Long-Term Follow-Up of Corridor Operation for Lone Atrial Fibrillation:

Late Results of Surgery for AF. Introduction: Currently, surgery- and catheter-mediated ablation is applied when drug refractoriness of atrial fibrillation is evident, although little is known about the long-term incidence of new atrial arrhythmia and the preservation of sinus node function.
Methods and Results: To address this issue, 30 patients with successful corridor surgery for lone paroxysmal atrial fibrillation and normal preoperative sinus node function were followed in a single outpatient department. Five years after surgery, the actuarial proportion of patients with recurrence of atrial fibrillation arising in the corridor was 8%± 5%, with new atrial arrhythmias consisting of atrial flutter and atrial tachycardia in the corridor 27%± 8%, and with incompetent sinus node requiring pacing therapy 13%± 6%. Right atrial transport was preserved in 69% of the patients without recurrence of atrial fibrillation and normal sinus node function. Stroke was documented in two patients.
Conclusions: Corridor surgery for atrial fibrillation is a transient or palliative treatment instead of a definitive therapy for drug refractory atrial fibrillation. This observation strongly affects patient selection for this intervention and constitutes a word of caution for other, non-pharmacologic interventions for drug refractory atrial fibrillation.     

Cardiomyopathy and atrioventricular block in Emery-Dreifuss muscular dystrophy--a case report

A 32-year-old woman is described as having the following characteristics of Emery-Dreifuss muscular dystrophy: humeroperoneal muscular atrophy and weakness, neck and elbow contractures with sinus bradycardia, first-degree atrioventricular block, and dilated cardiomyopathy. The biopsy specimen of skeletal muscle showed dystrophic character; a cardiac endomyocardial biopsy specimen showed adipose tissue infiltration and deposition of antihuman IgG. Emery-Dreifuss muscular dystrophy is an X-linked recessive myopathy. The patient had no familial background of the disease. This patient might have a sporadic inheritance pattern with severe cardiac involvement.     

Design and rationale of a randomized study to compare amiodarone and Class IC anti-arrhythmic drugs in terms of atrial fibrillation treatment efficacy in patients paced for sinus node disease: the PITAGORA trial.

AIMS: Many sinus node disease (SND) patients suffer from atrial fibrillation (AF). Anti-arrhythmic drugs (AADs) are the therapeutic mainstay for AF prophylaxis. The PITAGORA trial has a multicentre, prospective, randomized, single blind design to compare amiodarone with Class IC AADs in patients who have an AF history and are paced for SND. METHODS AND RESULTS: Starting from January 2001, 176 patients received a Medtronic AT500 pacemaker. AADs were randomly assigned with a 3 : 2 ratio between Class III and Class IC. Randomization was stratified in order to assign two patients to amiodarone and one patient to sotalol every three Class III AAD patients. After a 5-month observational period, Ramp or Burst+ ATP therapies were enabled in a randomized way, maintained for 4 months, and then crossed over. Total follow-up period is 21 months. The primary long-term objective is to show the non-inferiority of IC AADs compared with amiodarone in terms of time to first occurrence of a composite endpoint (death, atrial cardioversion, hospitalizations due to AF or heart failure, or change of AADs). Data will be analysed on an intention-to-treat basis. The primary short-term objective is to compare Ramp vs. Burst+ efficacy in terminating atrial tachyarrhythmias treated by the device. Secondary endpoints are major clinical events, medication toxicity, symptoms, AF burden, and quality-of-life. CONCLUSION: Given the high morbidity and healthcare costs associated with AF, new therapeutic strategies are needed. The results of the PITAGORA trial may help in guiding AADs therapy and ATP programming in SND patients suffering from AF.     

Emery-Dreifuss muscular dystrophy: case report

Emery-Dreifuss muscular dystrophy type 1 (EDMD1) is a familial disease with X-Linked recessive transmission, caused by a mutation in a nuclear envelope protein, emerin. Clinical manifestations usually occur in adolescence and include contractures, muscle atrophy and weakness, and cardiac conduction disturbances. We describe the case of a young male, aged 16, with first-degree atrioventricular (AV) block and limited extension of both forearms. He had elevated CK, and cardiac monitoring showed severe conduction tissue disease, with significant sinus pauses, chronotropic incompetence and periods of AV dissociation during exercise. Immunohistochemical staining using an emerin antibody showed absence of the protein in a fragment of muscle tissue and genetic study identified a mutation associated with EDMD1. Study of his brother, aged 21, also established a diagnosis of EDMD1. Both individuals received a permanent pacemaker but musculoskeletal manifestations at that time did not warrant any other intervention: Screening for certain genetic diseases, including muscular dystrophies, is mandatory following identification of conduction abnormalities in young people.     

Sinus Pacemaker Function after Cardioversion of Chronic Atrial Fibrillation: Is Sinus Node Remodeling Related with Recurrence?

INTRODUCTION: The objective of this study was to investigate the temporal changes in sinus node function in postcardioversion chronic atrial fibrillation (AF) patients and their possible relation with the recurrence rates of AF. METHODS AND RESULTS: In 37 chronic AF patients, internally cardioverted to sinus rhythm, corrected sinus node recovery time (CSNRT), and the pattern of corrected return cycle lengths were assessed 5 to 20 minutes and 24 hours after conversion. The last 20 consecutive patients also were evaluated after autonomic blockade. Twenty subjects with normal atrial structure and no history of AF served as the control group. Patients were followed-up for 1 month for recurrence, and the density of supraventricular ectopic beats per hour was obtained during the first 24 hours after conversion. Fifteen patients (40.5%) relapsed during follow-up. CSNRT values at 600 msec (371 +/- 182 msec) and 500 ms (445 +/- 338 msec) were significantly higher than those of control subjects (278 +/- 157 msec, P = 0.050, and 279 +/- 130 msec, P = 0.037, respectively). Significant temporal changes in CSNRT also were observed during the first 24 hours after conversion (600 msec: 308 +/- 120 msec, P = 0.034; 500 msec: 340 +/- 208 msec, P = 0.017). No significant interaction and temporal effects were observed with regard to corrected return cycle length pattern. Similar data regarding CSNRT and corrected return cycle length pattern were obtained after autonomic blockade. Patients with abnormal CSNRT after cardioversion had higher recurrence rates (50%) than those with normal function (37%; P = NS). Patients who relapsed had a higher density of supraventricular ectopic beats per hour (159 +/- 120) compared with those who did not (35 +/- 37; P = 0.001). CONCLUSION: Depressed sinus node function is observed after conversion of chronic AF. Recovery from this abnormality and its independence from autonomic function suggest that AF remodels the sinus node. Our data do not support a causative role of sinus node function in AF recurrence, but they do indicate such a role for the density of atrial ectopic beats.     

Ventricular arrhythmia in X-linked Emery-Dreifuss muscular dystrophy: a lesson from an autopsy case

Emery-Dreifuss muscular dystrophy (EDMD) is a distinctive form of muscular dystrophy which is often associated with cardiac abnormalities. Conduction disturbances are frequently observed, and may necessitate pacemaker implantation to prevent sudden death. In this case report, we present an autopsy of a 31-year-old man with X-linked EDMD who developed only minimal skeletal muscle symptoms, and who died from ventricular arrhythmia despite undergoing a previous pacemaker implantation. Ventricular arrhythmias in X-linked EDMD patients are also discussed.     

Newly detected atrial fibrillation following dual chamber pacemaker implantation

Introduction: Pacemaker (PPM)-detected atrial high-rate episodes (AHREs) of even 5-minute duration may identify patients at increased risk for stroke and death. In this study, we sought to determine the incidence of newly detected atrial fibrillation (AF defined as an AHRE ≥5 minutes) in patients following dual-chamber PPM implantation and to define the clinical predictors of developing AF.
Methods and Results: We evaluated 262 patients (142 male; age 74 ± 12 years) without documented AF who underwent PPM implantation for sinus node dysfunction (n = 122) or atrioventricular block (n = 140). Information regarding patient demographics, cardiovascular diseases, and medication history was obtained. The cumulative percentages of ventricular pacing as well as the frequency, duration, and time to first episode of an AHRE were also determined. During follow-up of 596 ± 344 days, an AHRE ≥5 minutes was detected in 77 (29%) patients. Of these, 47 (61%) patients had an AHRE ≥1 hour, 22 (29%) patients had an AHRE ≥1 day, and 12 (16%) patients had an AHRE ≥1 week. An AHRE ≥5 minutes was seen in 24% and 34% of patients at 1 year and 2 years, respectively. Among patients with sinus node dysfunction, ≥50% cumulative ventricular pacing was the only significant predictor of an AHRE ≥5 minutes (HR 2.2; CI 1.0–4.7; P = 0.04).
Conclusions: Within 1 year of PPM implantation, AF is detected in 24% of patients without history of AF. In patients with sinus node dysfunction, ≥50% cumulative right ventricular pacing is associated with a 2-fold increase in risk of developing AF.     

Interatrial Mechanical Dyssynchrony Worsened Atrial Mechanical Function in Sinus Node Disease With or Without Paroxysmal Atrial Fibrillation

Introduction: Atrial electromechanical dysfunction might contribute to the development of atrial fibrillation (AF) in patients with sinus node disease (SND). The aim of this study was to investigate the prevalence and impact of atrial mechanical dyssynchrony on atrial function in SND patients with or without paroxysmal AF. Methods: We performed echocardiographic examination with tissue Doppler imaging in 30 SND patients with (n = 11) or without (n = 19) paroxysmal AF who received dual‐chamber pacemakers. Tissue Doppler indexes included atrial contraction velocities (Va) and timing events (Ta) were measured at midleft atrial (LA) and right atrial (RA) wall. Intraatrial synchronicity was defined by the standard deviation and maximum time delay of Ta among 6 segments of LA (septal/lateral/inferior/anterior/posterior/anterospetal). Interatrial synchronicity was defined by time delay between Ta from RA and LA free wall. Results: There were no differences in age, P‐wave duration, left ventricular ejection fraction, LA volume, and ejection fraction between with or without AF. Patients with paroxysmal AF had lower mitral inflow A velocity (70 ± 19 vs 91 ± 17 cm/s, P = 0.005), LA active empting fraction (24 ± 14 vs 36 ± 13%, P = 0.027), mean Va of LA (2.6 ± 0.9 vs 3.4 ± 0.9 cm/s, P = 0.028), and greater interatrial synchronicity (33 ± 25 vs 12 ± 19 ms, P = 0.022) than those without AF. Furthermore, a lower mitral inflow A velocity (Odd ratio [OR]= 1.12, 95% Confidence interval [CI] 1.01–1.24, P = 0.025) and prolonged interatrial dyssynchrony (OR = 1.08, 95% CI 1.01–1.16, P = 0.020) were independent predictors for the presence of AF in SND patients. Conclusion: SND patients with paroxysmal AF had reduced regional and global active LA mechanical contraction and increased interatrial dyssychrony as compared with those without AF. These findings suggest that abnormal atrial electromechanical properties are associated with AF in SND patients.     

Sinus node dysfunction concomitant with Brugada syndrome.

BACKGROUND: A genetic correlation between Brugada syndrome (BS) and sinus node dysfunction (SND) has been proposed, although the clinical and electrophysiologic characteristics of this concomitant condition are unknown. METHODS AND RESULTS: The study comprised 5 patients with symptomatic BS (4 with spontaneous episodes of ventricular fibrillation (VF) and 1 with syncope) of whom 3 had a documented sinus pause > 3 s (a 42- and 62-year-old man, and a 49-year-old woman). Only 1 of them had a family history of sudden death; 2 of them had also had an episode of atrial fibrillation or flutter. Electrophysiologic study demonstrated prolonged sinus node recovery time in 2 patients (2.6 s and > 5 s), in whom a cardiac pacemaker had been implanted before the diagnosis of BS was made after episodes of VF. Finally, all 3 patients received an implantable cardioverter defibrillator, including 2 upgrades from pacemaker. CONCLUSIONS: SND is not a rare concomitant disorder in BS and there is a possible genetic connection.     

Dispersion of atrial refractoriness in patients with sinus node dysfunction.

Abnormal atrial refractoriness was examined as a cause of atrial fibrillation/flutter (AFF) in patients with bradycardia. Refractory periods at three disparate right atrial sites were compared in 17 patients with sinus node dysfunction (SND) and 16 controls. Atrial pacing shortened refractory periods, but failed to decrease dispersion of refractoriness significantly. During sinus rhythm, duration and dispersion of refractoriness were greater in SND patients than in controls. These differences persisted with atrial pacing. For example, at the paced rate, dispersion of effective refractory periods in SND patients was greater than in controls (62.9 +/- 34 vs 36.6 +/- 21 msec, p less than 0.01). Six SND patients had AFF, but they did not have greater dispersion than other SND patients, or unusually short or long refractory periods. Thus, prolonged and nonuniform refractoriness were features of SND. Abnormal refractoriness in SND reflected atrial disease and persisted with pacing. These abnormalities were not unique to patients with AFF.     

Influence of structural heart disease on characteristics of atrial fibrillation recurrence in patients with dual-chamber pacemakers

Aims

The aim of the study was to prospectively examine the influence of structural heart disease (SHD) and sinus node dysfunction (SND) on the frequency and duration of atrial fibrillation (AF) episodes in patients with implanted pacemakers.

Methods

We examined episodes of AF in 207 patients (93 with SHD; 165 with SND) with known or suspected paroxysmal AF who underwent dual-chamber pacing.

Results

Seventy-one percent of all patients experienced at least one episode of AF during follow-up, with a mean burden of 3.3 ± 6.4 h/d (median, 0.2 hours) and a mean frequency of 11.7 ± 26.0 episodes per day (median, 1.4). The proportion of episodes longer than 6 hours was greater in patients with SHD when compared to patients without SHD. In a logistic regression model adjusted for SND, gender, and the 2-way interactions of SND, sex, and SHD, SHD was a significant factor (P = .0188) with the odds ratio of having an episode longer than 6 hours 3.4 times higher for patients with SHD than for patients without SHD. Older patients with SHD had less frequent but longer episodes compared to younger patients. In patients without SHD, there was no comparable age difference. Burden, frequency, and average episode length were not influenced by the presence or absence of SND.

Conclusions

Patients with SHD have longer episodes of AF supporting the concept that SHD influences the underlying substrate to favor perpetuation.     

慢性心房颤动对扩张性心肌病患者长期预后的影响

探讨慢性心房颤动 (简称房颤 )对扩张性心肌病患者长期预后的影响。将扩张性心肌病并心力衰竭 (简称心衰 )患者分为窦性心律 (简称窦律 )组 (共 38例 ,其中男 2 5例、女 1 3例 )和房颤组 (共 37例 ,其中男 2 5例、女 1 2例 ) ,二组基础状态基本相似。房颤组只控制心室率。随访二组患者的临床预后情况 ,包括 :死亡人数 ,死亡原因 ,入选至死亡的生存时间。结果 :经过 4 8.3± 2 5 .0月随访 ,发现二组患者远期生存率相似 ,死亡患者生存时间相似 ,死亡方式相似 ;与窦律组相比 ,房颤组左房内径较大 (5 3.1± 5 .6mmvs4 7.1± 4 .8mm)、最快心室率较快 (1 6 2 .8± 1 9.3vs1 1 7.2± 1 6 .9) ,二组差异有显著性 (P <0 .0 5 )。结论 :慢性房颤对扩张性心肌病的远期预后可能无明显影响     

Dual tachycardias associating double-exit left aortic sinus cusp tachycardia with paroxysmal atrial fibrillation: evidence of a link between both arrhythmias by means of the autonomic nervous system

Introduction: Dual tachycardias associating paroxysmal atrial fibrillation (AF) with double-exit left aortic sinus cusp tachycardia (LASCT) are described for the first time in a patient referred for AF ablation.
Case: Both tachycardias were successfully ablated under Carto-Merge® guidance. Noteworthy, vagal denervation during AF ablation was responsible for an immediate decrease in LASCT occurrence and inducibility.
Conclusion: This case highlights the critical role that the autonomic nervous system plays within the cardiac arrhythmia framework.     

Echocardiographic assessment of left ventricular morphology and function in patients with Emery-Dreifuss muscular dystrophy

BACKGROUND: Emery-Dreifuss muscular dystrophy (EDMD) characterized by musculoskeletal abnormalities is often associated with atrioventricular conduction disturbances. Although some EDMD patients were reported to develop dilated cardiomyopathy, there are limited data on their left ventricular (LV) performance. METHODS: Therefore, we echocardiographically assessed 27 men (23 cases aged 26.4+/-6.8 years with X-linked, and four cases aged 22.2+/-8.6 years with autosomal dominant (AD)) EDMD. Control group included 16 male healthy controls aged 24.8+/-6.0 (18-37) years. RESULTS: Although LV end diastolic dimension was similar in EDMD and controls (4.9+/-0.6 and 4.99+/-1.1 cm, ns), dilated left ventricle was found in three X-linked EDMD subjects. LV ejection fraction was significantly reduced in EDMD (62.3+/-1% vs. 71.2+/-2%, p=0.01) and was below 50% in six (22.2%) X-linked EDMD patients. Doppler analysis disclosed prolonged isovolumetric relaxation time of the left ventricle in the studied group. This finding may indicate impaired LV relaxation. CONCLUSION: A significant subgroup of X-linked EDMD patients shows pronounced abnormalities of left ventricular function. This warrants cardiologic follow up of EDMD patients.     

窦房结功能障碍时心房电活动的变化

目的 :研究家兔窦房结功能障碍 (SND)时心房肌电生理变化。方法 :健康家兔 30只。用射频消融法消融窦房结区 ,建立SND模型。分别测定消融前及消融后 1、2、4、6h及 7d时心房有效不应期 (ERP)、期前收缩刺激时心房潜伏期 (S1 A1、S2 A2 )、S1、S2 刺激时心房反应时间 (A1、A2 )及心房肌波长指数 (WLI)。结果 :消融后 2、4、6h及 7d时心房ERP及WLI明显缩短 (P <0 .0 1) ,A1及A2 明显延长 (P<0 .0 1) ,以消融后 2h出现明显 ,6h已基本稳定。但消融后 1h与消融前比较 ,除WLI减少外 ,其他各项电生理指标差异无显著性意义。结论 :家兔SND时可导致心房ERP缩短 ,WLI降低 (心肌波长变小 ) ,传导缓慢及紊乱 ,可能是病态窦房结综合征出现房性心律失常的电生理基础     

Electrophysiologic characteristics of the atrium in sinus node dysfunction: atrial refractoriness and conduction

INTRODUCTION: Clinical electrophysiology (EP) has focused attention on the EP properties of atrial muscle in patients with atrial fibrillation (AF). Patients with sinus node dysfunction (SND) sometimes are included in these studies, but the characteristics of these patients with SND alone appear less well investigated. METHODS AND RESULTS: We reviewed EP data of 46 patients (mean age 70 +/- 8 years) with SND, who underwent EP study for evaluation of the atrial substrate. In 16 patients, a history of paroxysmal AF was documented, but not in the remaining 30 patients who had SND alone. We considered as control a group of 25 subjects (mean age 63 +/- 14 years), who were referred to our EP laboratory for unexplained syncope or AV conduction disturbances. Following pharmacologic washout and at a drive cycle of 600 msec, effective (ERP) and functional refractory periods (FRP), S1-A1 and S2-A2 latency, A1 and A2 width, latent vulnerability index (ERP/A2), and P wave duration on the surface ECG were measured. Intra-atrial conduction times were measured from the stimulus artifact by pacing the high right atrium (HRA), to the corresponding atriograms at the AV node (HRA-AVN), low lateral atrium (HRA-LLA), and low interatrial septum close to the coronary sinus ostium (HRA-CSO). Compared with the control group, SND patients did not show differences in ERP (238 +/- 26 msec vs 250 +/- 29 msec), FRP (274 +/- 25 msec vs 280 +/- 32 msec), S1-A1 (38 +/- 15 msec vs 33 +/- 11 msec) and S2-A2 latency (67 +/- 24 msec vs 63 +/- 25 msec), or HRA-AVN (81 +/- 24 msec vs 65 +/- 19 msec), HRA-LLA (36 +/- 30 msec vs 40 +/- 27 msec), and HRA-CSO (77 +/- 17 msec vs 80 +/- 15 msec) conduction times. In contrast, we observed strong differences in atriogram durations A1 (59 +/- 19 msec vs 39 +/- 13 msec; P < 0.001) and A2 (92 +/- 28 msec vs 57 +/- 18 msec; P < 0.001), as well as in the latent vulnerability index ERP/A2 (2.8 +/- 1.2 msec vs 4.8 +/- 1.7; P < 0.001). Also, the P wave was slightly longer (104 +/- 18 msec vs 94 +/- 45 msec; P < 0.05). No significant statistical difference in EP parameters was found between SND patients with or without documented AF. CONCLUSION: In patients with SND, atrial refractoriness appears similar to that of control subjects. The most important EP abnormality appears to be local conduction slowing disturbances, with prolonged basal and postextrastimuli atriograms, responsible for a lower vulnerability index. This could explain, at least in part, the tendency of patients with SND to develop AF during their natural history. Normality of atrial refractoriness, in contrast to atrial conduction disorders, might explain why atrial pacing shows a preventative effect on the development of AF and why antiarrhythmic drugs often are ineffective.     

A Systematic Review of Randomized Trials Comparing Radiofrequency Ablation with Antiarrhythmic Medications in Patients with Atrial Fibrillation

Introduction: Atrial fibrillation (AF) is the most frequent arrhythmia seen in clinical practice. Until recently, antiarrhythmic medications have been the only commonly employed treatment for maintaining sinus rhythm. However, antiarrhythmic medications have a modest long-term efficacy and the potential for serious side effects. Radiofrequency (RF) ablation is now emerging as a viable alternative to antiarrhythmic medications in maintaining sinus rhythm in patients with AF. Several randomized trials comparing RF ablation with antiarrhythmic medications have now been published.
Objectives: To perform a systematic review of published randomized trials comparing RF ablation with antiarrhythmic medications in the treatment of AF.
Methods: A systematic review of the literature was performed and two authors independently abstracted the data from trials. A statistical analysis was performed using Comprehensive Meta-Analysis Software™ (BIOSTAT, Englewood, NJ, USA).
Results: A total of six trials were identified. Overall, RF ablation reduced the risk of AF recurrence by 65% at 1 year compared with antiarrhythmic medications.
Conclusions: In selected patients with AF, RF ablation reduced the risk of AF recurrence at 1 year by 65% compared with antiarrhythmic medications.     

Emery-Dreifuss humeroperoneal muscular dystrophy: cardiac manifestations

Emery-Dreifuss muscular dystrophy (EDMD) is an inherited disorder affecting skeletal and cardiac muscles and characterized by muscular atrophy, contractures, and cardiomyopathy with conduction defects. It can be X-linked or autosomal. Not all patients with EDMD develop heart involvement, but heart disease associated with EDMD can be unpredictable and may be life threatening. In rare cases heart problems may be the first symptom of EDMD. Early recognition of heart involvement is of utmost importance as placement of a pacemaker and/or defibrillator may be lifesaving.     

Pacemaker utilization during permanent atrial fibrillation in patients who received pacemaker implantation for sinus node dysfunction

Patients who have pacemakers and sinus node dysfunction frequently have atrial fibrillation (AF). The need for continued pacemaker therapy after conversion to permanent AF remains uncertain. This study showed that, among 174 patients who received pacemaker implantation for sinus node dysfunction, 38% (n = 62) had the minimum intrinsic ventricular rate of >60 beats/min after conversion to AF. The pacemaker memory showed that 30 patients (18%) never used ventricular pacing during permanent AF. The study results suggest that patients who have a stable intrinsic ventricular rate during permanent AF by serial assessment may no longer need continued pacemaker therapy.     

Atrial fibrillation and conduction system disease: the roles of catheter ablation and permanent pacing

Atrial fibrillation (AF) and diseases of the cardiac conduction system frequently co-exist, and interactions between these rhythm disturbances can adversely impact patient outcomes. Concurrent AF and sinus node disease often manifests as the tachy-brady syndrome wherein the underlying sinus node dysfunction can pose a challenge to AF management. Similarly, the combination of AF and left bundle branch block increases mortality in individuals with co-existent heart failure and hampers effective delivery of cardiac resynchronization therapy. A thorough understanding of the therapeutic interventions available for these conditions, including the role of catheter ablation and permanent pacemaker programming, is crucial for optimal management in affected patients.