Effect of catheter ablation on progression of paroxysmal atrial fibrillation

Ablation and Progression of Atrial Fibrillation. Objective: The objective was to determine the effect of radiofrequency catheter ablation (RFA) on progression of paroxysmal atrial fibrillation (AF). Background: Progression to persistent AF may occur in up to 50% of patients with paroxysmal AF receiving pharmacological therapy. Hypertension, age, prior transient ischemic event, chronic obstructive pulmonary disease, and heart failure (HATCH score) have been identified as independent risk factors for progression of AF. Methods: RFA was performed in 504 patients (mean age: 58 ± 10 years) to eliminate paroxysmal AF. A repeat RFA procedure was performed in 193 patients (38%). Clinical variables predictive of outcome and their relation to progression of AF after RFA were assessed using multivariate analysis. Results: At a mean follow‐up of 27 ± 12 months after RFA, 434/504 patients (86%) were in sinus rhythm; 49/504 patients (9.5%) continued to have paroxysmal AF; and 14 (3%) were in atrial flutter. Among the 504 patients, 7 (1.5%) progressed to persistent AF. In patients with recurrent AF after RFA, paroxysmal AF progressed to persistent AF in 7/56 (13%, P < 0.001). The progression rate of AF was 0.6% per year after RFA (P < 0.001 compared to 9% per year reported in pharmacologically treated patients). Age >75 years, duration of AF >10 years and diabetes were independent predictors of progression to persistent AF. The HATCH score was not significantly different between patients with paroxysmal AF who did and did not progress to persistent AF (0.7 ± 0.8 vs 1.0 ± 0.5, P = 0.3). Conclusions: Compared to a historical control group of pharmacologically treated patients with paroxysmal AF, RFA appears to reduce the rate of progression of paroxysmal AF to persistent AF. Age, duration of AF, and diabetes are independent risk factors for progression to persistent AF after RFA. (J Cardiovasc Electrophysiol, Vol. 23, pp. 9‐14, January 2012)     

Studies on the potential use of CD38 expression as a marker for the efficacy of anti-retroviral therapy in HIV-1-infected patients in Thailand

The monitoring of the efficacy of anti-retroviral therapy (ART) is becoming an important issue in the developing world. The current use of CD4 counts, plasma viral loads, and monitoring of drug-resistant viruses are at present either uninformative or costly. Thus, more new cost-effective and practical techniques need to be established and implemented. Towards this goal, our lab has carried out studies on the potential use of CD38 frequency and density expression by flow analysis as a means to assess the efficacy of ART. Results of our studies using whole blood sample from normal healthy donors indicate that CD38 is expressed by a high frequency of not only CD4+ and CD8+ T cells but also most hematopoietic cell lineages analyzed. Detailed studies of CD38 expression along with other cell surface markers using whole blood sample from HIV-1-infected patients showed that the most discriminating change was the increased frequency and density of CD38 expression by CD3+CD8+ T cells. Of importance was our preliminary finding that a reversal of the increased frequency and density of CD38 expression by CD8+ T cells only appeared in the whole blood sample from patients who were responders to ART but not those who were drug failures. These initial data provide a platform and incentive for larger cohort studies including prospective pre- and post-ART for the institution of such monitoring techniques in resource limited settings.     

Pathogenicity of Eikenella corrodens in humans

Eikenella corrodens is resident flora of the normal adult human oral cavity. Four cases of verified infection and previous case reports of infections caused by this organism were reviewed and analyzed. Rarely has this bacillus been found as the sole isolate to initiate infection in the host with normal immune status. In the immunocompromised host, this organism was observed as the sole isolate in cases of persistent empyemas and/or overwhelming pneumonias with bacteremias. The potential of the organism singly to perpetuate an established infection appears real. In the immunocompromised patients such potentials are accentuated and can result in fulminant pulmonary infections and death. The finding of E corrodens in an infection site of a compromised patient should indicate specific therapy.     

The Significance of Eubacterium Bacteremia

Eubacterium is a commensal of the human gastrointestinal tract. In rare instances this organism can become blood-borne. Nine cases of bacteremia were described and eight cases were found in the medical literature. Thirteen of the 17 cases (76%) had active gastrointestinal disease leading to the Eubacterium bacteremia. It is suggested that recovery of Eubacterium in blood culture should alert the clinician to the possibility of active gastrointestinal disease including occult neoplasms.     

Causes of chronic diarrhea in patients with AIDS in Thailand: A prospective clinical and microbiological study

A prospective study was designed to investigate the causes of chronic diarrhea in AIDS patients in Thailand. Forty-five patients from Bamrasnaradura Infectious Diseases Hospital were enrolled. Extensive investigations included multiple stool examinations for ova and parasites, using the stool formalin-ether concentration method, stool culture, stool acid-fast bacilli (AFB) stain, stool modified AFB stain, esophago-gastroduoscopy with duodenal aspirate and biopsy, and colonoscopy with biopsy. Biopsied specimens were examined with H&E, Giemsa, Gram, Periodic acid Schiff, and AFB stains. Definitive causes were found in 29 patients (64.4%). Of these 29, 7 patients were found to habor more than 1 pathogen (15.5%). The most commonly found enteric pathogen wasCryptosporidium parvum (20.0%). Less frequently found pathogens wereMycobacterium tuberculosis (17.8%),Salmonella spp. (15.5%),Cytomegalovirus (11.1%),Mycobacterium avium intracellulare (6.6%), Strongyloides stercoralis (4.4%),Giardia lamblia (4.4%),Cryptococcus neoformans (2.2%),Histoplasma capsulatum (2.2%),Campylobacter jejun (2.2%), andCyclospora cayetanensis (2.2%).Salmonella spp., Mycobacterium tuberculosis, andMycobacterium avium intracellulare infections were shown to be more common in Thailand than in African countries.     

Anticoagulant therapy and risk of cerebrovascular events after catheter ablation of atrial fibrillation in the elderly

Stroke and Atrial Fibrillation Ablation . Introduction: Factors associated with cerebrovascular events (CVEs) after radiofrequency catheter ablation (RFA) of atrial fibrillation (AF) have not been well defined in elderly patients (≥65 years). The purpose of this study was to determine the prevalence and predictors of CVEs after RFA in patients with AF ≥65 years old, in comparison to patients <65 years, and with or without AF. Methods and Results: This study included 508 consecutive patients ≥65 years old (mean age: 70 ± 4 years), who underwent RFA for paroxysmal (297) or persistent (211) AF. A stratified group of 508 patients < 65 years old who underwent RFA for AF served as a control group. All patients were anticoagulated with warfarin for ≥3 months after RFA. A perioperative CVE (≤4 weeks after RFA) occurred in 0.8% and 1% of patients ≥65 and <65 years old, respectively (P = 1). Among the patients ≥65 years old who remained in sinus rhythm after RFA, warfarin was discontinued in 60% and 56% of the patients with a CHADS₂ score of 0 and ≥1, respectively. Paroxysmal AF, no history of CVE, and successful RFA were independent predictors of discontinuing warfarin. During a mean follow‐up of 3 ± 2 years, a late CVE (>4 weeks after the RFA) occurred in 15 of 508 (3%) of patients ≥65 years old (1% per year) and in 5 of 508 (1%) patients <65 years old (0.3% per year, P = 0.03). Among patients ≥65 years old, age >75 years old (OR = 4.9, ±95% CI: 3.3–148.5, P = 0.001) was the only independent predictor of a CVE. Among patients <65 years old, body mass index was the only independent predictor of a late CVE (OR = 1.2, ±95% CI: 1.03–1.33, P = 0.02). Conclusions: The risk of a periprocedural CVE after RFA of AF is similar among patients ≥65 and <65 years old. Late CVEs after RFA are more prevalent in older than younger patients with AF, and age >75 years old is the only independent predictor of late CVEs regardless of the rhythm, anticoagulation status, or the CHADS₂ score (Congestive heart failure, Hypertension, Age ≥ 75 years, Diabetes mellitus and prior Stroke or transient ischemic attack). (J Cardiovasc Electrophysiol, Vol. 23, pp. 36‐43, January 2012)     

Prevalence and predictors of complications of radiofrequency catheter ablation for atrial fibrillation

Complications of Atrial Fibrillation Ablation. Introduction: Up to 6% of patients experience complications after radiofrequency catheter ablation (RFA) of atrial fibrillation (AF). The purpose of this study is to determine the prevalence and predictors of periprocedural complications after RFA for AF. Methods and Results: The subjects were 1,295 consecutive patients (age = 60 ± 10 years) who underwent RFA (n = 1,642) for paroxysmal (53%) or persistent AF (47%) from January 2007 to January 2010. A complication occurred in 57 patients (3.5%); a vascular access complication in 31 (1.9%); pericardial tamponade in 20 (1.2%); a thromboembolic event in 4 (0.2%); deep venous thrombosis in 1 (<0.01%); and pulmonary vein stenosis in 1 patient (<0.01%). There were no procedure‐related deaths. On multivariate analysis, female gender (OR = 2.27; ±95% CI: 1.31–2.57, P < 0.01) and procedures performed in July or August (OR = 2.10; ±95% CI: 1.16–3.80, P = 0.01) were independent predictors of any complication. For vascular complications, treatment with clopidogrel (OR = 4.40; ±95% CI: 1.43–13.53, P = 0.01), female gender (OR = 3.65; ±95% CI: 1.72–7.75, P < 0.01) and performing RFA in July or August (OR = 2.71; ±95% CI: 1.25–5.87, P = 0.01) were independent predictors. The only predictor of cardiac tamponade was prior RFA (OR = 3.32; ±95% CI: 0.95–11.61; P < 0.05). Conclusion: Prevalence of perioperative complications for RFA of AF is 3.5% and vascular access complications constitute the majority. The need for clopidogrel therapy should be carefully considered prior to RFA. At teaching institutions close supervision should be exercised during vascular access early in the year. Improvements in ablation technology and elimination of the need for repeat procedures may decrease the risk of pericardial tamponade . (J Cardiovasc Electrophysiol, Vol. 22, pp. 626‐631, June 2011)