Complex fractionated electrograms (CFAEs) detected during substrate mapping for atrial fibrillation (AF) reflect etiologies that are difficult to separate. Without knowledge of local refractoriness ...and activation sequence, CFAEs may represent rapid localized activity, disorganized wave collisions, or far-field electrograms.
The purpose of this study was to separate CFAE types in human AF, using monophasic action potentials (MAPs) to map local refractoriness in AF and multipolar catheters to map activation sequence.
MAP and adjacent activation sequences at 124 biatrial sites were studied in 18 patients prior to AF ablation (age 57 ± 13 years, left atrial diameter 45 ± 8 mm). AF cycle length, bipolar voltage, and spectral dominant frequency were measured to characterize types of CFAE.
CFAE were observed at 91 sites, most of which showed discrete MAPs and (1) pansystolic local activity (8%); (2) CFAE after AF acceleration, often with MAP alternans (8%); or (3) nonlocal (far-field) signals (67%). A fourth CFAE pattern lacked discrete MAPs (17%), consistent with spatial disorganization. CFAE with discrete MAPs and pansystolic activation (consistent with rapid localized AF sites) had shorter cycle length (P <.05) and lower voltage (P <.05) and trended to have higher dominant frequency than other CFAE sites. Many CFAEs, particularly at the septa and coronary sinus, represented far-field signals.
CFAEs in human AF represent distinct functional types that may be separated using MAPs and activation sequence. In a minority of cases, CFAEs indicate localized rapid AF sites. The majority of CFAEs reflect far-field signals, AF acceleration, or disorganization. These results may help to interpret CFAE during AF substrate mapping.
Left atrial appendage (LAA) is implicated in maintenance of atrial fibrillation (AF) and atrial tachycardia (AT) associated with persistent AF (PsAF) ablation, although little is known about the ...incidence and mechanism of LAA AT.
The purpose of this study was to characterize LAA ATs associated with PsAF ablation.
In 74 consecutive patients undergoing stepwise PsAF ablation, 142 ATs were encountered during index and repeat procedures. Out of 78 focal-source ATs diagnosed by activation and entrainment mapping, 15 (19%) arose from the base of LAA. Using a 20-pole catheter, high-density maps were constructed (n = 10; age 57 ± 6 years) to characterize the mechanism of LAA-AT. The LAA orifice was divided into the posterior ridge and anterior-superior and inferior segments to characterize the location of AT.
Fifteen patients with LAA AT had symptomatic PsAF for 17 ± 15 months before ablation. LAA AT (cycle length CL 283 ± 30 ms) occurred during the index procedure in four and after 9 ± 7 months in 11 patients. We could map 89% ± 8% AT CLs locally with favorable entrainment from within the LAA, which is suggestive of localized reentry with centrifugal atrial activation. ATs were localized to inferior segment (n = 4), anterior-superior segment (n = 5), and posterior ridge (n = 6) with 1:1 conduction to the atria. Ablation targeting long fractionated or mid-diastolic electrogram within the LAA resulted in tachycardia termination. Postablation, selective contrast radiography demonstrated atrial synchronous LAA contraction in all but one patient. At 18 ± 7 months, 13/15 (87%) patients remained in sinus rhythm without antiarrhythmic drugs.
LAA is an important source of localized reentrant AT in patients with PsAF at index and repeat ablation procedures. Ablation targeting the site with long fractionated or mid-diastolic LAA electrogram is highly effective in acute and medium-term elimination of the arrhythmia.
Objectives Our purpose was to evaluate the efficacy of antiarrhythmic drugs (AADs) in recurrent ventricular fibrillation (VF) associated with inferolateral early repolarization pattern on the ...electrocardiogram. Background Although an implantable cardioverter-defibrillator is the treatment of choice, additional AADs may be necessary to prevent frequent episodes of VF and reduce implantable cardioverter-defibrillator shock burden or as a lifesaving therapy in electrical storms. Methods From a multicenter cohort of 122 patients (90 male subjects, age 37 ± 12 years) with idiopathic VF and early repolarization abnormality in the inferolateral leads, we selected all patients with more than 3 episodes of VF (multiple) including those with electrical storms (≥3 VF in 24 h). The choice of AAD was decided by individual physicians. Follow-up data were obtained for all patients using monitoring with implantable defibrillator. Successful oral AAD was defined as elimination of all recurrences of VF with a minimal follow-up period of 12 months. Results Multiple episodes of VF were observed in 33 (27%) patients. Electrical storms (34 ± 47 episodes) occurred in 16 and were unresponsive to beta-blockers (11 of 11), lidocaine/mexiletine (9 of 9), and verapamil (3 of 3), while amiodarone was partially effective (3 of 10). In contrast, isoproterenol infusion immediately suppressed electrical storms in 7 of 7 patients. Over a follow-up of 69 ± 58 months, oral AADs were poorly effective in preventing recurrent VF: beta-blockers (2 of 16), verapamil (0 of 4), mexiletine (0 of 4), amiodarone (1 of 7), and class 1C AADs (2 of 9). Quinidine was successful in 9 of 9 patients, decreasing recurrent VF from 33 ± 35 episodes to nil for 25 ± 18 months. In addition, quinidine restored a normal electrocardiogram. Conclusions Multiple recurrences of VF occurred in 27% of patients with early repolarization abnormality and may be life threatening. Isoproterenol in acute cases and quinidine in chronic cases are effective AADs.
Objectives The purpose of this study was to assess whether additional ablation in the right atrium (RA) improves termination rate in long-lasting persistent atrial fibrillation (PsAF). Background ...Prolongation of atrial fibrillation (AF) cycle length (CL) measured from the left atrial appendage predicts favorable outcome during catheter ablation of PsAF. However, in some patients, despite prolongation of AF CL in the left atrium (LA) with ablation, AF persists. We hypothesized that this persistence is due to RA drivers, and that these patients may benefit from RA ablation. Methods In all, 148 consecutive patients undergoing catheter ablation of PsAF (duration 25 ± 32 months) were studied. AF CL was monitored in both atria during stepwise ablation commencing in the LA. Ablation was performed in the RA when all LA sources in AF had been ablated and an RA-LA gradient existed. The procedural end point was AF termination. Results Two distinct patterns of AF CL change emerged during LA ablation. In 104 patients (70%), there was parallel increase of AF CL in LA and RA culminating in AF termination (baseline: LA 153 ms range 140 to 170 ms, RA 155 ms range 143 to 171 ms; after ablation: LA 181 ms range 170 to 200 ms, RA 186 ms range 175 to 202 ms). In 24 patients (19%), RA AF CL did not prolong, creating a right-to-left frequency gradient (baseline: LA 142 ms range 143 to 153 ms, RA 145 ms range 139 to 162 ms; after ablation: LA 177 ms range 165 to 185 ms, RA 152 ms range 147 to 175 ms). These patients had a longer AF history (23 months vs. 12 months, p = 0.001), and larger RA diameter (42 mm vs. 39 mm, p = 0.005), and RA ablation terminated AF in 55%. In the remaining 20 patients, biatrial ablation failed to terminate AF. Conclusions A divergent pattern of AF CL prolongation after LA ablation resulted in a right-to-left gradient, demonstrating that the right atrium is driving AF in ≈20% of PsAF.
Characterization of Electrograms Associated With Termination of Chronic Atrial Fibrillation by Catheter Ablation Yoshihide Takahashi, Mark D. O’Neill, Mélèze Hocini, Rémi Dubois, Seiichiro Matsuo, ...Sébastien Knecht, Srijoy Mahapatra, Kang-Teng Lim, Pierre Jaïs, Anders Jonsson, Frédéric Sacher, Prashanthan Sanders, Thomas Rostock, Pierre Bordachar, Jacques Clémenty, George J. Klein, Michel Haïssaguerre In 40 patients with chronic atrial fibrillation (AF), electrogram-based ablation was performed in the left atrium and coronary sinus after pulmonary vein isolation and left atrium roof line ablation. Electrogram characteristics at atrial regions targeted during electrogram-based ablation were evaluated. A greater percentage of continuous electrical activity and the presence of a temporal gradient of activation were associated with slowing or termination of AF during ablation, whereas bipolar voltage, mean absolute value of dV/dt, fractionation index, or dominant frequencies of electrograms were not different at regions with or without impact of ablation.
A Randomized Comparison of Triple-Site Versus Dual-Site Ventricular Stimulation in Patients With Congestive Heart Failure Christophe Leclercq, Fredrik Gadler, Wolfgang Kranig, Sue Ellery, Daniel ...Gras, Arnaud Lazarus, Jacques Clémenty, Eric Boulogne, Jean-Claude Daubert, for the TRIP-HF (Triple Resynchronization In Paced Heart Failure Patients) Study Group This multicenter, single-blind, crossover study examined the effects of triple- versus dual-site biventricular stimulation in 40 recipients of cardiac resynchronization therapy systems in permanent atrial fibrillation who required permanent pacing. After 3 months of triple- versus dual-site stimulation, significant differences in left ventricular function and dimensions were observed, all favoring triple-site stimulation.
Effects of Stepwise Ablation of Chronic Atrial Fibrillation on Atrial Electrical and Mechanical Properties Yoshihide Takahashi, Mark D. O’Neill, Mélĕze Hocini, Patricia Reant, Anders Jonsson, Pierre ...Jaïs, Prashanthan Sanders, Thomas Rostock, Martin Rotter, Frédéric Sacher, Stephane Laffite, Raymond Roudaut, Jacques Clémenty, Michel Haïssaguerre Electroanatomical mapping after stepwise catheter ablation of chronic atrial fibrillation showed the presence of scar, low-voltage atrial tissue, and prolongation of intra-atrial conduction. At 9 ± 5 months of follow-up, 98% of patients were in sinus rhythm, and the presence of left atrial contraction was shown in all patients. These results indicate that the electrical effects of widespread left atrial ablation are compensated for by recovery of left atrial contraction and are associated with an excellent clinical outcome.
The report from the 2nd Consensus Committee on BrS suggests that all patients with syncope without a "clear extracardiac cause" should have an implantable cardioverter-defibrillator (ICD). However, a ...clear extracardiac cause for syncope may be difficult to prove.
The purpose of this study was to characterize syncope in patients with Brugada syndrome (BrS).
All patients diagnosed with BrS at our institution between 1999 and 2010 were enrolled in a prospective registry. Patients with suspected arrhythmic syncope (group 1) were compared to patients with nonarrhythmic syncope (group 2) and to patients with syncope of doubtful origin (group 3).
Of 203 patients with BrS, 57 (28%; 44 male, age 46 ± 12 years) experienced at least 1 syncope. Group 1 consisted of 23 patients, all of whom received an ICD. In group 2 (17 patients), 3 received an ICD because of a positive electrophysiologic study. In group 3 (17 patients), 6 received an implantable loop recorder and 6 received an ICD. After mean follow-up of 65 ± 42 months, 14 patients in group 1 remained asymptomatic, 4 had recurrent syncope, and 6 had appropriate ICD therapy. In group 2, 9 patients remained asymptomatic and 7 had recurrent neurocardiogenic syncope. In group 3, 7 remained asymptomatic and 9 had recurrent syncope. One patient from each group died from a noncardiac cause.
In the present study, syncope occurred in 28% of patients with BrS. The ventricular arrhythmia rate was 5.5% per year in group 1. In 30%, the etiology of the syncope was questionable. No sudden cardiac death occurred in groups 2 and 3.
A pacemaker recipient may be hospitalized recurrently with an infection of unknown origin despite detailed investigations.
The purpose of this study was to investigate whether ...(18)F-fluorodeoxyglucose positron emission tomography/computerized tomography (FDG-PET/CT) scanning has a role in identifying pacing material infection in these difficult cases.
Ten patients who presented with fever of unknown origin despite detailed investigations including transesophageal echocardiography underwent FDG-PET/CT scanning. Identification of increased FDG uptake along a pacing lead prompted the removal of the entire pacing system, whereas in the absence of increased FDG uptake the pacing material was left in place. Forty control pacemaker recipients underwent FDG-PET/CT scanning as part of investigation of malignancy.
Among the 40 patients in the control group, FDG-PET/CT scanning was normal in 37 (92.5%) patients. Among the 10 patients who presented with suspected pacing system infections, FDG-PET/CT scanning showed increased FDG uptake along a lead in six patients; as a result of this finding, these patients subsequently underwent complete removal of the implanted material. Cultures of the leads were positive in all six patients, confirming involvement of the leads in the infectious process. In the other four patients, the pacing system was left in place without objective signs of active lead endocarditis during follow-up.
This study demonstrates the potential value of FDG-PET/CT scanning in the diagnosis of pacing lead endocarditis in difficult cases. Increased FDG uptake along a lead in this clinical context appears to be a reliable sign of active infection.
Background This multicenter, prospective, randomized, controlled, parallel trial compares the efficacy of biventricular (BIV) versus right ventricular (RV) antitachycardia pacing (ATP) in terminating ...all kinds of ventricular tachycardia (VT). Methods Five hundred twenty-six patients implanted with a cardiac resynchronization therapy defibrillator (CRT-D) device were enrolled and randomized 1:1 to either BIV (266) or RV (260) ATP (single burst 8 pulse, 88% coupling interval) and were followed up for 12 months. Results During 12 months' follow-up, 1,077 ventricular episodes in 180 patients were detected and classified: 634 true VTs divided into 69 ventricular fibrillation (VF) (11%), 202 fast ventricular tachycardia (FVT) (32%), and 363 VT (57%). A comparable first ATP efficacy (BIV 65% vs RV 68%, P = .59) was observed in FVT + VT, in VT zone (BIV 62% vs RV 71%, P = .25), and in FVT zone (BIV 71% vs RV 61%, P = .34). A trend toward lower accelerations during ATP applied to FVT was observed in the BIV group (3.5% BIV vs 10.2% RV, P = .163). No syncope/presyncope occurred during ATP for FVT in the BIV group versus 4 events (3.2%) in the RV group ( P = .016). biventricular ATP was more effective in treating FVT in coronary artery disease (CAD) patients ( P = .032), whereas both modalities presented similar efficacy in patients with non-CAD etiology ( P = .549). Conclusions Antitachycardia pacing is effective in patients implanted with a CRT-D device. No significant differences in efficacy emerged between BIV- and RV-delivered ATP in the general population, whereas BIV ATP seems to present a safer profile in ischemic patients.
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