Occurrence Of Atrial Fibrillation Episodes Research Articles

ECG-patch assessment of atrial fibrillation during the very-early blanking predicts late blanking period recurrence: preliminary data from a prospective registry

Abstract Funding Acknowledgements Type of funding sources: None. Background Ablation of atrial fibrillation (AF) is a procedure that causes significant atrial tissue lesions, with transient, albeit significant tissue oedema and inflammation. These mechanisms may trigger early rhythm abnormalities that do not necessarily correlate with future arrhythmias, and, therefore, evaluation of AF recurrence is currently validated by routine ECG and ambulatory 24h Holter monitoring, only after a 3-month blanking period. However, recent data have shown that AF episodes occurring during the blanking period are common and may predict late AF recurrences. The E-Patch (Bio Tel Heart) is an innovative, thin single-use adhesive electrode with extended continuous ECG monitoring for up to 120h. Aim To assess if continuous extended monitoring in the very-early blanking period can be associated with event recorder data performed in the late blanking period after AF ablation. Methods Single-centre, prospective, longitudinal study, including consecutive patients (P) 24h after AF ablation, monitored with the E-patch. The effectiveness of the device in continuously recording within 5 days after ablation was analyzed, as well as the occurrence of AF episodes during an external 7- day loop-recorder, obtained in the 2nd-month post-ablation. Results A total of 30P were included (57% male, 63±8 years). AF ablation was performed with radiofrequency (RF) energy in 14P and with a balloon of cryoenergy in 16P. All P were in sinus rhythm at the beginning of the recording. The mean number of hours of recording was 113±16, with no discomfort complaints in the use of the device or interpretation artefacts. During the E-patch monitoring, a total of 10P (33%) presented AF (AF burden 6.8% of the recording, IQR 3.0-20%). All 30P underwent an external loop recorder for 7 days 2 months post-ablation, with 40% showing AF periods (> 30 seconds duration). All 10P that had AF detection in the very-early E-patch recording had also recurrence in the 2 nd month of extended 7-day continuous recording. Very- early AF detection had a sensitivity of 83.3% and a specificity of 100% to detect late blanking period AF (ROC 0.916±0.06; 95%CI 080-1.0). Conclusions The use of the E-patch very-early after AF ablation is effective for AF detection and is highly predictive of AF recurrence in the late blanking period. These findings require validation in larger studies to assess the potential of very-early assessment in the determination of a higher risk for AF recurrence.

Diagnosis of atrial fibrillation in heart failure patients with implantable cardioverter defibrillator or cardiac resynchronisation therapy.

IntroductionImplantable cardioverter defibrillators register various types of arrhythmias. Thus they can be exploited to better identify patients with atrial fibrillation episodes and increase the proportion of patients who may benefit from implementation of pharmacological prophylaxis of thromboembolic events, most of which are asymptomatic. The aim of the study was to assess of the frequency, symptoms and predisposing factors for the occurrence of atrial fibrillation episodes in patients with an implanted implantable cardioverter defibrillator (ICD) and cardiac resynchronisation therapy with defibrillator (CRT-D) based on the analysis of intracardiac electrocardiograms (EGM/IEGM) records.Material and methodsThe study included 174 consecutive outpatients with heart failure, sinus rhythm and an implanted cardioverter defibrillator and cardiac resynchronisation therapy with defibrillator. Follow-up visits with analysis of IEGM records occurred every 3 months. During a mean follow-up of 20 months, 901 visits were carried out. One hundred forty-seven patients had at least 1 year of follow-up.ResultsAtrial fibrillation episodes in the study group occurred in 54 (31.0%) patients and 71.4% were asymptomatic. Predisposing factors were: history of paroxysmal atrial fibrillation (37.0% vs. 13.3%, p < 0.001), atrioventricular conduction abnormalities (42.6% vs. 20.0%, p = 0.002), intraventricular conduction abnormalities (59.3% vs. 40.8%, p = 0.02) and more severe mitral regurgitation (7.4% vs. 0.8%, p = 0.04). Chronic renal disease was a risk factor for death in the study group. No stroke occurred during the study.ConclusionsEpisodes of paroxysmal atrial fibrillation in patients with systolic heart failure and implanted cardioverter-defibrillator systems are quite common. The majority of the episodes recorded in the study were asymptomatic.

Atrial fibrillation after orthotopic heart transplantatation: Pathophysiology and clinical impact.

BackgroundAtrial fibrillation (AF) is a well-established post-cardiac surgery complication. Orthotopic heart transplantation (OHT) represents a peculiar condition where surgical thoracic veins isolation and autonomic denervation occur. This study aims at investigating AF incidence in OHT in order to define its risk factors and to evaluate its prognostic impact.Methods278 patients affected by OHT were recruited in our Cardiac Surgery Unit and retrospectively analyzed, using clinical, surgical and instrumental data.ResultsThe patients cohort showed 45 post-operative (16.5%) and 20 late AF cases (7.2%). Only paroxysmal AF episodes were observed. Elderly donors and acute rejection resulted as risk factors in patients with post-operative AF episodes, who presented higher all-cause mortality at 11 years post-OHT (p < 0.001, Kaplan Meier analysis). The majority of late AF episodes occurred during hospitalization, due to renal failure or infections and more frequently in male patients; no significant correlation was observed with acute or chronic rejection or other characteristics.ConclusionPulmonary vein isolation and vagal denervation lead to low AF incidence in OHT recipients. Acute rejection and graft status are the main risk factors for post-operative AF episodes, while other systemic conditions act as late AF triggers. The occurrence of AF episodes is associated with poor outcome and AF should be considered as a marker of clinical frailty.

Antiarrhythmic Effect of Ranolazine in Combination with Selective NCX-Inhibition in an Experimental Model of Atrial Fibrillation

The aim of this study was to investigate the effects of a combination of ranolazine with different selective inhibitors of the Na+/Ca2+-exchanger (NCX) in an established experimental model of atrial fibrillation (AF). Eighteen hearts of New Zealand white rabbits were retrogradely perfused. Atrial catheters were used to record monophasic action potentials (aPRR). Hearts were paced at three different cycle lengths. Thereby, atrial action potential durations (aAPD90), atrial effective refractory periods (aERP) and atrial post-repolarization refractoriness were obtained. Isoproterenol and acetylcholine were employed to increase the occurrence of AF. Thereafter, the hearts were assigned to two groups (n = 9 each group) and additionally perfused with a combination of 10 µM ranolazine and 1 µM of the selective NCX-inhibitor ORM-10103 (group A: Rano-ORM) or 10 µM ranolazine and 1 µM of another NCX-inhibitor, SEA0400 (group B: Rano-SEA). The infusion of Iso/ACh led to a shortening of aAPD90, aERP, aPRR and the occurrence of AF episodes was significantly increased. Additional perfusion with ranolazine and ORM-10103 (group A) significantly prolonged the refractory periods and aPRR and AF episodes were effectively reduced. In group B, Rano-SEA led to a slight decrease in aAPD90 while aERP and aPRR were prolonged. The occurrence of AF episodes was consecutively reduced. To our knowledge, this is the first study investigating the effect of ranolazine combined with different selective NCX-inhibitors in an isolated whole-heart model of AF. Both combinations prolonged aERP and aPRR and thereby suppressed the induction of AF.

La fibrillation atriale : un facteur ou un marqueur du risque thromboembolique ? Du concept à la thérapie

The main complication of atrial fibrillation is stroke. Twenty years ago, the interest of vitamin K antagonist has been clearly demonstrated but these drugs are difficult to manage. For the last 10 years, direct oral anticoagulants have been developed. These drugs have demonstrated a non-inferiority as compared to vitamin K antagonist and a clear decrease in intra cerebral hemorrhages. Anticoagulation is indicated in a large majority of patients with atrial fibrillation. Nevertheless, many points remained questionable, like the anticoagulation of low risk patients, the choice of oral anticoagulants dosages, the anticoagulation according to the type of atrial fibrillation and the strategy in coronary artery disease patients for example. Recently it has been demonstrated that in many patients there were no temporal relationship between the occurrence of atrial fibrillation episodes and stroke. That means that in many cases atrial fibrillation is not the factor but the marker of thromboembolic risk.

Electrical and Calcium Transient Alternans in Cell Pairs and Intact Atrium

Cardiac arrhythmias, such as atrial fibrillation (AF), require an arrhythmogenic focus (ectopic activity) and transient or permanent tissue inhomogeneity (conduction heterogeneity). Electrical and calcium alternans in atrial tissue represent a risk factor for the occurrence of AF. The aims of our study were to determine characteristics of the development of Ca transient (CaT) alternans in coupled pairs of atrial myocytes and the relationship between cellular atrial alternans and occurrence of AF episodes in the perfused intact heart. Atrial cell pairs isolated from rabbit hearts were field stimulated at increasing rates until CaT alternans occurred. The CaT alternans usually initiated in one cell first. Alternans in the second cell rarely occurred simultaneously (3/11 pairs), but rather started at higher frequencies (5/11 pairs), or did not occur at all (3/11pairs). Stimulation with angiotensin (Ang II) lowered the pacing threshold for CaT alternans (from 1.71±0.08 to 1.49±0.14 Hz) and enhanced the degree of alternans (increased alternans ratio), presumably through activation of IP3 receptor-induced Ca release. Under control conditions cell pairs spontaneously switched between periods of concordant and discordant CaT alternans. Concordant and discordant CaT alternans between cell pairs led to intercellular heterogeneity in the CaT amplitude resulting in beat-to-beat intercellular Ca gradients. Ang II further enhanced these intercellular Ca gradients. In Langendorff perfused rabbit hearts pacing-induced electrical alternans were recorded with atrial bipolar electrograms and multielectrode mapping of the epicardial surface. The data revealed a high temporal correlation between atrial alternans and episodes of AF: atrial electrical alternans in form of atrial T wave alternans triggered AF episodes, and AF induced by a burst pacing protocol was followed by episodes of atrial T wave alternans. Ang II perfusion enhanced tissue-wide atrial T wave variability, suggesting enhanced electrical tissue heterogeneity and possibly discordant alternans at tissue level.

708 Post mode-switch overdrive pacing (pmop) reduces the occurrence of atrial fibrillation episodes during the overdrive period

708 Post mode-switch overdrive pacing (pmop) reduces the occurrence of atrial fibrillation episodes during the overdrive period

708 Post mode-switch overdrive pacing (pmop) reduces the occurrence of atrial fibrillation episodes during the overdrive period

708 Post mode-switch overdrive pacing (pmop) reduces the occurrence of atrial fibrillation episodes during the overdrive period