Effect of radiofrequency catheter ablation for atrial fibrillation on left atrial cavity size

Left atrial (LA) remodeling is associated with atrial fibrillation (AF). Radiofrequency catheter ablation offers a good treatment option for AF, with reasonable long-term results. The purpose of the present study was to assess whether LA reverse remodeling occurs after successful catheter ablation. Fifty-seven consecutive patients (45 men; age 53 +/- 8 years) with symptomatic drug-refractory AF were treated with radiofrequency catheter ablation. The patients were divided into 2 groups on the basis of AF recurrence as determined by Holter monitoring and 12-lead electrocardiographic findings at 6 weeks and 3 months of follow-up (sinus rhythm [SR] group, no recurrence; AF group, AF recurrence). At baseline and 3 months of follow-up, 2-dimensional echocardiography was performed to assess LA size and dimensions. Furthermore, LA volumes were measured at end-systole and end-diastole. After 3 months, 39 of 57 patients (68%) maintained SR. At 3 months of follow-up, the LA anteroposterior diameter showed a significant reduction in the SR group (4.5+/- 0.3 vs 4.2 +/- 0.2 cm, p <0.01), and an additional increase was observed in the AF group (4.5+/- 0.3 vs 4.8 +/- 0.3 cm, p <0.05). Furthermore, the LA end-systolic and end-diastolic volumes decreased significantly in the SR group from baseline to follow-up (59 +/- 12 vs 50 +/- 11 ml, p <0.01, and 37 +/- 9 vs 31 +/- 7 ml, p <0.01, respectively). However, a tendency toward an increase in LA volumes was observed in the AF group. In conclusion, the results of this study have demonstrated that LA reverse remodeling occurs after successful radiofrequency catheter ablation for AF.     

Comparison of left atrial volume and function after linear ablation and after cardioversion for chronic atrial fibrillation

Several techniques for treatment of atrial fibrillation (AF) have been developed, including the direct placement of radiofrequency for lesions at open heart surgery. Detailed evaluation of left atrial (LA) function has not been performed after these procedures and has not been compared in patients with chronic AF. We compared the atrial function of patients with sustained sinus rhythm (SR) after linear ablation with a group who underwent direct-current cardioversion and a group of normal controls to investigate the measurable deleterious effects, if any, on atrial function after the surgical procedure. Twenty-one consecutive patients who had maintained SR for >6 months after a linear radiofrequency ablation (LRFA) procedure were studied. As control subjects, we examined 33 patients with chronic AF successfully restored to SR by cardioversion who maintained SR for >6 months and 42 age-matched normal subjects. LA function was decreased in both the LRFA and cardioverted AF groups compared with normal controls. The parameters of LA function, atrial fraction, LA ejection fraction, and the A' velocity were lowest in the LRFA group, intermediate in the cardioverted AF group, and highest in the normal controls (LA function: 15.8 +/- 10%, 26 +/- 10%, 33 +/- 7%; p = 0.0001; LA ejection fraction: 31 +13%, 41 +/- 12%, 51 +/- 9%; p = 0.0001; A' velocity: 4.2 +/- 1.4, 7.6 +/- 2.2, 9.5 +/- 1.9 cm/s; p = 0.0001). LA volumes were increased in the LRFA and cardioverted AF groups compared with normals (62.8 +/- 22 vs 70.6 +/- 17 vs 38.7 +/- 9.8 ml; p = 0.0001). Thus, although LA function is restored and maintained after LRFA has been performed during open heart surgery, LRFA use is associated with a measurable decrease in LA function over and above that found after conventional cardioversion.     

Effect of repeated radiofrequency catheter ablation on left atrial function for the treatment of atrial fibrillation

Radiofrequency catheter ablation (RFCA) is a potential curative treatment for atrial fibrillation (AF) by eliminating the arrhythmia and inducing left atrial (LA) reverse remodeling. However, the effect on LA function, especially after repeated procedures, has scarcely been studied. The aim of this study was to evaluate the impact of RFCA on LA size and function in patients with AF after a first and a repeated procedure. RFCA was performed in 154 patients with symptomatic drug-refractory AF. LA volumes and function were assessed with real-time 3-dimensional echocardiography before and 6 months after the procedure. Recurrence of the arrhythmia was defined as any atrial tachyarrhythmia lasting >30 seconds, clinically documented or by 24-hour Holter recording, after the first 6 months after ablation. Of the 154 patients, 104 (67%) required only a first ablation, and 50 (33%) required redo RFCA. LA volume was reduced after first RFCA (from 60 ± 19 to 52 ± 17 ml for 3-dimensional LA maximum volume, p <0.001, and from 38 ± 18 to 33 ± 15 ml for 3-dimensional LA minimum volume, p <0.000) without impairment of LA contractile function, measured as the active emptying percentage of total volume (39 ± 25% vs 43 ± 26%, p = NS). After repeated RFCA procedures, 3-dimensional LA maximum volume was reduced (from 57 ± 18 to 52 ± 18 ml, p = 0.04), also without further LA contractile function impairment (active emptying percentage of total volume) (36 ± 24% vs 36 ± 25% of total volume, p = NS). This effect was similar in paroxysmal and persistent AF. In conclusion, RFCA induces reductions in LA volumes without a deleterious impact on contractile function, even after repeated ablation.     

Atrial structural remodelling and restoration of atrial contraction after linear ablation for atrial fibrillation.

AIMS: We determined late atrial function following a surgical linear endocardial radiofrequency (RF) ablation procedure that aimed to restore and maintain sinus rhythm (SR) in atrial fibrillation (AF). We tested the hypothesis that successful restoration of SR is accompanied by measurable mechanical atrial function that is at normal or near normal levels. METHODS: Forty-seven patients who underwent the surgical RF procedure at least 6 months previously (median 2.86 years; range: 0.6-4.2 years) were studied using an array of echocardiographic variables. Two patient groups (SR restored [RF-SR], persistent AF [RF-AF]) and an age matched control group were studied. Among the echocardiographic variables measured were left atrial (LA) size and volume, LA active fractional emptying and mitral annular displacement corresponding to atrial contraction (A' velocity) by Doppler tissue imaging. RESULTS: At long term follow up 29/47of patients who underwent the RF procedure were in SR with atrial contraction present echocardiographically. Of the patients initially restored to SR, the proportion remaining in SR at 3 years was 79% (SE 9%). The atrial-emptying fraction was reduced in comparison to that seen in normal controls (27+/-14% vs 46+/-10%). The A' velocity was decreased in the surgical RF cohort vs controls (4.4+/-1.3 vs 9.7+/-1.7cm/s; P=0.0001). Despite LA size preoperatively being similar in both surgical groups, atrial size decreased in those in whom SR was restored (48.6+/-7.6 vs 44.8+/-4.7mm; P=0.0001) but increased in those in whom AF persisted (48.2+/-8.1mm vs 52.3+/-7.8mm; P=0.0001). CONCLUSION: The radial pattern of linear radiofrequency ablation used in the present study resulted in restoration of SR and atrial function. Procedural success was independent of preoperative atrial size. Restoration of SR results in 'reverse' atrial remodelling and improved atrial function. However atrial function remains modestly impaired, either due to the ablation lesions or pre-existing atrial disease.     

Prognostic predictors of sinus rhythm control by amiodarone and electrical cardioversion in patients undergoing percutaneous transluminal mitral valvuloplasty for rheumatic atrial fibrillation.

BACKGROUND: Conversion to sinus rhythm (SR) is rarely attempted in patients with rheumatic atrial fibrillation (AF) because the length of AF duration and the dilation of left atrium (LA) make maintenance of SR difficult. In this study, predictors of the successful maintenance of SR with amiodarone and electrical cardioversion in rheumatic AF patients receiving percutaneous transluminal mitral valvuloplasty (PTMV) were identified. METHODS AND RESULTS: This study included 23 consecutive patients undergoing PTMV for rheumatic AF (6 men, 53+/-11 years; AF duration 25 +/-24 months; LA diameter 44+/-6 mm; mitral valve area (MV) 1.1+/-0.2 cm(2)). Electrical cardioversion was required for the successful conversion to SR in all patients regardless of whether they had received amiodarone (400 mg/day) 2 months before PTMV (n=8) or 2 months after (n=15). After cardioversion, all patients received amiodarone 200 mg/day. With a follow-up period of 35+/-8 months, 14 patients (61%) remained in SR. A greater reduction in LA size (-4+/-3 mm vs 1+/-1 mm; p=0.004) and an greater increase in MV area (0.8+/-0.4 cm(2) vs 0.5+/-0.2 cm(2); p=0.01) by PTMV, not AF duration, were found to be the independent predictors for patients with successful maintenance of SR as compared with patients with recurrence of AF. CONCLUSION: In rheumatic AF patients receiving PTMV, the successful maintenance of SR with amiodarone and electrical cardioversion can be predicted by the degree to which LA size is reduced and MV area is increased.     

Left atrial volume: predictor of atrial fibrillation in patients with degenerative mitral regurgitation

BACKGROUND AND AIM OF THE STUDY: In patients with mitral regurgitation (MR) due to degenerative mitral valve prolapse (MVP), preoperative atrial fibrillation (AF) has been identified as an independent predictor of survival after surgery for MR. Thus, the determinants of preoperative AF may have critical implications to evaluate the timing of mitral valve repair. The study aim was to investigate the role of left atrial (LA) volume in predicting preoperative AF in patients with severe MR due to degenerative MVP. METHODS: Sixty-six patients with severe degenerative MR (regurgitant volume > or =60 ml, regurgitant fraction > or =50%, effective regurgitant orifice area > or =0.4 cm(2)) in sinus rhythm (SR) at diagnosis and conservatively managed were eligible for the study. Complete two-dimensional (2-D) echocardiographic and Doppler measurements, including the measurement of maximum LA volume, were performed in all patients. RESULTS: During follow up under conservative management (18.1+/-4.8 months), eight patients (12%) experienced conversion to AF, and 58 remained in SR. The mean LA dimension was 4.0+/-0.5 cm in patients with SR, and 5.1+/-0.8 cm in those who developed AF (p <0.0001). The mean LA volume and LA volume index (indexed to body surface area) were 95 +/-23 ml and 60+/-14 ml/m(2) respectively in patients with SR, and 166+/-66 ml and 104+/-42 ml/m(2) respectively in those who developed AF (both p <0.0001). The optimal cut-off value for LA volume to predict AF conversion was 117.5 ml (sensitivity 88%, specificity 83%), and for LA volume index was 75 ml/m(2) (sensitivity 88%, specificity 88%). CONCLUSION: LA volume measurement should be considered in patients with degenerative severe MR diagnosed in SR. A LA volume index > or =75 ml/m(2) reflects the risk of subsequent AF, and patients should be closely monitored.     

Results of complex left atrial ablation of long-lasting persistent atrial fibrillation

PURPOSE: The aim of the study was to identify variables associated with successful long-term maintenance of sinus rhythm (SR) after a single ablation of long-lasting persistent atrial fibrillation (AF). METHODS: Complex left atrial (LA) ablation was performed in 100 patients. Restoration of SR by ablation was the desired procedure endpoint. RESULTS: SR was restored by ablation in 38 patients during the first procedure. Following one ablation, 50 patients remained in SR for 31 +/- 14 months. SR maintenance was associated with shorter duration of the persistent AF (median 14 vs. 22 months; P = 0.05), lower proportion of the LA points exhibiting voltage <0.2 mV (median 20% vs. 33%; P = 0.006), and higher proportion of LA points showing voltage >1 mV (median 15% vs. 11%; P = 0.02). CONCLUSION: Among clinical variables, shorter duration of persistent AF and higher voltage recorded around the LA predicted long-term maintenance of SR after single ablation.     

Effect of left atrial circumferential ablation for atrial fibrillation on left atrial transport function

BACKGROUND: The effects of left atrial (LA) circumferential ablation on LA function in patients with atrial fibrillation (AF) have not been well described. OBJECTIVES: The purpose of this study was to determine the effect of LA circumferential ablation on LA function. METHODS: Gated, multiphase, dynamic contrast-enhanced computed tomographic (CT) scans of the chest with three-dimensional reconstructions of the heart were used to calculate the LA ejection fraction (EF) in 36 patients with paroxysmal (n = 27) or chronic (n = 9) AF (mean age 55 +/- 11 years) and in 10 control subjects with no history of AF. Because CT scans had to be acquired during sinus rhythm, a CT scan was available both before and after (mean 5 +/- 1 months) LA circumferential ablation (LACA) in only 10 patients. A single CT scan was acquired in 8 patients before and in 18 patients after LACA ablation. Radiofrequency catheter ablation was performed using an 8-mm-tip catheter to encircle the pulmonary veins, with additional lines along the mitral isthmus and the roof. RESULTS: In patients with paroxysmal AF, LA EF was lower after than before LACA (21% +/- 8% vs 32 +/- 13%, P = .003). LA EF after LA catheter ablation was similar among patients with paroxysmal AF and those with chronic AF (21% +/- 8% vs 23 +/- 13%, P = .7). However, LA EF after LA catheter ablation was lower in all patients with AF than in control subjects (21% +/- 10% vs 47% +/- 5%, P < .001). CONCLUSION: During medium-term follow-up, restoration of sinus rhythm by LACA results in partial return of LA function in patients with chronic AF. However, in patients with paroxysmal AF, LA catheter ablation results in decreased LA function. Whether the impairment in LA function is severe enough to predispose to LA thrombi despite elimination of AF remains to be determined.     

Serial evaluation of left atrial dimension after cardioversion for atrial fibrillation and relation to atrial function

The size of the left atrium is usually increased during atrial fibrillation (AF). The aim of the present study was to evaluate changes in left atrial (LA) dimension after cardioversion for AF, and the relation between LA dimension and atrial function. The initial study population included 171 consecutive patients. Patients who had spontaneous cardioversion to sinus rhythm (56 patients) were compared with patients who had random cardio-version with drugs (50 patients) or direct-current (DC) shock (50 patients). Echocardiographic evaluations included LA size and volume. LA passive and active emptying volumes were calculated, and LA function was assessed. Atrial stunning was observed in 18 patients reverted with DC shock and in 7 patients reverted with drugs. The left atrium was dilated in all patients during AF (48 +/- 5 mm). The size of the left atrium decreased after restoration of sinus rhythm in all patients with spontaneous reversion to sinus rhythm, in 73% of patients reverted with drugs, and in 50% of patients reverted with DC shock. The comparison between patients with a normal mechanical atrial function and patients with reduced atrial function showed that a higher atrial ejection force was associated with a more marked reduction in LA size after restoration of sinus rhythm. A relation between LA volumes and atrial ejection force was observed in the group of patients with depressed atrial mechanical function (r = -0.78; p <0.001). The active emptying fraction was lower, although not significantly, in this group, whereas the conduit volume was increased. Thus, a depressed atrial mechanical function after cardioversion for AF was associated with a persistence of LA dilation.     

The left atrial function index: a rhythm independent marker of atrial function.

AIMS: This study evaluates a simple echocardiographic rhythm independent expression of left atrial (LA) function, 'the left atrial function index' (LAFI). BACKGROUND: Quantitation of LA function is challenging and often established parameters including peak A are limited to sinus rhythm (SR). We hypothesized that atrial function could be characterized independent of rhythm by combining analogues of LA volume, reservoir function and LV stroke volume. METHODS: Seventy-two patients with chronic atrial fibrillation (CAF) were followed for six months post cardioversion (CV). Thirty-seven age matched healthy subjects were controls. The LAFI = LAEF x LVOT-VTI/LAESVI (LAEF = LA emptying fraction, LAESVI = maximal LA volume indexed to BSA, LVOT-VTI = outflow tract velocity time integral). RESULTS: The LAFI pre-CV in the CAF group was depressed vs controls (0.10 +/- 0.05 vs 0.54 +/- 0.17; P = 0.0001). Post-CV, LAFI was lower in persistent AF than in those restored to SR (AF vs SR: 0.08 +/- 0.03 vs 0.15 +/- 0.08; P = 0.0001), improved progressively in SR and was unchanged when AF persisted. CONCLUSION: The LAFI, a simple, rhythm independent expression of atrial function, appears sensitive to differences between individuals in AF and those restored to SR and justifies clinical and investigative applications.     

Management of persistent atrial fibrillation following balloon mitral valvotomy: safety and efficacy of low-dose amiodarone

BACKGROUND AND AIM OF THE STUDY: Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia encountered in clinical practice. In developing countries, rheumatic mitral stenosis (MS) is the most frequent underlying condition in patients with AF. Sinus rhythm (SR) is difficult to achieve and maintain in these patients, but would be more easily achieved with reduction of left atrial pressure after successful balloon mitral valvotomy (BMV). METHODS: Eighty-five patients with persistent AF following BMV received amiodarone (600 mg once daily for two weeks, 200 mg daily thereafter). Electrical cardioversion was performed in those with persistent AF (at six and 12 weeks of drug therapy). RESULTS: Among patients, 33 (39%) converted with amiodarone alone. Of 52 patients who underwent cardioversion at six weeks, 41 (79%) converted to SR. Overall, 87% of patients converted to SR. None of the 11 patients with persistent AF could be converted to SR, despite a second attempt with direct current (DC) cardioversion at 12 weeks. Those who converted to SR had significantly shorter AF duration (AFD) (2.7+/-1.1 versus 3.2+/-0.7 years) and smaller left atrial (LA) size (50.0+/-7.7 versus 57.9+/-4.7 mm). Patient age, gender, NYHA class, ejection fraction and post-BMV variables were comparable between the two groups. Successful maintenance of SR was possible in 61/74 (82%) patients at a mean follow up of 30.6+/-7.1 months (range: 16-43 months). Again, mean AFD was shorter (1.8+/-0.6 versus 3.0+/-0.7 years) and LA size smaller (48.9+/-7.5 versus 54.7+/-6.9 mm) among those who maintained SR. However, even in patients with AFD > or =2 years, successful conversion and maintenance of SR was possible in 74% and 62% of patients, respectively. Among patients with LA size > or =60 mm (n = 16), the corresponding value were 84% and 77%, respectively. On multivariate analysis, only AFD was a predictor of acute and long-term success. The probability of SR remaining in those with AFD <2 years at 21, 30 and 43 months was 96%, 95% and 94.6%, respectively, while for those with AFD > or =2 years these values were 62%, 48% and 40%. CONCLUSION: Low-dose amiodarone was safe and effective in restoring and maintaining SR in patients with AF and rheumatic heart disease.     

Time course of left atrial mechanical recovery after linear lesions: normal sinus rhythm versus a chronic atrial fibrillation dog model

INTRODUCTION: The extent of left atrial (LA) mechanical function recovery after creation of linear lesions using the loop catheter has not been determined. METHODS AND RESULTS: LA mechanical function was assessed before and after linear lesions using transthoracic two-dimensional and Doppler echocardiography in two groups: (1) normal, which consisted of eight healthy dogs in normal sinus rhythm (NSR); and (2) atrial fibrillation (AF), which consisted of nine dogs in spontaneous AF for 6 months following rapid pacing-induced AF. NSR was restored with linear lesions in all AF dogs. All animals were in NSR 5 months after linear lesions. In the normal dogs, the maximal velocity of the transmitral flow "A" wave was reduced by 42% during the first week postablation and by 24% at 5 months versus preablation. At 5 months, no differences in LA function were noted between the normal and the AF group for all measured Doppler parameters. At 5 months, the LA systolic area in AF dogs was reduced by 40% (preablation 12.9 +/- 2.9 cm2, postablation 7.6 +/- 1.2 cm2; P < 0.01) and in the normal dogs by 21% (preablation 10.0 +/- 0.9 cm2, postablation 7.8 +/- 1.2 cm2; P < 0.02), being the same in both groups within 3 months of recovery. CONCLUSION: The creation of linear lesions with the loop catheter does not result in LA expansion. In normal dogs, LA mechanical activity is reduced for 3 weeks postablation. The time course of LA mechanical function recovery is the same for the AF and the NSR dogs, and it is complete at 3 months postablation. At 5 months, LA systolic function parameters in both groups are reduced by 24% versus the preablation values of the normal dogs. Linear lesions result in a significant reduction in LA size.     

Early and late results of permanent atrial fibrillation ablation surgery in aortic valve and CABG patients

OBJECTIVE: The study investigates the early and late results of permanent atrial fibrillation (AF) ablation surgery concomitant to coronary artery bypass grafting (CABG) and/or aortic valve (AV) surgery. METHODS: Between February 2001 and April 2006, a selective group of 80 patients with permanent AF (median: 48 months [Perc25/75 24/110; range: 6 - 360 months]) underwent either bipolar (n = 60) or monopolar (n = 20) radiofrequency (RF) ablation procedures concomitant to CABG and/or AV surgery (CABG: n = 39; AV: n = 30; AV + CABG: n = 11). All patients were restudied to assess survival, conversion rate to stable sinus rhythm (SR) and New York Heart Association (NYHA) class early (3 +/- 1 months) and late after surgery (30 +/- 15 months). Data were analyzed exploratively. RESULTS: Survival at 3 and 30 months was 98 % and 96 %, respectively. Stable SR could be documented in 73 % and 77 % of patients. Long-term AF before surgery and larger LA size were predictive for AF return after surgery ( P = 0.004 and P = 0.032, respectively). Neither age, gender, the application modus of the RF energy nor the underlying cardiac disease influenced the postoperative cardiac rhythm significantly. NYHA class improved significantly after surgery ( P < 0.0005), particularly when stable SR was achieved ( P = 0.049). CONCLUSION: Preoperative permanent AF duration time and larger LA size are useful variables to predict the success rate of concomitant ablation surgery in CABG and/or AV patients. Further it could be demonstrated that established SR remained stable over time.     

A decrease of enlarged left atrium following cardioversion of atrial fibrillation predicts the long-term maintenance of sinus rhythm

BACKGROUND: Although increased left atrial size (LA) has been long regarded as one of the factors negatively influencing the long-term maintenance of sinus rhythm (SR) following cardioversion (CV) of atrial fibrillation (AF), some reports suggested that CV might be effective also in patients with large LA.Aim. We sought to determine the role of LA enlargement in long-term SR maintenance after CV of persistent AF. METHODS: 104 consecutive patients (33 females, 71 males, mean age 60.4+/-7.4 years) were assigned to SR restoration and maintenance with serial antiarrhythmic drugs. Transthoracic echocardiographic (TTE) variables were recorded prior to CV. Generalised additive logistic regression was used to investigate the impact of LA enlargement on the long-term SR maintenance. RESULTS: SR was present in 63.5% of patients after one year of follow-up. Increased LA area >28 cm (RR 1.72; 1.09-2.71; p<0.02) and increased fractional shortening values in ranges between 26-40% (1.2; 1.01-1.44; p<0.05) were significantly associated with SR maintenance after one year. In order to determine the influence of the LA diameter on the probability of SR maintenance, we analysed mean LA(ar) values prior to and after CV. Patients with large LA(ar) (28 cm(2)) presented a significant decrease of LA size (31.45+/-3.07 cm(2) vs 28.94+/-3.81 cm(2); p<0.008) during the first 30 days after SR restoration. In the group of patients with LA(ar) 28 cm(2) we noted decrease in LA size by 2.57+/-3.2 cm(2), whereas in patients with a smaller LA volume this decrease was significantly lower, being 0.47+/-2.9 cm(2) (p<0.004). CONCLUSIONS: LA enlargement does not preclude a favourable outcome after CV of AF. The decrease in LA area occurring during 30 days following CV favours long term SR maintenance.     

Rhythm control versus rate control in patients with persistent atrial fibrillation. Results of the HOT CAFE Polish Study

BACKGROUND. Patients with atrial fibrillation (AF) can be managed either by maintaining sinus rhythm using antiarrhythmic drugs and/or electrical cardioversion, or by leaving patients in AF and controlling ventricular rate without attempts to restore sinus rhythm. Which of these two strategies is superior, has not yet been definitively established. AIM. HOT CAFE Polish Study (How To Treat Chronic Atrial Fibrillation) was designed to evaluate in a randomised, multicentre and prospective manner the risks and advantages of two therapeutical strategies - rate control or rhythm control, in patients with persistent AF. METHODS. The study group consisted of 205 patients (71 females and 134 males; mean age 60.8+/-11.2 years) with a mean time of AF duration of 273.7+/-112.4 days; 101 patients were randomly assigned to rate control (Group I) whereas 104 patients were randomised to sinus rhythm (SR) restoration by DC cardioversion (CV) and subsequent antiarrhythmic drug treatment (Group II). At the end of follow-up (12 months) SR was present in 75% of patients. RESULTS. The incidence of hospital admissions was higher in group II in comparison to group I (12% vs 74%; p<0.001). Mortality was similar in both groups (1.0% versus 2.9%, NS). In both groups a significant improvement of heart failure symptoms was observed during the first 2 months (p<0.02 and p<0.001). In group II exercise tolerability measured by maximal workload during treadmill test significantly improved compared with baseline (5.2+/-5.1 vs 7.6+/-3.3 MET; p<0.0001). In patients in whom SR was restored, the left ventricular function improved and an increase in the shortening fraction was observed (29+/-7% vs 31+/-7%; p<0.01). No thromboembolic complications were observed in patients left with AF. Three patients from group II suffered ischaemic stroke; in two cases stroke was associated with CV whereas in the third patient - with late AF recurrence. CONCLUSIONS. The HOT CAFE Polish Study did not reveal significant differences in mortality between the two treatment strategies in patients with persistent AF. Although patients with SR had better improvement in some haemodynamical parameters, the hospitalisation rate was higher and the incidence of stroke was not reduced compared with the rate control group.     

Matrix metalloproteinases and atrial remodeling in patients with mitral valve disease and atrial fibrillation

BACKGROUND: Atrial fibrillation (AF) is associated with extracellular matrix remodeling involving atrial fibrosis and atrial dilatation. Angiotensin II mediated pathways and matrix metalloproteinases (MMPs) have been implicated in these processes. Our aim was to study atrial structural remodeling and the expression of the angiotensin receptor subtypes and MMPs and their inhibitors (TIMPs) in patients with mitral valve disease with and without AF. METHODS AND RESULTS: Biopsies from right and left atrial appendages (RA and LA) were taken from patients undergoing CABG (n=9, all in sinus rhythm (SR)) or mitral valve surgery (MVS; n=19; 9 with permanent AF and 10 in SR). Patients with MVS and AF had significantly larger atria (versus MVS and SR: p=0.02; versus CABG: p<0.01). The MVS patients had significantly more fibrosis than the control CABG group. Fibrosis was increased in both the AF and SR MVS groups in the LA, but only in the MVS-AF group in the RA. These AF patients had significantly more tricuspid regurgitation than SR patients. MMP-1 was down-regulated in LA of MVS patients (p=0.02) independent of the underlying rhythm (SR or AF; p=0.95). In RA biopsies, MMP-1 was down-regulated only in the MVS and AF group. MMP-9 was down-regulated in the MVS patients compared to CABG both in the RA and LA, and without a difference between the SR and AF groups. Protein expression of AT-1, AT-2, MMP-2, TIMP-1, -2 and -4, TNF-alpha, and TNF-alpha-converting enzyme did not differ significantly between the 3 groups. CONCLUSIONS: Concordant changes between MMP-expression and fibrosis during mitral valve disease, both in LA and RA, suggest involvement of MMPs in structural atrial remodeling. AF itself did not contribute to altered fibrosis or MMP-expression in the LA. The association between AF and RA changes may be precipitated by greater hemodynamic load due to tricuspid regurgitation in these patients.     

Impact of left atrial size reduction and endocardial radiofrequency ablation on continuous atrial fibrillation in patients undergoing concomitant cardiac surgery: three-year results

BACKGROUND AND AIM OF THE STUDY: The study aim was to evaluate the efficacy of left atrial (LA) size reduction combined with radiofrequency (RF) ablation in the treatment of continuous atrial fibrillation (AF), by comparative analysis of the outcomes of patients undergoing RF ablation with and without LA size reduction. METHODS: A total of 46 patients with continuous AF and cardiac disease underwent cardiac surgery and RF ablation alone (group I, n = 20) or combined with LA size reduction (group II, n = 26). Patients were followed for three years postoperatively, with evaluation of cardiac rhythm, neurological complications, LA size (by echocardiography) and atrial contractility. RESULTS: At three years after surgery, sinus rhythm (SR) was restored in 61.1% and 70% of patients in groups I and II, respectively. Mean LA diameter was reduced from 60 +/- 15 mm to 57 +/- 5 mm in group I, and from 69 +/- 19 mm to 55 +/- 6 mm in group II. The overall three-year survival was 90% in group I, and 88.5% in group II. Three-year freedom from stroke was 88.9% and 86.2% in groups I and II, respectively. Two patients in each group received transvenous permanent pacemaker implantation. Atrial contractility was recovered in all patients with stable SR. CONCLUSION: LA size reduction improves SR conversion rate after RF ablation for continuous AF in patients undergoing concomitant cardiac surgery.     

Pre-treatment with Irbesartan attenuates left atrial stunning after electrical cardioversion of atrial fibrillation.

AIMS: Left atrial (LA) stunning, the transient impairment of LA function, is responsible for an increased thrombo-embolic risk after cardioversion of atrial fibrillation (AF). Angiotensin receptor blockers (ARBs) attenuate atrial remodelling in AF and could theoretically influence LA stunning. We studied the effect of Irbesartan on LA stunning. METHODS AND RESULTS: We prospectively assigned 50 patients from the outpatient clinic undergoing electrical cardioversion for AF with duration of >4 weeks, into two matched groups: 25 patients were treated with Irbesartan (228+/-93 mg/day) for at least 2 weeks prior to cardioversion (Irbesartan group); 25 patients did not receive ARBs (control group). The groups did not differ concerning age (64+/-13 vs. 63+/-13 years, respectively), AF duration (20+/-18 vs. 20+/-19 weeks), underlying disease, LA diameter (46+/-7 vs. 47+/-9 mm), left ventricular dimensions, and ejection fraction (47.7+/-11.6 vs. 49.7+/-14.5%). We assessed LA appendage emptying velocities (LAAEV) and LA spontaneous echo contrast (LASEC) by transoesophageal echocardiography before and after cardioversion and at 2 weeks, and the A-wave by transthoracic echocardiography after cardioversion, at 2 and at 4 weeks. LA stunning was significantly attenuated in the Irbesartan group. The reduction of LAAEV immediately after cardioversion was significantly less in the Irbesartan group (LAAEV reduction of 9+/-49% from 28+/-9 cm/s before cardioversion to 25+/-13 cm/s immediately afterwards) than in the control group (reduction of 48+/-20% from 34+/-15 cm/s before cardioversion to 16+/-6 cm/s afterwards) (P = 0.048). New or increased LASEC occurred in eight patients (32%) in the Irbesartan vs. 16 patients (64%) in the control group (P = 0.046). CONCLUSION: Irbesartan significantly attenuates LA stunning after electrical cardioversion of AF. Therefore, ARBs may represent an important pharmacological supplementation in patients being prepared for cardioversion.     

Usefulness and safety of transcatheter ablation of atrial fibrillation in patients with hypertrophic cardiomyopathy

Atrial fibrillation (AF) is common in patients with hypertrophic cardiomyopathy (HC) and predicts adverse outcome. Radiofrequency catheter ablation (RFCA) represents a potentially advantageous alternative to lifelong pharmacologic treatment. However, its efficacy in patients with HC is not established. In the present study, the feasibility, safety, and efficacy of RFCA of AF in patients with HC were evaluated. Twenty-six patients with HC with paroxysmal (n = 13) or permanent (n = 13) AF refractory to antiarrhythmic therapy (age 58 +/- 11 years, time from AF onset 7.3 +/- 6.2 years, left atrial volume 170 +/- 48 ml) underwent RFCA. A schema with pulmonary vein isolation plus linear lesions was used. No major periprocedural complication occurred. One patient died from a hemorrhagic stroke 4 weeks after RFCA while in sinus rhythm. During a 19 +/- 10-month follow-up, 9 of the remaining 25 patients (36%) experienced recurrence of AF (despite repeated RFCA in 3) and were considered failures, whereas 16 remained in sinus rhythm (i.e., 64% overall success rate). Ten of these 16 patients were off antiarrhythmic drug therapy at final evaluation. RFCA was highly successful in patients with paroxysmal AF (77% success rate compared with 50% in the subgroup with permanent AF). Patients with restoration of sinus rhythm showed marked symptomatic improvement (final New York Heart Association functional class 1.2 +/- 0.5 vs 1.7 +/- 0.7 before the procedure, p = 0.003). Conversely, patients for whom RFCA failed showed no change (final functional class 1.9 +/- 0.8 vs 1.7 +/- 0.9 before the procedure, p = 0.59). In conclusion, in most studied patients with HC, RFCA proved a safe and effective therapeutic option for AF, improved functional status, and was able to reduce or postpone the need for long-term pharmacologic treatment.     

Atrial rhythm influences catheter tissue contact during radiofrequency catheter ablation of atrial fibrillation: comparison of contact force between sinus rhythm and atrial fibrillation

Catheter tissue contact force (CF) is an important factor for durable lesion formation during radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF). Since CF varies in the beating heart, atrial rhythm during RFCA may influence CF. A high-density map and RFCA points were obtained in 25 patients undergoing RFCA of AF using a CF-sensing catheter (Tacticath, St. Jude Medical). The operators were blinded to the CF information. Contact type was classified into three categories: constant, variable, and intermittent contact. Average CF and contact type were analyzed according to atrial rhythm (SR vs. AF) and anatomical location. A total of 1364 points (891 points during SR and 473 points during AF) were analyzed. Average CFs showed no significant difference between SR (17.2 ± 11.3 g) and AF (17.2 ± 13.3 g; p = 0.99). The distribution of points with an average CF of ≥20 and <10 g also showed no significant difference. However, the distribution of excessive CF (CF ≥40 g) was significantly higher during AF (7.4 %) in comparison with SR (4.2 %; p < 0.05). At the anterior area of the right inferior pulmonary vein (RIPV), the average CF during AF was significantly higher than during SR (p < 0.05). Constant contact was significantly higher during AF (32.2 %) when compared to SR (9.9 %; p < 0.01). Although the average CF was not different between atrial rhythms, constant contact was more often achievable during AF than it was during SR. However, excessive CF also seems to occur more frequently during AF especially at the anterior part of RIPV.