Predictors of atrial fibrillation recurrence in patients with long-lasting atrial fibrillation

BACKGROUND:

Limited data are available on the predictors of atrial fibrillation (AF) recurrence in patients with chronic AF.

OBJECTIVES:

To evaluate potential clinical, echocardiographic and electrophysiological predictors of AF recurrence after internal cardioversion for long-lasting AF.

METHODS:

A total of 99 consecutive patients (63 men and 36 women, mean age 63.33±9.27 years) with long-standing AF (52.42±72.02 months) underwent internal cardioversion with a catheter that consisted of two defibrillating coils. Shocks were delivered according to a step-up protocol. Clinical follow-up and electrocardiographic recordings were performed on a monthly basis for a 12-month period or whenever patients experienced symptoms suggestive of recurrent AF.

RESULTS:

Ninety-three patients (93.94%) underwent a successful uncomplicated cardioversion, with a mean atrial defibrillation threshold of 10.69±6.76 J. Immediate reinitiation of AF was observed in 15 patients (15.78%) of whom a repeated cardioversion restored sinus rhythm in 13 cases. Early recurrence of AF (within one week) was observed in 12 of 93 patients (12.90%). At the end of the 12-month follow-up period, during which seven patients were lost, 42 of the 86 remaining patients (48.84%) were still in sinus rhythm. Multivariate regression analysis showed that left atrial diameter (OR 1.126, 95% CI 1.015 to 1.249; P=0.025) and mitral A wave velocity (OR 0.972, 95% CI 0.945 to 0.999; P=0.044) were significant and independent predictors of AF recurrence, whereas age, left ventricular ejection fraction and AF cycle length were not predictive of arrhythmia recurrence.

CONCLUSION:

The present study showed that the left atrial diameter and mitral A wave velocity are the only variables associated with AF recurrence after successful cardioversion.     

Atrial Fibrillation Ablation in Systolic Dysfunction: Clinical and Echocardiographic Outcomes

Background

Heart failure and atrial fibrillation (AF) often coexist in a deleterious cycle.

Objective

To evaluate the clinical and echocardiographic outcomes of patients with ventricular systolic dysfunction and AF treated with radiofrequency (RF) ablation.

Methods

Patients with ventricular systolic dysfunction [ejection fraction (EF) <50%] and AF refractory to drug therapy underwent stepwise RF ablation in the same session with pulmonary vein isolation, ablation of AF nests and of residual atrial tachycardia, named "background tachycardia". Clinical (NYHA functional class) and echocardiographic (EF, left atrial diameter) data were compared (McNemar test and t test) before and after ablation.

Results

31 patients (6 women, 25 men), aged 37 to 77 years (mean, 59.8±10.6), underwent RF ablation. The etiology was mainly idiopathic (19 p, 61%). During a mean follow-up of 20.3±17 months, 24 patients (77%) were in sinus rhythm, 11 (35%) being on amiodarone. Eight patients (26%) underwent more than one procedure (6 underwent 2 procedures, and 2 underwent 3 procedures). Significant NYHA functional class improvement was observed (pre-ablation: 2.23±0.56; postablation: 1.13±0.35; p<0.0001). The echocardiographic outcome also showed significant ventricular function improvement (EF pre: 44.68%±6.02%, post: 59%±13.2%, p=0.0005) and a significant left atrial diameter reduction (pre: 46.61±7.3 mm; post: 43.59±6.6 mm; p=0.026). No major complications occurred.

Conclusion

Our findings suggest that AF ablation in patients with ventricular systolic dysfunction is a safe and highly effective procedure. Arrhythmia control has a great impact on ventricular function recovery and functional class improvement.     

Impact of Atrial Fibrillation Ablation on Left Ventricular Filling Pressure and Left Atrial Remodeling

Background

Left ventricular (LV) diastolic dysfunction is associated with new-onset atrial fibrillation (AF), and the estimation of elevated LV filling pressures by E/e'' ratio is related to worse outcomes in patients with AF. However, it is unknown if restoring sinus rhythm reverses this process.

Objective

To evaluate the impact of AF ablation on estimated LV filling pressure.

Methods

A total of 141 patients underwent radiofrequency (RF) ablation to treat drug-refractory AF. Transthoracic echocardiography was performed 30 days before and 12 months after ablation. LV functional parameters, left atrial volume index (LAVind), and transmitral pulsed and mitral annulus tissue Doppler (e'' and E/e'') were assessed. Paroxysmal AF was present in 18 patients, persistent AF was present in 102 patients, and long-standing persistent AF in 21 patients. Follow-up included electrocardiographic examination and 24-h Holter monitoring at 3, 6, and 12 months after ablation.

Results

One hundred seventeen patients (82.9%) were free of AF during the follow-up (average, 18 ± 5 months). LAVind reduced in the successful group (30.2 mL/m² ± 10.6 mL/m² to 22.6 mL/m² ± 1.1 mL/m², p < 0.001) compared to the non-successful group (37.7 mL/m² ± 14.3 mL/m² to 37.5 mL/m² ± 14.5 mL/m², p = ns). Improvement of LV filling pressure assessed by a reduction in the E/e'' ratio was observed only after successful ablation (11.5 ± 4.5 vs. 7.1 ± 3.7, p < 0.001) but not in patients with recurrent AF (12.7 ± 4.4 vs. 12 ± 3.3, p = ns). The success rate was lower in the long-standing persistent AF patient group (57% vs. 87%, p = 0.001).

Conclusion

Successful AF ablation is associated with LA reverse remodeling and an improvement in LV filling pressure.     

P Wave Indices to Predict Atrial Fibrillation Recurrences Post Pulmonary Vein Isolation

Background

P-wave indices are appealing markers for predicting atrial fibrillation (AF) recurrences post ablation.

Objective

This study evaluates the value of P wave indices to predict recurrences post pulmonary vein isolation (PVI) in patients with paroxysmal AF.

Methods

We selected 198 patients (57 ± 8 years, 150 males) with symptomatic drug-refractory paroxysmal AF undergoing PVI in our hospital. A 12-lead electrocardiogram was used to measure P wave duration in lead II, P wave terminal force (PWTF) in lead V1, P wave axis and dispersion.

Results

During a follow-up of 9 ± 3 months, recurrences occurred in 60 (30.3%) patients. The patients that had AF recurrence had longer mean P wave duration (122.9 ± 10.3 vs 104.3 ± 14.2 ms, p < 0.001), larger P wave dispersion (40.7 ± 1.7 ms vs 36.6 ± 3.2 ms, p < 0.001). P wave duration ≥ 125 ms has 60% sensitivity, 90% specificity, positive predictive value (PPV) of 72% and negative predictive value (NPV) of 83.7%, whereas P wave dispersion ≥ 40 ms has 78% sensitivity, 67% specificity, PPV of 51% and NPV of 87.6% 48/66 (72.7%) patients with PWTF ≤ - 0.04 mm/second vs 12/132(9%) with PWTF > -0.04 mm/second showed recurrence of AF (p < 0.001). P wave axis was not different between two groups. On multivariate analysis, P wave indices were not independent from left atrial size and age.

Conclusions

P wave duration ≥ 125 ms, P wave dispersion ≥ 40 ms and PWTF in V1 ≤ - 0.04 mm/sec are good clinical predictors of AF recurrences post PVI in patients with paroxysmal atrial fibrillation; however they were not independent from left atrial size and age.     

Modified radial v/s biatrial maze for atrial fibrillation in rheumatic valvular heart surgery

Background

Atrial fibrillation (AF) is commonest sustained atrial arrhythmia producing high morbidity. Although Cox''s Maze III procedure cures AF in majority, reduced atrial transport function (ATF) is a concern. Radial approach with ablation lines radial from sinus node towards atrioventricular annulii and parallel to atrial coronary arteries, has shown better ATF.

Methods

Single blind open randomized prospective study of 80 patients was undertaken in two groups (40 each) of modified Cox''s maze III and modified radial approach, to evaluate conversion to normal sinus rhythm (NSR) and ATF. Patients undergoing surgery for rheumatic valvular heart disease with continuous AF were prospectively randomized. Ablation lines were created with radiofrequency (RF) bipolar coagulation with cryoablation for the isthmal lesions and coronary sinus. Results were compared at 6 months and ATF was evaluated by atrial filling fraction (AFF) and A/E ratio on echocardiography.

Results

The rate of conversion to NSR in both groups was statistically insignificant by Fisher''s exact test (p > 0.05). ATF was better in modified radial approach compared to modified Cox''s Maze III (A/E compared by unpaired t test:0.52 ± 0.08 v/s 0.36 ± 0.10; p < 0.05. AFF compared using Mann Whitney U test: median AFF for radial group was 23 v/s 20 for biatrial group; p < 0.05).

Discussion

In patients with AF undergoing rheumatic valvular surgery, radiofrequency radial approach is as effective as modified Cox''s maze III for conversion to NSR with better atrial transport function.     

The impact of hypertension on the electromechanical properties and outcome of catheter ablation in atrial fibrillation patients

Background

Although hypertension is associated with atrial fibrillation (AF), the impact of hypertension on the electromechanical properties and outcome of catheter ablation in AF patients is unclear.

Methods

AF patients [n=213, 136 paroxysmal AF (PAF) patients and 77 persistent AF patients] undergoing circumferential pulmonary vein (PV) isolation guided by CARTO mapping were enrolled, and then were divided into normotension group and hypertension group. Several left atrial (LA) electroanatomical parameters determined by the CARTO system were compared between groups.

Results

The LA bipolar voltage was lower in PAF patients with than without hypertension (1.44±1.09 vs. 1.92±0.76 mV, P=0.048); a significant difference was also observed in persistent AF patients. Hypertension significantly increased the size of the LA scar and low-voltage zones (LVZs) in both PAF and persistent AF patients. However, hypertension did not significantly affect recurrence in either PAF or persistent AF patients. The LA bipolar voltage was higher in PAF patients without recurrence than in those with recurrence (1.77±1.01 vs. 1.29±0.93 mV, P=0.048); a significant difference was also observed in persistent AF patients. PAF and persistent AF patients with AF recurrence had significantly larger LA scar and LVZs than patients without recurrence.

Conclusions

Hypertension has a significant impact on the LA electromechanical properties in AF patients, and the LA substrate has an important influence on the outcome of catheter ablation.     

Predictors of Atrial Fibrillation Recurrence in Hyperthyroid and Euthyroid Patients

Background

Atrial fibrillation (AF) is the most common arrhythmia in adults, and is encountered in 10-15% of the patients with hyperthyroidism. Unless euthyroidism is restored, pharmacological or electrical cardioversion is controversial in patients with AF who remain hyperthyroid.

Objective

The aim of this study was to assess the efficacy of electrical cardioversion and predictors of AF recurrence in hyperthyroid and euthyroid patients.

Methods

The study included 33 hyperthyroid (21 males) and 48 euthyroid (17 males) patients with persistent AF. The patients were sedated with intravenous midazolam before undergoing electrical cardioversion delivered by synchronized biphasic shocks. Rates of AF recurrence were recorded.

Results

Mean follow-up was 23.63 ± 3.74 months in the hyperthyroid group and 22.78 ± 3.15 months in the euthyroid group (p = 0.51). AF recurred in 14 (43.8%) and 21 (44.7%) patients in each group, respectively (p = 0.93). Multivariate regression analysis in each group showed that AF duration was the only predictor of AF recurrence, with odds ratios of 1.38 (95% confidence interval [CI] = 1.05 - 1.82, p = 0.02) in the hyperthyroid group and 1.42 (95% CI = 1.05 - 1.91, p= 0.02) in the euthyroid group.

Conclusion

Rates of long-term AF recurrence were similar in successfully cardioverted hyperthyroid and euthyroid patients. The only predictor of AF recurrence in both groups was AF duration.     

External Cardioversion of Atrial Fibrillation Causes an Early Improvement of Cardiac Performance: A Longitudinal Strain Analysis Study

Introduction:

Atrial fibrillation (AF) is often associated with heart failure. Several studies have demonstrated that resumption of sinus rhythm (SR) improves cardiac output in the long-term. Aims of this study were to evaluate the acute variations of left ventricular (LV) performance, following successful external cardioversion (ECV) of persistent AF using longitudinal strain (LSt) analysis, and the influence of inflammation.

Materials and Methods:

We enrolled 48 patients with AF (age: 73 ± 12 years, men: 83.3%). A standard transthoracic echocardiographic evaluation was performed before the procedure and 6 h later; this included the analysis of LV endocardial peak LSt, a measure of myocardial deformation. In the last 32 patients, plasma concentration of interleukin-6 (IL-6) was also determined.

Results:

Restoration of SR led to the decrease of heart rate (HR) (74 ± 21 vs 64 ± 10 bpm, P < 0.001) and LV end-systolic volume (30 ± 16 vs 27 ± 17 mL/m², P = 0.001), and to the increase of LV end-diastolic volume (LVEDV) (56 ± 20 vs 60 ± 21 mL/m², P = 0.036) and ejection fraction (EF) (48 ± 10 vs 57 ± 11%, P < 0.001). Peak LSt improved in 43 (89.6%) patients (-12.9 ± 3.3 vs -18.0 ± 4.7%, P < 0.001). Multivariate analysis (R = 0.729, P < 0.001) showed that strain changes were directly correlated with basal HR and the appearance of atrial mechanical activity and inversely correlated with corrected thyroid dysfunction, LVEDV and the presence of a permanent pacemaker. Higher levels of IL-6 negatively affected LV performance improvement.

Conclusions:

Effective ECV of AF determines a significant and fast improvement of LV performance, which is readily captured by LSt analysis. Inflammatory status may impact the response to SR restoration.     

Wenxin Keli suppresses atrial substrate remodelling after epicardial ganglionic plexi ablation

BACKGROUND:

The chronic effects of ganglionic plexi (GP) ablation on atrial fibrillation (AF) inducibility have not been elucidated.

OBJECTIVE:

To investigate the effect of Wenxin Keli (WK) on the inducibility of AF and atrial substrate remodelling after epicardial GP ablation.

METHODS:

Twenty dogs were randomly divided into a sham-operated group, a GP ablation group and a WK-treated group. All animals underwent a left thoracotomy at the fourth intercostal space. AF inducibility was assessed by burst rapid pacing at the right atrium. Both the GP ablation group and the WK-treated group received four major GP ablations. In the WK-treated group, dogs were treated with oral WK once per day, and all animals were allowed to recover for eight weeks, after which AF inducibility and AF duration were measured again.

RESULTS:

After eight weeks of WK treatment, AF inducibility was lower than in the GP ablation group, and was similar to that of the sham-operated group. Compared with the sham-operated group, the levels of atrial natriuretic peptide (ANP), tumour necrosis factor-alpha (TNF-α) and interleukin (IL)-6 in right atrial tissues were increased in GP ablation group (143.6±33.7 pg/mg versus 206.2±41.4 pg/mg, P=0.02; 75.3±12.1 pg/mg versus 141.3±64 pg/mg, P=0.03; and 175.1±42.5 pg/mg versus 351.7±101 pg/mg, P<0.01, respectively). There were no significant differences in levels of ANP, TNF-α and IL-6 in atrial tissues between the sham-operated group and WK treated group. Expression of connexin 43 in atrial tissues was increased after eight weeks of GP ablation, while WK administration inhibited connexin 43 remodelling.

CONCLUSIONS:

Epicardial GP ablation can induce atrial substrate remodelling, including Cx43 upregulation and increased levels of ANP, TNF-α and IL-6. These changes may be suppressed by long-term oral WK administration.     

Feasibility and efficacy of electrical cardioversion after cardiac resynchronization implantation in patients with permanent atrial fibrillation

Purpose

Patients with permanent atrial fibrillation (AF) who undergo cardiac resynchronization therapy (CRT) may spontaneously recover sinus rhythm during follow-up. We tested the feasibility and efficacy of electrical cardioversion attempted after 3?months of CRT in patients with permanent AF and measured the long-term maintenance of sinus rhythm.

Methods

Twenty-eight consecutive patients with permanent AF in whom CRT defibrillators had been implanted were scheduled for internal electrical cardioversion after 3 months (group A) and were compared with a control group of 27 patients (group B).

Results

In group A, 22 patients (79?%) were eligible for cardioversion; sinus rhythm was restored in 18 (82?%) of these, with no procedural complications. After 12?months, 16 patients (58?%) in group A were in sinus rhythm, compared with one group B patient who spontaneously recovered sinus rhythm (4?%, p?<?0.001). On 12-month evaluation, ejection fraction had improved in both groups, but a reduction in left ventricular end-systolic volume was recorded only in group A patients (p?=?0.018 versus baseline).

Conclusions

In patients with permanent AF, the rhythm control strategy consisting of internal cardioversion, performed by means of the implanted cardioverter?Cdefibrillator after 3?months of CRT, was associated with a high rate of sinus rhythm resumption on long-term follow-up and with a better echocardiographic response to CRT than that seen in patients treated according to a rate control strategy.     

Detection of paroxysmal atrial fibrillation or flutter in patients with acute ischemic stroke or transient ischemic attack by Holter monitoring

Background and purpose

Paroxysmal atrial fibrillation and flutter are strong risk factors for stroke. Due to high recurrence rate of ischemic events and given the benefit of oral anticoagulation over antiplatelet drugs, it is important to identify this arrhythmia. Unfortunately, paroxysmal AF or flutter is asymptomatic in majority and therefore, difficult to detect.

Methods

Consecutive patients presenting with symptoms of acute ischemic stroke or transient ischemic attack were included. All patients free of AF or flutter on presentation underwent 24 h Holter monitoring within 7 days of admission.

Results

Overall, fifty two (52) patients (mean age 59.51 ± 13.45 years) with acute stroke (80.8%) and TIA (19.8%) underwent 24 h Holter monitoring. Paroxysmal AF was detected in 3 cases (5.8%), all 3 patients had acute stroke and were older than age 60 years. Type of stroke was the only factor which was associated with greater risk of having paroxysmal AF or flutter, AF accounted for 50% cases (2 out of 4) of clinically suspected cardio embolic stroke.

Conclusion

Screening consecutive patients with ischemic stroke with routine Holter monitoring will identify new atrial fibrillation/flutter in approximately one in 17 patients. Older age and type of stroke are strongly associated with increased risk. By carefully selecting the patients, the detection rates could be further increased.     

Midterm results of left atrial bipolar radiofrequency ablation combined with a mitral valve procedure in persistent atrial fibrillation

Introduction

The aim of the study was to assess the midterm results of left atrial bipolar radiofrequency ablation combined with a mitral valve procedure in patients with mitral valve disease and persistent atrial fibrillation.

Methods

Between October 2006 and July 2009, 95 patients with mitral valve disease and persistent atrial fibrillation underwent a mitral valve procedure and left atrial bipolar radiofrequency ablation. The postoperative data of the combined procedure were collected at the time of discharge and at one, three, six and 12 months after the operation.

Results

Hospital mortality rate was 6.3% (six patients). Normal sinus rhythm was achieved in 77.2% of patients during the early postoperative period in hospital, and in 73.3, 72.0 and 75% of patients at three, six and 12 months postoperatively, respectively. Patients were followed up for a mean duration of 14.02 ± 5.71 months (range: 6–19 months). During this midterm follow-up period, nine patients had late recurrence of atrial fibrillation. No risk factor was identified for late recurrence of atrial fibrillation.

Conclusion

Our midterm follow-up results suggest that the addition of left atrial bipolar radiofrequency ablation to mitral valve surgery is an effective and safe procedure to restore sinus rhythm in patients with chronic atrial fibrillation.     

One-year outcome of cardioversion of atrial fibrillation in patients with mitral stenosis after percutaneous balloon mitral valvuloplasty

Our objectives were to study the success rate of electrical cardioversion after percutaneous balloon mitral valvuloplasty (PBMV) in patients with symptomatic moderate-to-severe mitral stenosis and atrial fibrillation (AF) and the maintenance rate of sinus rhythm for < or =1 year. We studied patients with mitral stenosis and AF who were scheduled for PBMV. Electrical cardioversion was performed 1 month after PBMV. Amiodarone 200 mg/day was started the day after PBMV. The primary outcomes studied were the rate of successful cardioversion and the maintenance rate of sinus rhythm at 12 months. Of 272 patients scheduled for PBMV, 70 were enrolled. The average age was 45 +/- 10 years. The average mitral valve area was 0.82 +/- 0.22 cm(2). Cardioversion was successful in 50 patients (71%). Logistic regression analysis revealed that left atrial size and associated aortic valvular disease were predictors of successful cardioversion. Of the 50 patients with successful cardioversion, AF recurred in 24 (48%). An increased left atrial diameter was the only factor associated with AF recurrence at 12 months. In conclusion, good candidates for cardioversion after PBMV were those with a left atrial diameter of <60 mm and no associated aortic valvular disease -- approximately 43% of patients with AF scheduled for PBMV. In this group, about 2/3 were in sinus rhythm at 12 months after cardioversion.     

附加扩大左房减容与直流电转复模式对瓣膜病合并心房颤动患者心房颤动的影响

目的研究在进行基础瓣膜置换或成形手术时附加左房减容和直流电复律术对瓣膜病合并心房颤动(简称房颤)患者房颤的影响。方法选取有心脏瓣膜病变且合并左房扩大病例298例,均伴有诊断明确的房颤病史,根据左房内径大小分成Ⅰ、Ⅱ、Ⅲ3组:左房内径40～59mm为Ⅰ组,共83例,60～79mm为Ⅱ组,共161例,80mm以上为Ⅲ组,共54例。按照住院号单双数随机将三组又分为2个亚组行瓣膜手术附加左房减容术和直流电转复为a组,未附加手术为b组;左房减容包括左房折叠和左房壁切除,直流电电转复包括电复律,起始量为10J,依次10J累加,最大达30J。如果a组自动复跳为窦性心律,依然加10J电击一次。所有病例均于术前口服可达龙并术后维持治疗。结果Ⅰa组和Ⅰb组术后早期和出院时的窦性转复率无明显差异,但随访9～12个月,Ⅰa组的窦性转复率明显高于Ⅰb组(35.3%vs28.6%P(0.05);Ⅱ组和Ⅲ组中a亚组的窦性转复率在术后早期、出院时以及随访期间均明显高于b亚组。Ⅰa组与在出院和随访期间窦性转复率高于Ⅱa、Ⅲa(44.1%vs34.4%、27.3%;35.3%vs30.0%、12.1%,P均(0.05),Ⅱa组在出院和随访期间窦性转复率亦高于Ⅲa组(34.4%vs27.3%;30.0%vs12.1%,P(0.05)。结论对于左房扩大的瓣膜病变伴房颤患者,在进行基础瓣膜置换或成形手术时附加左房减容和直流电复律手术,可以达到一个非常理想的房颤转复率和维持率,但左房内径达80mm以上的病例其远期效果不佳。     

口服奎尼丁转复心房颤动的临床分析

应用口服奎尼丁转复心房颤动（AF）393例次，评价其效果、安全性、血药浓度的意义及相关因素对转复的影响。奎尼了用量第1日每次0．2g，每2h1次，共5次。如未能转复逐日每次递增0．1g，至第3日仍未转复逐停药。有47例测了血药浓度。393例次AF中324例次（82．4％）转复成功，平均转复时间为13．7±5．1（2～42）h。高血压病、冠心病、心肌病及孤立性AF的转复率较风湿性心脏病者为高（93．8％、88．9％、88.9％、95.7％vs76.4％，P＜0．05）。AF持续时间＜6个月者转复率高于6～12及＞12个月者（88．2％vs69．2％、56．3％，P＜0．01）。左房内径＜50mm者转复率高于≥50mm者（89．7％vs72．0％，P＜0.05）。有效见药浓度为1．5～6．0ng／ml。未发现与奎尼丁有关的严重副作用。表明口服奎尼丁转复AF的成功率高，严重不良反应的发生率低，其仍不失为治疗AF的一种较好方法。     

Atrial synchronous left ventricular only pacing with VDD pacemaker system – A cost effective alternative to conventional cardiac resynchronization therapy

Introduction

Atrial synchronous left ventricular (LV) only pacing using two leads and VDD pacemaker could be a cost effective alternative to conventional cardiac resynchronization therapy (CRT).

Methods

We implanted right atrial (RA) and LV leads with VDD pulse generator (LV only pacing) in five carefully screened heart failure patients who could not afford conventional CRT. All had NYHA class III/IV symptoms despite maximal guideline directed medical therapy. The sensed atrioventricular delay was programmed to pre-excite the LV and achieve fusion beat. Response to treatment was assessed at 6 months.

Results

Four patients were males. The mean age was 58 ± 12 years. At follow up, there was improvement in electrocardiographic, and echocardiographic parameters: Mean QRS duration decreased from 174 ± 17 msec to 128 ± 10.9 msec (p = 0.009), LV end-diastolic diameter decreased from 73.2 ± 12 mm to 65.8 ± 9.6 mm (p = 0.026), LV end-systolic diameter decreased from 65 ± 12 mm to 54 ± 10 mm (p = 0.020). There was a trend towards reduction of LV end-systolic and end-diastolic volumes. LV ejection fraction improved from 25 ± 6% to 34 ± 6% (p = 0.013) and left atrial dimension reduced from 44 ± 4 mm to 39 ± 5 mm (p = 0.045). All patients improved clinically.

Conclusion

RA-LV pacing using VDD pacemaker is a safe and effective technique of CRT. This may be a cost effective alternative to conventional CRT for patients in developing countries.     

In vitro study of coronary flow occlusion in transcatheter aortic valve implantation

Background

Transcatheter aortic valve implantation (TAVI) has been developed recently for patients with high morbidities and who are believed to be not tolerate standard surgical aortic valve replacement. Nevertheless, the TAVI is associated with complications such as potential obstruction of coronary ostia, mitral valve insufficiency, and stent migration although it seems promising. Impairment of the coronary blood flow after TAVI is catastrophic and it was believed to be associated with the close position of the coronary orifice and the aortic leaflets and valve stent. However, few data was available as to the anatomic relationship between valve stent and aortic root anatomic structures including the coronary arterial ostia, aortic leaflets.

Methods

The aortic roots were observed in 40 hearts specimens. The width of aortic leaflet, height of aortic sinus annulus to the sinutubular junction (STJ), distance between aortic sinus annulus to its corresponding coronary ostia, and coronary arterial ostia to its corresponding STJ level were measured. Moreover, the relationships of valve stent, aortic leaflets and coronary ostia before/post stent implantation and after the open of aorta were evaluated respectively.

Results

Approximate three quarters of the coronary ostia were located below the STJ level. The mean distances from left, right and posterior aortic sinus annulus to the related STJ level was comparable, which was 18.5±2.7, 18.9±2.6, 18.7±2.6 mm, respectively. Meanwhile, the height of left and right aortic sinus annulus to its corresponding coronary ostia was 16.6±2.8 and 17.2±3.1 mm for left and right side respectively.

Conclusions

Most of the coronary ostia were located below the STJ level and could be covered by the leaflets. This highlights the need of modified stents to prevent occlusion of coronary flow after TAVI.     

Serum Potassium Levels Inversely Correlate with D-Dimer In Patients with Acute-Onset Atrial Fibrillation

Background

D-dimer values are frequently increased in patients with atrial fibrillation (AF) compared to subjects in sinus rhythm. Hypokalemia plays a role in several cardiovascular diseases, but little is known about the association with AF.

Objective

D-dimer values are frequently increased in patients with atrial fibrillation (AF) compared with subjects in sinus rhythm. Hypokalemia plays a role in several cardiovascular diseases, but little is known about the association with AF. The aim of this study was to investigate correlations between D-dimer and serum potassium in acute-onset AF (AAF).

Methods

To investigate the potential correlation between the values of serum potassium and D-dimer in patients with AAF, we retrospectively reviewed clinical and laboratory data of all emergency department visits for AAF in 2013.

Results

Among 271 consecutive AAF patients with D-dimer assessments, those with hypokalemia (n = 98) had significantly higher D-dimer values than normokalemic patients (139 versus 114 ng/mL, p = 0.004). The rate of patients with D-dimer values exceeding the diagnostic cut-off was higher in the group of patients with hypokalemia than in those with normal serum potassium (26.5% versus 16.2%; p = 0.029). An inverse and highly significant correlation was found between serum potassium and D-dimer (r = −0.21; p < 0.001), even after adjustments for age and sex (beta coefficient −94.8; p = 0.001). The relative risk for a positive D-dimer value attributed to hypokalemia was 1.64 (95% CI, 1.02 to 2.63; p = 0.040). The correlation remained statistically significant in patients free from antihypertensive drugs (r = −0.25; p = 0.018), but not in those taking angiotensin-receptor blockers, angiotensin-converting enzyme inhibitors, or diuretics.

Conclusions

The inverse correlation between values of potassium and D-dimer in patients with AAF provides important and complementary information about the thromboembolic risk of these patients.     

Catheter ablation of atrial fibrillation in the elderly

Background Atrial fibrillation （AF） catheter ablation has emerged as a promising treatment strategy for AF, but has not been widely adopted in the elderly population. The present study aimed to determine the safety and efficacy of AF catheter ablation in the elderly popula-tion. Methods and Results The study population consisted of 316 patients with paroxysmal AF who underwent left atrial ablation. Ninety-five patients were≥65 years （48 males, mean age 68.9 ± 3.0 years old） and 221 patients were〈65 years old （130 males, mean age 52.5 ± 10.4 years old）. After a mean follow-up period of 34.0 ± 15.1 months, 55 （57.9%） patients in the elderly group were free from ar-rhythmia recurrence compared with 149 （67.4%） patients in the younger group （P=0.169）. Procedural complications were uncommon in both study groups. In logistic regression analysis, left atrial diameter （P=0.003）, hypertension （P=0.001）, dyslipidemia （P=0.039）, and coronary artery disease （P=0.018） were independent predictors of AF recurrence in the elderly population. Conclusions Catheter ablation of AF is safe and effective in older patients. Invasive strategies should be considered as an alternative choice in symptomatic elderly patients with AF.     

Pulmonary venous structural remodeling in a canine model of chronic atrial dilation due to mitral regurgitation

OBJECTIVE:

Structural remodelling plays an important role in the genesis and maintenance of atrial fibrillation (AF). Although some studies that associate structural remodelling with atrial dilation have been reported, structural pulmonary venous (PV) remodelling due to chronic atrial dilation remains unclear.

METHODS:

Six sham dogs and five mitral regurgitation (MR) dogs (three months after partial mitral valve avulsion) were studied. Separate cryosections from the PV and left atrium (LA) were immunolabelled with antibodies against connexin (Cx) 40 and Cx43 and analyzed by confocal laser scanning microscopy. Tissue samples from the PV and LA were stained with hematoxylin and eosin, and Masson’s trichrome.

RESULTS:

In MR models, a decrease in Cx40 (0.57±0.2% versus 1.18±0.3%, P<0.05) and Cx43 (0.48±0.2% versus 1.56±0.5%, P<0.05) expression was observed compared with sham dogs. The distribution pattern of Cx40 and Cx43 changed from homogeneous to heterogeneous. Gap junction remodelling was not observed in the LA. In Masson’s trichrome-stained sections from MR dogs, regions with increased interstitial fibrosis were present in the PV. Thickness in the PV and the PV-LA junction did not change in the MR group.

CONCLUSION:

The present study demonstrated a decrease in Cx40 and Cx43 expression and increased interstitial fibrosis in PV due to MR. These changes may potentially be a mechanism that renders the dilated atria more susceptible to AF.