Atrial fibrillation

Teaching an Old Dog New Tricks: Colchicine in Cardiovascular Medicine

Colchicine is one of the oldest known drugs that remains part of the current pharmacopeia. Recent studies have examined the efficacy of colchicine in cardiology with promising results. We conducted a search of electronic databases for studies on colchicine in cardiovascular medicine published through October 2016. As the utilization of colchicine in the management of cardiac conditions grows, it is paramount that internists and cardiologists are familiarized with its benefits and risks. We present a comprehensive review of the role of colchicine in the management of cardiovascular diseases with a strong emphasis on side effects and potential drug interactions.

Long working hours as a risk factor for atrial fibrillation: a multi-cohort study

AIMS

Studies suggest that people who work long hours are at increased risk of stroke, but the association of long working hours with atrial fibrillation, the most common cardiac arrhythmia and a risk factor for stroke, is unknown. We examined the risk of atrial fibrillation in individuals working long hours (≥55 per week) and those working standard 35-40 h/week.

METHODS AND RESULTS

In this prospective multi-cohort study from the Individual-Participant-Data Meta-analysis in Working Populations (IPD-Work) Consortium, the study population was 85 494 working men and women (mean age 43.4 years) with no recorded atrial fibrillation. Working hours were assessed at study baseline (1991-2004). Mean follow-up for incident atrial fibrillation was 10 years and cases were defined using data on electrocardiograms, hospital records, drug reimbursement registers, and death certificates. We identified 1061 new cases of atrial fibrillation (10-year cumulative incidence 12.4 per 1000). After adjustment for age, sex and socioeconomic status, individuals working long hours had a 1.4-fold increased risk of atrial fibrillation compared with those working standard hours (hazard ratio = 1.42, 95% CI = 1.13-1.80, P = 0.003). There was no significant heterogeneity between the cohort-specific effect estimates (I2 = 0%, P = 0.66) and the finding remained after excluding participants with coronary heart disease or stroke at baseline or during the follow-up (N = 2006, hazard ratio = 1.36, 95% CI = 1.05-1.76, P = 0.0180). Adjustment for potential confounding factors, such as obesity, risky alcohol use and high blood pressure, had little impact on this association.

CONCLUSION

Individuals who worked long hours were more likely to develop atrial fibrillation than those working standard hours.

Red Blood Cell Distribution Width: A Novel Predictive Indicator for Cardiovascular and Cerebrovascular Diseases

The red blood cell distribution width (RDW) obtained from a standard complete blood count (CBC) is a convenient and inexpensive biochemical parameter representing the variability in size of circulating erythrocytes. Over the past few decades, RDW with mean corpuscular volume (MCV) has been used to identify quite a few hematological system diseases including iron-deficiency anemia and bone marrow dysfunction. In recent years, many clinical studies have proved that the alterations of RDW levels may be associated with the incidence and prognosis in many cardiovascular and cerebrovascular diseases (CVDs). Therefore, early detection and intervention in time of these vascular diseases is critical for delaying their progression. RDW as a new predictive marker and an independent risk factor plays a significant role in assessing the severity and progression of CVDs. However, the mechanisms of the association between RDW and the prognosis of CVDs remain unclear. In this review, we will provide an overview of the representative literatures concerning hypothetical and potential epidemiological associations between RDW and CVDs and discuss the underlying mechanisms.

New-onset, postoperative tachyarrhythmias in critically ill surgical patients

Tachyarrhythmias in critically ill surgical patients can have varying effects, from minimal consequence to lifetime sequelae. Atrial fibrillation can be common in the post-operative period, often a result of fluctuations in volume status and electrolyte derangements. While there is extensive literature regarding the critically ill medical or cardiac patient, there is less focusing on the critically ill surgical or trauma patient. More specifically, there is minimal regarding tachyarrhythmias in burn patients. The latter population tends to have frequent and wide variations in volume status given initial resuscitation and after major excisions, concomitant with acute blood loss anemia, which can contribute to cardiac disturbances. A literature review was conducted to investigate the incidence and consequences of tachyarrhythmias in critically ill surgical and trauma patients, with a focus on the burn population. While some similarities and conclusions can be drawn between these surgical populations, further inquiry into the unique burn patient is necessary.

Analytical Management of Patients Undergoing Oral Anticoagulant Therapy Could Have a Strong Impact on Clinical Outcomes: A Follow-up Study

Introduction

Oral anticoagulant therapy, such as vitamin K antagonists (VKAs), is prominent for the prevention of cerebral ischemic stroke or systemic embolism and all-cause mortality in patients with atrial fibrillation, venous thromboembolism, and mechanical or biological valve. VKA treatment requires monitoring of the international normalized ratio (INR) in order to maintain it in a therapeutic range, avoiding side effects, the main and most significant of which is bleeding. The aim of the present study was to evaluate the event rates of several clinical composite outcomes, such as bleeding, thromboembolic events, and all-cause death.

Methods

We compared three organizational models distinguished by a total (from 1 January to 31 December 2015 in which PT/INR analysis with the relative internal and external quality controls was performed by the surveillance center) or partial (from 15 January to 15 July 2016 and from 15 August to 15 November 2016, in which the surveillance center had the ability to view only the PT/INR results or all patients analyses, including blood count, creatinine, liver enzymes, etc., respectively) analytical patient management. The present longitudinal follow-up study included 1225 patients, recruited from 1 January 2015 to 15 November 2016 at a surveillance center for the prevention of cerebral ischemic stroke and systemic embolism in Chieti (Italy).

Results

The results show a significant rise of the incidence rate ratio in patients undergoing VKA treatment during the period 15 January to 15 July 2016 compared to the previous one regarding total bleeding, especially for minor bleeding and digestive bleeding; thromboembolic events; and all-death cause.

Conclusions

These findings show that analytical and clinical data and information should be under the direct supervision and responsibility of the surveillance center. In fact, this approach seems to highlight the best results in terms of safety and therapeutic effectiveness.

Cardiac hyaluronan may be associated with the persistence of atrial fibrillation

Hyaluronan (HA), a primary component of the extracellular matrix, is associated with several cardiovascular diseases. However, its precise cardiac origin and role in atrial fibrillation (AF) remain unclear. We investigated chamber-specific HA levels in patients with paroxysmal AF (PAF) or persistent AF (PSAF). The levels of HA, a diacron-reactive oxygen metabolite (dROM) as a marker for oxidative stress, at different cardiac sites, and peripheral brain natriuretic peptide (BNP) levels were measured in patients with PAF (n = 50) or PSAF (n = 35). HA levels in the coronary sinus (CS-HA) were significantly higher than those other sites, in both PAF and PSAF patients, and CS-HA levels were significantly higher in PSAF patients than in PAF patients [37.1 (interquartile range, 31.2-48.3) vs. 30.6 (23.7-40.2) pg/mL, P < 0.01]. CS-HA levels were correlated with CS-dROM levels and peripheral BNP levels in PSAF patients (r = 0.417, P = 0.03 and r = 0.579, P < 0.001, respectively), but not in PAF patients (r = -0.115, P = 0.421 and r = 0.048, P = 0.740, respectively). CS-HA levels were elevated in both PAF and PSAF patients and were correlated with cardiac oxidative stress and BNP levels in PSAF patients. Cardiac HA may be associated with the persistence of AF.

Atrial fibrillation among patients under investigation for suspected obstructive sleep apnea

Study objectives

Obstructive sleep apnea is common among patients with atrial fibrillation, but the prevalence and risk factors for atrial fibrillation among patients who are being investigated on suspicion of sleep apnea are not well known. The aim of the study was to estimate the prevalence of atrial fibrillation among patients investigated for suspected obstructive sleep apnea and to identify risk factors for atrial fibrillation among them.

Methods

The prevalence of atrial fibrillation was investigated among 201 patients referred for suspected obstructive sleep apnea. Patients without known atrial fibrillation were investigated with a standard 12-lead ECG at hospital and short intermittent handheld ECG recordings at home, during 14 days.

Results

Atrial fibrillation occurred in 13 of 201 subjects (6.5%), and in 12 of 61 men aged 60 years and older (20%). The prevalence of atrial fibrillation increased with sleep apnea severity (p = 0.038). All patients with atrial fibrillation were men and all had sleep apnea. Age 60 or older, the occurrence of central sleep apnea and diabetes mellitus were independent risk factors for atrial fibrillation after adjustments for body mass index, gender, sleep apnea and cardiovascular disease.

Conclusions

Atrial fibrillation is common among subjects referred for sleep apnea investigation and the prevalence of atrial fibrillation increases with sleep apnea severity. Independent risk factors for atrial fibrillation among patients investigated for suspected obstructive sleep apnea include the occurrence of coexisting central sleep apnea, age 60 years or older and diabetes mellitus.

Atrial fibrillation: review of current treatment strategies

Atrial fibrillation (AF) is the most prevalent cardiac arrhythmia in modern clinical practice, with an estimated prevalence of 1.5-2%. The prevalence of AF is expected to double in the next decades, progressing with age and increasingly becoming a global medical challenge. The first-line treatment for AF is often medical treatment with either rate control or anti-arrhythmic agents for rhythm control, in addition to anti-coagulants such as warfarin for stroke prevention in patient at risk. Catheter ablation has emerged as an alternative for AF treatment, which involves myocardial tissue lesions to disrupt the underlying triggers and substrates for AF. Surgical approaches have also been developed for treatment of AF, particularly for patients requiring concomitant cardiac surgery or those refractory to medical and catheter ablation treatments. Since the introduction of the Cox-Maze III, this procedure has evolved into several modern variations, including the use of alternative energy sources (Cox-Maze IV) such as radiofrequency, cryo-energy and microwave, as well as minimally invasive thoracoscopic epicardial approaches. Another recently introduced technique is the hybrid ablation approach, where in a single setting both epicardial thoracoscopic ablation lesions and endocardial catheter ablation lesions are performed by the cardiothoracic surgeon and cardiologist. There remains controversy surrounding the optimal approach for AF ablation, energy sources, and lesion sets employed. The goal of this article is review the history, classifications, pathophysiology and current treatment options for AF.

Atrial Fibrillation After Cardiac Surgery: Pathophysiology and Treatment

Atrial fibrillation (AF) occurs in 25% to 60% of patients after cardiac surgery. It is most consistently associated with advanced age and valvular heart operations. Despite improving knowledge of the pathophysiology of chronic AF, postoperative AF remains an obstinate clinical problem. It is associated with an increased risk of stroke, longer hospital stay, and higher hospital expenditure. Consequently, there has been great interest in strategies to prevent and treat this arrhythmia. Treatment for postoperative AF may require immediate electrical cardioversion for hemodynamically unstable patients. Heart rate control is useful in most patients, with anticoagulation considered after 48 hours. Antiarrhythmic therapy is often effective in restoring sinus rhythm but its use needs to be balanced against the patient's risk of proarrhythmic side effects such as torsade de pointes.

Short-Term Exposure to Air Pollution and Cardiac Arrhythmia: A Meta-Analysis and Systematic Review

The objective was to assess the transient association between air pollution and cardiac arrhythmia. Five databases were searched for studies investigating the association between daily increases in air pollutants (PM2.5, PM10, carbon monoxide, nitrogen dioxide, sulfur dioxide and ozone) and arrhythmia hospitalization or arrhythmia mortality. Two reviewers independently selected studies, extracted data, and assessed risk of bias. Outcomes were analyzed via a random-effects model and reported as relative risk and 95% confidence interval. 25 studies satisfied our inclusion criteria and 23 contributed to the meta-analysis. Arrhythmia hospitalization or mortality were associated with increases in PM2.5 (RR = 1.015 per 10 μg/m³, 95% CI: 1.006-1.024), PM10 (RR = 1.009 per 10 μg/m³, 95% CI: 1.004-1.014), carbon monoxide (RR = 1.041 per 1 ppm, 95% CI: 1.017-1.065), nitrogen dioxide (RR = 1.036 per 10 ppb, 95% CI: 1.020-1.053), and sulfur dioxide (RR = 1.021 per 10 ppb, 95% CI: 1.003-1.039), but not ozone (RR = 1.012 per 10 ppb, 95% CI: 0.997-1.027). Both particulate and gaseous components, with the exception of ozone, have a temporal association with arrhythmia hospitalization or mortality. Compared with Europe and North America, a stronger association was noted in Asia.

Use of Vitamins K antagonists in non-valvular atrial fibrillation thromboembolic risk prevention in Burkina Faso

Introduction

Atrial fibrillation is the commonest cardiac rythm disorder. Thromboembolic accidents are common complications that should be prevented by anticoagulant treatment. The aim of our study is to assess the use of vitamins K antagonists in the prevention of thromboembolic risk in atrial fibrillation.

Methods

It was a descriptive retrospective study of patients folders, performed in the cardiology department from January 1st 2010 to December 31st 2011. The study included all patients with non valvular atrial fibrillation. Thromboembolic risk was assessed through the CHA2DS2VASc score, and hemorrhagic risk through the HAS-BLED score.

Results

Atrial fibrillation accounted for 10.6% of all hospitalizations (103/970). Five patients had contra indication to anticoagulants. Non valvular AF was noticed in 68 cases (66%). The non valvular AF was chronic in 40 cases (59%) and paroxystic in eight cases (12%). The median age of the population was 64.5+13.8 years old. Median CHA2DS2VASc score was 3.9 + 1.6. Two patients had a score < 1. Sex, place of residence, age > 65, and cardiac failure did not interfere with prescription of vitamins K antagonists. Ischemic stroke and intra cavity thrombus were the indications for vitamins K antagonists’ prescriptions. The median HAS-BLED score was 3.5 + 1.5. The rate of vitamins K antagonists use was 35.3%. One case of death due to hemorrhagic stroke was noticed.

Conclusion

Guidelines on thromboembolic risk prevention are poorly used in the cardiology department. But the use of scoring systems allows the assessment of vitamins K antagonists treatment benefit/risk in atrial fibrillation, and minimizes the hemorrhagic risk.

Management of antithrombotic therapy during cardiac implantable device surgery

Anticoagulants are commonly used drugs that are frequently encountered during device placement. Deciding when to halt or continue the use of anticoagulants is a balance between the risks of thromboembolism versus bleeding. Patients taking warfarin with a high risk of thromboembolism should continue to take their warfarin without interruption during device placement while ensuring their international normalized ratio remains below 3. For patients who are taking warfarin and have low risk of thromboembolism, either interrupted or continued warfarin may be used, with no evidence to clearly support either strategy. There is little evidence to support continuing direct acting oral anticoagulants (DOACs) for device implantation. The timing of halting these medications depends largely on renal function. If bleeding occurs, warfarin׳s anticoagulation effect is reversible with vitamin K and activated prothrombin complex concentrate. There are no DOAC reversal agents currently available, but some are under development. Regarding antiplatelet agents, aspirin alone can be safely continued while clopidogrel alone may also be continued, but with a slightly higher bleeding risk. Dual antiplatelet therapy for bare-metal stent/drug-eluting stent implanted within 4 weeks/6 months, respectively, should be continued due to high risk of stent thrombosis; however, if they are implanted after this period, then clopidogrel can be halted 5 days before the procedure and resumed soon after, while aspirin is continued. If the patient is taking both aspirin and warfarin, aspirin should be halted 5 days prior to the procedure, while warfarin is continued.

Effects of Persistent Atrial Fibrillation-Induced Electrical Remodeling on Atrial Electro-Mechanics - Insights from a 3D Model of the Human Atria

Aims

Atrial stunning, a loss of atrial mechanical contraction, can occur following a successful cardioversion. It is hypothesized that persistent atrial fibrillation-induced electrical remodeling (AFER) on atrial electrophysiology may be responsible for such impaired atrial mechanics. This simulation study aimed to investigate the effects of AFER on atrial electro-mechanics.

Methods and Results

A 3D electromechanical model of the human atria was developed to investigate the effects of AFER on atrial electro-mechanics. Simulations were carried out in 3 conditions for 4 states: (i) the control condition, representing the normal tissue (state 1) and the tissue 2–3 months after cardioversion (state 2) when the atrial tissue recovers its electrophysiological properties after completion of reverse electrophysiological remodelling; (ii) AFER-SR condition for AF-remodeled tissue with normal sinus rhythm (SR) (state 3); and (iii) AFER-AF condition for AF-remodeled tissue with re-entrant excitation waves (state 4). Our results indicate that at the cellular level, AFER (states 3 & 4) abbreviated action potentials and reduced the Ca²⁺ content in the sarcoplasmic reticulum, resulting in a reduced amplitude of the intracellular Ca²⁺ transient leading to decreased cell active force and cell shortening as compared to the control condition (states 1 & 2). Consequently at the whole organ level, atrial contraction in AFER-SR condition (state 3) was dramatically reduced. In the AFER-AF condition (state 4) atrial contraction was almost abolished.

Conclusions

This study provides novel insights into understanding atrial electro-mechanics illustrating that AFER impairs atrial contraction due to reduced intracellular Ca²⁺ transients.

Coagulation Testing For New Oral Anticoagulants

Atrial fibrillation is the most common and important cardiac rhythm disorder, which increases the risk of stroke and mortality. New oral anticoagulants are an alternative for vitamin K antagonists to prevent stroke in patients with non-valvular atrial fibrillation. New oral anticoagulants do not require routine monitoring of coagulation. However, the quantitative assessment of the anticoagulant effect drug levels may be needed in emergency situations, such as a serious bleeding or need for urgent surgery, or in patient with renal or hepatic insufficiency. In the paper we focus on the coagulation testing for new oral anticoagulants.

Inflammatory bowel "Cardiac" disease: Point prevalence of atrial fibrillation in inflammatory bowel disease population

BACKGROUND/AIM

Proinflammatory markers such as interleukin (IL)-6 have been closely associated with atrial fibrillation (AF). These markers are characteristically elevated in chronic inflammatory bowel disease (IBD) and positively correlate with disease activity. Although IBD and AF have similar pathogenesis, there have been very limited studies looking at their association. The aim of this study is to determine the prevalence of AF in patients with IBD.

PATIENTS AND METHODS

Medical records of patients with biopsy proven IBD (n = 203, both in and outpatient) were retrospectively reviewed. One hundred and forty-one IBD patients with documentary evidence of electrocardiograms (ECG's) were included. The "Anticoagulation and Risk Factors in Atrial Fibrillation (ATRIA)" study, a large cross-sectional study (n = 1.89 million) done to evaluate the prevalence of AF among the US population, was our control population. All ECGs available till December 2010 for each IBD patient were reviewed carefully for evidence of AF. We studied the prevalence of AF among IBD population and compared it to that of control (ATRIA) population.

RESULTS

The prevalence of AF was significantly higher among IBD patients compared with the ATRIA study patients (11.3% vs 0.9%, P < 0.0001). Additionally, the IBD patient population were much younger compared with the controls (64.4 ± 10.7 vs 71.2 ± 12.2, P = 0.02).

CONCLUSION

AF has an overall higher prevalence across all age groups in IBD compared with the subjects of ATRIA study, which could be due to the chronic inflammatory state of IBD. Further studies are needed to study the association in detail.

Management of osteoporosis of the oldest old

This consensus article reviews the diagnosis and treatment of osteoporosis in geriatric populations. Specifically, it reviews the risk assessment and intervention thresholds, the impact of nutritional deficiencies, fall prevention strategies, pharmacological treatments and their safety considerations, the risks of sub-optimal treatment adherence and strategies for its improvement.

INTRODUCTION

This consensus article reviews the therapeutic strategies and management options for the treatment of osteoporosis of the oldest old. This vulnerable segment (persons over 80 years of age) stands to gain substantially from effective anti-osteoporosis treatment, but the under-prescription of these treatments is frequent.

METHODS

This report is the result of an ESCEO (European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis) expert working group, which explores some of the reasons for this and presents the arguments to counter these beliefs. The risk assessment of older individuals is briefly reviewed along with the differences between some intervention guidelines. The current evidence on the impact of nutritional deficiencies (i.e. calcium, protein and vitamin D) is presented, as are strategies to prevent falls. One possible reason for the under-prescription of pharmacological treatments for osteoporosis in the oldest old is the perception that anti-fracture efficacy requires long-term treatment. However, a review of the data shows convincing anti-fracture efficacy already by 12 months.

RESULTS

The safety profiles of these pharmacological agents are generally satisfactory in this patient segment provided a few precautions are followed.

CONCLUSION

These patients should be considered for particular consultation/follow-up procedures in the effort to convince on the benefits of treatment and to allay fears of adverse drug reactions, since poor adherence is a major problem for the success of a strategy for osteoporosis and limits cost-effectiveness.

Percutaneous left atrial appendage closure with a novel self-modelizing device: a pre-clinical feasibility study

The aim of the study is to evaluate the feasibility and safety of a new left atrial appendage (LAA) occluder. Twelve pigs were included. In 2 pigs the implantation process failed due to pericardial tamponade in 1 pig and device embolization in the other pig. The placement of the devices was controlled via TEE and fluoroscopy. After 6 weeks of implantation the hearts were explanted. The devices were found to be easy to deploy and showed a very good adaptation to the LAA tissue. Eight out of 10 pigs had full closure of the LAA directly after implantation. After six weeks, due to the self-modelizing properties of the device, all pigs had a full closure of the LAA. The macroscopic evaluation of the explanted hearts showed that all devices were securely integrated in LAA tissues. There was one case of mild pericarditis but no macroscopic signs of inflammation on the device surrounding endocardium. The explantation revealed that device loops had penetrated the LAA tissue in three pigs. However, no signs of bleeding, pericardial effusion, or other damage to the LAA wall could be detected and the pigs were in good condition with normal weight gain and no clinical symptoms. The Occlutech® LAA occluder achieved complete closure of the LAA in all pigs, and remained in the LAA, with benign healing and no evidence of new thrombus or damage to surrounding structures. Moreover, the uncompromised survival of all implanted pigs demonstrates the feasibility and safety of the device.

Atrial electrical activity detection using linear combination of 12-lead ECG signals

ECG analysis is the method for cardiac arrhythmia diagnosis. During the diagnostic process many features should be taken into consideration, such as regularity and atrial activity. Since in some arrhythmias, the atrial electrical activity (AEA) waves are hidden in other waves, and a precise classification from surface ECG is inapplicable, a confirmation diagnosis is usually performed during an invasive procedure. In this paper, we study a "semiautomatic" method for AEA-waves detection using a linear combination of 12-lead ECG signals. This method's objective is to be applicable to a variety of arrhythmias with emphasis given to detect concealed AEA waves. It includes two variations--using maximum energy ratio and a synthetic AEA signal. In the former variation, an energy ratio-based cost function is created and maximized using the gradient ascent method. The latter variation adapted the linear combiner method, when applied on a synthetic signal, combined with surface ECG leads. A study was performed evaluating the AEA-waves detection from 63 patients (nine training, 54 validation) presenting eight arrhythmia types. Averaged sensitivity of 92.21% and averaged precision of 92.08% were achieved compared to the definite diagnosis. In conclusion, the presented method may lead to early and accurate detection of arrhythmias, which will result in a better oriented treatment.

Recognising and managing atrial fibrillation in the community

Atrial fibrillation (AF) is the most common cardiac arrhythmia and has greater prevalence in the increasing ageing population, with an estimated 10% of those over 80 years having AF. Symptoms associated with AF include palpitations, dizziness, shortness of breath and fatigue. Those presenting with these symptoms need to be investigated and the appropriate treatment should be initiated if AF is detected. For those with AF, there is a significant risk of stroke if patients are not adequately anti-coagulated. This article outlines methods for detecting AF in the community and provides an overview of current treatment options, including the newer anti-coagulant agents. The importance of assessing stroke risk and conveying this risk to those with AF is essential. Community health professionals play an important role in monitoring, treating and managing AF within the community setting and supporting and educating the patient in minimising the risk of serious thromboembolic complications such as stroke.

Left atrial appendage closure in patients with atrial fibrillation in whom warfarin is contra-indicated: initial South African experience

Atrial fibrillation is a common cause of cardiac embolic events, especially stroke. Oral anticoagulation therapy is used to reduce these events. Many patients however are unable to take such therapy. Percutaneous occlusion of the left atrial appendage (the source of 90% of these emboli) is an option in these patients. Presented here are the first 12 patients to have this procedure done in South Africa.

Diastolic Function in Normal Sinus Rhythm vs. Chronic Atrial Fibrillation: Comparison by Fractionation of E-wave Deceleration Time into Stiffness and Relaxation Components

Although the electrophysiologic derangement responsible for atrial fibrillation (AF) has been elucidated, how AF remodels the ventricular chamber and affects diastolic function (DF) has not been fully characterized. The previously validated Parametrized Diastolic Filling (PDF) formalism models suction-initiated filling kinematically and generates error-minimized fits to E-wave contours using unique load (x_o), relaxation (c), and stiffness (k) parameters. It predicts that E-wave deceleration time (DT) is a function of both stiffness and relaxation. Ascribing DT_s to stiffness and DTr to relaxation such that DT=DT_s+DT_r is legitimate because of causality and their predicted and observed high correlation (r=0.82 and r=0.94) with simultaneous (diastatic) chamber stiffness (dP/dV) and isovolumic relaxation (tau), respectively. We analyzed simultaneous echocardiography-cardiac catheterization data and compared 16 age matched, chronic AF subjects to 16, normal sinus rhythm (NSR) subjects (650 beats). All subjects had diastatic intervals. Conventional DF parameters (DT, AT, E_peak, E_dur, E-VTI, E/E') and E-wave derived PDF parameters (c, k, DT_s, DT_r) were compared. Total DT and DT_s, DT_r in AF were shorter than in NSR (p<0.005), chamber stiffness, (k) in AF was higher than in NSR (p<0.001). For NSR, 75% of DT was due to stiffness and 25% was due to relaxation whereas for AF 81% of DT was due to stiffness and 19% was due to relaxation (p<0.005). We conclude that compared to NSR, increased chamber stiffness is one measurable consequence of chamber remodeling in chronic, rate controlled AF. A larger fraction of E-wave DT in AF is due to stiffness compared to NSR. By trending individual subjects, this method can elucidate and characterize the beneficial or adverse long-term effects on chamber remodeling due to alternative therapies in terms of chamber stiffness and relaxation.

Rac1-mediated effects of HMG-CoA reductase inhibitors (statins) in cardiovascular disease

SIGNIFICANCE

HMG-CoA reductase inhibitors (statins) lower serum cholesterol concentrations and are beneficial in the primary and secondary prevention of coronary heart disease. The positive clinical effects have only partially been reproduced with other lipid-lowering interventions suggesting potential statin effects in addition to cholesterol lowering. In experimental models, direct beneficial cardiovascular effects that are mediated by the inhibition of isoprenoids have been documented, which serve as lipid attachments for intracellular signaling molecules such as small Rho guanosine triphosphate-binding proteins, whose membrane localization and function are dependent on isoprenylation.

RECENT ADVANCES

Rac1 GTPase is an established master regulator of cell motility through the cortical actin reorganization and of reactive oxygen species generation through the regulation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity.

CRITICAL ISSUES

Observations in cells, animals, and humans have implicated the activation of Rac1 GTPase as a key component of cardiovascular pathologies, including the endothelial dysfunction, cardiac hypertrophy and fibrosis, atrial fibrillation, stroke, hypertension, and chronic kidney disease. However, the underlying signal transduction remains incompletely understood.

FUTURE DIRECTIONS

Based on the recent advance made in Rac1 research in the cardiovascular system by using mouse models with transgenic overexpression of activated Rac1 or conditional knockout, as well as Rac1-specific small molecule inhibitor NSC 23766, the improved understanding of the Rac1-mediated effects statins may help to identify novel therapeutic targets and strategies.

Surgical options for treatment of atrial fibrillation

If we want to improve the outcomes, increase the success and reduce the complication rate of existing treatment strategies in concomitant and stand-alone atrial fibrillation (AF) procedures, we will have to increase our understanding of the pathophysiology, and of the disease, the limitations of current energy sources and ablation catheters, the different possible lesion sets, as well as improve communication between the electrophysiologist and cardiac surgeon. The technical limitations of percutaneous endocardial ablation procedures and the empirical techniques in surgical AF procedures necessitate new and innovative approaches. Surgeons should aim to improve the quality of the lesion set and minimize the invasiveness of existing techniques. The Maze procedure remains the basis upon which most of the more limited concomitant ablation procedures are and will be designed, but in stand-alone patients, recent progress has directed us towards either a single-step or sequential combined percutaneous endocardial procedure with a thoracoscopic epicardial procedure on the beating heart. A dedicated team of electrophysiologists and cardiothoracic surgeons can now work together to perform AF procedures. This can guide us to determine if there is an additional value of limiting the lesion set of the Maze procedure in concomitant surgery, and of an epicardial access in the treatment of stand-alone AF on the beating heart. If so, we will better understand which energy sources, lesion sets and surgical techniques are able to give us a three-dimensional knowledge and a three-dimensional treatment of AF. As a result, we can expect to obtain a higher single procedure long-term success rate with an acceptable low complication rate.

Curative surgery for atrial fibrillation: current status and minimally invasive approaches

Atrial fibrillation (AF) is the most common disorder of heart rhythm. Affecting 2.2 million Americans and millions more worldwide, AF is a dangerous and costly epidemic. AF is associated with an increased risk of stroke, premature death and billions of dollars in healthcare expenditures. Traditional treatments of AF, which include medications aimed at rate or rhythm control have been disappointing, leaving most patients in AF and failing to eliminate the risk of stroke. In contrast, advances in surgical and catheter-based therapies offer the chance to cure AF. With more than a decade of experience, surgical treatment of AF is the most effective means of curing this arrhythmia. The classic Maze procedure eliminates AF in more than 90% of patients. A complex but safe operation, the Maze procedure is applied by relatively few surgeons. Recently, however, there has been a resurgence of interest in surgical treatment of AF. Advances in the understanding of the pathogenesis of AF and development of new ablation technologies enable surgeons to perform pulmonary vein ablation and create linear left atrial lesions rapidly and safely. Such procedures, which are generally applied to patients with AF and valvular heart disease, add 15 minutes to operative time and cure AF in approximately 80% of patients. New ablation technologies have been adapted to enable thoracoscopic and minimally invasive surgical AF ablation in patients with isolated AF, extending the possibility of cure to large numbers of patients.

Antithrombotic therapy in atrial fibrillation: ximelagatran, an oral direct thrombin inhibitor

The oral direct thrombin inhibitor ximelagatran (Exanta, AstraZeneca) is rapidly absorbed, is efficiently bioconverted to the active form, melagatran (AstraZeneca) and has shown efficacy and relative safety as an anticoagulant for prophylaxis and therapy of thromboembolism. Two Phase III trials, Stroke Prevention using an ORal Thrombin Inhibitor in atrial Fibrillation (SPORTIF V), have tested the hypothesis that oral ximelagatran, administered 36 mg twice daily without coagulation monitoring or dose adjustment, prevents stroke and systemic embolism at least as effectively as adjusted-dose warfarin (international normalized ratio, 2.0-3.0) in patients with nonvalvular atrial fibrillation. Both were randomized, multicenter trials (n > 3000 per trial) with blinded end-point assessment. The open-label SPORTIF III trial confirmed the noninferiority of ximelagatran versus warfarin. Publication of the full results from SPORTIF V is pending.

The Relationship Between Serum Bilirubin Concentration and Atrial Fibrillation

Background

Several studies have demonstrated that higher serum bilirubin inhibits the inflammation and proliferation of vascular smooth muscle cells; also there is a relationship between serum bilirubin and cardiovascular disease. However, the relationship between bilirubin and atrial fibrillation (AF) is still unknown. In our study, we compared serum bilirubin, between nonvalvular AF patients and controls.

Materials and Method

One hundred and two patients with nonvalvular chronic AF without any other cardiovascular disease (mean age 62.51 ± 5.88) were included in our study. One hundred age-matched healthy people with sinus rhythm were accepted as control groups (mean age 61.35 ± 5.44). Routine biochemical parameters and serum bilirubin levels were performed.

Results

No statistically significant difference was found between two groups in terms of basic characteristics. Total, direct and indirect serum bilirubin levels were significantly lower among persons with AF compared to controls (0.82 ± 0.8 vs. 0.48 ± 0.5, 0.30 ± 0.2 vs. 0.19 ± 0.1 and 0.52 ± 0.5 vs. 0.29 ± 0.3 mg/dL; all P < 0.001, respectively).

Conclusion

As a result, our study revealed a relationship between serum bilirubin and nonvalvular AF.

Supraventricular arrhythmias after thoracotomy: is there a role for autonomic imbalance?

Supraventricular arrhythmias are common rhythm disturbances following pulmonary surgery. The overall incidence varies between 3.2% and 30% in the literature, while atrial fibrillation is the most common form. These arrhythmias usually have an uneventful clinical course and revert to normal sinus rhythm, usually before patent's discharge from hospital. Their importance lies in the immediate hemodynamic consequences, the potential for systemic embolization and the consequent long-term need for prophylactic drug administration, and the increased cost of hospitalization. Their incidence is probably related to the magnitude of the performed operative procedure, occurring more frequently after pneumonectomy than after lobectomy. Investigators believe that surgical factors (irritation of the atria per se or on the ground of chronic inflammation of aged atria), direct injury to the anatomic structure of the autonomic nervous system in the thoracic cavity, and postthoracotomy pain may contribute independently or in association with each other to the development of these arrhythmias. This review discusses currently available information about the potential mechanisms and risk factors for these rhythm disturbances. The discussion is in particular focused on the role of postoperative pain and its relation to the autonomic imbalance, in an attempt to avoid or minimize discomfort with proper analgesia utilization.

CYP2J2 overexpression protects against arrhythmia susceptibility in cardiac hypertrophy

Maladaptive cardiac hypertrophy predisposes one to arrhythmia and sudden death. Cytochrome P450 (CYP)-derived epoxyeicosatrienoic acids (EETs) promote anti-inflammatory and antiapoptotic mechanisms, and are involved in the regulation of cardiac Ca(2+)-, K(+)- and Na(+)-channels. To test the hypothesis that enhanced cardiac EET biosynthesis counteracts hypertrophy-induced electrical remodeling, male transgenic mice with cardiomyocyte-specific overexpression of the human epoxygenase CYP2J2 (CYP2J2-TG) and wildtype littermates (WT) were subjected to chronic pressure overload (transverse aortic constriction, TAC) or β-adrenergic stimulation (isoproterenol infusion, ISO). TAC caused progressive mortality that was higher in WT (42% over 8 weeks after TAC), compared to CYP2J2-TG mice (6%). In vivo electrophysiological studies, 4 weeks after TAC, revealed high ventricular tachyarrhythmia inducibility in WT (47% of the stimulation protocols), but not in CYP2J2-TG mice (0%). CYP2J2 overexpression also enhanced ventricular refractoriness and protected against TAC-induced QRS prolongation and delocalization of left ventricular connexin-43. ISO for 14 days induced high vulnerability for atrial fibrillation in WT mice (54%) that was reduced in CYP-TG mice (17%). CYP2J2 overexpression also protected against ISO-induced reduction of atrial refractoriness and development of atrial fibrosis. In contrast to these profound effects on electrical remodeling, CYP2J2 overexpression only moderately reduced TAC-induced cardiac hypertrophy and did not affect the hypertrophic response to β-adrenergic stimulation. These results demonstrate that enhanced cardiac EET biosynthesis protects against electrical remodeling, ventricular tachyarrhythmia, and atrial fibrillation susceptibility during maladaptive cardiac hypertrophy.

Intracerebral hemorrhage in patients receiving oral anticoagulation therapy

Intracerebral hemorrhage (ICH) in patients with oral anticoagulation therapy is an increasingly prevalent problem in large part due to the aging population and the increased use of anticoagulants for patients at high risk of thrombosis. Warfarin has been virtually the only outpatient anticoagulant choice until fairly recently. The development of subcutaneously injected heparinoids, and more recently, of direct thrombin inhibitors, has made the treatment and prognostication of ICH in anticoagulated patients more difficult. In this review, we will review the current state of diagnosis, prognostication, and treatment for patients with this often-devastating type of bleeding. We will focus on warfarin therapy, because the preponderance of evidence comes from studies of warfarin treatment. Where there is evidence, we will contrast warfarin with some of the newer treatment modalities. We review the evidence of the 4 major reversal agents for warfarin, vitamin K, prothrombin complex concentrates, activated factor VII, and fresh frozen plasma as well as rational treatment choices. We offer possible treatments for the newer anticoagulants based on the limited evidence available. Finally, we review recommendations from the major societies and studies that support early and aggressive therapies in intensive care units with dedicated neurological specialists.

The effects of eosinophil on the left atrial thrombus in patients with atrial fibrillation

BACKGROUND

Atrial fibrillation (AF) is the most common cardiac rhythm disorder. Atrial fibrillation causes a 5-fold increased risk for thromboembolic stroke. It is known that eosinophils play an important role in thrombosis. We aimed to compare the number of eosinophil counts of the patients with and without thrombi in the left atrium (LA) or in the left atrial appendage (LAA) and to ascertain the association of eosinophil counts with the presence of thrombi.

METHOD

The study included 89 patients diagnosed with persistent AF who underwent transesophageal echocardiography and designated to undergo cardioversion. The patients were divided into 2 groups: group 1 consisted of 40 patients (18 male; average age 63.27 ± 1.4) who had thrombus formation in the LA or LAA, and group 2 consisted of 49 patients (23 male; average age 66.53 ± 1.56) who did not have any thrombus in the LA or LAA. These patients underwent concurrent routine biochemical tests and eosinophil count on whole blood count was also performed.

RESULTS

Baseline characteristics of the study groups were comparable. Group 1 patients had higher eosinophil and mean platelet volume values than group 2 (233.0 ± 30.7 vs 118.9 ± 11.8 and 9.77 ± 0.20 vs 8.27 ± 0.12 fL, P < .001, respectively). In group 1, the patients' LA diameter is higher than that in group II.

CONCLUSION

As a result, our study revealed a relationship between eosinophil count and LA thrombus in patients with nonvalvular AF.

Oral anticoagulation to reduce risk of stroke in patients with atrial fibrillation: current and future therapies

Atrial fibrillation (AF) is associated with an increased incidence and severity of strokes. The burden of AF-related stroke is expected to increase in parallel with the aging of the population. Oral anticoagulation with warfarin has been the pharmacologic standard for stroke risk reduction in patients with AF. When used with close attention to dosing and monitoring, warfarin is effective prophylactic therapy against thromboembolic stroke. However, it is underused by physicians, in part because of the known risks of adverse events with warfarin. Consequently, many patients with AF live with an avoidably elevated risk of stroke. New options, ie, oral anticoagulants with novel mechanisms of action, have recently been approved to reduce the risk of stroke in AF, and others are in development. These newer agents may address some of the complexities of warfarin use while providing similar or better efficacy and safety.