Occurrence of persistent atrial fibrillation during pacing for sinus node disease: The influence of His bundle pacing versus managed ventricular pacing.

INTRODUCTION: In patients with sinus node disease (SND), the dual-chamber pacemaker (PM) is programmed in DDDR mode with an algorithm to avoid unnecessary right ventricular (RV) pacing. This pacing mode may prolong PR interval with consequently atrioventricular (AV) asynchrony which is associated with a higher risk of atrial fibrillation (AF). We evaluate whether preserving AV synchrony by setting a fixed AV delay during physiological RV pacing, that is, His bundle pacing (HBP), could reduce the risk of AF occurrence in comparison with a standard pacing mode with an algorithm to avoid unnecessary RV pacing (DDD-VPA). METHODS AND RESULTS: We collected retrospective data from 313 consecutive patients who had undergone PM for SND. The first occurrence of persistent AF (>7 consecutive days) as a function of the pacing mode was evaluated. HBP and DDD-VPA were implemented in 82 and 231 patients, respectively. Persistent AF occurred in 128 (40.9%) patients over a median follow-up of 70 months (67-105). The DDD-VPA pacing mode was significantly correlated with the occurrence of persistent AF only when the basal PR was long (>180 ms). The risk of persistent AF was significantly lower in patients on HBP than in those on DDD-VPA, adjusted HR = .57 (95% CI, .36- .89, p=.014). Other independent predictors of persistent AF occurrence were: A history of AF (HR = 3.91; 95% CI, 2.48-6.19, p = .001), age, and long PR interval (HR = 2.98; 95% CI, 2.00-4.43, p=.001). CONCLUSION: In SND patients and long basal PR interval, the HBP may reduce the risk of persistent AF in comparison with the DDD-VPA.

The QR-max index, a novel electrocardiographic index for the determination of left ventricular conduction delay and selection of cardiac resynchronization in patients with non-left bundle branch block.

Non-left bundle branch block (non-LBBB) remains an uncertain indication for cardiac resynchronization therapy (CRT). Non-LBBB includes right bundle branch block (RBBB) and non-specific LV conduction delay (NSCD), two different electrocardiogram (ECG) patterns which are not generally considered to be associated with LV conduction delay as judged by the invasive assessment of the Q-LV interval. We evaluated whether a novel ECG interval (QR-max index) correlated with the degree of LV conduction delay regardless of the type of non-LBBB ECG pattern, and could, therefore, predict CRT response. In 173 non-LBBB patients on CRT (92 NSCD, 81 RBBB), the QR-max index was measured as the maximum interval from QRS onset to R-wave offset in the limb leads. The correlation between QR-max index and Q-LV interval and the impact of the QR-max index on time to first heart failure hospitalization during 3-year follow-up were assessed. Q-LV correlated better with the QR-max index than with QRSd, particularly in the RBBB group (r = 0.91; p < 0.001 vs. r = 0.19; p < 0.089), while the correlations were r = 0.79 (p < 0.01) and r = 0.68 (p < 0.01), respectively, in the NSCD group. In both groups, the QR-max index was significantly more able than QRSd to identify CRT responders (AUC 0.825 vs. 0.576; p = 0.0008 in RBBB; AUC 0.738 vs. 0.701; p = 0.459 in NSCD). A QR-max index exceeding a cutoff value of 120 ms was associated with CRT response, with predictive values of 86.8 and 81.4% in RBBB and NSCD, respectively. The QR-max index reflects the degree of LV electrical delay regardless of QRS duration in RBBB and NSCD patients and is a useful indicator of suitability for CRT in non-LBBB patients.

Patients with right bundle branch block and concomitant delayed left ventricular activation respond to cardiac resynchronization therapy.

Aims: Right bundle branch block (RBBB) typically presents with only delayed right ventricular activation. However, some patients with RBBB develop concomitant delayed left ventricular (LV) activation. Such patients may show a specific electrocardiographic (ECG) pattern resembling RBBB in the precordial leads in association with an insignificant S-wave in lateral limb leads (atypical RBBB). We therefore postulated that the ECG pattern of atypical RBBB might be able to identify a subgroup of patients likely to respond to cardiac resynchronization therapy (CRT). The purpose of this study was to assess the impact of RBBB ECG morphology on CRT response in patients with heart failure (HF). Methods and results: We evaluated the echocardiographic clinical response of 66 patients with RBBB treated with CRT and followed up for almost 2 years. The patients were divided electrocardiographically into 2 groups: 31 with typical RBBB and 35 with atypical RBBB. Responders were classified in terms of reduction in LV end-systolic volume index (ESVi) ≥ 15% or reduction in the New York Heart Association (NYHA) Class ≥ 1 or Packer score variation (NYHA response with no HF-related hospitalization events or death). The atypical RBBB group presented a longer LV activation time compared with the typical RBBB group (111.9 ± 17.6 vs. 73.2 ± 15.4 ms; P < 0.001). In the atypical and typical RBBB groups, respectively, 71.4% and 19.4% of patients were ESVi responders (P = 0.001) 74.3% and 32.3% were NYHA responders (P = 0.002); similarly, 71.4% and 29.0% of patients exhibited a 2-year Packer score of 0 (P = 0.002). Conclusion: Patients with atypical RBBB, which is a pattern highly suggestive of concomitant delayed LV conduction, may show a satisfactory response to CRT.

ECG parameters predict left ventricular conduction delay in patients with left ventricular dysfunction.

BACKGROUND: Estimating left ventricular electrical delay (Q-LV) from a 12-lead ECG may be important in evaluating cardiac resynchronization therapy (CRT). OBJECTIVE: The purpose of this study was to assess the impact of Q-LV interval on ECG configuration. METHODS: One hundred ninety-two consecutive patients undergoing CRT implantation were divided electrocardiographically into 3 groups: left bundle branch block (LBBB), right bundle branch block (RBBB), and nonspecific intraventricular conduction delay (IVCD). The IVCD group was further subdivided into 81 patients with left (L)-IVCD and 15 patients with right (R)-IVCD (resembling RBBB, but without S wave in leads I and aVL). The Q-LV interval in the different groups and the relationship between ECG parameters and the maximum Q-LV interval were analyzed. RESULTS: Patients with LBBB presented a long Q-LV interval (147.7 ± 14.6 ms, all exceeding cutoff value of 110 ms), whereas RBBB patients presented a very short Q-LV interval (75.2 ± 16.3 ms, all <110 ms). Patients with an IVCD displayed a wide range of Q-LV intervals. In L-IVCD, mid-QRS notching/slurring showed the strongest correlation with a longer Q-LV interval, followed, in decreasing order, by QRS duration >150 ms and intrinsicoid deflection >60 ms. Isolated mid-QRS notching/slurring predicted Q-LV interval >110 ms in 68% of patients. The R-IVCD group presented an unexpectedly longer Q-LV interval (127.0 ± 12.5 ms; 13/15 patients had Q-LV >110 ms). CONCLUSION: Patients with LBBB have a very prolonged Q-LV interval. Mid-QRS notching in lateral leads strongly predicts a longer Q-LV interval in L-IVCD patients. Patients with R-IVCD constitute a subgroup of patients with a long Q-LV interval.

Left Axillary Implantation of Loop Recorder versus the Traditional Left Chest Area: A Prospective Randomized Study.

BACKGROUND: Based upon the results of a previous small pilot study, we present the results of a prospective single-center randomized study comparing the performance of the implantable loop recorder (ILR) at two implanting sites. METHODS: A group of patients whose ILRs were implanted via a left axillary approach were compared with a group who received an ILR in the traditional left site of the chest. Follow-up (FU) was scheduled every 6 months or when symptoms occurred. All patients enrolled in the study had a complete FU from implantation to explantation. R- and P-wave amplitudes were measured at implantation and during FU. Explantation of the device was programmed at the end of service life or when ILR analysis resulted in a complete and exhaustive diagnosis. RESULTS: Sixty-three patients were enrolled (70 ± 12 years, range: 21-92, 59% male): 31 standard and 32 with axillary access. The R-wave amplitude obtained with the new technique was comparable with that obtained with the standard procedure. The diagnostic accuracy of the ILR was comparable in the two groups. The axillary implantation procedure was slightly longer but no complications were observed. CONCLUSION: This long-term randomized study confirmed that axillary access for ILR implantation is feasible, safe, well tolerated, and reliable in terms of device performance. Moreover, it is aesthetically superior to the standard approach and carries the potential of minimizing permanent scarring after ILR extraction.

The risk of atrial fibrillation during right ventricular pacing.

AIMS: Right ventricular pacing adversely affects left atrial (LA) structure and function that may trigger atrial fibrillation (AF). This study compares the occurrence of persistent/permanent AF during long-term Hisian area (HA), right ventricular septal (RVS), and right ventricular apex (RVA) pacing in patients with complete/advanced atrioventricular block (AVB). METHODS AND RESULTS: We collected retrospective data from 477 consecutive patients who underwent pacemaker implantation for complete/advanced AVB. Ventricular pacing leads were located in the HA, RVS, and RVA in 148, 140, and 189 patients, respectively. The occurrence of persistent/permanent AF was observed in 114 (23.9%) patients (follow-up 58.5 ± 26.5 months). Hisian area groups presented a lower rate of AF occurrence (16.9%) compared with RVS and RVA groups (25.7 and 28.0%, respectively), P = 0.049. Cox's proportional hazard model was used to estimate HR. The risk of persistent/permanent AF was significantly lower in the patients paced from HA compared with those paced from RVA, HR = 0.28 (95% CI 0.16-0.48, P = 0.0001). The RVS and RVA pacing groups showed a similar AF risk: HR 1.04 (95% CI 0.66-1.64, P = 0.856). Other independent predictors of persistent/permanent AF occurrence included previous (before device implantation) paroxysmal AF (HR = 4.08; 95% CI 3.15-7.31, P = 0.0001), LA diameter, and age, whereas baseline bundle-branch block was associated with a lower risk of AF occurrence (HR = 0.56; 95% CI 0.35-0.81, P = 0.003). CONCLUSIONS: HA pacing compared with RVA or RVS pacing seems to be associated with a lower risk of persistent/permanent AF occurrence. The risk of persistent/permanent AF was similar in the RVA vs. RVS groups.

Hisian area and right ventricular apical pacing differently affect left atrial function: an intra-patients evaluation.

AIMS: Right ventricular apex (RVA) pacing has adverse effects on left atrial (LA) function and may contribute to atrial arrhythmias. The effects of Hisian area (HA) pacing on LA function are still lacking. The objective of this study is to assess the left ventricular (LV) electromechanical activation/relaxation, systolic (S), diastolic (D) phases, and their effects on LA function during pacing from HA and RVA. METHODS AND RESULTS: Thirty-seven patients with normal cardiac function underwent permanent HA pacing. In all patients, a RVA backup lead was added. The patients first underwent 3 months of HA pacing, followed by 3 months of RVA pacing. After each 3-month period, we compared by echocardiography: S-D LV electromechanical delay (S-D EMD), S-D intra-LV dyssynchrony, LV S-D phases, and their function evaluated by myocardial performance index (MPI) and mitral annular tissue Doppler early diastolic velocity (E'), pulmonary arterial systolic pressure (PASP), and LA function (LA phasic volumes and their emptying fraction). Right ventricular apex compared with HA pacing increased S-D EMD (P < 0.001) and intra-LV dyssynchrony (P < 0.001). As a consequence, a significant longer LV isovolumetric contraction time (P < 0.001) and LV isovolumetric relaxation time (P = 0.05) were measured during RVA compared with HA pacing, whereas LV ejection time was shorter (P = 0.033). Moreover, HA pacing resulted in significantly better MPI (P = 0.039), higher value of E' (P = 0.049), and lower PASP (P < 0.001). Finally, RVA compared with HA pacing was associated to higher LA volumes pre-atrial contraction (P = 0.001) and minimal volume (P = 0.003) with reduction in passive emptying fraction (P < 0.001) and total emptying fraction (P = 0.005). CONCLUSION: Hisian area compared with RVA pacing resulted in a more physiological LV electromechanical activation/relaxation and consequently better LA function.

Left atrial appendage closure: a new technique for clinical practice.

BACKGROUND/OBJECTIVE: Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia. It is associated with increased risk for stroke mainly due to cardiac embolism from the left atrial appendage (LAA). Occlusion of the LAA by means of a device represents a valid alternative to oral anticoagulation, mainly in patients who cannot tolerate this therapy because of a high bleeding risk. Recent data on the endocardial device WATCHMAN show encouraging results for this patient population in terms of stroke risk reduction compared to the expected rate as well as in terms of implant success. This article reviews all relevant publications related to the main surgical and transcatheter devices used for LAA closure (LAAC). METHODS/RESULTS: PROTECT-AF, the first prospective randomized trial conducted on this technique, showed that LAA occlusion using the WATCHMAN was noninferior to warfarin for a combined end-point in patients with nonvalvular AF. There is a lack of large-scale randomized trials on long-term stroke risk in patients submitted to LAAC. Most studies are relatively small and focus on the comparison of different surgical techniques with regard to complete/incomplete closure success. More recently, PROTECT-AF long-term results (4-year follow-up) demonstrated that LAAC was statistically superior to warfarin in terms of efficacy. CONCLUSION: This review concludes that it is now appropriate to consider these techniques for patients with AF who are at high risk for stroke for whom effective conventional or novel anticoagulant therapy is not available or who present problems in managing drug treatment.

Ventricular Rate Stabilization In Patients With Permanent Atrial Fibrillation And Single-Chamber Ventricular Pacemaker: RARE-PEARL Study.

Background: In patients with permanent atrial fibrillation (AF) rate irregularity can cause symptoms and impair the pumping function of the heart. Ventricular pacing at a rate close to the mean spontaneous ventricular rate can result in a more stable ventricular rate. Specific algorithms for automatic Ventricular Rate Stabilization (VRS) were designed and implemented in commercially available pacemakers. To assess this dynamic rate control we designed the RARE-PEARL study: prospective, randomized, cross-over, double-blinded. Methods: Patients with permanent AF, symptomatic episodes of brady-tachycardia, left ventricular ejection fraction (LVEF) >40%, NYHA class I/II/III, were eligible for enrolment. Each patient (n = 67) was implanted with a single-chamber VVIR pacemaker (models C20 or T20, Vitatron BV, The Netherlands) equipped with the VRS algorithm. At the end of a four week stabilization period, patients were randomized to VRS algorithm ON or OFF (2 months) and then crossed-over for the second phase (2 months). Primary endpoint was patient's preference. Results: Sixty six patients ended the study: 19 (29%) had no preference; 15 (23%) preferred algorithm OFF, 32 (48%) algorithm ON (p<0.0001, algorithm ON vs OFF). In 58% of patients the algorithm ON caused an increase of ventricular pacing percentage > 10%. The ventricular pacing percentage was 82±10% with algorithm ON vs 59±26% with algorithm OFF (p<0.0001). Symptoms did not differ significantly. Conclusions: The VRS algorithm significantly increases the ventricular pacing percentage in patients with permanent AF. This pacing function is preferred by the majority of patients implanted with a single-chamber VVIR pacemaker.

How can we identify the optimal pacing site in the right ventricular septum? A simplified method applicable during the standard implanting procedure.

AIMS: A short paced (p) QRS duration (d) can be a marker for selecting the most appropriate RV pacing site. Although this could be achieved by continual 12-Lead ECG monitoring, such a technique is not applicable during pacemaker (PM) implantation. The purpose of this study was to validate a method for identifying the optimal site for RV septum pacing using simple markers derived from few real-time ECG leads and fluoroscopy (F). METHODS AND RESULTS: An overall of 304 measurements of pQRSd in different RV sites was performed in 102 patients undergoing PM implant. In accordance with F position the lead placement was classified high, medium, and low septum. Paced electrocardiographic/fluoroscopic parameters (q-wave/negative QRS in lead I, notching in limb leads, R/S wave in lead II, QRS precordial leads transition, and F septal segments pacing site) were analyzed to predict short pQRSd (≤ 160 ms). Logistic regression analysis showed that pQRSd > 160 ms was predicted by presence of pQRS notching in limb leads (OR = 3.24, p < 0.001), and with negative amplitude of QRS in lead II (OR = 2.53, p = 0.03). Short pQRSd (≤ 160 ms) was observed with mid F position (OR = 0.31, p < 0.001) and with the presence of a q-wave/negative QRS in lead I. CONCLUSION: In RV septum pacing, simple QRS markers of few limb leads (lead I/II) added to F position are usefull to identifying the optimal site to place the RV lead.

A randomized comparison of pulmonary vein isolation with versus without concomitant renal artery denervation in patients with refractory symptomatic atrial fibrillation and resistant hypertension.

OBJECTIVES: The aim of this prospective randomized study was to assess the impact of renal artery denervation in patients with a history of refractory atrial fibrillation (AF) and drug-resistant hypertension who were referred for pulmonary vein isolation (PVI). BACKGROUND: Hypertension is the most common cardiovascular condition responsible for the development and maintenance of AF. Treating drug-resistant hypertension with renal denervation has been reported to control blood pressure, but any effect on AF is unknown. METHODS: Patients with a history of symptomatic paroxysmal or persistent AF refractory to ≥2 antiarrhythmic drugs and drug-resistant hypertension (systolic blood pressure >160 mm Hg despite triple drug therapy) were eligible for enrolment. Consenting patients were randomized to PVI only or PVI with renal artery denervation. All patients were followed ≥1 year to assess maintenance of sinus rhythm and to monitor changes in blood pressure. RESULTS: Twenty-seven patients were enrolled, and 14 were randomized to PVI only, and 13 were randomized to PVI with renal artery denervation. At the end of the follow-up, significant reductions in systolic (from 181 ± 7 to 156 ± 5, p < 0.001) and diastolic blood pressure (from 97 ± 6 to 87 ± 4, p < 0.001) were observed in patients treated with PVI with renal denervation without significant change in the PVI only group. Nine of the 13 patients (69%) treated with PVI with renal denervation were AF-free at the 12-month post-ablation follow-up examination versus 4 (29%) of the 14 patients in the PVI-only group (p = 0.033). CONCLUSIONS: Renal artery denervation reduces systolic and diastolic blood pressure in patients with drug-resistant hypertension and reduces AF recurrences when combined with PVI.

Analysis of atrial fibrillatory rate during spontaneous episodes of atrial fibrillation in humans using implantable loop recorder electrocardiogram.

Atrial fibrillatory rate (AFR) can predict outcome of interventions for atrial fibrillation (AF); however, AFR behavior at AF onset in humans is poorly described. We studied AFR during spontaneous AF episodes in patients with lone paroxysmal AF who received implantable loop recorders and had AF episodes of 1 hour or more recorded (n = 4). Mean AFR per minute was assessed from continuous implantable loop recorder electrocardiogram using spatiotemporal QRST cancellation and time-frequency analysis. Atrial fibrillatory rate increased from 290 ± 20 to 326 ± 39 fibrillations per minute during the first 3 hours (P<.05) and reached plateau then. Atrial fibrillatory rate beyond the initial 3 hours can, therefore, be considered stable and may be evaluated for prediction of intervention effect.

Usefulness of continuous electrocardiographic monitoring for atrial fibrillation.

The problem of early recognition of atrial fibrillation (AF) is greatly aggravated by the often silent nature of the rhythm disturbance. In about 1/3 of patients with this arrhythmia, patients are not aware of the so-called asymptomatic AF. In the past 15 years, the diagnostic data provided by implanted pacemakers and defibrillators have dramatically increased knowledge about silent AF. The unreliability of symptoms to estimate AF burden and to identify patients with and without AF has been pointed out not only by pacemaker trials but also in patients without implanted devices. The technology for continuous monitoring of AF has been largely validated. It is a powerful tool to detect silent paroxysmal AF in patients without previously documented arrhythmic episodes, such as those with cryptogenic stroke or other risk factors. Early diagnosis triggers earlier treatment for primary or secondary stroke prevention. Today, new devices are also available for pure electrocardiographic monitoring, implanted subcutaneously using a minimally invasive technique. In conclusion, this recent and promising technology adds relevant clinical and scientific information to improve risk stratification for stroke and may play an important role in testing and tailoring the therapies for rhythm and rate control.

Ablation for atrial fibrillation during mitral valve surgery: 1-year results through continuous subcutaneous monitoring.

Continuous monitoring of cardiac rhythm may play an important role in measuring the true symptomatic/asymptomatic atrial fibrillation (AF) burden and improve the management of anti-arrhythmic and anti-thrombotic therapies. Forty-seven patients with mitral valve disease and longstanding persistent AF (LSPAF) underwent a left atrial maze procedure with bipolar radiofrequency and valve surgery. The follow-up data recorded by an implanted loop recorder were analysed after 3, 6 and 12 months. On discharge, 40 (85.1%) patients were in stable sinus rhythm, as documented by in-office electrocardiography (ECG), 4 (8.5%) were in pacemaker rhythm and 3 (6.4%) were in AF. One (2.1%) patient died after 7 months. On 12-month follow-up examination, 30 (65.2%) patients had an AF burden <0.5% and were classified as responders. Three (6.5%) of the 16 non-responders had atrial flutter and 13 (27.7%) had documented AF recurrences with an AF burden >0.5%. Two (4.3%) patients with AF recurrences were completely asymptomatic. Among the symptomatic events stored by the patients, only 27.6% was confirmed as genuine AF recurrences according to the concomitant ECG recorded by the implanted loop recorder. A concomitant bipolar maze procedure during mitral valve surgery is effective in treating AF, as proved by detailed 1-year continuous monitoring.

Does atrial fibrillation burden measured by continuous monitoring during the blanking period predict the response to ablation at 12-month follow-up?

BACKGROUND: Recurrences are common within the first months following atrial fibrillation (AF) ablation. However, prior studies using only intermittent ECG recording have not shown a powerful correlation with ultimate response. OBJECTIVE: The purpose of this study was to use continuous AF monitoring with an implanted monitor to assess the AF burden measured continuously during the first months postablation and the relationship to subsequent AF recurrences. METHODS: Six hundred thirteen patients with symptomatic drug-refractory AF (17% with persistent AF) were part of this retrospective analysis. All patients underwent circumferential pulmonary vein isolation and were implanted with a subcutaneous AF monitor (Reveal XT, Medtronic) for collecting data on AF burden (AF%) during a 12-month follow-up period. AF freedom (responders) was defined as AF% ≤0.5% during each monthly telemetric follow-up. A receiver operating characteristic curve analysis was performed to identify the value in AF% during the first months in the postablation blanking period that was predictive of later recurrence of AF. Sensitivity of 90% was selected as the target value. RESULTS: After the first ablation procedure, 396 of the 613 patients (65%) were responders (AF ≤0.5%) at 12 months: 346 of 508 (68%) in the paroxysmal AF group and 50 of 105 (47%) in the persistent AF group. Using the receiver operating characteristic curve, the specificity corresponding to 90% sensitivity was 85% for AF% at 2 months. The corresponding threshold in the AF burden during the blanking period able to identify patients at risk for late recurrences was 4.5%, corresponding to a cumulative 65.9 hours (2.75 days) spent in AF during the first 2 months. In a multivariate analysis, AF% <4.5% during the first 2 months was highly significant (P <.001), and the odds ratio of responders/nonresponders was 39.8 (95% CI, 19.1-82.9). CONCLUSION: The AF burden measured during the blanking period can predict the response to catheter ablation at 12 months. AF% ≥4.5% at 2 months assessed by continuous monitoring is a powerful predictor of subsequent AF recurrences after initial ablation, thus providing relevant clinical information to select patients for early reintervention.

Benefit of ablation of first diagnosed paroxysmal atrial fibrillation during coronary artery bypass grafting: a pilot study.

OBJECTIVES: Whether patients with recent onset of paroxysmal atrial fibrillation (PAF) might benefit of epicardial atrial fibrillation (AF) ablation concomitant to coronary artery bypass graft (CABG) is not known. The aim of this prospective, randomized, single-centre pilot study is the comparison of patients with first diagnosed AF submitted to CABG and treated with and without epicardial pulmonary vein isolation (PVI). METHODS: Patients with first diagnosed PAF and indication for CABG were enrolled in this prospective randomized pilot study. The primary endpoint was AF-free survival (AF burden <0.5%) between the two groups at 18-month follow-up. The secondary endpoints were the percentage of AF burden defined through continuous monitoring using an implantable loop recorder, thromboembolic events and procedural complications. All patients were implanted with a subcutaneous cardiac monitor to track the cardiac rhythm and measure the AF burden. RESULTS: This study enrolled 35 patients (mean age 59 ± 7 years, 74% males), followed up for 18 months after CABG. The patients were randomly allocated to two groups, CABG alone (n = 17) and CABG with concomitant PVI (n = 18). At 18-month follow-up after surgery, 16 (89%) patients in the CABG + PVI group were AF-free (i.e. AF% < 0.5%) vs 8 (47%) in the CABG only group (log-rank test, P = 0.007). At the end of follow-up, the mean AF burden in the CABG and the CABG + PVI group was 7.8 ± 5.1 and 1.6 ± 1.8%, respectively (P < 0.001). Two (18.2%) of the 11 patients with AF recurrences were completely asymptomatic. CONCLUSIONS: Patients with recent-onset AF submitted to CABG may benefit of concomitant ablation of the arrhythmia for preventing recurrences.

Use of an implantable monitor to detect arrhythmia recurrences and select patients for early repeat catheter ablation for atrial fibrillation: a pilot study.

BACKGROUND: Catheter ablation of atrial fibrillation (AF) has proved effective in curing highly symptomatic patients with paroxysmal AF. The aim of this prospective, randomized study was to identify the optimal treatment of patients with AF recurrences after the first ablation. METHODS AND RESULTS: Two hundred eighty-six patients with paroxysmal AF underwent ablation (circumferential pulmonary vein isolation with linear lesions) and were monitored with an implantable cardiac monitor (Reveal XT, Medtronic). Patients without AF recurrences during the 3-month postablation period were assigned to group 1; those with AF recurrences to group 2. Patients in group 2 were randomly assigned to group 3 or group 4. Group 3 patients were treated only with antiarrhythmic drugs for 6 weeks, with no early reablation during the 3-month postablation period. In the case of AF recurrence after the 3-month postablation period, patients underwent reablation. Group 4 patients were treated according to the onset mechanism of AF recurrences, as detected and stored by the implantable cardiac monitor: antiarrhythmic drug therapy, but no reablation if AF was not preceded by triggers; early reablation if premature atrial beats or atrial tachycardias or flutter triggered AF. All patients were followed up for 1 year to assess maintenance of sinus rhythm in each group. On 12-month follow-up examination, of the 119 (42%) patients in group 1, 112 (94%) had no AF recurrences. Among the 83 patients in group 3, only 27 (33%) had no recurrences. Of the 84 group 4 patients, 67 (80%) had no AF recurrences (P<0.0001 versus group 3). CONCLUSIONS: Patients with recurrences after the first AF ablation are likely to respond to a second early ablation when AF is triggered by supraventricular arrhythmias or premature contractions. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01164319.

Efficacy of low interatrial septum and right atrial appendage pacing for prevention of permanent atrial fibrillation in patients with sinus node disease: results from the electrophysiology-guided pacing site selection (EPASS) study.

BACKGROUND: The role of pacing sites and atrial electrophysiology on the progression of atrial fibrillation (AF) to the permanent form in patients with sinus node dysfunction (SND) has never been investigated. The aim of the study was to investigate the relationship between atrial electrophysiology and the efficacy of atrial pacing at the low interatrial septum (IAS) or at the right atrial appendage (RAA) to prevent persistent/permanent AF in patients with SND. METHODS AND RESULTS: The Electrophysiology-Guided Pacing Site Selection (EPASS) Study was a prospective, controlled, randomized study. Atrial refractoriness, basal and incremental conduction times from the RAA to the coronary sinus ostium were measured before implantation, and the difference (ΔCTos) was calculated. Patients with ΔCTos ≥ 50 ms (study group) and those with ΔCTos <50 ms (control group) were randomly assigned to RAA or IAS with algorithms for continuous atrial stimulation "on." The primary end point was time to development of permanent or persistent AF within a 2-year follow-up in the study group, IAS versus RAA. Data were analyzed by intention to treat. One hundred two patients (77 ± 7 years, 44 mol/L) were enrolled, 69 (68%) in the study group and 33 (32%) in the control group. Of these, 97 ended the study, respectively, randomly assigned: 29 IAS versus 36 RAA and 18 IAS versus 14 RAA. After a mean follow-up of 15 ± 7 (median, 17) months, 11 (16.6%) patients in the study group met the primary end point: 2 IAS versus 9 RAA (log rank=3.93, P=0.047). CONCLUSIONS: In patients with SND and intra-atrial conduction delay, low IAS pacing was superior to RAA pacing in preventing progression to persistent or permanent AF. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00239226.

Ablation of paroxysmal atrial fibrillation during coronary artery bypass grafting: 12 months' follow-up through implantable loop recorder.

OBJECTIVES: The study aimed to identify responders to atrial fibrillation (AF) ablation, through continuous subcutaneous monitoring in patients with paroxysmal atrial fibrillation (PAF), who underwent epicardial pulmonary vein isolation (PVI) concomitantly with coronary artery bypass grafting (CABG). METHODS: Seventy-two patients aged 61.6±4.7 years with PAF underwent epicardial PVI with bipolar radiofrequency during CABG. Conduction block was confirmed by pacing. At the end of the procedure, the implantable loop recorder (ILR) for continuous monitoring was implanted in all patients. Follow-up data were collected through the ILR telemetry. Patients with an AF burden (AF%)<0.5% were considered AF free (responders). Patients with AF%>0.5% were classified as non-responders. The AF episodes stored by the implanted device were visually inspected by the investigators to confirm the arrhythmia. The data were collected each month during 1-year follow-up. RESULTS: No procedure-related complications occurred either for ablation or for the monitoring device. At the first post-ablation follow-up (1 month) during the blanking period, 37 patients (51%) were AF free, that is, with AF%<0.5%. At the end of the blanking period (3rd follow-up), 44 (61%) patients were AF free. At 12 months' follow-up, 52 (72%) patients were AF free. Among 20 (28%) patients with AF recurrence, six (30%) patients were completely asymptomatic. There were no ischaemic strokes during the 1-year follow-up. CONCLUSION: Concomitant AF ablation during CABG is effective in the treatment of AF, as assessed through 1 year of continuous monitoring. Use of subcutaneous monitors is safe and accurate for AF detection, clinically relevant in identifying responders and non-responders and managing the medical therapies accordingly.