Electrocardiographic P wave changes after thoracoscopic pulmonary vein isolation for atrial fibrillation

Background

Changes in P wave duration (PWD) and P wave area (PWA) have been described following catheter ablation for atrial fibrillation (AF). We hypothesize that video-assisted thoracoscopic pulmonary vein isolation (VATS-PVI) for AF results in decrease of PWD, PWA and P wave dispersion, which may resemble reverse electrical remodeling of the atrium after restoration of sinus rhythm.

Methods

VATS-PVI consisted of PVI and ganglionic plexus ablation in 29 patients (mean age, 59?±?7 years; 23 males; 17 paroxysmal AF) and additional left atrial lesions in patients with persistent AF. PWD and PWA were measured in ECG lead II, aVF and V2 of ECGs during sinus rhythm before, directly after, and 6 months postprocedure. P wave dispersion was derived from the 12 lead ECG.

Results

Prior to VATS-PVI, PWD did not correlate with left atrial size and no difference in left atrial size was found between patients with paroxysmal or persistent AF (p?=?0.27). Following VATS-PVI, PWD initially prolonged in all patients from 115?±?4.6 ms to 131?±?3.6 ms (p?<?0.01) but shortened to 99?±?3.2 ms after 6 months (p?<?0.01). PWA was 5.60?±?0.32 mV*ms at baseline, 6.44?±?0.32 mV*ms post-VATS-PVI (P?=?NS), and 5.40?±?0.28 mV*ms after 6 months (p?=?NS vs. baseline, p?<?0.05 vs. post-VATS-PVI). P wave dispersion decreased in the persistent AF group from baseline 67?±?3.3 to 64?±?2.5 ms post-VATS-PVI (p?=?0.30) and to 61?±?3.4 ms after 6 months (p?<?0.05).

Conclusions

PWD increases significantly directly after successful VATS-PVI in both groups. There was significant decrease in PWD after 6 months. Similarly, P wave dispersion decreased in the persistent group. These changes suggest an immediate procedure related effect, but the later changes may represent reverse electrical atrial remodeling following cessation of AF.     

Why atrial fibrillation recurs in patients who obtained current ablation endpoints with longstanding persistent atrial fibrillation

Purpose

Although several techniques for modification of atrial fibrillation (AF) substrate, such as linear ablation and complex fractionated atrial electrograms (CFAEs) ablation, have been proposed for longstanding persistent AF (LS-AF) and improved the outcome, there was still a certain recurrence rate, even if current ablation endpoints of these techniques were completely achieved. The purpose of this study was to describe the determinants of recurrent AF in patients who obtained current ablation endpoints with LS-AF.

Methods and results

In all, 208 consecutive patients who obtained current ablation endpoints with LS-AF were studied. The current ablation endpoints were defined as complete pulmonary vein isolation, bidirectional block of lines, and disappearance of CFAEs. After a follow-up of 19.9?±?4.1 months, the patients were classified as AF recurrence group and non-AF recurrence group (including patients with sinus rhythm and atrial tachycardia), and 34 (16 %) patients were in the AF recurrence group. The patients in AF recurrence group had higher rates of right atrium (RA) enlargement (67.7 vs. 45.4 %, p?=?0.018) and ≥2 procedure times (58.8 vs. 27.0 %, p?<?0.001), longer AF duration (82.4?±?44.8 vs. 50.8?±?42.8 months, p?<?0.001), and larger left atrium (LA) diameter (49.4?±?6.2 vs. 46.5?±?5.3 mm, p?=?0.007). In the multivariate analysis, RA enlargement, ≥2 procedure times, and AF duration were independent predictors of AF recurrence.

Conclusion

RA enlargement, ≥2 procedure times, and AF duration played important roles in AF recurrence in patients who obtained current ablation endpoints. For these patients with AF recurrence who had already underwent ≥2 procedure times, enlarged RA may contribute to other AF foci and/or substrate, and the ablation strategy may be transformed from LA to RA in the next ablation procedures.     

Fibrosis and electrophysiological characteristics of the atrial appendage in patients with atrial fibrillation and structural heart disease

Purpose

This study was conducted to investigate the degree of fibrosis in atrial appendages of patients with and without atrial fibrillation (AF) undergoing cardiac surgery. In addition, we hypothesized that areas of atrial fibrosis can be identified by electrogram fractionation and low voltage for potential ablation therapy.

Methods

Interstitial fibrosis from right (RAA) and/or left atrial appendages (LAA) was studied in patients with sinus rhythm (SR, n?=?8), paroxysmal (n?=?21), and persistent AF (n?=?20) undergoing coronary artery bypass and/or aortic or mitral valve surgery. Atrial fibrosis quantification was performed with Masson trichrome staining. Intraoperative bipolar epicardial electrophysiological measurements were performed to correlate fibrosis to electrogram fractionation, voltage, and AF cycle length.

Results

The average degree of fibrosis was 11.2?±?7.2 % in the LAA and 22.8?±?7.6 % in the RAA (p?<?0.001). Fibrosis was not significantly higher in paroxysmal AF patients compared to SR subjects (18.2?±?8.7 versus 20.7?±?5.3 %). Persistent AF patients had a higher degree of LAA and RAA fibrosis compared to paroxysmal AF patients (LAA 14.6?±?8.7 versus 8.6?±?4.7 %, p?=?0.02, and RAA 28.2?±?7.9 versus 18.2?±?8.7 %, respectively, p?=?0.04). The left atrial end diastolic volume index was higher in persistent AF patients compared to SR controls (38.3?±?16.4 and 28?±?11 ml/m², respectively, p?=?0.04). No correlation between atrial fibrosis and electrogram fractionation or voltage was found.

Conclusion

Patients with structural heart disease undergoing cardiac surgery have more fibrosis in the RAA than in the LAA. Furthermore, RAA fibrosis is increased in persistent AF but not paroxysmal AF patients compared to control subjects. Electrogram fractionation and low voltage did not provide accurate identification of the fibrotic substrate.     

N-terminal pro-B-type natriuretic peptide level at long-term follow-up after atrial fibrillation ablation: a marker of reverse atrial remodelling and successful ablation

Aims

We investigated the relationship between arrhythmia burden, left atrial volume (LAV) and N-terminal pro-B-type natriuretic peptide (NT-pro-BNP) at baseline and after long-term follow-up of atrial fibrillation (AF) ablation.

Methods

We studied 38 patients (23 paroxysmal, 6 women, mean age 56?±?11) scheduled for AF ablation. LAV was calculated on the basis of computed tomography images at baseline and long-term follow-up, and arrhythmia burden was graded from self-reported frequency and duration of AF episodes.

Results

After a mean period of 22?±?5?months, 28/38 patients (11/15 persistent) were free from AF recurrence. At baseline there were no differences in mean LAV (125 vs. 130?cm³, p?=?0.7) or median NT-pro-BNP (33.5 vs. 29.5?pmol/L, p?=?0.9) between patients whose ablation had been successful or otherwise. At long-term follow-up, there was a marked decrease in LAV (105 vs. 134?cm³, p?p?r?=?0.71, p?r?=?0.57, p?r?=?0.47, p?r?=?0.52, p?25% of baseline value had a specificity of 0.89 and a sensitivity of 0.6 (receiver operator characteristics, accuracy 0.82) for ablation success.

Conclusions

NT-pro-BNP correlates with LAV and arrhythmia burden in AF patients and both NT-pro-BNP and LAV decrease significantly after successful ablation. A decrease in NT-pro-BNP of >25% from the baseline value could be useful as a marker of ablation success.     

Left atrial wall thickness and outcomes of catheter ablation for atrial fibrillation in patients with hypertrophic cardiomyopathy

Purpose

Catheter ablation of atrial fibrillation (AF) in patients with hypertrophic cardiomyopathy (HCM) is still challenging, and it is unclear whether the difficulty is caused by the hypertrophy of left atrial (LA) myocardial wall thickness. The objective of the study was to compare the LA wall thickness and AF ablation outcomes between patients with HCM and those without structural heart disease.

Methods

The present study enrolled 17 consecutive HCM patients (63?±?12 years) with drug-refractory AF and 34 control patients without any detectable heart disease, whose age, gender, type of AF, and LA dimension were matched to the HCM patients. The myocardial wall thickness of 11 distinct LA locations, measured using 64-slice computed tomography images, and AF ablation outcomes were compared between the two groups.

Results

The LA wall thickness did not differ at 9 of the 11 locations and was significantly thinner in the HCM patients than in the control patients at the mid-posterior wall (1.44?±?0.17 vs. 1.58?±?0.22, p?=?0.04) and infero-posterior wall (1.62?±?0.16 vs. 1.74?±?0.18, p?=?0.03). Although antiarrhythmic drugs were used more frequently in the HCM patients (p?=?0.008), the rate of maintaining sinus rhythm during the follow-up did not differ between the HCM and control patients (53 vs. 56 % after the initial ablation [log-rank p?=?0.78] and 82 and 88 % after the repeat procedure [log-rank p?=?0.35]).

Conclusions

The LA wall in the HCM patients with AF was not thicker than that of the matched patients without structural heart disease. Catheter ablation of AF showed favorable outcomes in both patient groups.     

Hemodynamic impact of percutaneous left atrial appendage closure in patients with paroxysmal atrial fibrillation

Purpose

Percutaneous left atrial appendage (LAA) closure has become a valid alternative to anticoagulation therapy for the prevention of thromboembolic events in patients with atrial fibrillation (AF). However, scarce data exist on the impact of LAA closure on left atrial and ventricular function. We sought to assess the acute hemodynamic changes associated with percutaneous LAA closure in patients with paroxysmal AF.

Methods

The study population consisted of 31 patients (mean age 73?±?10 years; 49% women) with paroxysmal AF who underwent successful percutaneous LAA closure. All patients were in sinus rhythm and underwent 2D transthoracic echocardiography at baseline and the day after the procedure. A subset of 14 patients underwent preprocedural cardiac computed tomography (CT) with 3D LA and LAA reconstruction.

Results

Left ventricular systolic function parameters and LA volumetric indexes remained unchanged after the procedure. No significant changes in left ventricular stroke volume (72.4?±?16.0 vs. 73.3?±?15.7 mL, p?=?0.55) or LA stroke volume (total 15.6?±?4.2 vs. 14.6?±?4.2 mL, p?=?0.21; passive 9.0?±?2.8 vs. 8.3?±?2.6 mL, p?=?0.31; active 10.3?±?5.6 vs. 10.0?±?6.4 mL, p?=?0.72) occurred following LAA closure. Mean ratio of LAA to LA volume by 3D CT was 10.2?±?2.3%. No correlation was found between LAA/LA ratio and changes in LA stroke volume (r?=?0.35, p?=?0.22) or left ventricular stroke volume (r?=?0.28, p?=?0.33).

Conclusions

The LAA accounts for about 10% of the total LA volume, but percutaneous LAA closure did not translate into any significant changes in LA and left ventricular function.

     

Predictive value of left atrial volume measured by non-invasive cardiac imaging in the treatment of paroxysmal atrial fibrillation

Purpose

We investigate the role of left atrial volume (LAV) as a predictor of outcome following pulmonary vein isolation (PVI) in patients with exclusive paroxysmal atrial fibrillation (AF).

Methods

PVI was performed in 213 patients (80 females, aged 60?±?10?years) with paroxysmal AF using either the pulmonary vein ablation catheter (PVAC, n?=?78) or conventional single-tip ablation (n?=?135). LAV was assessed by multi-detector computed tomography (n?=?39) or cardiac magnetic resonance imaging (n?=?174) prior to ablation. LA diameter (LAD) and LA area were determined by echocardiography. Patients were followed up for 12?months clinically and with 72-h Holter ECG.

Results

The mean LAV was 85?±?28?ml (range, 22?C189?ml). Mean LAD and mean LA area were 43?±?6?mm and 23?±?6?cm2. After a follow-up period of 18?±?5?months, 202 patients were analyzed. AF recurrence was documented in 50 (23%) patients. Univariate analysis showed age (59?±?11 vs. 65?±?6?years, p?=?0.049), LA area (23?±?5 vs. 27?±?6?cm2, p?=?0.03), and LAV (80?±?27 vs. 96?±?28?ml, p?=?0.04) to be significantly associated with the outcome. Multivariate analysis revealed that none of these parameters were statistically significant (hazards ratio LAV, 0.52?C1.12, p?=?0.058; LA area, 0.63?C1.14, p?=?0.069; and age, 0.90?C1.09, p?=?0.41). In the case of AF recurrence, patients with LAV >95?ml showed a significantly higher probability for the occurrence of persistent AF (24% vs. 8%, p?=?0.02).

Conclusions

The assessment of LA size should not be incorporated as a main factor with regard to predicted ablation success in patients with paroxysmal AF being considered for PVI, as PVI may be successful even with considerable LA enlargement. Ablation should be performed promptly in patients with LAV ??95?ml to prevent further LA dilatation, as patients with LAV >95?ml have an increased probability to develop persistent AF in the case of ablation failure.     

Mitral regurgitation recovery and atrial reverse remodeling following pulmonary vein isolation procedure in patients with atrial fibrillation: a clinical observation proof-of-concept cardiac MRI study

Background

Reverse remodeling of the left atrium (LA) following successful pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF) has been well documented. However, mitral regurgitation (MR) recovery after successful PVI has never been demonstrated systematically. The objective of our study was to retrospectively analyze the effectiveness of PVI in patients with AF on recovery of MR using cardiac magnetic resonance (CMR) imaging.

Methods

Prior to PVI, patients underwent a clinically indicated CMR imaging. Post-PVI (6?±?2 months), patients underwent a follow-up MRI and were classified into two groups—responders (R) and non-responders (NR) to PVI—as assessed by cessation of AF at the end of the prespecified 6-month (14-day “P” sensitive event monitor defined) follow-up period. Furthermore, CMR was used to evaluate the severity of MR (0 to 4+) and to relate changes in MR to LA volumes as well as mitral apparatus geometry. Patients who had mild and higher MR (2+) on baseline CMR and had a post-PVI CMR were selected for final analysis.

Results

Out of the consecutive 122 patients with AF who underwent PVI, 74 patients that had mitral regurgitation on initial CMR were included in the study. Of these74 patients with AF with MR, 52 (70 %) were classified as R and 22 (30 %) were classified as NR. Baseline demographics were similar between the groups. In the subgroup with mild to severe MR, pre vs. post in the R group MR severity significantly improved (mean?=?2.3, median?=?2.0 vs. mean?=?1.0, median?=?1.0, p?<?0.0001) and was matched by favorable reverse remodeling of the mitral apparatus geometry (annulus?=?35?±?4 vs. 33?±?3 mm, p?<?0.002; tenting area?=?175?±?56 vs.137?±?37 mm², p?<?0.003; tenting height?=?8?±?2 vs.7?±?2 mm, p?<?0.02; and tenting angle?=?129?±?10° vs. 131?±?11°, p?=?0.1). However, in the NR subgroup, MR failed to improve (mean?=?2.2, median?=?2.0 vs. mean?=?1.5, median?=?1.0, p?=?NS) and paralleled general failure of mitral geometry reverse remodeling (annulus?=?35?±?4 vs. 35?±?4 mm, p?=?0.2; tenting area?=?153?±?39 vs. 152?±?34 mm², p?=?NS; tenting height?=?7?±?1 vs. 7.0?±?2, p?=?0.1; and tenting angle?=?131?±?11° vs. 133?±?10°, p?=?NS). In those with lesser degrees of MR, favorable remodeling was predicated on responder status to PVI. Similarly, other cardiac dimensions pre- to post-PVI favorably improved in the R group, but not in the NR group.

Conclusion

In those with durable maintenance of normal sinus rhythm (NSR), cardiac reverse remodeling demonstrated by 3D CMR occurs and is matched by marked improvements in MR and mitral apparatus, likely contributing to continued maintenance of NSR.     

Immediate and medium-term outcomes of cryoballoon-based pulmonary vein isolation in patients with paroxysmal and persistent atrial fibrillation: single-centre experience

Background

Pulmonary vein (PV) isolation with cryoballoon is a recently developed technique for the treatment of atrial fibrillation (AF) with acceptable mid-term results in terms of the success and safety. The purpose of our study is to identify the periprocedural complications, mid-term success rates and predictors of recurrence after AF ablation with cryoballoon.

Method

A total of 236 patients (54 % male, mean age 54.6?±?10.45 years and 79.6 % paroxysmal AF) with symptomatic AF underwent PV isolation with cryoballoon due to failure with ≥1 antiarrhythmic drug previously. Procedural success, complications and follow-up data were defined according to recent guidelines.

Results

Acute procedural success rate was 99.5 %. Mean procedural and fluoroscopy times were 72.5?±?5.3 and 14?±?3.5 min. At a median of 18 (6–27)?months follow-up, 80.8 % of paroxysmal AF patients and 50.0 % of persistent AF patients were free from AF recurrence. In multivariate regression analysis, body mass index (BMI) (hazard ratio (HR), 1.35; 95 % confidence interval (CI), 1.18–2.93, p?=?0.001), smoking (HR, 2.12; 95 % CI, 1.36–6.67, p?<?0.001), non-paroxysmal AF (HR, 1.26; 95 % CI, 1.12–2.56, p?=?0.024), duration of AF (HR, 1.42; 95 % CI, 1.18–2.61, p?=?0.015), left atrium (LA) diameter (HR, 2.42; 95 % CI, 1.64–5.88, p?<?0.001) and early AF recurrence (HR, 4.88; 95 % CI, 2.86–35.6, p?<?0.001) were independent predictors of AF recurrence following cryoablation.

Conclusion

Our results showed that AF ablation with cryoballoon is effective and safe. Non-paroxysmal AF, duration of AF, smoking, BMI, LA diameter and early recurrence were found to be the most powerful predictors and could be helpful to select patients for appropriate therapeutic strategy.     

Robotic ablation of atrial fibrillation with a new remote catheter system

Purpose

Pulmonary vein isolation (PVI) is widely established as a curative treatment option for atrial fibrillation (AF). A wide range of techniques to improve catheter manipulation and steerability has been developed over the past years. A new remote catheter system (RCS) has recently become available (Amigo Remote Catheter System, Catheter Robotics, Budd Lake, NJ, USA). Here, we present a dual-center study on the RCS for left atrial mapping and PVI in patients with paroxysmal AF compared to a control group undergoing conventional PVI.

Methods

One hundred nineteen patients who underwent PVI for paroxysmal AF were studied. Forty patients underwent PVI with the use of the RCS. Seventy-nine patients, who underwent conventional PVI, served as control group. Procedural data were compared between the two groups.

Results

PVI was achieved in all patients. In the RCS group compared to standard ablation group, there were no significant differences in procedure duration (159.1?±?45.4 vs. 146?±?30.1 min, p?=?0.19), total energy delivery (78,146.3?±?26,992.4 vs. 87,963.9?±?79,202.1 Ws, p?=?0.57), and total fluoroscopy time (21.2?±?8.6 vs. 23.9?±?5.4 min, p?=?0.15). Operator fluoroscopy exposure was significantly reduced in the RCS group (13.4?±?6.1 vs. 23.9?±?5.4 min, p?Conclusions These initial results suggest that left atrial mapping and PVI are feasible with the use of the Amigo RCS. Acute procedural efficacy is comparable to the standard approach. The use of the Amigo RCS leads to a significant reduction of operator fluoroscopy exposure.     

Outcome of pulmonary vein isolation ablation for paroxysmal atrial fibrillation: predictive role of left atrial mechanical dyssynchrony by speckle tracking echocardiography

Introduction

Although few clinical variables have been associated with recurrence of atrial fibrillation (AF) after pulmonary vein isolation (PVI) the role of left atrial (LA) mechanical function in the outcome of catheter ablation of AF is not adequately defined. The aim of our study was to determine whether LA mechanical dyssynchrony as evaluated by speckle tracking echocardiography can predict outcome of PVI ablation procedure in patients with paroxysmal AF.

Methods

Twenty-five patients (age 58?±?11 years, [mean ± standard deviation], 17 males) with paroxysmal AF who met specific enrollment criteria pertaining to clinical presentation and follow-up, assessment of LA mechanical dyssynchrony, and strategy of catheter ablation procedure were enrolled. For LA mechanical dyssynchrony assessment, the time to peak longitudinal strain (TPk) in opposing walls in the midportion of the LA walls at peak atrial contraction in standard two- and four-chamber echocardiographic views by vector velocity imaging (VVI) was measured. Outcome of PVI procedure, whether no recurrence (NR) or AF recurrence (AFR) after 3 months of post-procedural blanking period, was evaluated based on AF-related symptoms and documentation of AF by electrocardiogram, continuous 24-h Holter, and intermittent event monitor recordings.

Results

During a follow-up period of 20.3?±?8.6 months, 18 out of 25 (72 %) patients had no recurrence (NR group), and 7 out of 25 (28 %) patients had recurrence of AF (AFR group). Significant gender difference was observed in terms of outcome such that all AFR patients were men and no woman had recurrence of AF. Between the NR and AFR groups, neither the left atrial diameter, 4.0?±?0.3 and 4.2?±?0.2 cm, respectively (p?=?0.2), nor the left atrial volume indexes, 45?±?15 and 48?±?20 ml/m², respectively (p?=?0.56), were statistically significantly different. For LA mechanical function, compared to the patients in NR group who had maximum opposing wall TPk delay of 39.9?±?12.0 ms, those in the AFR group demonstrated significantly more LA mechanical dyssynchrony with maximum opposing wall TPk delay of 64.4?±?17.0 ms prior to ablation (p?=?0.007). Using receiver operative characteristic analyses of the data that had an area under the curve of 0.865, we identified a maximum opposing wall delay cutoff value of 51 ms which predicted AF recurrence with sensitivity and specificity values of 89 and 72 %, respectively (p?=?0.005).

Conclusions

Speckle tracking strain analysis echocardiography can evaluate the LA mechanical dyssynchrony quantitatively. The severity of LA mechanical dyssynchrony by VVI can predict the outcome of PVI catheter ablation for paroxysmal AF.     

Left atrial pressure as predictor for recurrence of atrial fibrillation after pulmonary vein isolation

Purpose

Identification of reliable risk factors for recurrence of atrial fibrillation (AF) after pulmonary vein isolation (PVI) has important implications. Left atrial (LA) pressure is a largely observator-independent parameter that can easily be determined after transseptal puncture. The purpose of this study was to investigate the predictive value of LA pressure for AF recurrence after PVI.

Methods

Two hundred five consecutive patients with paroxysmal or persistent AF scheduled for first PVI were included. Baseline clinical data were collected. During PVI, LA pressure was determined invasively after transseptal puncture. PVI was performed with radiofrequency or cryoenergy, and patients were followed for 25?±?7 months.

Results

One hundred five (51 %) patients had AF recurrence. Patients with persistent AF prior to ablation had significantly more recurrences than patients with paroxysmal AF (70.1 vs. 42.0 %, p?<?0.001). Mean LA pressure was significantly higher in patients with recurrence of AF (13.4?±?7.1 vs. 11.0?±?5.2 mmHg, p?=?0.007), as was mean LA volume index (40.1?±?18.5 vs. 33.0?±?11.2 mL/m², p?<?0.001). In the multivariate analysis, mean LA pressure was predictive in patients with normal or mildly enlarged LA, while AF type was not predictive. For each 1-mmHg increase in LA pressure, the risk of AF recurrence increased by 11 % in this subgroup. In patients with moderately or severely enlarged LA, AF type was predictive whereas LA pressure was not.

Conclusion

LA pressure, AF type, and LA volume index are independent predictors for recurrence of AF after PVI. LA pressure may be helpful especially in patients with small atria, where AF type is not predictive.     

Anatomical analysis of the left atrial appendage using segmented, three-dimensional cardiac CT: a comparison of patients with paroxysmal and persistent forms of atrial fibrillation

Purpose

Successful implantation of percutaneous left atrial appendage (LAA) occlusion devices requires an accurate understanding of LAA anatomy and orifice dimensions. We sought to quantitatively compare LAA anatomy in patients with paroxysmal and persistent patterns of atrial fibrillation (AF).

Methods

Fifty-nine consecutive patients undergoing catheter ablation for AF underwent pre-procedural multislice cardiac computed tomography (CT) scans. Maximal LAA orifice dimensions and left atrial and LAA volumes were measured from three-dimensional segmented CT reconstructions. Thirty-six patients with paroxysmal and 23 with persistent AF were analysed.

Results

The mean maximal LAA orifice dimension was larger in persistent (27.2?±?4?mm) than paroxysmal AF (22.9?±?3?mm, p?r?=?0.76), maximal LAA orifice dimension (r?=?0.63) and left atrial volume.

Conclusions

Increased LAA orifice dimension is associated with left atrial enlargement in AF. This finding may impact LAA occlusion device sizing.     

Predictive value of total atrial conduction time measured with tissue Doppler imaging for postoperative atrial fibrillation after coronary artery bypass surgery

Objective

Postoperative atrial fibrillation (POAF) complicating coronary artery bypass grafting surgery (CABG) increases morbidity and stroke risk. Total atrial conduction time (PA-TDI duration) has been identified as an independent predictor of new-onset atrial fibrillation (AF). We aimed to assess whether PA-TDI duration is a predictor of AF after CABG.

Methods

In 128 patients who had undergone CABG, preoperative clinical and echocardiographic data were compared between patients with and without POAF. The PA-TDI duration was assessed by measuring the time interval between the beginning of the P wave on the surface ECG and point of the peak A wave on TDI from left atrium (LA) lateral wall just over the mitral annulus.

Results

Patients with POAF (38/128, 29.6 %) were older (68.1?±?11.1 vs. 59.3?±?10.2 years; p?<?0.001), had higher LA maximum volume, had prolonged PA-TDI duration, and had lower ejection fraction compared with patients without POAF. PA-TDI duration was found to be significantly increased in POAF group (134.3?±?19.7 vs. 112.5?±?17.7 ms; p?=?0.01). On multivariate analysis, age (95 % CI?=?1.03–1.09; p?=?0.003), LA maximum volume (95 % CI?=?1.01–1.06; p?=?0.03), and prolonged PA-TDI duration (95 % CI, 1.02–1.05; p?=?0.001) were found to be the independent risk factors of POAF.

Conclusions

In this study, LA maximum volume and PA-TDI duration were found to be the independent predictors of the development of POAF after CABG. Echocardiographic predictors of left atrial electromechanical dysfunction may be useful in risk stratifying of patients in terms of POAF development after CABG.     

Long-term outcomes of adjunctive complex fractionated electrogram ablation to pulmonary vein isolation as treatment for non-paroxysmal atrial fibrillation

Purpose

The adjunctive ablation of areas of complex fractionated electrogram (CFE) to pulmonary vein isolation (PVI) is an emerging strategy for patients with non-paroxysmal atrial fibrillation (AF). We studied the long-term outcomes of this approach.

Methods

Sixty-six patients (mean age 58?±?9, 86.4 % male) with non-paroxysmal AF underwent ablation procedures consisting of PVI plus extensive CFE ablation. Post-ablation atrial tachycardia (AT) was also targeted if presented. All patients were followed up regularly on an ambulatory basis by means of ECG and Holter recordings.

Results

After a mean follow-up period of 40?±?14 months and 1.7?±?0.7 procedures, 38 patients (57.6 %) were free of arrhythmias, 15 (22.7 %) displayed clinical improvement and 13 (19.7 %) suffered recurrences of persistent AF/AT. Females displayed poorer long-term outcomes than males (arrhythmia-free 22.2 vs. 63.2 %, p?<?0.05). Multivariate analysis demonstrated that long duration of uninterrupted AF prior to the procedure was an additional predictor of long-term failure (odds ratio 1.49, p?<?0.01). ROC analysis (area under curve 0.80; p?<?0.001) estimated 3.5 years as the optimal cut-off point for predicting long-term failure (sensitivity 85 %, specificity 74 %). The cumulative data showed a significantly higher percentage of arrhythmia-free patients when the duration of AF had been ≤2 years (69.7 %) and ≤4 years (68.9 %) than when it was >4 years (33.3 %; p?<?0.01).

Conclusions

PVI?+?CFE ablation in non-paroxysmal AF appears to provide a reasonable proportion of arrhythmia-free patients during long-term follow-up. Poorer long-term results can be expected among female patients and those with an uninterrupted AF duration of >4 years.     

Acute procedural and cryoballoon characteristics from cryoablation of atrial fibrillation using the first- and second-generation cryoballoon: a retrospective comparative study with follow-up outcomes

Purpose

There is limited data available on the safety and efficacy of the second-generation cryoballoon (CB-2) for cryoablation of atrial fibrillation (Cryo-AF). We evaluated the procedural, biophysical, and clinical outcomes of Cryo-AF in a large patient cohort using CB-2 as compared with the first-generation cryoballoon (CB-1).

Methods

Three-hundred and forty consecutive patients undergoing Cryo-AF with CB-1 (n?=?140) and CB-2 (n?=?200) were retrospectively evaluated.

Results

Paroxysmal AF was more prevalent in CB-1 (86 %) versus CB-2 (72 %) (p?=?0.001). During Cryo-AF, the mean balloon temperature was lower with CB-2 at 30 s (8 versus ?4 °C; p?p?p?=?0.542). With CB-2, time-to-nadir temperature was shorter (232 versus 209 s; p?p?p?=?0.036) despite reduced cryoablation time (61 versus 47 min; p?p?p?p?p?=?0.037).

Conclusions

With CB-2, acute and long-term PV isolation rates were higher despite shorter ablations, faster balloon cooling, and longer thaw times, with similar AE rates and freedom from AF.     

Effect of renal sympathetic denervation on the inducibility of atrial fibrillation during rapid atrial pacing

Background

Atrial fibrillation (AF) is associated with activity of renin–angiotensin–aldosterone system (RAAS). Reduction in renal noradrenaline spillover could be achieved after renal sympathetic denervation (RSD). The relationship between RSD and AF is unknown.

Objective

The objective of the study was to investigate the inducibility of AF during atrial rapid pacing after RSD.

Methods

Thirteen dogs were used for the study as follows: control group (seven dogs) and RSD group (six dogs). In the control group, dogs were subjected to atrial pacing at 800 beats/min for 7 h, and atrial effective refractory period (AERP) was measured every hour in the status of non-pacing. Subsequently, pacing was stopped and the burst pacing (500 bpm) was repeated to induce AF three times. In the RSD group, after each renal artery ablation, the procedure of pacing and electrophysiological measurement was exactly same as in the control group. Blood was collected before and after pacing to measure the levels of renin, angiotensin II and aldosterone.

Results

There was a persistent decrease in AERP in both groups. However, 7 h after cessation of pacing, the induced number of times and duration of AF were higher in the control group than that in the RSD group (1.0?±?1.26 vs 3.14?±?2.54, P?=?0.03; 16.5?±?25.1 vs 86.6?±?116.4, P?=?0.02). The plasma aldosterone concentration increased significantly 7 h after rapid pacing in control group (renin, 119.8?±?31.1 vs 185.3?±?103.5 pg/ml, P?<?0.01; aldosterone, 288.2?±?43.1 vs 369.6?±?109.8 pg/ml, P?=?0.01). The levels of renin and aldosterone showed a decreasing trend in RSD group, but this did not attain statistical significance.

Conclusions

Episodes of AF could be decreased by renal sympathetic denervation during short-time rapid atrial pacing. This effect might have relationship with decreased activity of RAAS.     

A combination of P wave electrocardiography and plasma brain natriuretic peptide level for predicting the progression to persistent atrial fibrillation: comparisons of sympathetic activity and left atrial size

Purpose

Development of atrial fibrillation (AF) is complexly associated with electrical and structural remodeling and other factors every stage of AF development. We hypothesized that P wave electrocardiography with an elevated brain natriuretic peptide (BNP) level would be associated with the progression to persistence from paroxysmal AF.

Methods

P wave electrocardiography such as a maximum P wave duration (MPWD) and dispersion by 12-leads ECG, heart/mediastinum (H/M) ratio by delayed iodine-123 metaiodobenzylguanidine scintigraphic imaging, left ventricular ejection fraction (LVEF), and left atrial dimension (LAD) by echocardiography, and plasma BNP level were measured to evaluate the electrical and structural properties and sympathetic activity in 71 patients (mean ± standard deviation, age: 67?±?13 years, 63.4 % males) with idiopathic paroxysmal AF.

Results

Over a 12.9-year follow-up period, AF developed into persistent AF in 30 patients. A wider MPWD (>129 ms) (p?=?0.001), wider P wave dispersion (>60 ms) (p?=?0.001), LAD enlargement (>40 mm) (p?=?0.001), higher BNP level (>72 pg/mL) (p?=?0.002), lower H/M ratio (≤2.7) (p?=?0.025), and lower LVEF (≤60 %) (p?=?0.035) were associated with the progression to persistent AF, and the wide MPWD was an independently powerful predictor of the progression to persistent AF with a hazard ratio (HR) of 5.49 [95 % confidence interval (CI) 2.38–12.7, p?<?0.0001] after adjusting for potential confounding variables, such as age and sex. The combination of wide MPWD and elevated BNP level was additive and incremental prognostic power with 13.3 [2.16–13, p?<?0.0001].

Conclusion

The wide MPWD with elevated BNP level was associated with the progression to persistent AF.     

Predictors of left atrium appendage clot detection despite on-target warfarin prevention for atrial fibrillation

Background and purpose

The antithrombotic management of atrial fibrillation (AF) is currently based on clinical scores (CHADS₂ or CHA₂DS₂VASc). The prevalence of left atrium (LA) thrombi in effectively anticoagulated AF patients has been reported as being up to 7.7 %. We tried to correlate LA/LA appendage (LAA) thrombus detection with possible clinical predictors in warfarin-treated patients.

Methods

We performed trans-esophageal echocardiography on 430 patients (mean age, 60.3?±?9.8 years) receiving oral anticoagulant (OAC) therapy and undergoing pulmonary vein isolation. In 10/430 (2.3 %), an LA thrombus was found despite therapeutic OAC (mean INR 2.6?±?0.6; range, 2.0–3.8) over the previous 4 weeks.

Results

Two study groups were identified:

1. T-positive group?=?with LAA thrombus (10 patients)
2. T-negative group?=?without LAA thrombus (420 patients)

The T-positive patients had a higher CHADS₂ score (1.5?±?0.7 versus 0.7?±?0.8; p?=?0.004), a lower LVEF (54.7?±?9.5 % versus 60.2?±?7.4; p?=?0.02), and a larger LA size (LA diameter, 56?±?12.2 mm versus 46?±?6.5 mm; p? <?0.001and normalized LA volume: 140.2?±?66 ml/m² vs. 67?±?39 ml/m²; p?<?0.05). On multivariate analysis, a larger LA diameter and normalized LA volume (OR, 1.14; 95 % C.I., 1.04–1.26; p?=?0.006 and OR, 1.02; 95 % C.I., 1.01–1.03; p?=?0.001, respectively) and a higher CHA₂DS₂VASc score (OR, 2.4; 95 % C.I., 1.4–4.2; p?=?0.001) predicted left atrium appendage (LAA) thrombus. In another 42/430 (9.8 %) patients, an LA spontaneous echo-contrast (SEC) was detected. Thus, cumulatively, 52/430 (12.1 %) patients had either LAA thrombi (10 patients) or SEC (42 patients). LA diameter continued to predict the presence of either thrombi or SEC (OR, 1.14; 95 % C.I., 1.07–1.2; p?<?0.05).

Conclusions

We found a 2.3 % prevalence of LA thrombus (12.1 % when SEC was also considered). The thrombus was present despite on-target warfarin prevention. In addition to a higher CHA₂DS₂VASc score, a larger LA size was a strong predictor of clot detection.     

The effects of radio-frequency ablation on blood pressure control in patients with atrial fibrillation and hypertension

Purpose

The effects of radio-frequency ablation (RFA) on blood pressure (BP) regulation in patients with atrial fibrillation (AF) and hypertension remain unknown. We hypothesized that patients with successful ablation had a lower BP and/or lesser utilization of antihypertensive drug therapy during follow-up when compared to patients with failed ablation.

Methods and results

This was a retrospective evaluation of patients with AF and hypertension treated with ablation at the University of Utah between July 2006 and June 2010. BP and use of antihypertensive medications were assessed at baseline and 1?year follow-up. A total of 167 patients were identified. Eight patients were excluded due to the need for AAD therapy beyond the blanking period thus leaving 80 patients in the success group and 79 patients in the failure group. The mean BP and HR at baseline were not significant between the groups. In the success group, the mean systolic BP decreased from a baseline value of 129?±?17 to 125?±?14?mmHg at 1?year (p?=?0.075). In contrast, in the failure group, the mean systolic BP increased from a baseline value of 124?±?16 to 127?±?14?mmHg at 1?year (p?=?0.176). Between-group comparison revealed a p value of 0.026. Minimal changes in diastolic BP were noted in both groups. No significant changes in antihypertensive therapy were noted.

Conclusion

We have shown that successful catheter ablation in patients with AF and hypertension is associated with a decrease in systolic BP when compared to an increase in patients with failed ablation. Our findings suggest that restoring sinus rhythm could have an antihypertensive effect in patients with AF and hypertension.