Prevalence,clinical profile,and stroke risk of atrial fibrillation in rural Andhra Pradesh,India (the AP-AF study)

The burden of atrial fibrillation (AF) is increasing worldwide. It is often asymptomatic, with stroke being the first manifestation in some. AF burden in the community and the practice of stroke prophylaxis has not been studied in India. The problem might be higher in rural regions due to poor health awareness and challenges to healthcare access. This study aimed to estimate the prevalence of AF, clinical profile and stroke risk in rural India.MethodsThis is a community-based cross-sectional study done in rural Andhra Pradesh (AP). Adults from 40 villages formed the study population. We did a door-to door survey to collect information on demographics, and medical history. Electrocardiogram was recorded using a smart phone based Alivecor device. Participants diagnosed with AF underwent echocardiogram. Study cardiologists assessed the cardiovascular risk profile and collected detailed medical history.ResultsFourteen of the 4281 individuals screened had AF (0.3%). The mean age of the sampled population was 44 ± 16.5 years with 56% women. The mean age of participants with AF was 71 ±7.8 years; males were 71%. Except for one, all were non-valvular AF. Majority had a CHA₂D₂S₂Vasc score of ≥2. Three had history of stroke. Two were on anticoagulant therapy but without INR monitoring.ConclusionThe prevalence of AF is lower in this study compared to studies from the developed countries. Non-rheumatic cardiovascular risk factors were primary causes for AF. Non-adherence to stroke prophylaxis is a major threat that needs to be addressed.     

Should We Reintroduce Previous Venous Thromboembolism Into Decision-Making for Anticoagulation in Atrial Fibrillation?

BackgroundWe aimed to investigate whether history of venous thromboembolism should be considered a prognostic factor for future thromboembolic events in patients with atrial fibrillation.MethodsThis was a nationwide cohort study of patients with incident atrial fibrillation from 2000-2017, defined and characterized using Danish health registries. Cox regression analyses were used to calculate hazard ratios and 95% confidence intervals for the outcomes ischemic stroke or systemic embolism, and ischemic stroke, systemic embolism, or venous thromboembolism, according to history of venous thromboembolism. Analyses were adjusted for components of the CHA₂DS₂-VASc score and time-varying use of oral anticoagulation.ResultsThe study included 246,313 patients with incident atrial fibrillation, of which 6,516 (2.6%) had previous venous thromboembolism. Patients with previous venous thromboembolism carried an overall similar adjusted risk of ischemic stroke or systemic embolism compared with patients without previous venous thromboembolism (reference; hazard ratio 0.99; 95% confidence interval, 0.90-1.09). When analyzing a composite thromboembolic outcome of ischemic stroke, systemic embolism, or venous thromboembolism, patients with previous venous thromboembolism were at high-risk (hazard ratio 1.76; 95% confidence interval, 1.64-1.90). Similar conclusions were drawn when stratifying by venous thromboembolism subtype, and when restricting to patients with low CHA₂DS₂-VASc scores or the non-anticoagulated subset of the study population.ConclusionPatients with atrial fibrillation and previous venous thromboembolism carried similar risk of ischemic stroke or systemic embolism compared with patients with atrial fibrillation without previous venous thromboembolism. Nonetheless, patients with previous venous thromboembolism remain a high-risk population due to an excess risk of future venous thromboembolism. Patients and physicians should keep this excess thromboembolic risk in mind when weighing the expected risks and benefits of oral anticoagulation in patients with atrial fibrillation.     

Intracardiac thrombus in a patient with mitral bioprosthesis and atrial fibrillation treated with direct oral anticoaugulant: A case report

Rationale:Atrial fibrillation (AF) is the most common cardiac arrhythmia and is associated with increased morbidity, especially stroke and heart failure. There is also increasing awareness that atrial fibrillation is a major cause of embolic events which in 75% of cases are complicated by cerebrovascular accidents.Patient concerns:A 50-year-old woman with mitral bioprosthesis under warfarin for nonvalvular atrial fibrillation was referred to our Coronary Intensive Care Unit due to acute myocardial infarction without evidence of significant coronary artery stenosis.Diagnoses:Cardiovascular examination showed an irregular pulse and a grade II diastolic murmur was audible at the apical area. The patient underwent coronary angiography showing absence of obstructive coronary artery disease. We decided to replace Warfarin with direct oral anticoagulants as anticoagulant therapy.Interventions:Transoesophageal echocardiography revealed a thrombus in left atrial appendage that was treated by replacing warfarin with an oral direct thrombin inhibitor.Outcomes:At 2-month follow-up, the therapy showed to be effective for thrombus resolution.Lessons:Our case demonstrated how AF has high risk of thromboembolic complications, not only in terms of stroke but also of myocardial infarction and death.The use of direct oral anticoagulants in AF patients with bioprosthetic heart valves is still debated due to an unclear definition of “nonvalvular” AF.     

Comparison of continuous versus intermittent monitoring of atrial arrhythmias

BACKGROUND: The ability of intermittent or symptom-based monitoring to accurately identify patients with atrial tachycardia/atrial fibrillation (AT/AF) and to quantify AT/AF burden is not well established. OBJECTIVES: The purpose of this study was to compare intermittent and symptom-based monitoring to continuous monitoring for (1) identification of patients with any AT/AF, (2) identification of patients with long-duration AT/AF, and (3) assessment of AT/AF burden. METHODS: Data from 574 pacemaker (AT500, Medtronic) patients were analyzed retrospectively over 1 year. The device recorded the amount of AT/AF detected each day. Intermittent monitoring (annual, quarterly, and monthly 24-hour Holter; 7-day and 30-day annual long-term recordings) was simulated by analyzing data from randomly selected days within a prescribed monitoring window. Symptom-based monitoring was approximated by analyzing days when patients indicated symptoms with an external activator. RESULTS: All intermittent and symptom-based monitoring resulted in significantly lower sensitivity (range 31%-71%) and negative predictive value (range 21%-39%) for identification of patients with any AT/AF (P <.001) and underestimated AT/AF burden (P <.001) compared with continuous monitoring. Sensitivity for identifying patients with long-duration episodes ranged from 23% to 58% (P <.001 vs continuous monitoring). Identification of patients with AT/AF and assessment of AT/AF burden with intermittent monitoring depended on the patient's actual AT/AF burden and improved with increasing frequency or duration of intermittent monitoring. CONCLUSION: Intermittent and symptom-based monitoring is highly inaccurate for identifying patients with any or long-duration AT/AF and for assessing AT/AF burden. Further investigation is required to determine if full AT/AF disclosure with implantable devices is effective in reducing stroke risk and facilitating maintenance of sinus rhythm.     

Risk of Thromboembolism in Non-Valvular Atrial Fibrillation With or Without Clinical Hyperthyroidism

Background:Patients with hyperthyroidism have higher risk of atrial fibrillation (AF). However, the risk of thromboembolic event in patients with hyperthyroidism-related AF is controversial.Objectives:The aim of the study was to examine the risk of thromboembolic events in AF patients with/without hyperthyroidism.Methods:The national retrospective cohort study enrolled AF population was derived from the Taiwan National Health Insurance Research Database. The comparison between the AF patients with clinical hyperthyroidism (HT-AF group) and AF patients without hyperthyroidism (non-thyroid AF group) was made in a propensity score matched cohort and in a real-world setting, of which, the CHA₂DS₂-VASc level was treated as a stratum variable. The outcomes were ischemic stroke and systemic thromboembolism.Results:There were 3,880 patients in HT AF group and 178,711 in non-thyroid AF group. After propensity score analysis, the incidence of thromboembolism event and ischemic stroke were lower in HT AF patients than non-thyroid AF patients (1.6 versus 2.2 events per 100 person-years; HR, 0.73; 95% CI, 0.64–0.82 and 1.4 versus 1.8 events per 100 person-years; HR, 0.74; 95% CI, 0.64–0.84, respectively) in the 4.3 ± 3.2 year follow up period. The differences persistently existed in those receiving anticoagulants or not. In AF patients without anticoagulants, the incidence densities of ischemic stroke/systemic thromboembolism were significantly lower in HT AF group than those in non-thyroid AF group at CHA₂DS₂-VASc scores ≤ 4 (HR, 0.41; 95% CI, 0.35–0.48, p < 0.001), while the differences disappeared in case of score ≥ 5 (HR, 0.80; 95% CI, 0.63–1.02, p = 0.071).Conclusion:Patients with HT AF had lower incidence of thromboembolic events as compared to non-thyroid AF patients. The threshold of CHA₂DS₂-VASc score for anticoagulation in AF patients with clinical hyperthyroidism should be further evaluated.Highlights

• The incidence of thromboembolic event was different between hyperthyroidism-related atrial fibrillation (HT-AF) and non-thyroid AF patients.
• Hyperthyroidism did not confer additional risk of thromboembolic event at CHA₂DS₂-VASc of ≤ 4.
• The benefit of anticoagulation strategy in patients with hyperthyroidism-related AF should be further evaluated, especially at low CHA₂DS₂-VASc score.

     

Stroke event rates in anticoagulated patients with paroxysmal atrial fibrillation

Aims. To test the hypothesis that stroke and systemic embolic events (SEE) in the stroke prevention using an oral thrombin inhibitor in atrial fibrillation (SPORTIF) III and V trials are different between paroxysmal and persistent atrial fibrillation (AF). Methods. Data analysis from two cohorts of patients enroled in the prospective SPORTIF III and V clinical trials (n = 7329); 836 subjects (11.4%) with paroxysmal AF [mean age 70.1 years (SD = 9.5)] were compared with 6493 subjects with persistent AF for this ancillary study. Results. The annual event rates for stroke/SEE are 1.73% for persistent AF and 0.93% for paroxysmal AF. In a multivariate analysis, after adjusting for stroke risk factors, gender and aspirin usage, the differences remained statistically significant with a higher hazard ratio (HR) for stroke/SEE in persistent AF [vs. paroxysmal AF, HR 1.87, 95% confidence interval (CI) 1.04–3.36; P = 0.037]. In ‘high risk’ patients (with ≥2 stroke risk factors) annual event rates for stroke/SEE were 2.08% for persistent AF and 1.27% for paroxysmal AF (adjusted HR = 1.68, 95% CI 0.91–3.1, P = 0.098). Elderly patients had annual event rates for stroke/SEE of 2.38% for persistent AF and 1.13% for paroxysmal AF (adjusted HR = 2.27, 95% CI 0.92–5.59, P = 0.075). Vitamin K antagonist (VKA)‐naïve paroxysmal AF patients had a 1.89%/year stroke/SEE rate, compared with 0.61% for previous VKA takers (HR = 0.33, 95% CI 0.11–1.01, P = 0.052). Conclusion. In this large clinical trial cohort of anticoagulated AF patients, those with paroxysmal AF had stroke rates which were lower than for patients with persistent AF, although both groups had broadly similar stroke risk factors. Subjects with paroxysmal AF at ‘high risk’ had stroke/SEE rates that were not significantly different to persistent AF subjects.     

Combined efficacy of atrial septal lead placement and atrial pacing algorithms for prevention of paroxysmal atrial tachyarrhythmia

INTRODUCTION: The combined role of atrial septal lead location and atrial pacing algorithms in the prevention of atrial tachyarrhythmias (AT/AF), including both atrial fibrillation and flutter, is unknown. We tested the hypothesis that atrial prevention pacing algorithms could decrease AT/AF frequency in patients with atrial septal leads, bradycardia, and paroxysmal AT/AF. METHODS AND RESULTS: A total of 298 patients (age 70 +/- 10 years; 61% male) from 35 centers were implanted with a DDDRP pacing system including three AT/AF prevention pacing algorithms. Lead site was randomized at implant to right atrial septal or nonseptal. Patients were randomized 1 month postimplant to AT/AF prevention ON or OFF for 3 months and then crossed over for 3 months. Patients logged symptomatic AT/AF episodes via a manual activator. Prevention efficacy was evaluated based on intention-to-treat in 277 patients (138 septal) with complete follow-up. No changes in device-recorded AT/AF frequency or burden were observed with algorithms OFF versus ON or between patients randomized to septal versus nonseptal lead location. Analysis of other secondary outcomes revealed that AT/AF prevention pacing resulted in decreased atrial premature contractions in both the septal (1.9 [0.2-8.7] vs 3.3 [0.3-10.6]x 103/day; P < 0.01) and nonseptal groups (0.9 [0.2-3.3] vs 1.3 [0.3-5.5]x 103/day; P < 0.001). Patients with septal leads had fewer symptomatic AT/AF episodes ON versus OFF (1.4 +/- 3.0 vs 2.5 +/- 5.2/month, P = 0.01). CONCLUSION: The combination of three atrial prevention pacing algorithms did not decrease device classified atrial tachyarrhythmia frequency or burden during a 3-month cross-over period in bradycardic patients and septal or nonseptal atrial pacing leads. Prevention pacing was associated with decreased frequency of premature atrial contractions and with decreased symptomatic atrial tachyarrhythmia frequency in patients with atrial septal leads.     

Intraprocedural and long-term incomplete occlusion of the left atrial appendage following placement of the WATCHMAN device: a single center experience

Incomplete LAA Occlusion by WATCHMAN Device . Introduction: Transcatheter left atrial appendage (LAA) closure with the WATCHMAN device has become one of the therapeutic options in atrial fibrillation (AF) patients who are at high risk for ischemic stroke. However, the incidence and evolution of incomplete occlusion of the LAA during and after placement of the WATCHMAN device has not been reported. Methods and Results: Fifty‐eight consecutive patients who had undergone WATCHMAN device implant were included in the study. Intraprocedural, 45‐day and 12‐month transesophageal echocardiogram images were reviewed and analyzed. Peridevice gap was noted in 16 (27.6%), 17 (29.3%), and 20 (34.5%) patients across the 3 time points. Intraprocedural gaps are more likely to be persistent until 12 months and become larger in size over time. New gap also occurs during follow‐up even if the LAA was completely sealed at implantation. One patient had an ischemic stroke 4.7 months after implant; another patient developed a left atrial thrombus over the device 21.6 months after implant. Both patients had intraprocedural gap and discontinued warfarin therapy after the 45‐day evaluation. Conclusion: Incomplete LAA occlusion with a gap between the WATCHMAN device surface and the LAA wall is relatively common. Intraprocedural gaps are more likely to become bigger over time and persist, while new gaps also occur during follow‐up. Further studies are warranted to verify whether the presence and persistence of a peridevice gap is associated with increased risk of thromboembolic event in AF patients implanted with a WATCHMAN device. (J Cardiovasc Electrophysiol, Vol. 23, pp. 455‐461, May 2012)     

Transesophageal Echocardiographic Correlates of Clinical Risk of Thromboembolism in Nonvalvular Atrial Fibrillation

Objectives. This study explored the mechanisms linking clinical and precordial echocardiographic predictors to thromboembolism in atrial fibrillation (AF) by assessing transesophageal echocardiographic (TEE) correlations.

Background. Clinical predictors of thromboembolism in patients with nonvalvular AF have been identified, but their mechanistic links remain unclear. TEE provides imaging of the left atrium, its appendage and the proximal thoracic aorta, potentially clarifying stroke mechanisms in patients with AF.

Methods. Cross-sectional analysis of TEE features correlated with low, moderate and high thromboembolic risk during aspirin therapy among 786 participants undergoing TEE on entry into the Stroke Prevention in Atrial Fibrillation III trial.

Results. TEE features independently associated with increased thromboembolic risk were appendage thrombi (relative risk [RR] 2.5, p = 0.04), dense spontaneous echo contrast (RR 3.7, p < 0.001), left atrial appendage peak flow velocities ≤20 cm/s (RR 1.7, p = 0.008) and complex aortic plaque (RR 2.1, p < 0.001). Patients with AF with a history of hypertension (conferring moderate risk) more frequently had atrial appendage thrombi (RR 2.6, p < 0.001) and reduced flow velocity (RR 1.8, p = 0.003) than low risk patients. Among low risk patients, those with intermittent AF had similar TEE features to those with constant AF.

Conclusions. TEE findings indicative of atrial stasis or thrombosis and of aortic atheroma were independently associated with high thromboembolic risk in patients with AF. The increased stroke risk associated with a history of hypertension in AF appears to be mediated primarily through left atrial stasis and thrombi. The presence of complex aortic plaque distinguished patients with AF at high risk from those at moderate risk of thromboembolism.     

Encerramento percutâneo do apêndice auricular esquerdo para profilaxia de tromboembolismo na fibrilhação auricular em doentes com contraindicação ou falência da hipocoagulação oral: experiência de um serviço

IntroductionIn non-valvular atrial fibrillation 90% of thrombi originate in the left atrial appendage (LAA). Percutaneous LAA closure has been shown to be non-inferior to warfarin for prevention of thromboembolism.ObjectiveTo evaluate the initial experience of a single center in percutaneous LAA closure in patients with high thromboembolic risk and in whom oral anticoagulation was impractical or contraindicated or had failed.MethodsPatients with non-valvular atrial fibrillation and CHADS2 score ≥2 in whom oral anticoagulation was impractical or contraindicated or had failed underwent percutaneous LAA closure according to the standard technique. After the procedure, dual antiplatelet therapy was maintained for one month, followed by single antiplatelet therapy indefinitely. Patients were followed by clinical assessment and transthoracic and transesophageal echocardiography.ResultsThe procedure was performed in 22 of the 23 selected patients (95.7%), mean age 70±9 years, CHADS2 score 3.2±0.9 and CHA2DS2-VASC score 4.7±1.4. Intraprocedural device replacement was necessary only in the first patient, due to oversizing. The following periprocedural complications were observed: one femoral pseudoaneurysm, three femoral hematomas and two minor oropharyngeal bleeds, resolved by local hemostatic measures. During a 12±8 month follow-up a mild peri-device flow and a thrombus adhering to the device, resolved under with enoxaparin therapy, were identified. The rate of transient ischemic attack (TIA)/stroke was lower than expected according to the CHADS2 score (0 vs. 6.7±2.2%).ConclusionsIn our initial experience, this procedure proved to be a feasible, safe and effective alternative for atrial fibrillation patients in whom oral anticoagulation is not an option. Only relatively minor complications were observed, with a lower than expected TIA/stroke rate.     

Increased serum interleukin-6 level as a predictive biomarker for atrial fibrillation: A systematic review and meta-analysis

BackgroundAtrial fibrillation (AF) is related to a higher risk of thromboembolic events and mortality. Some studies have demonstrated that the inflammatory biomarker interleukin-6 (IL-6) is associated with a higher risk of higher thrombosis in AF patients, but the real effect of IL-6 remains a controversy.MethodsWe conducted a systematic review and meta-analysis to investigate the association between IL-6 and thromboembolic events, as well as bleeding events, acute coronary syndrome (ACS) events and all-cause mortality in AF.ResultsA total of five studies involving 22 928 patients met our inclusion criteria for the systematic review. The higher level of IL-6 in AF patients is related to long-term thromboembolic events including stroke (RR 1.44, CI 95% 1.09-1.90, p=0.01). IL-6 meant a higher risk of long-term bleeding risk (RR 1.36, CI 95% 1.06-1.74, p=0.02), ACS risk (RR 1.81, CI 95% 1.43-2.30, p<0.001) and all-cause mortality (RR 2.35, CI 95% 2.09-2.65, p<0.001).ConclusionA higher level of IL-6 may predict a greater number of long-term thromboembolic events and bleeding events, ACS events and mortality in AF patients. Further studies such as the cut-off point of IL-6 need to be conducted in the future.     

Pacemaker-detected atrial fibrillation burden and risk of ischemic stroke or thromboembolic events—A cohort study

BackgroundAtrial fibrillation (AF) burden might link to increased risk of systemic embolism. Current scoring systems for evaluating stroke risks such as CHA₂DS₂-VASc do not incorporate AF burden partly because of the difficulty to assess these data. Patients with dual-chamber pacemakers implanted have opportunities to acquire incidence and duration of AF.ObjectivesWe aimed to evaluate the AF burden and its association with thromboembolism in patients with dual-chamber pacemakers.MethodsThis retrospective cohort study enrolled patients who underwent dual-chamber pacemaker implantation at our center between October 2003 and May 2017. We excluded patients with prior thromboembolism or receiving anticoagulants. The incidence and duration of pacemaker-detected AF were compared between patients with and without thromboembolic outcomes. Propensity score matching (1:1) was conducted based on clinical characteristics. Multivariate regressions were performed to determine the predictors of thromboembolic outcomes. Survival free from stroke and thromboembolism was assessed using Kaplan–Meier analysis in groups with different AF burden.ResultsAmong the 152 patients enrolled (43.4% women; age 73.2 ± 13.3 years), ten experienced thromboembolic events within a median follow-up of 67 months. Patients with thromboembolisms had higher CHA₂DS₂-VASc scores but not higher AF burden. Higher CHA₂DS₂-VASc score was associated with increased risk for systemic thromboembolism [hazard ratio (HR), 1.87; 95% confidence interval (CI), 1.07–3.24; P = 0.027). In the propensity score-matched cohort with comparable CHA₂DS₂-VASc score, patients with thromboembolism had higher AF burden. Pacemaker-detected AF was associated with increased risk for thromboembolism (propensity-adjusted HR, 9.33; 95% CI, 1.19–72.99; P = 0.033). Experiencing AF episodes lasting >6 min was a predictor of significantly higher risk of future stroke or thromboembolism (propensity-adjusted HR, 6.75; 95% CI, 1.30–35.11; P = 0.023).ConclusionIn patients with dual-chamber pacemakers and comparable CHA₂DS₂-VASc score, pacemaker-detected AF burden is associated with elevated risk for thromboembolism. Further research is needed to clarify how pacemaker-detected AF burden could incorporate with CHA₂DS₂-VASc score variables and help to guide anticoagulation.     

Prior History of Falls and Risk of Outcomes in Atrial Fibrillation: The Loire Valley Atrial Fibrillation Project

BackgroundPatients with nonvalvular atrial fibrillation are often denied oral anticoagulation due to falls risk. The latter is variably defined, and existing studies have not compared the associated risk of bleeding with other cardiovascular events. There are no data about outcomes in individuals with nonvalvular atrial fibrillation with a prior history of (actual) falls, rather than being “at risk of falls.” Our objective was to evaluate the risk of cardiovascular outcomes associated with prior history of falls in patients with atrial fibrillation in a contemporary “real world” cohort.MethodsPatients with nonvalvular atrial fibrillation in a 4-hospital institution between 2000 and 2010 were included. Stroke/thromboembolism event rates were calculated according to prior history of falls. Risk factors were investigated by Cox regression.ResultsAmong 7156 atrial fibrillation patients, prior history of falls/trauma was uncommon (n = 76; 1.1%). Compared with patients without history of falls, those patients were older and less likely to be on oral anticoagulation; they also had higher risk scores for stroke/thromboembolism but not for bleeding. Compared with no prior history of falls, rates of stroke/thromboembolism (P = .01) and all-cause mortality (P < .0001) were significantly higher in patients with previous falls. In multivariable analyses, prior history of falls was independently associated with stroke/thromboembolism (hazard ratio [HR] 5.19; 95% confidence interval [CI], 2.1-12.6; P < .0001), major bleeding (HR 3.32 [1.23-8.91]; P = .02), and all-cause mortality (HR 3.69; 95% CI, 1.52-8.95; P = .04), but not hemorrhagic stroke (HR 4.20; 95% CI, 0.58-30.48; P = .16) in patients on oral anticoagulation.ConclusionIn this large “real world” atrial fibrillation cohort, prior history of falls was uncommon but independently increased risk of stroke/thromboembolism, bleeding, and mortality, but not hemorrhagic stroke in the presence of anticoagulation. Prior history of (actual) falls may be a more clinically useful risk prognosticator than “being at risk of falls.”     

Effect of remote ischemic preconditioning on electrophysiological and biomolecular parameters in nonvalvular paroxysmal atrial fibrillation (RIPPAF study): Rationale and study design of a randomized,controlled clinical trial

Remote ischemic preconditioning (RIPC) has been studied in models of different cardiovascular entities. Recently, a beneficial effect of RIPC on incidence of atrial fibrillation (AF) in postsurgical patients has been suggested. However, the potential impact of RIPC on electrophysiological‐ and thrombogenesis‐related parameters in the setting of paroxysmal nonvalvular AF has not been investigated. The aim of the study is to answer the following questions: (1) Does RIPC have impact on inducibility of AF in patients with known paroxysmal AF? If yes, what are the direct electrophysiological mechanisms of this phenomenon, and could RIPC be implemented to reduce AF burden? (2) Does RIPC have the potential to minimize thrombogenic effects of simulated episodes of AF? If so, what are inhibited components of thrombogenesis and can this be used to reduce thromboembolic risk related to paroxysmal AF? The presented study is a 2‐arm, randomized, placebo‐controlled, double‐blinded, single‐center trial in a cohort of 146 patients with paroxysmal AF referred for AF ablation in sinus rhythm. The study will collect electrophysiological data such as variability of P‐wave morphology, atrial refractory period, conduction times, and inducibility/sustainability of AF. Furthermore, AF‐induced prothrombotic processes will be analyzed by quantification of platelet aggregates, analysis of platelet function, and measurement of thrombogenesis‐related plasma markers. Moreover, the study will provide a unique bio‐database for further analysis of molecular and genetic mechanisms responsible for observed results.     

The effect of atrial pacing therapies on atrial tachyarrhythmia burden and frequency: results of a randomized trial in patients with bradycardia and atrial tachyarrhythmias

OBJECTIVES: The Atrial Therapy Efficacy and Safety Trial (ATTEST) was a prospective, randomized study to evaluate preventive pacing and antitachycardia pacing (ATP) in patients with symptomatic atrial fibrillation (AF) or atrial tachycardia (AT). BACKGROUND: The effect of the combination of atrial prevention and termination algorithms on AT/AF burden and frequency in pacemaker patients is unknown. METHODS: A DDDRP pacemaker (AT500, Medtronic Inc., Minneapolis, Minnesota) with three atrial preventive pacing algorithms and two ATP algorithms was implanted in 368 patients. Patients were randomized one-month post-implant to all prevention and ATP therapies ON or OFF and followed for three months. The OFF group had DDDR pacing at a lower programmed rate of 60 ppm. The AT/AF burden and frequency were determined from daily device counters in 324 patients treated according to protocol. RESULTS: In 17,018 episodes with stored electrograms, appropriate detection was confirmed in 17,004 (99.9%). The median percentage of atrial pacing was 98% in the ON group versus 75% in the OFF group (p < 0.001). Using device-defined criteria for successful termination, ATP terminated 8,590 (54%) of 15,789 treated episodes. The median AT/AF burden during the three-month study period was 4.2 h/month ON versus 1.1 h/month OFF (p = 0.20). The median AT/AF frequency was 1.3 episodes/month ON versus 1.2 episodes/month OFF (p = 0.65). System-related, complication-free survival at four months was 90.2% (Kaplan-Meier estimate). CONCLUSIONS: This DDDRP pacemaker is safe, has accurate AT/AF detection, and provides ATP with 54% efficacy as defined by the device. The atrial prevention and termination therapies combined did not reduce AT/AF burden or frequency in this patient population.     

Low molecular weight heparin versus unfractionated heparin for thromboprophylaxis in patients with acute atrial fibrillation: A randomized control trial

While long-term anticoagulation prevents ischemic stroke in high-risk patients with atrial fibrillation (AF), the optimal initial anti-thrombotic regime in acute AF is less well defined. We randomized 96 patients with new onset acute AF in an emergency admission ward to receive (1) once-daily preparation of low molecular weight heparin (LMWH), tinzaparin or (2) conventional intravenous unfractionated heparin (target APTT 50–70 s). 5 patients in unfractionated heparin group compared with no patients in LMWH group (0%, P = 0.04) developed ischemic stroke/transient ischemic attack during the first 48 h. An initial subcutaneous LMWH was safe and effective in ischemic stroke prevention in patients with acute AF.     

Screening for Atrial Fibrillation in Sub-Saharan Africa: A Health Economic Evaluation to Assess the Feasibility in Nigeria

Background:Cardiovascular disease reflects a major burden of non-communicable disease in Sub-Saharan Africa (SSA). Early detection and treatment of atrial fibrillation (AF), as a preventive measure against stroke, is currently not in the scope of the World Health Organization recommendation to reduce cardiovascular disease.Objective:We hypothesized that screening for AF would be an important approach to determine the true AF prevalence in the general population in African countries and to identify asymptomatic AF patients at risk for stroke to optimize prevention.Methods:A decision analytic model was developed to study the health-economic impact of AF screening in Nigeria over a life-time horizon. The patient population explored in the model was a population of newly detected AF cases that would be diagnosed with a one-time systematic screening for AF with a single lead ECG device in community health centres across Nigeria.Conclusions:The health gain per newly detected AF patient (N = 31,687) was 0.41 QALY at a cost of $5,205 per patient with 100% NOAC use, leading to an ICER of $12,587 per QALY gained. The intervention was cost-effective with a 99.9% warfarin use with an ICER of $1,363 per QALY gained. The total cost of a single screening session was $7.3 million for the total screened population in Nigeria or $1.60 per patient screened. Screening for AF to detect AF patients in need for stroke prevention can be a cost-effective intervention in the Sub-Saharan region, depending on type of anticoagulant used and drug costs.     

Long-Term Clinical Outcomes of Underdosed Direct Oral Anticoagulants in Patients with Atrial Fibrillation and Atrial Flutter

BackgroundAlthough direct oral anticoagulants (DOACs) have been shown to be effective at reducing the risk of stroke in patients with atrial fibrillation/flutter (AF), they are sometimes underdosed off-label to mitigate their associated higher bleeding risk. We sought to evaluate frequency and clinical outcomes of inappropriate underdosing of DOACS in patients with AF.MethodsWe conducted a study of subjects with AF who had a clinical indication for stroke prophylaxis (with a congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, stroke or transient ischemic attack, vascular disease, age 65 to 47 years, sex category [CHA₂DS₂-VASc] of 2 or greater) and were prescribed 1 of the 4 clinically approved DOACs (apixaban, rivaroxaban, dabigatran, or edoxaban). We compared all-cause mortality, composite of stroke and systemic embolism, composite of myocardial infarction (MI), acute coronary syndromes (ACS), and coronary revascularization, and major bleeding between patients appropriately dosed and inappropriately underdosed.ResultsA total of 8125 patients met inclusion criteria, with a mean follow up of 2.2 ± 2 years. Of those, 1724 patients (21.2%) were inappropriately dosed. After adjusting for baseline variables, there was no difference in all-cause mortality, risk of stroke or systemic embolism, International Society on Thrombosis and Haemostasis (ISTH) major bleeding, or composite of myocardial infarction, acute coronary syndromes, or coronary revascularization between patients appropriately dosed and inappropriately underdosed. In subgroup analysis, only apixaban demonstrated an increased incidence all-cause mortality (hazard ratio [HR] 1.24, 95% confidence interval [CI] 1.03-1.49) with inappropriate underdosing. There was no difference in the remaining clinical outcomes noted on subgroup analysis.ConclusionUnderdosing of DOACs did not minimize risk of bleeding, systemic embolization or all-cause mortality in patients with AF. Inappropriate underdosing with apixaban in particular was associated with increased all-cause mortality.     

Catheter ablation of atrial fibrillation to reduce stroke risk

Stroke is the most devastating complication of atrial fibrillation (AF), and the latter increases the risk of stroke by almost fivefold. AF elimination by catheter ablation should lower the risk of thromboembolic complications. Several studies support this hypothesis, demonstrating rates of stroke in AF patients similar to non-AF populations after successful catheter ablation. Widespread discontinuation of oral anticoagulation after catheter ablation is currently not supported by scientific data but it may be a viable option for patients with a CHA₂DS₂VASc score of less than 2 and a well-documented stable sinus rhythm.     

An overview of current and emerging devices for percutaneous left atrial appendage closure

Atrial fibrillation (AF) is common and is a prominent risk factor for ischemic stroke. Oral anticoagulant (OAC) therapy has been the main strategy for stroke prevention in AF patients; however, OAC therapy carries a bleeding risk and is not tolerated by all patients. Left atrial appendage (LAA) closure offers a non-pharmacological alternative for stroke prevention in patients with non-valvular AF. In this update, an overview of current and emerging LAA occluders is given – with special attention to the key design features of every single device and, if available, preclinical or clinical data.