Maintenance Of Normal Sinus Rhythm Research Articles

Obstetric anesthesia considerations in pregnancy-associated myocardial infarction: a focused review

Pregnancy-associated myocardial infarction (PAMI) is a rare but serious complication that can occur either during pregnancy or postpartum. The etiologies of PAMI are atherosclerosis, spontaneous coronary artery dissection, coronary thrombosis, coronary embolism, and coronary vasospasm. Therapy of acute PAMI depends largely on the ECG presentation, hemodynamic stability, and suspected etiology of myocardial infarction. Anesthetic management during delivery in patients with PAMI should consist of early and carefully titrated neuraxial analgesia and anesthesia, maintenance of normal sinus rhythm, preservation of afterload, and monitoring for and avoiding myocardial ischemia. To improve the care of women with PAMI, a multidisciplinary team of cardiologists, maternal fetal medicine specialists, obstetric providers, neonatologists, and anesthesiologists must work collectively to manage these complex patients.

Epicardial adipocytes in the pathogenesis of atrial fibrillation: An update on basic and translational studies.

Epicardial adipose tissue (EAT) is an endocrine organ containing a host of cell types and undoubtedly serving a multitude of important physiologic functions. Aging and obesity cause hypertrophy of EAT. There is great interest in the possible connection between EAT and cardiovascular disease, in particular, atrial fibrillation (AF). Increased EAT is independently associated with AF and adverse events after AF ablation (e.g., recurrence of AF, and stroke). In general, the amount of EAT correlates with BMI or visceral adiposity. Yet on a molecular level, there are similarities and differences between epicardial and abdominal visceral adipocytes. In comparison to subcutaneous adipose tissue, both depots are enriched in inflammatory cells and chemokines, even in normal conditions. On the other hand, in comparison to visceral fat, epicardial adipocytes have an increased rate of fatty acid release, decreased size, and increased vascularity. Several studies have described an association between fibrosis of EAT and fibrosis of the underlying atrial myocardium. Others have discovered paracrine factors released from EAT that could possibly mediate this association. In addition to the adjacent atrial cardiomyocytes, EAT contains a robust stromal-vascular fraction and surrounds the ganglionic plexi of the cardiac autonomic nervous system (cANS). The importance of the cANS in the pathogenesis of atrial fibrillation is well known, and it is quite likely that there is feedback between EAT and the cANS. This complex interplay may be crucial to the maintenance of normal sinus rhythm or the development of atrial fibrillation. The extent the adipocyte is a microcosm of metabolic health in the individual patient may determine which is the predominant rhythm.

Abstract 9757: Real World Experience With Anticoagulation in Atrial Fibrillation Patients After Pulmonary Vein Isolation: Associations With Cha 2 Ds 2 -vasc Score, Sex and Maintenance of Sinus Rhythm

Background: Guidelines recommend using the CHA 2 DS 2 -VASc score to determine anticoagulation decisions in atrial fibrillation (AF) patients, including those who undergo pulmonary vein isolation (PVI), however this may not consistently occur in the real-world setting because of other clinical factors. We sought to evaluate the anticoagulation prescription patterns in AF patients 1 year PVI at our institution. Methods: Consecutive AF patients undergoing PVI in our prospective registry during 2014-2018 who were alive at 1-year post-PVI were studied. Anticoagulation prescription rates at this time-point were adjudicated, and correlated to CHA 2 DS 2 -VASc score, sex and maintenance of normal sinus rhythm (NSR) at 1 year. Results: Amongst 4596 patients undergoing PVI, mean age was 64.1±10.0 years, 3308 (71.2%) were male, and based on CHA 2 DS 2 -VASc Score anticoagulation was not indicated, can be considered and indicated in 872 (19.0%), 1183 (25.7%) and 2541 (55.3%) patients respectively. At 1-year after PVI, 3504 (76.2%) patients were on anticoagulation, and 792 (17.2%) had recurrence of AF. Anticoagulation rates by sex, CHA 2 DS 2 -VASc Score category and NSR at 1-year after PVI are illustrated in the Figure. Anticoagulation was continued in over half of AF patients without classic CHA 2 DS 2 -VASc indication particularly in those with AF recurrence and women, while they were mildly under-prescribed in those with indication, especially for those without AF recurrence and men. Conclusion: In a large real world cohort of patients post PVI, anticoagulation is prescribed independent of CHA 2 DS 2 -VASc score, and is affected by both sex and NSR status. Factors determining continuous anticoagulation after successful PVI may include parameters not covered in the CHA 2 DS 2 -VASc score such as return of atrial mechanical function on echocardiography, valve disease or extra-cardiac pathologies.

Catheter ablation for atrial fibrillation - standard of care and future perspectives

Atrial fibrillation is the most frequent cardiac arrhythmia in adults. For symptomatic atrial fibrillation, catheter ablation has proven to be an effective and safe treatment that is superior to antiarrhythmic drug treatment regarding quality of life and maintenance of normal sinus rhythm. Moreover, there is increasing evidence that early rhythm control and catheter ablation can be of prognostic benefit. Especially heart failure patients with impaired left ventricular systolic function seem to benefit from rhythm control therapy by catheter ablation. Furthermore, technological innovations such as novel single-shot devices, contact force mapping, the concept of high-power-short-duration (HPSD) ablation and implementation of electroporation (pulsed field ablation) offer the prospect of further improving ablation efficiency and safety. This review provides an overview of current standards of care as well as future trends in atrial fibrillation catheter ablation techniques.

Correlation of heart rate recovery and heart rate variability with atrial fibrillation progression.

ObjectiveTo examine the combination of heart rate recovery (HRR) and heart rate variability (HRV) in predicting atrial fibrillation (AF) progression.MethodsData from patients with a first detected episode of AF who underwent treadmill exercise testing and 24-h Holter electrocardiography were retrospectively analysed. Autonomic dysfunction was verified using HRR values. Sympathetic and parasympathetic modulation was analysed by HRV. AF progression was defined as transition from the first detected paroxysmal episode to persistent/permanent AF.ResultsOf 306 patients, mean LF/HF ratio and HRR did not differ significantly by AF progression regardless of age (< or ≥65 years). However, when the LF/HF ratio was divided into tertiles, in patients aged <65 years, the mid LF/HF (1.60–2.40) ratio was significantly associated with lower AF progression rates and longer maintenance of normal sinus rhythm. For patients aged <65 years, less metabolic equivalents were related to higher AF progression rates. For patients aged ≥65 years, a low HRR was associated with high AF progression rates.ConclusionIn relatively younger age, high physical capacity and balanced autonomic nervous system regulation are important predictors of AF progression. Evaluation of autonomic function assessed by age could predict AF progression.

Atrial Fibrillation in Transthyretin Cardiac Amyloidosis: Predictors, Prevalence, and Efficacy of Rhythm Control Strategies.

This study sought to determine the incidence and prevalence of atrial fibrillation (AF) in transthyretin cardiac amyloidosis (ATTR-CA); to study the factors associated with the development of AF in this population; to study the prognostic implications of AF and maintenance of normal sinus rhythm (NSR) in patients with ATTR-CA; and to determine the impact of ATTR-CA stage on AF prevalence, outcomes, and efficacy of rhythm control strategies. AF is common in patients with ATTR-CA. The aim of this study was to determine the predictors, prevalence, and outcomes of AF in patients with ATTR-CA in addition to the efficacy of rhythm control strategies. This was a retrospective cohort study of 382 patients with ATTR-CA diagnosed at our institution between January 2004 and January 2018. Means testing, and univariable and multivariable models were used. AF occurred in 265 (69%) patients. Factors associated with the development of AF included older age, advanced ATTR-CA stage, and higher left atrial volume index. Antiarrhythmic therapy (AAT) was used in 35% of patients with AF; cardioversion was performed in 45%, and 5% underwent AF ablation. Rhythm control strategies were substantially more effective when performed earlier in the disease course. During a mean follow-up of 35months, no difference in mortality between patients with AF and those without AF was observed (65% vs. 49%; p=0.76). On Cox proportional hazards analyses, maintenance of normal sinus rhythm and tafamidis use were associated with improved survival, whereas advanced ATTR-CA stage and higher New York Heart Association functional class were associated with increased mortality. With advancing ATTR-CA stage, AF became more prevalent, occurring in 69% of our entire study cohort. Rhythm control strategies including AAT, direct-current cardioversion, and AF ablation were substantially moreeffective when performed earlier during the disease course.

Effect of Intraoperative Loading Dose of Amiodarone for Prophylaxis Against Atrial Fibrillation in Patients with Rheumatic Valvular Heart Disease Undergoing Valve Replacement Surgery

Background: Atrial Fibrillation (AF) is the most common arrhythmia occurring after cardiac surgery and its peak incidence is between second or third postoperative day. It occurs in 40% to 50% of patients after valve surgery alone or combined valve and CABG surgery respectively. Among all the anti-arrhythmic drugs evaluated for AF, amiodarone has shown the most promising results with successful conversion and maintenance of normal sinus rhythm achieved in 50%–70% of patients.&#x0D; Methods: Sixty diabetic patients purposively selected who underwent isolated off pump coronary artery bypass procedure in NICVD. Group A – 30 patients receiving loading dose of amiodarone intra-operatively before establishment of CPB during valve replacement surgery and Group B- 30 patients without receiving loading dose of amiodarone intra-operatively during valve replacement surgery. Incidence of atrial fibrillation in postoperative period was evaluated.&#x0D; Results: Atrial fibrillation was observed in 8 (26.7%) patients in group A and 18 (60%) patients in group B (p=0.009). Ventricular tachycardia developed in 6.7% patients in group B and none in group A (p=0.47). Mean duration of ICU stay was 2.04±0.30 days in Group A and Group B was 2.98±0.77 days (p=0.03). Mean duration of post-operative stay was 7.20±0.66 days in Group A and Group B was 7.85±0.60 days (p=0.10).&#x0D; Conclusion: A single intra operative dose of intravenous amiodarone increases the incidence of conversion of AF to normal sinus rhythm. When AF persisted, use of amiodarone reduces the frequency of need for cardioversion and the energy required for it.&#x0D; Cardiovasc. j. 2020; 12(2): 102-108

Pulmonary vein remodeling following pulmonary vein isolation in patients with atrial fibrillation-do pulmonary veins represent only an epiphenomenon? A cardiac MRI study.

After successful pulmonary vein isolation (PVI) for atrial fibrillation (AF), the left atrium (LA) undergoes reverse remodeling. However, few studies have directly studied pulmonary vein (PV) remodeling and focused on whether pre PVI-PV conditions could predict outcome of the procedure. We hypothesize that: (I) post PVI, in addition to LA remodeling the PVs undergo a parallel degree of remodeling; and (II) that PV characteristics pre PVI can be used to identify patients more likely to sustain normal sinus rhythm (NSR). Patients (n=100) scheduled for PVI had a cardiovascular magnetic resonance (CMR) imaging before and 6±2 months following PVI. PV cross sectional areas (CSA) within 0.5 cm of the ostium and LA volumes were measured. Patients were categorized as responders (R) or non-responders (NR), based on two separate 14-day Holter monitoring. PVs CSA were significantly reduced post procedure in both groups, R (233±53 to 192±52 mm2, P<0.001) and NR (241±54 to 207±44 mm2, P<0.001), however, the difference between R and NR post PVI was not significant (192±52 to 207±44 mm2, P=0.19). Reduction in PVs CSAs post procedure moderately correlated with the 3D LA volume reduction (r=0.48, P<0.001). PVs mirror the LA in that they significantly change in size following PVI yet they were not found to directly predict maintenance of NSR.

Evaluation of the Impact of an Institution-Specific Dofetilide Initiation Protocol on Mean Hospital Length of Stay and Cost for Dofetilide Initiation.

BackgroundDofetilide is a class III antiarrhythmic drug indicated for the conversion and maintenance of normal sinus rhythm in symptomatic patients with atrial fibrillation/atrial flutter. Delay in initiation of dofetilide therapy may increase the duration of hospitalization from two nights to three nights to complete US Food and Drug Administration-required monitoring. Therefore, substantial cost savings may be associated with implementation of an institution-specific dofetilide initiation protocol in order to reduce hospitalization to two nights. This could potentially be achieved through protocol-defined utilization of the option for a condensed dosing interval for the first three doses of dofetilide in order to ensure the administration of two doses on the first day of hospitalization.ObjectiveThe primary objective of this study was to assess the impact of an institution-specific dofetilide initiation protocol on mean hospital length of stay and cost for dofetilide initiation.MethodsThe study design was a retrospective review of 150 patients admitted to the Clement J. Zablocki Veterans Affairs Medical Center for the purpose of dofetilide initiation. Matching time periods of 18 months before and after implementation of the institution-specific dofetilide initiation protocol were used to randomly select 75 patients from each time period for comparison.ResultsA significant reduction in mean hospital length of stay of 0.56 nights post-implementation of the institution-specific dofetilide initiation protocol was identified (95% confidence interval 0.20–0.92; P = 0.0029). Assuming hospital adjusted expenses per inpatient day of US$1831–2413, a reduction in hospital length of stay of 0.56 nights resulted in estimated cost savings of US$1025–1351 per admission for dofetilide initiation.ConclusionImplementation of an institution-specific dofetilide initiation protocol decreases mean hospital length of stay and cost for dofetilide initiation.

Right minithoracotomy versus conventional median sternotomy for patients undergoing mitral valve surgery and Cox-maze IV ablation with entirely bipolar radiofrequency clamp.

Cox-maze IV ablation by bipolar radiofrequency clamp was considered to be only performed through median sternotomy (MS), but impossible through right minithoracotomy (RM). Now, we developed a novel technique of performing Cox-maze IV ablation entirely by bipolar clamp through RM. To compare the outcomes of RM or MS for patients undergoing mitral valve surgery and concomitant Cox-maze IV ablation with entirely bipolar clamp. All 152 patients underwent mitral valve surgery and concomitant Cox-maze IV ablation with bipolar clamp through RM (n=69) or MS (n=83) were analyzed for outcome differences. The etiology of mitral valve disease was rheumatic (n=97) and degenerative (n=55). All patients had long-standing persistent atrial fibrillation (AF). Diameter of left atrium ranged from 42 to 60mm. All patients successfully underwent Cox-maze IV ablation by bipolar clamp. RM group had longer cardiopulmonary bypass time (130.3±17.7 vs 115.3±14.4min; P<0.001) and aortic cross-clamp time (91.8±12.7 vs 74.6±9.3min; P<0.001). But mechanical ventilation time (14.2±6.6 vs 21.3±9.0h; P<0.001) and hospital length of stay (9.3±2.6 vs 11.7±3.0days; P<0.001) were shorter in RM group. At discharge, the maintenance of normal sinus rhythm (NSR) was 94.2% in RM group and 95.1% in MS group (P=1.000). Cumulative maintenance of NSR at 2years postoperatively was 85.1±5.8% in RM group and 88.6±3.6% in MS group (P=0.767). RM can achieve similar therapeutic effect to MS for patients undergoing mitral valve surgery and concomitant Cox-maze IV ablation with entirely bipolar clamp. In addition, patients through RM had faster recovery.

The Role of Superior Vena Cava Isolation in the Management of Atrial Fibrillation.

The superior vena cava (SVC) has been identified as one of the most common sources of non-pulmonary vein triggers for atrial fibrillation (AF). SVC isolation has been shown to improve long-term maintenance of normal sinus rhythm in patients with paroxysmal AF. However, ablation at the SVC is associated with risks of phrenic nerve injury, sinus node dysfunction, and SVC stenosis. The use of electroanatomical mapping, intracardiac echocardiography, compound motor action potentials, and segmental (rather than circumferential) ablation are all strategies to reduce complications. Given these risks, SVC isolation is most effective as an adjunct to pulmonary vein isolation for patients with paroxysmal AF who have been found to have an arrhythmogenic SVC.

Catheter Ablation for Atrial Fibrillation in Patients With Watchman Left Atrial Appendage Occlusion Device: Results from a Multicenter Registry.

There have been an increasing number of atrial fibrillation (AF) patients with Watchman left atrial appendage occlusion (LAAO) device, requiring catheter ablation (CA) for maintenance of normal sinus rhythm. In this study, we describe our experience with the feasibility and safety of CA in patients with a preexisting Watchman LAAO device. This was a retrospective multicenter AF registry of 60 patients with Watchman LAAO device who underwent CA for AF. Baseline clinical and procedural characteristics of the included subjects were retrieved from review of medical records and were analyzed. The mean age was 72.7 ± 4.9 years and the mean CHADS2 score was 2.3 ± 0.6. All patients had successful pulmonary vein isolation (PVI). The left atrial appendage (LAA) was electrically active in 34 (56%) while reentrant tachycardia and AF triggers were seen in 17 (28%) patients. Electrical isolation was attempted in these 17 patients with only 10 achieving complete LAA isolation. Repeat imaging showed new peri-device leaks in 30% (12/40) patients, while new significant peri-device leaks (≥5 mm) were noted in 10% (10/40) of patients after RFA, respectively, requiring continuation of oral anticoagulation. There were a higher proportion of patients with severe peri-device leaks (≥5 mm) after LAA isolation. However, >50% of those leaks sealed off on follow-up transesophageal echocardiogram. AF ablation is a feasible and safe in patients with preexisting Watchman LAAO device. Electrical isolation of the LAA could be difficult and when attempted can result in increased risk of short-term peri-device leak and recurrence of AT/AF in almost all patients.

Antimicrobial Natural Product Berberine Is Efficacious for the Treatment of Atrial Fibrillation.

The purpose of this study is to test the efficacy of bioactive natural product berberine in the treatment of patients with atrial fibrillation (AF). Data of 45 paroxysmal AF patients treated with berberine and 43 age, gender, New York Heart Association functional classification score, and concomitant cardiovascular disease matched patients treated with amiodarone were analyzed retrospectively to examine conversion rate, average conversion time, average heart rate, and echocardiographic parameters. There was no statistical difference between berberine and amiodarone on conversion rate or echocardiographic parameters. Berberine treatment showed a significantly longer average time to conversion and higher heart rate during sinus rhythm (SR) than amiodarone. Echocardiographic parameters showed that E/A ratio and left atrial diameter were significantly improved after 6- and 12-month berberine treatment, but only E/A ratio improved significantly at the same time points after amiodarone treatment. This is the first report to specifically compare efficacy of berberine and amiodarone in the treatment of patients with AF. We find that berberine and amiodarone are equally effective for conversion of AF and maintenance of normal SR.

Medication Use Evaluation of Dronedarone in Comparison to Amiodarone

Amiodarone is the most effective rhythm-control for atrial fibrillation, but produces serious potential side effects. Dronedarone was designed to eliminate amiodarone toxicities, but increased the risk of mortality in clinical trials. This medication use evaluation compares one year of dronedarone use with a matched cohort of amiodarone patients at a single hospital in Greensboro, NC. Forty-eight patients were included with an average age of 71.8 years and 37.5% female population. No significant difference was found for the primary composite outcome of death, myocardial infarction, stroke, and systemic embolism (OR = 2.4, p = 0.148). Likewise, no statistical significance was demonstrated between the two groups for QTc prolongation, hypothyroidism, liver dysfunction or maintenance of normal sinus rhythm. In conclusion, the clinical decision process demonstrated no increased risk of death or other adverse events in the use of dronedarone.&#x0D; Conflict of Interest&#x0D; We declare no conflicts of interest or financial interests that the authors or members of their immediate families have in any product or service discussed in the manuscript, including grants (pending or received), employment, gifts, stock holdings or options, honoraria, consultancies, expert testimony, patents and royalties&#x0D; &#x0D; Type: Student Project

Sotalol versus Amiodarone in Treatment of Atrial Fibrillation.

The availability of intravenous (IV) Sotalol has equalized the treatment options since both amiodarone and sotalol are available in both IV and oral formulations. A review of the efficacy of sotalol as compared to amiodarone both for conversion of atrial fibrillation (AF) and maintenance of normal sinus rhythm (NSR) following cardiac surgery was undertaken. Standard methods of meta-analysis were employed. Full text publications of clinical trials written in English that compared the efficacy of sotalol to amiodarone were included in the analysis. For the conversion of AF to NSR, five studies were found eligible for the analysis. Two studies clinically compared sotalol to amiodarone for the maintenance of NSR after cardiac surgery. The common relative success of sotalol was 0.947 (95Cl: 0.837 to 1.071, P = 0.385), revealing essentially no differences in efficacy for conversion between amiodarone and sotalol. The average conversion rate was 47% with sotalol and 52% with amiodarone. The conversion rates were lower for persistent AF (sotalol 22% and amiodarone 27%), while greatest for recent onset AF (88% sotalol and 77% for amiodarone). The risk of developing post-operative atrial fibrillation was practically the same in both regimes, relative risk = 1.214 (95% CI: 0.815-1.808, p=0.339). In summary, sotalol and amiodarone are equally effective in AF conversion and maintenance of NSR post-cardiac surgery.

Trends and predictors of repeat catheter ablation for atrial fibrillation

Atrial fibrillation (AF) ablation is superior to pharmacologic therapy in achieving maintenance of normal sinus rhythm in selected patient populations. However, the procedure is resource intensive, and repeat ablations are sometimes required. We examined the predictors and trends of repeat ablation using a large national administrative claims database. Privately insured and Medicare Advantage patients who underwent catheter ablation for AF between January 1, 2004, and September 30, 2014, were included in the study. The primary outcome was repeat AF ablation during enrollment. We examined the associations between repeat ablation and patient demographics (age, gender, socioeconomic demographics), comorbid conditions (CHA2DS2-Vasc score and Charlson index), and year of the index ablation. Cox proportional hazard models were used to identify predictors of repeat ablation. We included 8,648 adult patients in the analysis. Median age was 61.0 (interquartile range [IQR] 54-68) years, and 70.9% were men. Median follow-up was 1.1 (IQR 0.5-2.3) years. A total of 1,263 patients underwent repeat ablation (14.6%) over a total of 14,280 person-years (12.1% at 1 year). The hazard ratio (HR) for repeat ablation was higher in younger patients (HR 0.75 [0.61-0.91; P < .01] for age 65-75 and 0.55 [0.4-0.75; P < .001] for age ≥ 75 compared with age 18-54), those with higher household income (HR 1.24 [1-1.54; P < .05] for household income ≥ $100,000 compared with household income < $40,000), patients treated in the south (HR 1.15 [1-1.31]; P < .05), and those on antiarrhythmic medications (HR 1.15 [1.01-1.31]; P < .05). In particular, younger patients (ages 18-54 years) continued to undergo repeat ablations over the entire follow-up period, and the cumulative rate was approximately 40% among those followed for 5 years. Clinical characteristics including those included in the CHA2DS2-Vasc score and Charlson index did not predict likelihood of repeat ablation. The rate of repeat ablation remained constant over the available follow-up. Approximately 1 in 8 patients treated with catheter ablation for AF will undergo a second procedure within 1 year, although the rate is as high as 40% in young patients at 5 years. The rate of repeat ablation appears to be associated with demographic characteristics (younger age and higher household income) rather than medical comorbidities.

Management of atrial fibrillation.

Atrial fibrillation is a very common clinical problem with a high prevalence that is expected to rise over time because of increasing risk factors (eg, age, obesity, hypertension). This high prevalence is also associated with high cost, because atrial fibrillation represents about 1% of overall health care spending. The management of atrial fibrillation involves multiple facets: (1) management of underlying disease if present and the management of atrial fibrillation risk factors, (2) prevention of thromboembolism, (3) control of the ventricular rate during atrial fibrillation, and (4) restoration and maintenance of normal sinus rhythm.

Sequential hybrid procedure for persistent atrial fibrillation.

BackgroundCatheter ablation of persistent atrial fibrillation yields an unsatisfactorily high number of failures. The hybrid approach has recently emerged as a technique that overcomes the limitations of both surgical and catheter procedures alone.Methods and ResultsWe investigated the sequential (staged) hybrid method, which consists of a surgical thoracoscopic radiofrequency ablation procedure followed by radiofrequency catheter ablation 6 to 8 weeks later using the CARTO 3 mapping system. Fifty consecutive patients (mean age 62±7 years, 32 males) with long‐standing persistent atrial fibrillation (41±34 months) and a dilated left atrium (>45 mm) were included and prospectively followed in an unblinded registry. During the electrophysiological part of the study, all 4 pulmonary veins were found to be isolated in 36 (72%) patients and a complete box‐lesion was confirmed in 14 (28%) patients. All gaps were successfully re‐ablated. Twelve months after the completed hybrid ablation, 47 patients (94%) were in normal sinus rhythm (4 patients with paroxysmal atrial fibrillation required propafenone and 1 patient underwent a redo catheter procedure). The majority of arrhythmias recurred during the first 3 months. Beyond 12 months, there were no arrhythmia recurrences detected. The surgical part of the procedure was complicated by 7 (13.7%) major complications, while no serious adverse events were recorded during the radiofrequency catheter part of the procedure.ConclusionsThe staged hybrid epicardial–endocardial treatment of long‐standing persistent atrial fibrillation seems to be extremely effective in maintenance of normal sinus rhythm compared to radiofrequency catheter or surgical ablation alone. Epicardial ablation alone cannot guarantee durable transmural lesions.Clinical Trial RegistrationURL: www.ablace.cz Unique identifier: cz‐060520121617

Percutaneous ligation of the left atrial appendage results in atrial electrical substrate modification

Debulking of electrically active atrial tissue may reduce the mass of fibrillating tissue during atrial fibrillation, eliminate triggers, and promote maintenance of normal sinus rhythm (NSR). We investigated whether left atrial appendage (LAA) ligation results in modification of atrial electrical substrate. Healthy male mongrel dogs (N = 20) underwent percutaneous epicardial LAA ligation. The ligation system grabber recorded LAA local electrograms (EGM) continuously before, during, and after closure. Successful ligation with a preloaded looped suture was confirmed intraprocedurally by LAA Doppler flow cessation on transesophageal echocardiography (TEE) and loss of LAA electrical activity, and after procedure by direct necropsic visualization. P-wave duration on surface electrocardiograms was measured immediately before and after LAA closure. Percent P-wave duration reduction was correlated with preclosure LAA internal dimensions measured by TEE and external dimensions measured on necropsy specimens to investigate associations of LAA geometry with the extent of electrical substrate modification. LAA ligation was successful in all dogs and accompanied by loss of LAA EGM. P-wave duration reduced immediately on ligation (mean 75 ms preligation to 63 ms postligation; mean difference ± standard error, 12 ± 1 ms; P < 0.0001). Percent P-wave reduction was associated with larger LAA longitudinal cross-sectional area (R(2) = 0.263, P = 0.04) and smaller external circumference (R(2) = 0.687, P = 0.04). All dogs were in sinus rhythm. Percutaneous LAA ligation results in its acute electrical isolation and atrial electrical substrate modification, the degree of which is associated with LAA geometry. These electrical changes raise the possibility that LAA ligation may promote NSR by removing LAA substrate and triggers.

Putative Role of Right Atrial Ablation in Atrial Fibrillation.

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and associated with significant morbidity and mortality. AF is currently estimated to affect over seven million people worldwide and is predicted to increase in prevalence (1, 2). Medical, surgical, and interventional approaches have been utilized to treat AF. Systemic toxicity and limited therapeutic efficacy of antiarrhythmic medications has resulted in extensive development of surgical and interventional techniques for treatment of AF. In addition to limiting the use of antiarrhythmic medications, these approaches have the added benefit of restoration of normal sinus rhythm (NSR). Although restoration of NSR was not shown to be superior to a rate control management strategy in the AFFIRM trial, follow-up analysis indicated a 47% reduction in mortality associated with the presence of NSR (3). Maintenance of NSR presumably provides an increase in cardiac output due to restoration of atrial systolic function and allows for the possible cessation of anticoagulation thus reducing risk of bleeding.