Pharmacological Treatment for Atrial Fibrillation—Modalities in Equines and Companion Animals

Cardiac arrhythmias are probably more common in horses than in any other domestic animal species where poor performance and exercise intolerance is the most frequent clinical complaint. Atrial fibrillation is a type of cardiac arrhythmia that appears as a common finding during medical examinations in humans, large breed dogs and horses. Clinical presentations are of a particular value in racehorses in high performing activities. Atrial fibrillation is characterized by an irregular heart rhythm, secondary to a primary disease or without any sign of comorbidity. The generation and maintenance of Atrial Fibrillation requires a substrate. Some breeds have a genetic predisposition to developing Atrial Fibrillation. Most cases of Atrial Fibrillation are of the paroxysmal type and self-regulate within a few hours to days without the need for treatment. The focus of this study is on the arrhythmic agents that are used for the treatment of Atrial Fibrillation, therefore other arrhythmic agents may not be included, or are included to demonstrate their effect on increasing, inhibiting or decreasing efficacy when used together with medications for the treatment of Atrial Fibrillation. The “working horse” for the pharmacological treatment of Atrial Fibrillation is Quinidine.

Atrial fibrillation in the elderly: Is ablation ready for prime time ?

Atrial fibrillation is the most common sustained arrhythmia and results in significant morbidity, especially in the elderly. The prevalence of atrial fibrillation increases dramatically with advancing age to almost 6% in individuals older than 65 years. In fact, 84% of people with atrial fibrillation are over 65 years of age.1 Additionally, the risk of stroke increases with advancing age, such that one-third of strokes in patients over the age of 65 are caused by atrial fibrillation.

Predisposing factors for atrial fibrillation in the elderly

Atrial fibrillation （AF） in the elderly occurs as a consequence of cardiovascular aging and an age related increase of comorbidity. Several predisposing factors for AF have been identified for the overall AF population. Most of them, cardiovascular disease in particular, play a role in younger and older patients. The longer time period during which these risk factors can cause structural changes that ultimately lead to AF may, at least in part, explain the association between age and AF. In addition, less well defined age-related changes in cellular electrophysi- ologic properties and structure predispose to AF in the elderly.

Atrial fibrillation in the elderly

This review discusses atrial fibrillation according to the guidelines of Brazilian Society of Cardiac Arrhythmias and the Brazilian Cardiogeriatrics Guidelines. We stress the thromboembolic burden of atrial fibrillation and discuss how to prevent it as well as the best way to conduct cases of atrial fibrillatios in the elderly, reverting the arrhythmia to sinus rhythm, or the option of heart rate control. The new methods to treat atrial fibrillation, such as radiofrequency ablation, new oral direct thrombin inhibitors and Xa factor inhibitors, as well as new antiarrhythmic drugs, are depicted.

Catheter ablation of atrial fibrillation in the elderly

Background Atrial fibrillation （AF） catheter ablation has emerged as a promising treatment strategy for AF, but has not been widely adopted in the elderly population. The present study aimed to determine the safety and efficacy of AF catheter ablation in the elderly popula-tion. Methods and Results The study population consisted of 316 patients with paroxysmal AF who underwent left atrial ablation. Ninety-five patients were≥65 years （48 males, mean age 68.9 ± 3.0 years old） and 221 patients were〈65 years old （130 males, mean age 52.5 ± 10.4 years old）. After a mean follow-up period of 34.0 ± 15.1 months, 55 （57.9%） patients in the elderly group were free from ar-rhythmia recurrence compared with 149 （67.4%） patients in the younger group （P=0.169）. Procedural complications were uncommon in both study groups. In logistic regression analysis, left atrial diameter （P=0.003）, hypertension （P=0.001）, dyslipidemia （P=0.039）, and coronary artery disease （P=0.018） were independent predictors of AF recurrence in the elderly population. Conclusions Catheter ablation of AF is safe and effective in older patients. Invasive strategies should be considered as an alternative choice in symptomatic elderly patients with AF.

Catheter ablation for atrial fibrillation is associated with reduced risk of mortality in the elderly:a prospective cohort study and propensity score analysis

Background It is unclear whether catheter ablation(CA)for atrial fibrillation(AF)affects the long-term prognosis in the elderly.This study aims to evaluate the relationship between CA and long-term outcomes in elderly patients with AF.Methods Patients more than 75 years old with non-valvular AF were prospectively enrolled between August 2011 and December 2017 in the Chinese Atrial Fibrillation Registry Study.Participants who underwent CA at baseline were propensity score matched(1:1)with those who did not receive CA.The outcome events included all-cause mortality,cardiovascular mortality,stroke/transient ischemic attack(TIA),and cardiovascular hospitalization.Results Overall,this cohort included 571 ablated patients and 571 non-ablated patients with similar characteristics on 18 dimensions.During a mean follow-up of 39.75±19.98 months(minimum six months),24 patients died in the ablation group,compared with 60 deaths in the non-ablation group[hazard ratio(HR)=0.49,95%confidence interval(CI):0.30-0.79,P=0.0024].Besides,6 ablated and 29 non-ablated subjects died of cardiovascular disease(HR=0.25,95%CI:0.11-0.61,P=0.0022).A total of 27 ablated and 40 non-ablated patients suffered stroke/TIA(HR=0.79,95%CI:0.48-1.28,P=0.3431).In addition,140 ablated and 194 non-ablated participants suffered cardiovascular hospitalization(HR=0.84,95%CI:0.67-1.04,P=0.1084).Subgroup analyses according to gender,type of AF,time since onset of AF,and anticoagulants exposure in initiation did not show significant heterogeneity.Conclusions In elderly patients with AF,CA may be associated with a lower incidence of all-cause and cardiovascular mortality.

Atrial fibrillation in the elderly

Atrial fibrillation(AF)is the most common arrhythmia in elderly population,with age being one of the most important factors involved in its pathogenesis.Conduction disturbances may be present on the surface electrocardiogram before AF onset in some patients.Once this arrhythmia is diagnosed,antithrombotic therapy is mandatory in most cases,as this is the only treatment that has demonstrated to improve survival.Age increases both the risk of thromboembolic and bleeding complications,while benefits from anticoagulant therapy outweigh that from bleeding in most scenarios,also in very elderly patients.However,elderly patients with AF are often undertreated.Non-vitamin K antagonist oral anticoagulants have emerged as an alternative to vitamin K antagonists,with significant less adverse events and better profile in terms of efficacy and safety.Other conditions related to age should be carefully evaluated in these patients(including frailty,comorbidity and polypharmacy)to ensure an individualized clinical and therapeutic approach.

Cognitive function and adherence to anticoagulation treatment in patients with atrial fibrillation

Background Medication adherence is an integral part of the comprehensive care of patients with atrial fibrillation （AF） receiving oral anticoagulations （OACs） therapy. Many patients with AF are elderly and may suffer from some form of cognitive impairment. This study was conducted to investigate whether cognitive impairment affects the level of adherence to anticoagulation treatment in AF patients. Me- thods The study involved 111 AF patients （mean age, 73.5±8.3 years） treated with OACs. Cognitive function was assessed using the Mini Mental State Examination （MMSE）. The level of adherence was assessed by the 8-item Mot^sky Medication Adherence Scale （MMAS-8）. Scores on the MMAS-8 range from 0 to 8, with scores 〈 6 reflecting low adherence, 6 to 〈 8 medium adherence, and 8 high adherence. Re- sults 46.9% of AF patients had low adherence, 18.8% had moderate adherence, and 33.3% had high adherence to OACs. Patients with lower adherence were older than those with moderate or high adherence （76.6 ±8.7 vs. 71.3 ~ 6.4 vs. 71.1 ± 6.7 years） and obtained low MMSE scores, indicating cognitive disorders or dementia （MMSE = 22.3 ± 4.2）. Patients with moderate or high adherence obtained high MMSE test results （27.5 ±1.7 and 27,5 ± 3.6）. According to Spearman＇s rank correlation, worse adherence to treatment with OACs was determined by older age （rs = -0.372） and lower MMSE scores （rs = 0.717）. According to multivariate regression analysis, the level of cognitive function was a significant independent predictor of adherence （b = 1.139）. Conclusions Cognitive impairment is an independent determinant of compliance with pharmacological therapy in elderly patients with AF. Lower adherence, beyond the assessment of cognitive function, is related to the age of patients.

Atrial fibrillation in the elderly

Atrial fibrillation (AF) is an extremely common condition in the elderly, with increasing prevalence around the world as the population ages. AF may be associated with serious health consequences, including stroke, heart failure, and decreased quality of life, so that careful management of AF by geriatric health care providers is required. With careful attention to anticoagulation therapy, and prudent use of medications and invasive procedures to minimize symptoms, many of the adverse health consequences of AF can be prevented.

Clinical Characteristics and Risk Factors of Atrial Fibrillation in the Elderly

Objective: To investigate the epidemiobgical characteristics of the elderly with atrial fibrillation (AF) in age, gender, the types of AF and relative causes. And To analyze the risk factors of persistent AF (PeAF), then use them to guide to prevent and treat for AF in the elderly.Methods: Collect the data of elderly patients with AF who were admitted to Liaoning People's Hospital from September 1, 2016 to September 30, 2017, and summarize the epidemiological characteristics of AF in the elderly. The risk factors for PeAF were analyzed by Spearman correlation analysis and mltivariate logistic regression analysis. Result: 1. In the elderly, the number of AF cases increase with age. The group of 75-84 years old was the largest part. The number of older females was larger than male in all ages. It was important to pay more attention to old woman with AF. 2.In the elderly, nonvalvular atrial fibrillation is popular. The top three causes of AF in the elderly were CHD, hypertension and heart failure. In the elderly, comorbidities were frequent, and the management was a major therapeutic objective. 3.CRP, 1eft atria diameter were the independent risk factors for PeAF in the elderly.

Diabetes mellitus and atrial fibrillation-from pathophysiology to treatment

Type 2 diabetes mellitus(T2DM)is a leading risk factor for cardiovascular complications around the globe and one of the most common medical conditions.Atrial fibrillation(AF)is the most common supraventricular arrhythmia,with a rapidly increasing prevalence.T2DM has been closely associated with the risk of AF development,identified as an independent risk factor.Regarding cardiovascular complications,both AF and T2DM have been linked with high mortality.The underlying pathophysiology has not been fully determined yet;however,it is multifactorial,including structural,electrical,and autonomic pathways.Novel therapies include pharmaceutical agents in sodium-glucose cotransporter-2 inhibitors,as well as antiarrhythmic strategies,such as cardioversion and ablation.Of interest,glucose-lowering therapies may affect the prevalence of AF.This review presents the current evidence regarding the connection between the two entities,the pathophysiological pathways that link them,and the therapeutic options that exist.

Is dual therapy the correct strategy in frail elderly patients with atrial fibrillation and acute coronary syndrome?

Atrial fibrillation(AF)is a very common arrhythmia in clinical practice.Its incidence and prevalence are age-related and are growing in the last years.Age is a risk factor also for coronary artery disease(CAD),and with the evolution of preventive care,the first event(acute coronary syndrome(ACS)or percutaneous coronary intervention(PCI))takes place at a later age.If elderly patients with AF and CAD undergo ACS or PCI,they have indication to assume triple therapy.Triple therapy(oral anticoagulation(OAC)plus dual antiplatelet therapy(DAPT))exposes patients to high bleeding risk.In the last 10 years,several clinical trials have tested dual therapy(OAC plus single antiplatelet therapy)in AF patients who undergo ACS or elective PCI.WOEST trial has tested warfarin+clopidogrel against triple therapy.PIONEER AF-PCI trial has tested low-dose rivaroxaban+P2Y12 inhibitor or very low-dose rivaroxaban+DAPT against standard triple therapy with warfarin.RE-DUAL PCI trial has tested two doses of dabigatran+P2Y12 inhibitor against standard triple therapy with Warfarin.AUGUSTUS trial has tested apixaban against warfarin both in dual therapy with P2Y12 inhibitor and in triple therapy with a P2Y12 inhibitor and aspirin.ENTRUST-AF PCI,last published study,has tested edoxaban+P2Y12 inhibitor against triple therapy.All these trials show dual therapy reduces significantly bleeding risk than triple therapy.In this paper,we analyze these clinical trials to understand if dual therapy results can be applied to elderly patients and what is probably the better approach in elderly AF patients undergo to ACS or PCI.

Compliance and adherence to oral anticoagulation therapy in elderly patients with atrial fibrillation in the era of direct oral anticoagulants

Thromboembolic complications represent a substantial problem in patients with atrial fibrillation （AF）. The prevalence of AF burden and associated arterial and venous thrombosis progressively increases with age. At the same time, representative national data regarding stroke incidence in AF patients aged 80 and older are limited.

Catheter ablation of atrial fibrillation in elderly population

Background Although elderly patients have been included in published series of catheter ablation for atrial fibrillation （AF）, clinicalbenefit and safety remain still less defined in this population. A retrospective analysis of the results of catheter ablation for AF in a large volumecenter focused on comparison of elderly patients with the rest of the patient cohort was conducted in this study. Methods Consecutive patientswho underwent catheter ablation for AF between January 2001 and December 2016 were analysed. A total population of 3197 patients wasdichotomized by the age of 70 years （394 elderly vs. 2803 younger subjects）. Patients were followed in terms of arrhythmia status and sur-vival for a median period of 18 vs. 21 and 35 vs. 57 months, respectively. Results Elderly patients were more frequently females （49% vs.29%, P 〈 0.0001）, had a history of hypertension （79% vs. 57%, P 〈 0.0001）, diabetes （16% vs. 11%, P 〈 0.01）, stroke （9% vs. 6%, P 〈 0.01）,coronary/peripheral artery disease （14% vs. 8%, P 〈 0.0001）, and CHAzDS2-VASc score （3.1 ± 1.3 vs. 1.5 ± 1.2 s, P 〈 0.0001）. Major com-plications were more frequent in elderly （5.3% vs. 3.2%, P = 0.03）; however, this difference was driven by vascular complications （3.6% vs.1.9%, P = 0.04）. There were comparable rates of cerebrovascular （0.3 vs. 0.3%） or nonvascular complications （1.8 vs. 1.2%）. Good arrhyth-mia control was inferior in elderly patients as compared with the rest of the cohort, both without and with antiarrhythmic drugs： 44.2% vs.58.2% （P 〈 0.0001） and 78.2 vs. 83.2% （P 〈 0.01）, respectively. Poor arrhythmia control was associated with relative risk of all-cause mor-tality of 2.7 （95% CI： 1.1-6.4） in elderly patients and 1.4 （95% CI： 0.9-2.0） in younger subjects. Conclusions Catheter ablation for AF inelderly patients is safe although somewhat less effective. Good arrhythmia control is associated with better survival, especially in elderly patients.

Analysis of the Impact Factors on a Stable Warfarin Dose in Extreme Elderly (Age ≥ 80 Years) Chinese Patients with Non-Valvular Atrial Fibrillation

Purpose: The aim of this study was to investigate non-genetic and genetic factors contributing to stable warfarin dose change in the extreme elderly patients with non-valvular atrial fibrillation. Methods: A total of 40 elderly patients with stable warfarin doses were included in this study. Clinical basic data, such as age, sex, body mass index, basic disease like hypertension, diabetes and coronary heart disease had been recorded. Two nucleotide polymorphisms about VKORC1-1639G^A and CYP2C9 1075A^C genes were detected via sequencing by hybridization. Results: The elderly patients with CYP2C9 1075A^C (CA) genotype needed less warfarin daily doses than those?with CYP2C9 1075A^C (AA) genotype (1.93 ± 0.79 mg/d VS 2.15 ± 0.64 mg/d), but there was no significant difference (p = 0.601). While the daily warfarin dose required for patients with VKORC1-1639G^A (AA) genotype was significantly lower than that for patients with VKORC1-1639G^A (GA) genotype (2.00 ± 0.67 mg/d VS 2.63 ± 0.38 mg/d, p = 0.012). VKORC1-1639G^A together with age and diabetes status accounted 41.7% for dose variability. The new algorithm was developed using multivariate linear regression analysis;the model was developed for: Dose = 7.731 – 0.056 * age + 0.527 * DM - 0.785 * VKORC1. Conclusions: VKORC1-1639G^A together with age and diabetes status might predict warfarin doses in age ≥ 80 years patients with non-valvularatrial fibrillation. In contrast, the polymorphism of CYP2C9 1075A^C was not associated with dose variability.

Prevalence of atrial fibrillation in Thai elderly

Atrial fibrillation （AF） is an important health problem due to its association with serious complications.Ill Stroke is one of the most serious complications and is the leading cause of death and disabilities in this population. AF in- creases the risk of embolic stroke five times compared to general population. The prevalence of AF varies from 0.5%-15% depending on studied populations such as age,

Progress in the study and treatment of peri-device leak after left atrial appendage closure

For patients with atrial fibrillation with an increased risk of stroke and contraindications to long-term anticoagulation,percutaneous left atrial appendage closure(LAAC)has become an important alternative to long-term oral anticoagulation.Incomplete closure of the LAAC during the procedure leads to faster blood flow in the interstitial space around the device,resulting in peri-device leak(PDL),which is not uncommon.Studies are still inconclusive in determining the incidence,long-term safety,and management of PDL.Therefore,this article reviewed the progress made in the research and treatment of PDL after LAAC.

Clinical outcomes of radiofrequency catheter ablation of atrial fibrillation in octogenarians lO-year experience of a one high-volume center

Background Prevalence of atrial fibrillation （AF） increases with age. Radiofrequency catheter ablation （RFCA） is an establishedtreatment option superior to antiarrhythmics （AAs）. In this study, we investigated safety and efficacy of RFCA of AF in octogenarians.Methods From our database, we extracted procedural and follow-up data for patients 〉 80 years with symptomatic AF undergoing RFCAand compared this population to RFCA patients 〈 50 years. All patients underwent pulmonary vein isolation （PVI） supplemented by linearlesions in PVI-nonresponders. Arrhythmia-free survival was assessed using seven day Holter every three months post procedure. All patientscompleted their 12 months follow-up. Results Fifty patients aged ≥80 years （80.5 ± 1.6 years） were compared to 259 patients aged 〈 50years （43.5±5.5 years）. The RFCA complication rate did not vary between groups. No differences in procedural characteristics were seenafter being analyzed by type of AF. Among patients with paroxysmal AF, 71.4% octogenarian vs. 84.7% young patients was free of anyarrhythmia, without AAs, after single procedure. For non-paroxysmal AF, arrhythmia-free survival without AAs, was considerably lower（58.6% octogenarians vs. 81.2% younger patients, P = 0.023）. If AAs were used, arrhythmia-free survival for paroxysmal AF increased to90.5% and 92.1% in octogenarians and younger patients, respectively; and in non-paroxysmal AF it increased to 79.3% vs. 88.4%. ConclusionsRFCA is a safe and effective strategy to achieve normal sinus rhythm in a highly selected group of octogenarians. Paroxysmal AF ablation inoctogenarians has similar clinical effectiveness as that seen in much younger patients. Non-paroxysmal AF ablation has lower, but still rea-sonable clinical effectiveness.

Analyses of risk factors and prognosis for new-onset atrial fibrillation in elderly patients after dual-chamber pacemaker implantation

Objective To retrospectively identify risk factors and the prognosis for new-onset atrial fibrillation (AF)after implantation of dual-chamber pacemakers in elderly patients.Methods Consecutive patients aged >65years who underwent their first implantation of a dual-chamber permanent pacemaker in Beijing Anzhen Hospital from October 2013to May 2016were enrolled.Their complete program- ming and follow-up data were recorded.Follow-up end points included new-onset AF and major adverse cardiovascular and cerebrovascular events.Restdts Altogether,322patients were enrolled,with new-onset AF observed in 79(24.5%)during their follow-up.Multivariable analysis identified four independent predictors of new-onset AF in elderly patients after pacemaker implantation:hypertension (HR =3.040, 95%CI:1.09-3.05,P =0.00),age (HR =1.966,95%CI:1.57-3.68,P =0.01);left atrial enlargement (HR =1.645,95%CI:1.05-1.25,P = 0.03);high ventricular pacing rate (HR =1.137,95%CI:1.01-1.06,P =0.01).Univariable analysis indicated that the CHA2DS2-VASc score was also a risk factor for AF (HR =1.368,95%CI:1.178-1.589,P =0.002),whereas multivariable regression analysis did not. Kaplan-Meier survival analysis showed that the risk for ischemic stroke was significantly higher in the new-onset AF group than in the non-AF group (P <0.05).Conclusion Hypertension,age,left atrial enlargement,and high ventricular pacing rate were independent predictors of new-onset AF in elderly patients after implantation of a permanent pacemaker.New-onset AF increased the risk for ischemic stroke.

Percutaneous interventions in elderly patients with atrial fibrillation： leftatrial ablation and left atrial appendage occlusion

Heart rhythm disturbances become of special importancewhen patients reach a senior age. Atrial fibrillation （AF） isthe most prevalent arrhythmia among the old age groups,and its impact on morbidity and mortality becomes of para-mount significance. In this population, AF is responsible forsignificant amount of thromboembolic cerebrovascularevents, especially for disabling and fatal strokes, Follow-ing announcement of the special issue of the Journal of Geri-atric Cardiology devoted to heart rhythm disorders in theelderly, a number of submissions have been received withAF as the major topic of authors＇ researches.