subjects were stratified into blocks by platelet count. Samples were obtained simultaneously for serum and plasma potassium and phosphorus concentrations and complete blood counts. The serum minus plasma concentrations for potassium (Kdiff) and phosphorus (Pdiff) were calculated and analyzed against each other and the platelet count by linear regression. A control group of 20 subjects with normal platelet counts was used to verify laboratory results with literature values. The Kdiffand Pdiffvalues in the control group very closely approximated literature values of 0.4 mmol/L and 0.08 mmol/L, respectively. Platelet count was a moderate predictor of Kdiff, r2= 0.55 (p = 0.00001). Kdiffexceeded the upper limit of control at a platelet count of approximately 600 × 109/L. Platelet count also correlated with Pdiff, r2= 0.31 (p = 0.00001). Additionally, Kdiffcorrelated with Pdiff, r2= 0.39 (p = 0.00001). Thrombocytosis is associated with false elevations in measured serum potassium and phosphorus concentrations. Additionally, the magnitude of elevations in potassium and phosphorus concentrations appear to be related.

ISSN:0002-9629    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Ventricular arrhythmia production in the ischemic heart is considered to be influenced by prior infarction. Although beta-ad-renergic blockade is known to have beneficial effects during acute ischemia, its anti-arrhythmic efficacy during post-infarction ischemia is not known. To explore this question, we have used a model with a relatively high incidence of ischemic arrhythmias. Mongrel dogs 2 to 3 years of age were studied intact under anesthesia. An irreversible injury of the infero-posterior myocardium was produced with an electrode catheter 1 week earlier. The arrhythmic response to acute ischemia was assessed using serial, transient 15-minute occlusions of the left-anterior descending coronary artery with a balloon catheter. During ischemia alone, the incidence of ventricular fibrillation in animals who underwent all phases of the study was 6 of 9; with atenolol (0.2 mg/kg intravenously) and ischemia, 1 of 9 (p < 0.05). To assess the role of the bradycardic response, the latter was repeated 1 week subsequently during atrial pacing at the heart rate that existed before ischemia. Fibrillation occurred in 8 of 9, a significant reversal of the therapeutic effect. To exclude the potential artifact of a fixed intervention protocol, a study was undertaken with the short-acting esmolol, in which three ischemic periods were alternated at 1-hour intervals: (A) ischemia without treatment, (B) ischemia with continuous infusion of 150 jug/kg/min esmolol, and (C) same as B except that heart rate was maintained by atrial pacing. Ventricular fibrillation occurred in 7 of 10 in period A, 1 of 10 (p < 0.03) in period B, and 8 of 10 in period C (p < 0.02). Therefore, despite the high incidence of fibrillation without treatment, beta-adrenergic blockade was effective in reducing the incidence of ventricular fibrillation during early ischemia.

ISSN:0002-9629    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Although multifocal atrial tachycardia (MAT) has been recognized since 1968, few data exist on its associated anatomic correlates. Using echocardiography, the authors describe the cardiac anatomy observed in hospitalized patients with MAT. Because MAT closely resembles atrial fibrillation (AF), these echocardiographic data are compared with those from an age- and sex-matched population with AF. There were 25 patients in each of the MAT and AF groups. Biatrial enlargement was present in both groups. However, the atrial enlargement was mild and significantly less in the MAT group. The MAT group had normal ventricular and aortic dimensions. Right ventricular dysfunction was rare in both groups. Moderate to severe global left ventricular dysfunction was present in 7 of 25 in the MAT group and in 9 of 25 in the AF group. Systolic wall-motion abnormalities were significantly less in the MAT group. Severe Doppler and structural abnormalities were not common in the MAT group. Based on these parameters, physiologic and not anatomic factors are probably more important in the genesis of MAT as compared with AF.

ISSN:0002-9629    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

To see if a modest amount of soluble fiber reduced blood lipids in subjects with hyperlipidemia who were on a low-fat diet, 42 subjects (21 men, 21 women) consuming an American Heart Association step 2 diet took two servings of breakfast cereal daily for two 2-week periods in a randomized crossover trial. There were two types of test cereals, each providing 6.7 g psyllium fiber daily, and two types of wheat bran control cereals, matched for available carbohydrate and total fiber. Half the subjects tested each type of cereal, and the results were pooled because the psyllium cereals had similar effects on serum cholesterol levels. Comparing values at the end of 2 weeks, psyllium reduced serum total (6.33 ± 0.12 mmol/L versus 6.76 ± 0.12 mmol/L, p < 0.001), low-density lipoprotein (LDL; 4.36 ±0.11 mmol/L versus 4.73 ± 0.12 mmol/L, p < 0.001) and high-density lipoprotein cholesterol levels (HDL; 1.10 ± 0.05 mmol/L versus 1.14 ± 0.05 mmol/L, p < 0.05) and the LDL/HDL cholesterol ratio (4.27 ± 0.20 versus 4.48 ± 0.22, p < 0.02) with no effect on triglycerides. There was no significant interaction between the effects of treatment and sex for any of the blood lipid variables. Women tended to have greater decreases in total, LDL, and HDL cholesterol levels than men, but the percent decrease in LDL/HDL ratio on psyllium was similar in men, 4.9%, and women, 4.7%. It is concluded that 6.7 g of psyllium fiber daily, with a low-fat diet, reduces serum cholesterol levels in both men and women with hyperlipidemia.

ISSN:0002-9629    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

A 41-year-old man presented with night sweats, fever, and substernal chest pain approximately 5 months after being treated for community-acquired pneumonia. Chest radiograph revealed a mediastinal mass that was confirmed by computed tomography (CT) of the thorax. During surgery, enlarged paratracheal lymph nodes and a mass surrounding the right lower lobe bronchus and bronchus intermedius were found. Multiple biopsies from the mass showed that it consisted mainly of acellular fibrous tissue, but a small number of fungal forms typical ofHistoplasma capsulatumwere seen at the edge of the fibrotic reaction. The lymph nodes contained granulomatous inflammation and areas of necrosis, but no organisms were identified. The patient was treated with fluconazole for 6 weeks with resolution of symptoms. After completion of therapy, a follow-up CT scan of the thorax showed involution of the mediastinal mass. There has been no recurrence of symptoms or radiographic abnormalities for 24 months since cessation of fluconazole. This case illustrates isolated mediastinal involvement by histoplasmosis and suggests that therapy with fluconazole at this stage may prevent the often devastating late complications of mediastinal fibrosis.

ISSN:0002-9629    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

A case of Wegener's granulomatosis (WG) accompanied by communicating hydrocephalus is described. An elderly woman with rapidly progressive renal failure was referred to the authors' hospital. Renal histologic study showed necrotizing granulomatous glomerulo-nephritis with some multinucleated giant cells, which suggested a diagnosis of WG. After admission, a gait disturbance, incontinence, and dementia developed in the patient. Diagnostic procedures including lumbar puncture, computed tomography (CT), and scintigraphy showed findings compatible with communicating hydrocephalus with a normal cerebrospinal fluid (CSF) pressure. Removal of 20 mL of CSF led to a marked improvement in symptoms. Because the presence of subarachnoid hemorrhage, meningitis, and brain tumor was excluded, the final diagnosis was communicating hydrocephalus secondary to WG.

ISSN:0002-9629    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Chronic mucocutaneous candidiasis (CMC) is usually characterized by onset in childhood and is almost never complicated by deep fungal infection. The authors report two cases of fatal Candida meningitis in patients who suffered from mild, adult-onset CMC. The pedigrees suggest an autosomal recessive disorder. In the index cases and in a symptomatic sibling, the immunologic work-up showed a specific cellular deficit as opposed toCandida albicans, as is typical of other forms of CMC. Both families were of French Canadian descent and originated from eastern Quebec. Three other cases of primary Candida meningitis in patients of the same ethnic origin are also reported and reviewed. It is suggested that these cases may represent a variant of familial adult-onset CMC, in which there is a striking predisposition to deep infection.

ISSN:0002-9629    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Reperfusion of ischemic organs can result in tissue injury that is manifested as microvascular and parenchymal cell dysfunction. Reactive oxygen metabolites and polymorphonuclear leukocytes (PMN) have been implicated in the pathobiology of reperfusion injury. Reactive oxygen metabolites mediate the lipid per-oxidation detected in postischemic tissues and promote the formation of inflammatory agents that recruit and activate PMN. These PMN appear to inflict reperfusion-induced tissue injury. Drugs that scavenge or inhibit the formation of reactive oxygen metabolites and/or prevent the recruitment of PMN may be useful in the treatment of reperfusion injury.

ISSN:0002-9629    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Demands for less invasive, more cost-effective therapy have revolutionized the management of gallstones over the past 10 years. There are no reliable methods of permanently reversing the pathophysiologic defects that cause gallstones. Open cholecystectomy (OC), the gold standard for managing symptomatic cholelithiasis, has been largely replaced by laparoscopic cholecystectomy (LC), which has the advantages of a minimal hospital stay and quicker return to work. Other adjunctive therapies, limited in applicability to selected patients, include oral bile acid therapy (BAT), dissolutional agents, and extracorporeal shock wave lithotripsy. Choledocholithiasis (CDL), formerly managed exclusively with surgical common duct exploration, is increasingly treated with therapeutic biliary endoscopy. Methods of laparoscopic common bile duct exploration are being developed. Optimal algorithms for applying these techniques to patients undergoing LC are evolving. In a sense, the solution to all, or certainly most, gallstones now can be seen through a scope.

ISSN:0002-9629    

出版商:OVID    

年代:1994

数据来源: OVID