The Impact of Atrial Fibrillation and Its Treatment on Dementia

Atrial fibrillation (AF) is a very common tachyarrhythmia and is becoming increasingly prevalent, while dementia is a neurological condition manifested as loss of memory and cognitive ability. Both these conditions share several common risk factors. It is becoming increasingly evident that AF increases the risk of dementia. There are several pathophysiological mechanisms by which AF can cause dementia. AF increases the stroke risk and strokes are strongly associated with dementia. Besides stroke, altered cerebral blood flow in AF and cerebral microbleeds from anticoagulation may enhance the risk of dementia. Maintaining sinus rhythm may therefore decrease this risk. Catheter ablation is emerging as an effective alternative to maintain patients in sinus rhythm. This procedure has also shown promise in decreasing the risk of all types of dementia. Besides maintaining sinus rhythm and oral anticoagulation, aggressive risk factor modification may reduce the likelihood or delay the onset of dementia.     

Incidence,predictors, and clinical course of atrial tachyarrhythmias in patients with pulmonary hypertension

Background

The prevalence and predictors of atrial tachyarrhythmias (ATa) in patients with pulmonary hypertension (PH) is less well understood.

Methods

We performed a retrospective study including 311 patients with PH, confirmed by right heart catheterization in our center between 2007 and 2011. Baseline characteristics, clinical, echocardiographic, and hemodynamic data were collected and compared between patients with and without ATa.

Results

The mean age was 61?±?13 years with 64 % females. The mean pulmonary artery pressure (mPAP) was 46?±?20 mmHg, mean left ventricular ejection fraction (LVEF) was 55?±?13 %, and mean pulmonary capillary wedge pressure (PCWP) was 19?±?9 mmHg. Of the 311 patients with PH, 121 (39 %) patients had ATa. Patients with ATa were older (p?p?=?0.03), diabetes (p?=?0.015), coronary artery disease (p?p?p?=?0.001), impaired LVEF (p?=?0.02), and left atrial enlargement (p?p?=?0.022). In multivariate analysis using Cox-proportional hazard model, the independent predictors of mortality were age (HR 1.05; p?=?0.003), coronary artery disease (HR 2.34; p?=?0.047), LVEF (HR 0.793; p?=?0.023), and mPAP (HR 1.023; p?=?0.003).

Conclusion

ATa are common in patients with PH. Left heart disease, left atrial enlargement, and elevated PCWP but not right atrial enlargement or mPAP predict the occurrence of ATa in patients with PH.     

Atrial fibrillation following open heart surgery: long-term incidence and prognosis

Introduction

While early postoperative atrial fibrillation (post op AF) following valve and coronary artery bypass surgery is a known common cause of increased morbidity and mortality, the late recurrence of AF long term in this group of patients has not been well studied.

Objective

The objective of this study was to assess the late recurrence and predictors of AF in patients undergoing open heart surgery.

Methods

From a prospective cardiovascular surgery registry, 519 patients with no prior history of AF who underwent open heart surgery for cardiac bypass/valvular surgeries between May 2000 and April 2004 were followed until May 2009. A Cox proportional hazards model was used to assess the impact of early post op AF on the long-term AF after adjusting for significant covariates

Results

Of these patients, 25.6 % (133) had early (0–3 months) post op AF (group A). The remainder of patients were considered as controls (group B, n?=?386). Late occurrence of AF (3–84 months) was 5.3 % (n?=?28) after a mean follow up duration of 5?±?1.9 years. The late occurrence of AF in group A (recurrent AF) was significantly higher than in group B (11 vs 3 % n?=?15 vs 13, p?=?0.0002). Early postoperative AF was a significant predictor of late recurrence of AF in multivariate analysis (hazard ratio (HR) 3.9, CI 1.8–8.4, p?=?0.0003). Group A also had higher mortality compared to group B (21 vs 13 %, n?=?28 vs n?=?51, p?=?0.003) with early postoperative AF showing a trend towards higher mortality on multivariate analysis (HR 1.7, p?=?0.06).

Conclusions

Late recurrence of AF is higher than was previously thought to be in patients experiencing early post operative AF with a trend towards higher long-term mortality. Post op AF should not be dismissed as a benign entity and these patients should be followed closely.     

Impedance Changes on Defibrillation Coils after Atrial Fibrillation Ablation: Lead Damage or Electromechanical Interference?

Fluctuation of impedance on defibrillator leads is highly suggestive of lead failure. A drop in impedance is associated with insulation defects while high impedance is suggestive of lead fracture. In this case report, we described a patient where electromagnetic interference from radiofrequency ablation near the site of superior vena cava coil caused the sensed impedance to fluctuate without uneventful outcomes and we discussed the possible mechanism. Both electromagnetic interference and defibrillator lead insulation defect can result in low threshold and inappropriate shocks. Sometimes electromagnetic interference may result in physical damage of the implanted system and may result in subsequent fluctuations in impedance. Awareness of electromagnetic interference that can cause fluctuating impedance without structural damage can help in making appropriate diagnosis and may avoid unnecessary procedures.     

Anti-anaphylactic and anti-inflammatory activities of a bioactive alkaloid from the root bark of Plumeria acutifolia Poir

Objective

To investigate the anti-anaphylactic, anti-inflammatory and membrane stabilizing properties of plumerianine (compound 1) isolated from the root bark of Plumeria acutifolia Poir.

Methods

The anti-anaphylactic activity of compound 1 (10, 25 and 50 mg/kg) was studied by using models such as passive cutaneous anaphylaxis, passive paw anaphylaxis and its anti-inflammatory activity against carrageenin induced paw edema and cotton pellet granuloma in albino rats was also investigated using ketotifen and indomethacin as reference drugs.

Results

A dose-dependent beneficial effect was observed on leakage of evans blue dye in skin challenged with antigen and on paw anaphylaxis induced by antiserum. The compound 1 also exhibited significant (P<0.01) inhibition of rat paw edema and granuloma tissue formation, including significant protection of RBC against the haemolytic effect of hypotonic solution, an indication of membrane-stabilizing activity.

Conclusions

Anti-anaphylactic activity of compound 1 may be possibly due to inhibition of the release of various inflammatory mediators. Anti-inflammatory activity of compound may be related to the inhibition of the early phase and late phase of inflammatory events.     

Does marital status matter in an HIV hyperendemic country? Findings from the 2012 South African National HIV Prevalence,Incidence and Behaviour Survey

South Africa has experienced declining marriage rates and the increasing practice of cohabitation without marriage. This study aims to improve the understanding of the relationship between marital status and HIV in South Africa, an HIV hyperendemic country, through an analysis of findings from the 2012 South African National HIV Prevalence, Incidence and Behaviour Survey. The nationally representative population-based cross-sectional survey collected data on HIV and socio-demographic and behavioural determinants in South Africa. This analysis considered respondents aged 16 years and older who consented to participate in the survey and provided dried blood spot specimens for HIV testing (N?=?17,356). After controlling for age, race, having multiple sexual partners, condom use at last sex, urban/rural dwelling and level of household income, those who were married living with their spouse had significantly reduced odds of being HIV-positive compared to all other marital spouses groups. HIV incidence was 0.27% among respondents who were married living with their spouses; the highest HIV incidence was found in the cohabiting group (2.91%). Later marriage (after age 24) was associated with increased odds of HIV prevalence. Our analysis suggests an association between marital status and HIV prevalence and incidence in contemporary South Africa, where odds of being HIV-positive were found to be lower among married individuals who lived with their spouses compared to all other marital status groups. HIV prevention messages therefore need to be targeted to unmarried populations, especially cohabitating populations. As low socio-economic status, low social cohesion and the resulting destabilization of sexual relationships may explain the increased risk of HIV among unmarried populations, it is necessary to address structural issues including poverty that create an environment unfavourable to stable sexual relationships.     

Acute renal failure and renal replacement therapy in the postoperative period of orthotopic liver transplant patients versus nonelective abdominal surgery patients

Acute renal failure (ARF) often complicates the postoperative period of patients undergoing orthotopic liver transplantation (OLT); it is habitually associated with high mortality rates. Similarly, patients undergoing major nonelective abdominal surgery are prone to ARF because of their frequent preexistent morbidities, abdominal sepsis, and needed for extended surgical procedures. The aim of this study was to evaluate the incidence of ARF and use of renal replacement therapy (RRT) among OLT versus nonelective abdominal surgery patients and associations with clinical outcomes. We studied all the patients admitted to a surgical intensive care unit (ICU) from January 2008 to December 2009 after OLT or nonelective abdominal surgery. The inclusion criteria were an ICU stay of at least 48 hours and without prior end-stage renal failure. OLT patients (n = 84) were younger and less severly ill than surgery patients (n = 60). ARF occurrence was lower among the OLT (29%) than the surgery group (47%) requiring RRT in 71% and 53% of patients due to ARF, respectively. The ICU mortality of ARF patients in both groups (29% OLT and 51% surgery) were greater than among subjects without ARF (2% and 6%). The occurrence of ARF is common among these two patient groups, and associated with increased risk of death among in surgery (+45%) versus in OLT (+27%) patients.