Pre- and post-cardioversion transesophageal echocardiography for brief anticoagulation therapy with enoxaparin in atrial fibrillation patients: a prospective study with a 1-year follow-up

Non-invasive electromechanical assessment during atrial fibrillation identifies underlying atrial myopathy alterations with early prognostic value

Electromechanical characterization during atrial fibrillation (AF) remains a significant gap in the understanding of AF-related atrial myopathy. This study reports mechanistic insights into the electromechanical remodeling process associated with AF progression and further demonstrates its prognostic value in the clinic. In pigs, sequential electromechanical assessment during AF progression shows a progressive decrease in mechanical activity and early dissociation from its electrical counterpart. Atrial tissue samples from animals with AF reveal an abnormal increase in cardiomyocytes death and alterations in calcium handling proteins. High-throughput quantitative proteomics and immunoblotting analyses at different stages of AF progression identify downregulation of contractile proteins and progressive increase in atrial fibrosis. Moreover, advanced optical mapping techniques, applied to whole heart preparations during AF, demonstrate that AF-related remodeling decreases the frequency threshold for dissociation between transmembrane voltage signals and intracellular calcium transients compared to healthy controls. Single cell simulations of human atrial cardiomyocytes also confirm the experimental results. In patients, non-invasive assessment of the atrial electromechanical relationship further demonstrate that atrial electromechanical dissociation is an early prognostic indicator for acute and long-term rhythm control.

Three-dimensional Transesophageal Echocardiographic Diagnosis of Catheter Endocarditis Hidden in Intracaval Stent

In recent years, with an increasing number of central venous access procedures and cardiac implantable electronic device implantation, the incidence of infective endocarditis (IE) has become more prevalent. Two-dimensional transthoracic echocardiography (2D-TTE) and transesophageal echocardiography (TEE) are a key part of the evaluation of IE, but advances in three-dimensional echocardiography have enabled a better spatial resolution and visualization of cardiac structures, allowing the identification of any valvular vegetations, abscesses, or nodules. Herein, we report the usefulness of 3D-TEE in a difficult diagnosis of hemodialysis catheter endocarditis hidden in intracaval stent.

Evaluation of left atrial appendage function and thrombi in patients with atrial fibrillation: from transthoracic to real time 3D transesophageal echocardiography

The detection of embolic sources in patients with atrial fibrillation (AF) is important to guide anticoagulant therapy. Two-dimensional transesophageal echocardiography (TEE) is the gold standard to study left atrial appendage (LAA) anatomy and morphology, despite some false-positive diagnosis. We hypothesized that real time 3D TEE (RT3DTEE) is superior to 2DTEE in detecting and/or excluding LAA thrombi. We studied 93 patients with non-valvular AF (60 males, age = 67.1 ± 14.2 years) referred for electric cardioversion with transthoracic, 2DTEE and RT3DTEE. Before cardioversion, TTE allowed a confident measurement of emptying velocity of LAA (LAAeV) only in 59/93 patients (63%). On the contrary a good quality TEE LAAeV was obtained in all patients with 49/93 (53%) dysfunctional LAA (LAAeV < 40 cm/s). A subgroup of 5 patients (7.2% of the 69 effective cardioversion) presented a persistent dysfunction after cardioversion (with LAAeV values of <40 cm/s on the TEE post-CV). TEE allowed to observe a bilobed shape in 45 patients (48.4%) and three lobes in 22 patients (23.7%). In addition, besides to several additional findings, 2DTEE managed to detect thrombi with certainty in 8/93 patients (8.6%). In other 5 cases with diagnostic doubts for thrombi with 2DTEE (5/93 patients: 5.4%), the addition of the RT3DTEE mode allowed to discriminate with certainty the presence of just pectinate muscles in 4 patients RT3DTEE in patients with AF at risk of embolism is feasible, accurate and showed an additional diagnostic capability in the differential diagnosis of selected cases with suspected LAA thrombi.

Antithrombotic therapy for atrial fibrillation: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

The risk of stroke varies considerably across different groups of patients with atrial fibrillation (AF). Antithrombotic prophylaxis for stroke is associated with an increased risk of bleeding. We provide recommendations for antithrombotic treatment based on net clinical benefit for patients with AF at varying levels of stroke risk and in a number of common clinical scenarios.

METHODS

We used the methods described in the Methodology for the Development of Antithrombotic Therapy and Prevention of Thrombosis Guidelines: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines article of this supplement.

RESULTS

For patients with nonrheumatic AF, including those with paroxysmal AF, who are (1) at low risk of stroke (eg, CHADS(2) [congestive heart failure, hypertension, age ≥ 75 years, diabetes mellitus, prior stroke or transient ischemic attack] score of 0), we suggest no therapy rather than antithrombotic therapy, and for patients choosing antithrombotic therapy, we suggest aspirin rather than oral anticoagulation or combination therapy with aspirin and clopidogrel; (2) at intermediate risk of stroke (eg, CHADS(2) score of 1), we recommend oral anticoagulation rather than no therapy, and we suggest oral anticoagulation rather than aspirin or combination therapy with aspirin and clopidogrel; and (3) at high risk of stroke (eg, CHADS(2) score of ≥ 2), we recommend oral anticoagulation rather than no therapy, aspirin, or combination therapy with aspirin and clopidogrel. Where we recommend or suggest in favor of oral anticoagulation, we suggest dabigatran 150 mg bid rather than adjusted-dose vitamin K antagonist therapy.

CONCLUSIONS

Oral anticoagulation is the optimal choice of antithrombotic therapy for patients with AF at high risk of stroke (CHADS(2) score of ≥ 2). At lower levels of stroke risk, antithrombotic treatment decisions will require a more individualized approach.

Low molecular weight heparin (parnaparin) for cardioembolic events prevention in patients with atrial fibrillation undergoing elective electrical cardioversion: a prospective cohort study

Systemic thromboembolism is a severe complication in patients undergoing electrical cardioversion (ECV) for atrial fibrillation (AF). Vitamin K antagonists greatly reduce the risk of thromboembolic events, but the administration scheme before ECV is troublesome as difficulties in reaching and maintaining the target therapeutic range for 3 weeks often delay the restoration and likelihood of maintaining sinus rhythm. Low molecular weight heparins (LMWHs) do not need dose adjustment, and may be preferable in this clinical setting. In this multicentre study, the LMWH parnaparin was used at a dose of 85 anti-factor Xa U/kg b.i.d. 2 weeks before and 3 weeks after ECV of AF. In an intention to treat analysis of 102 patients, there was no systemic thromboembolism or major bleeding (0%, 95% CI 0-3.6). Two clinically relevant non-major bleeds (2.5%, 95% CI 0.7-8.8) and three minor bleeds (3.8%, 95% CI 1.3-10.6) were recorded. No heparin-induced thrombocytopenia or other major adverse events were recorded. Parnaparin appears effective and safe for thromboprophylaxis of elective ECV in patients with AF.

Conventional oral anticoagulation may not replace prior transesophageal echocardiography for the patients with planned catheter ablation for atrial fibrillation

INSTRUCTION

Preablation transesophageal echocardiography (TEE) is dispensable for the patients with planned catheter ablation for atrial fibrillation (AF) and having received at least a 3-week oral anticoagulation therapy according to the recommendations of the Venice Consensus. But the role of prior TEE and the effect of preablation short-term oral anticoagulation drugs (OACs) under the circumstance are still unclear.

METHODS AND RESULTS

A total of 188 patients with planned catheter ablation for AF and without previous long-term oral anticoagulation, whose duration of AF exceeded 48 h, were randomly divided into receiving 3-week OACs (OACs group) before heparin bridging or receiving no prior OACs (N-OACs group). Follow-up was performed until a TEE had been performed on all the cases before ablation. Consequently, the prevalence of atrial thrombi is 6.3% and 11.7%, respectively (P < 0.05), and the prevalence of minor bleeding is 5.3% and 0%, respectively (P < 0.05), in OACs and N-OACs group. There was no thrombotic event, major hemorrhage, in both groups.

CONCLUSION

After a 3-week effective oral anticoagulation, atrial thrombi could be resolved partly but not completely in the patients with AF who had not received long-term oral anticoagulation previously. To ensure safety, prior TEE may be necessary for the patients with planned catheter ablation for AF.

AFFECT: a prospective, open-label, multicenter trial to evaluate the feasibility and safety of a short-term treatment with subcutaneous certoparin in patients with persistent non-valvular atrial fibrillation

BACKGROUND

Patients with persistent atrial fibrillation (AF) scheduled for electrical cardioversion need immediate anticoagulation. Unfractionated heparin (UFH) is often used for early anticoagulation in these patients before oral anticoagulation becomes effective. However, dose adjustment is required to achieve a two- to three-fold prolongation of the activated partial thromboplastin. Low molecular weight heparins, given in body weight-adjusted or independent fixed dosage, require less laboratory monitoring and are also effective within hours of first dosing. They seem to be an attractive alternative to UFH. Previous evidence has shown that these drugs are safe and effective in this indication.

PATIENTS AND METHODS

In this prospective, open-label, multicenter pilot study, 203 patients were enrolled with persistent non-valvular AF scheduled for electrical cardioversion. Patients received a fixed dose of 8000 U anti-Xa certoparin twice daily starting immediately after enrolment and before cardioversion was performed. Patients with AF > 48 h underwent transoesophageal echocardiography (TEE) before cardioversion to exclude intra-atrial thrombi. After cardioversion, overlapping oral anticoagulation was started. Treatment with certoparin was stopped only after two consecutive days with INR values >2.

OBJECTIVES

The objective was to document the feasibility and safety of a short-term treatment with a fixed, body weight-independent certoparin regimen (2 x 8000 U anti-Xa).

RESULTS

Out of 203 patients enrolled, 200 received at least one dose of certoparin and were included in the analysis (safety population). Median treatment duration with certoparin was 7 days. Bleedings were observed in 8 patients (4.0%) and were classified as major (1.5%) or minor (2.5%). Cerebral ischemia was reported for 1 patient (0.5%). One patient showed mild thrombocytopenia (0.5%). There were no reports of venous thromboembolism or death during the treatment period.

CONCLUSION

Certoparin administered at 8000 U anti-Xa twice daily independent of body weight was safe and appeared to be effective in patients with non-valvular AF undergoing electrical cardioversion. Its ease of use and the possibility of treatment on an outpatient basis make it an attractive option for early anticoagulation in AF.

Anatomical remodeling of left atria in subjects with chronic and paroxysmal atrial fibrillation evaluated by multislice computed tomography

PURPOSE

We used ECG-gated enhance multislice computed tomography (MSCT) to evaluate and compare anatomical change to left atria (LA) including left atrial appendage (LAA) in subjects with chronic and paroxysmal atrial fibrillation (CAF and PAF, respectively).

MATERIALS AND METHODS

Retrospective ECG-gated MSCT (Light Speed Ultra 16, General Electric) was performed in 16 subjects with CAF (10 male, median age 68/period of CAF 6 years, 3 severe or moderate mitral stenosis (MS), 3 mitral regurgitation (MR)) and 17 with PAF (11 male, median age 62/period of PAF 3 years, one MS, one MR) 30 s and 8 min after injection of contrast. We evaluated: qualified observed morphology of pectinate muscles (PM) in LAA (well/poorly/non-developed); absolute thickness of LA anterior wall; presence of abnormal late enhancement (LE) of LA wall suggesting fibrotic changes; defect of contrast in LAA only in early phase and LAA enlargement; comparison of LA diameter evaluated by 4-chamber view obtained by transthoracic echocardiogram.

RESULTS

CAF group: well-developed PM (19% subjects), poor PM (43%), no PM (38%). PAF group: well-developed PM (41%), poor PM (47%), no PM (12%). Incidences of well- and non-developed PM were significantly less and more in CAF group, respectively. CAF subjects with no PM had longer periods of CAF and larger LA diameter than those with developed PM (p<0.01). By contrast, there was no relation between PM morphology and PAF periods or LA diameter. Incidence and mean thickness of abnormal LE of LA wall were similar in both groups (2.6 mm): 25% (CAF); 24% (PAF). There was a negative correlation in the CAF group between thickness of LA wall and LA diameter (R2=0.19), but not in the PAF group. Contrast defect in LAA only in early phase and enlargement of LAA were observed in 56%, 88% (CAF) and 24%, 41% (PAF); ratios were significantly higher in CAF group (p<0.01).

CONCLUSIONS

There were anatomical differences between CAF and PAF groups in MSCT. In CAF group, depending on the period of CAF or degree of LA diameter enlargement, anatomical remodeling (e.g. recession of PM, thinning of LA wall, enlargement of LAA) may appear, which may cause blood flow stagnation, seen as contrast defect in LAA in early phase.

Antithrombotic therapy in atrial fibrillation: beyond the AFFIRM study

In the last few decades several clinical studies evaluated the efficacy and safety of different strategies for antithrombotic prophylaxis to prevent thromboembolic events in patients with atrial fibrillation (AF). Nowadays, a frequently debated point is related to the high embolic risk deriving from the asymptomatic and symptomatic AF recurrence after cardioversion or in paroxysmal AF, especially in patients with a large number of prolonged episodes of AF. In fact, after the recent AFFIRM and RACE trials, patients after successful cardioversion at risk for thromboembolism could also need lifelong anticoagulation. Considering this, should we anticoagulate all patients with clinical risk factors for thromboembolism with a single episode of AF, without considering the hemorrhagic risk? Based on recent trials, it is reasonable to hypothesize that long AF recurrences (> 48 h), both symptomatic and asymptomatic, are present mostly (if not exclusively) in patients with structural left atrial appendage (LAA) dysfunction and remodeling. Conversely, AF recurrences in patients without LAA dysfunction and remodeling, could be too short to allow thrombi formation in the LAA, and the anticoagulation could also be avoided. Once other clinical and echocardiographic determinants of stroke have been excluded, the LAA velocity could select patients with a normal appendage function at low embolic risk who could benefit from anti-aggregation and patients with irreversible appendage dysfunction, at high embolic risk, who need lifelong anticoagulation.