Mapping of Atrial Fibrillation: Back to the Drawing Board

New high-resolution mapping approach for mapping of atrial fibrillation in patients during cardiac surgery and the discovery of asynchronous activation of the endocardial and epicardial layers of the atria during atrial fibrillation

Right versus left atrial pacing in patients with sick sinus syndrome and paroxysmal atrial fibrillation (Riverleft study)

_Background:_ The incidence of sick sinus syndrome will increase due to population ageing. Consequently, this will result in an increase in the number of pacemaker implantations. The atrial lead is usually implanted in the right atrial appendage, but this position may be ineffective for prevention of atrial fibrillation. It has been suggested that pacing distally in the coronary sinus might be more successful in preventing atrial fibrillation episodes. The aim of this trial is to study the efficacy of distal coronary sinus versus right atrial appendage pacing in preventing atrial fibrillation episodes in patients with sick sinus syndrome. _Methods/Design:_ This study is designed as a multicenter, randomized controlled trial. Patients with sick sinus syndrome and at least one atrial fibrillation episode of 30 seconds or more in the six months before recruitment will be eligible for participation in this study. _Discussion:_ This randomized controlled trial is the first in which home monitoring will be used to compare atrial fibrillation recurrences between pacing in the distal coronary sinus or right atrial appendage. Home monitoring gives the opportunity to accurately detect atrial fibrillation episodes and to study characteristics of atrial fibrillation episodes. Should distal coronary sinus pacing significantly diminish atrial fibrillation recurrences, this study will redefine the preferential location of an atrial lead for preventive pacing

Impact of atrial programmed electrical stimulation techniques on unipolar electrogram morphology

Introduction: Intra-atrial conduction abnormalities are associated with the development of atrial fibrillation (AF) and cause morphological changes of the unipolar atrial electrogram (U-AEGM). This study examined the impact of

A Rare Case of the Digenic Inheritance of Long QT Syndrome Type 2 and Type 6

We report a 37-year-old woman with an out-of-hospital cardiac arrest caused by ventricular fibrillation due to digenic inheritance of long QT syndrome type 2 (KCNH2 gene) and type 6 (KCNE2 gene). During hospitalization, prolonged QTc intervals and frequent episodes of ventricular tachyarrhythmias manifested. Genetic testing identified a mutation of the KCNH2 gene and an unclassified variant, most likely pathogenic, of the KCNE2 gene. This digenic inheritance is extremely rare

Intraoperative Inducibility of Atrial Fibrillation Does Not Predict Early Postoperative Atrial Fibrillation

Background Early postoperative atrial fibrillation ( EP o AF ) is associated with thromboembolic events, prolonged hospitalization, and development of late Po AF ( LP o AF ). It is, however, unknown if EP o AF can be predicted by intraoperative AF inducibility. The aims of this study are therefore to explore (1) the value of intraoperative inducibility of AF for development of both EP o AF and LP o AF and (2) the predictive value of de novo EP o AF for recurrence of LP o AF . Methods and Results Patients (N=496, 75% male) undergoing cardiothoracic surgery for coronary and/or valvular heart disease were included. AF induction was attempted by atrial pacing, before extracorporeal circulation. All patients were on continuous rhythm monitoring until discharge to detect EP o AF . During a follow‐up period of 2 years, LP o AF was detected by ECG s and Holter recordings. Sustained AF was inducible in 56% of patients. There was no difference in patients with or without AF before surgery ( P =0.159), or between different types of surgery ( P =0.687). In patients without a history of AF , incidence of EP o AF and LP o AF was 37% and 2%, respectively. EP o AF recurred in 58% patients with preoperative AF , 53% developed LP o AF . There were no correlations between intraoperative inducibility and EP o AF or LP o AF ( P &gt;0.05). EP o AF was not correlated with LP o AF in patients without a history of AF ( P =0.116), in contrast to patients with AF before surgery ( P &lt;0.001). Conclusions Intraoperative AF inducibility does not predict development of either EP o AF or LP o AF . In patients with AF before surgery, EP o AF is correlated with LP o AF recurrences. This correlation is absent in patients without AF before surgery. </jats:sec

Impact of ischemic and valvular heart disease on atrial excitation

Background--The influence of underlying heart disease or presence of atrial fibrillation (AF) on atrial excitation during sinus rhythm (SR) is unknown. We investigated atrial activation patterns and total activation times of the entire atrial epicardial surface during SR in patients with ischemic and/or valvular heart disease with or without AF. Methods and Results--Intraoperative epicardial mapping (N=128/192 electrodes, interelectrode distances: 2 mm) of the right atrium, Bachmann's bundle (BB), left atrioventricular groove, and pulmonary vein area was performed during SR in 253 patients (186 male [74%], age 66±11 years) with ischemic heart disease (N=132, 52%) or ischemic valvular heart disease (N=121, 48%). As expected, SR origin was located at the superior intercaval region of the right atrium in 232 patients (92%). BB activation occurred via 1 wavefront from right-to-left (N=163, 64%), from the central part (N=18, 7%), or via multiple wavefronts (N=72, 28%). Left atrioventricular groove activation occurred via (1) BB: N=108, 43%; (2) pulmonary vein area: N=9, 3%; or (3) BB and pulmonary vein area: N=136, 54%; depending on which route had the shortest interatrial conduction time (P < 0.001). Ischemic valvular heart disease patients more often had central BB activation and left atrioventricular groove activation via pulmonary vein area compared with ischemic heart disease patients (N=16 [13%] versus N=2 [2%]; P=0.009 and N=86 [71%] versus N=59 [45%]; P < 0.001, respectively). Total activation times were longer in patients with AF (AF: 136±20 [92-186] ms; no AF: 114±17 [74-156] ms; P < 0.001), because of prolongation of right atrium (P=0.018) and BB conduction times (P < 0.001). Conclusions--Atrial excitation during SR is affected by underlying heart disease and AF, resulting in alternative routes for BB and left atrioventricular groove activation and prolongation of total activation times. Knowledge of atrial excitation patterns during SR and its electropathological variations, as demonstrated in this study, is essential to further unravel the pathogenesis of AF

Simultaneous Endo-Epicardial Mapping of the Human Right Atrium: Unraveling Atrial Excitation

Background The significance of endo-epicardial asynchrony (EEA) and atrial conduction block (CB), which play an important role in the pathophysiology of atrial fibrillation (AF) during sinus rhythm is poorly understood. The aim of our study was therefore to examine 3-dimensional activation of the human right atrium (RA). Methods and Results Eighty patients (79% men

Intraoperative inducibility of atrial fibrillation does not predict early postoperative atrial fibrillation

Background--Early postoperative atrial fibrillation (EPoAF) is associated with thromboembolic events, prolonged hospitalization, and development of late PoAF (LPoAF). It is, however, unknown if EPoAF can be predicted by intraoperative AF inducibility. The aims of this study are therefore to explore (1) the value of intraoperative inducibility of AF for development of both EPoAF and LPoAF and (2) the predictive value of de novo EPoAF for recurrence of LPoAF. Methods and Results--Patients (N=496, 75% male) undergoing cardiothoracic surgery for coronary and/or valvular heart disease were included. AF induction was attempted by atrial pacing, before extracorporeal circulation. All patients were on continuous rhythm monitoring until discharge to detect EPoAF. During a follow-up period of 2 years, LPoAF was detected by ECGs and Holter recordings. Sustained AF was inducible in 56% of patients. There was no difference in patients with or without AF before surgery (P=0.159), or between different types of surgery (P=0.687). In patients without a history of AF, incidence of EPoAF and LPoAF was 37% and 2%, respectively. EPoAF recurred in 58% patients with preoperative AF, 53% developed LPoAF. There were no correlations between intraoperative inducibility and EPoAF or LPoAF (P > 0.05). EPoAF was not correlated with LPoAF in patients without a history of AF (P=0.116), in contrast to patients with AF before surgery (P < 0.001). Conclusions--Intraoperative AF inducibility does not predict development of either EPoAF or LPoAF. In patients with AF before surgery, EPoAF is correlated with LPoAF recurrences. This correlation is absent in patients without AF before surgery