Biomedical subjects

Fei Lu

Publications and source records attributed to Fei Lu.

22 records · Page 2Linked to original sources

PubMed2004

Syncope.

Syncope is a syndrome consisting of a relatively short period of temporary and self-limited loss of consciousness caused by transient diminution of blood flow to the brain (most often the result of systemic hypotension). Syncope comprises part of a subset of clinical conditions in which loss of consciousness is transient. Other conditions in this group, which are not syncope and should be clearly distinguished from syncope, include, for example, seizure disorders, posttraumatic loss of consciousness, and cataplexy. Recent surveys indicate that syncope accounts for approximately 1% of emergency department visits in Europe, although older reports from the United States placed this number closer to 3%. The reported prevalence of syncope in the population varies: 15% of children before the age of 18 years; 25% of a military population aged 17 to 26 years; 16% and 19%, respectively, in men and women aged 40 to 59 years; and up to 23% in a nursing home population older than 70 years. The highest frequency of syncope occurs in patients with cardiovascular comorbidity and older patients in institutional care settings. The causes of syncope are numerous and, not infrequently, multiple factors may contribute. The diagnostic evaluation is benefited by availability of a detailed medical history and reports of eyewitnesses. In this context, the physician must consider the classification of the causes of syncope, and address the most likely causes first. The principal groups of causes may be summarized as: (1) neurally mediated reflex syncope (eg, vasovagal faint, carotid sinus syndrome); (2) orthostatic (postural) syncope; (3) cardiac arrhythmias; (4) structural cardiac and pulmonary causes; and (5) cerebrovascular disorders (rare). In addition, conditions that may mimic syncope but are not true syncope (eg, psychogenic pseudosyncope) must be considered. Only after a definitive cause is established can appropriate treatment be initiated. In this regard, the syncope evaluation is facilitated by maintaining an organized diagnostic approach. The practitioner should avoid wasteful use of short-term ambulatory electrocardiographic recordings (eg, Holter monitors) and rarely positive neurologic tests (eg, electroencephelography, head magnetic resonance imaging/computed tomography) in the absence of head trauma or evident neurologic signs. In many medical centers the evaluation of patients with syncope is haphazard, and may be substantially enhanced by establishment of a multidisciplinary syncope evaluation unit or team.

Diagnosis, Differential↗

PubMed2004

Biventricular implantable cardioverter defibrillators improve survival compared with biventricular pacing alone in patients with severe left ventricular dysfunction.

INTRODUCTION: Biventricular cardiac pacemakers provide important hemodynamic benefit in selected patients with heart failure and severe left ventricular (LV) dysfunction. Nevertheless, these patients remain at high mortality risk. To address this issue, we examined mortality outcome in patients with heart failure treated with biventricular pacemakers alone and those treated with biventricular implantable cardioverter defibrillators (ICDs). METHODS AND RESULTS: The study population consisted of 126 consecutive patients with LV dysfunction and heart failure who received either a biventricular ICD (n = 62) or a biventricular pacemaker (n = 64) between January 1998 and December 2002. A minimum 12 months of follow-up was obtained in all survivors. ICD indications were conventional in all patients. Kaplan-Meier actuarial method and log rank statistics were used to calculate and compare survival rates in both groups. Comparison of mortality rates utilized Chi-square test. The two groups had similar clinical and demographic features, LV ejection fraction, and medication use. Average follow-up times were 13 +/- 11.8 months (range 4-60) and 18 +/- 13.2 months (range 0.5-53) for biventricular ICD and pacemaker groups, respectively. Overall mortality rate was significantly lower in the biventricular ICD group (13%, 8 deaths) compared to the pacemaker group (41%, 26 deaths) (P = 0.01). Further, the predominant survival benefit for ICD-treated patients becomes evident after the first 12 months of follow-up. CONCLUSION: The findings in this study, although necessarily limited in their interpretation by the absence of treatment randomization, suggest that biventricular ICDs offer a survival benefit compared to biventricular pacing alone. Furthermore, this benefit may be most apparent if other clinical factors do not preclude patient survival >1 year postimplant.

Aged↗

PubMed2003

Comparison of automatic and patient-activated arrhythmia recordings by implantable loop recorders in the evaluation of syncope.

The implantable loop recorder (ILR) has become an important tool for evaluating patients with recurrent syncope. Second generation ILRs have the ability to record events either automatically (auto activated) or by manual activation (patient activated). In an attempt to evaluate the relative utility of the auto-activation feature, this study stratified ILR events based on a grading system designed to classify detected arrhythmias in terms of the likelihood that they provide a diagnostic basis for syncope. Data from 50 patients (27 men, mean age 64 +/- 22 years) who underwent ILR implantation for investigation of recurrent syncope were assessed. The arrhythmia syncope grading system used 5 levels, ranging from grade 0 (rhythm recorded during syncope) to grade IV (rhythm unlikely to provide a diagnostic basis for syncope). Thirty-six patients (72%) demonstrated > or =1 auto-activated or patient-activated recording during a follow-up of 14.3 +/- 7.9 months. Of the total of 529 recordings, 223 (194 after auto activation [86.9%]) from 30 patients showed a rhythm abnormality. Auto activation was more effective for documenting arrhythmias that were recorded during syncope or those with highest probability of providing a syncope diagnosis (grade 0 or I arrhythmias: auto activated, 19 patients, patient activated, 3 patients). Times from ILR implantation to first grade 0 and grade I arrhythmias were 13.4 and 7.8 months, respectively. The ILR auto-activation feature proved effective in providing a high probability basis for syncope (196 arrhythmia recordings [87.1%] in 27 patients) and enhanced the diagnostic effectiveness of the device compared with patient activation alone (29 arrhythmia recordings [12.9%] in 6 patients).

Arrhythmias, Cardiac↗

PubMed2002

[Comparison of curative effect between decompression and incision of endolymphytic sac].

OBJECTIVE: We compared the curative effect between endolymphytic sac decompression and incision of endolymphytic sac to explore a simple, effective surgical way with less complication. METHOD: 23 endolymphatic sac decompression and 22 incision of endolymphatic sac were performed routinely under general anesthesia. RESULT: 41 of 45 patients were followed up more than 2 years after the surgical procedure, 21 of which received endolymphatic sac decompression, while others received incision of endolymphatic sac. According to Chinese Meniere disease's diagnosis and curative effect standard evaluation criteria tried out in 1996, 13 got grade A(completely controlled), 4 got grade B (fundamentally controlled), 3 got grade C (partially controlled) while 1 got grade D (not controlled) among 21 patients who received endolymphatic sac decompression. The fully control rate is 61.9%. Among 20 patients who received incision of endolymphatic sac, 12 got grade A (completely controlled), 5 got grade B (fundamentally controlled), 2 got grade C (partially controlled) while 1 got grade D (not controlled). The fully control rate is 60%. CONCLUSION: There is no significant difference between endolymphatic sac decompression and incision of endolymphatic sac in curative effect,but endolymphatic sac decompression is more convenient,safe and has less complication compared with incision of endolymphatic sac. From this,we favor endolymphatic sac decompression in selection of surgical method.

Adult↗