Inter-atrial septal balloon dilation to facilitate intracardiac echocardiography guided left atrial appendage occlusion.

INTRODUCTION: Percutaneous left atrial appendage occlusion (LAAO) is traditionally performed under general anesthesia with trans-esophageal echocardiography guidance. Intracardiac echo (ICE)-guided LAAO closure is increasing in clinical use. The ICE catheter is crossed into LA via interatrial septum (IAS) after the septum is dilated with LAAO delivery sheath. This step can be time-consuming and requires significant ICE catheter manipulation, which increases the risk of cardiac perforation. Pre-emptive septal balloon dilation can potentially help with ICE advancement in the LA. We sought to evaluate the effect of pre-dilation of the IAS with an 8 mm balloon on the ease of crossing the ICE catheter, fluoroscopy time for crossing, and overall procedure time. METHODS: The Piedmont LAAO registry was used to identify consecutive patients who underwent LAAO. The initial 25 patients in whom balloon dilation of the IAS was performed served as the experimental cohort, and the 25 consecutive patients before that in whom balloon dilation was not performed served as controls. In the experimental group, after a trans-septal puncture, the sheath was retracted to the right atrium with a guidewire still in the LA. An 8 × 40 mm Evercoss™ over the wire balloon was inflated across the IAS. The ICE catheter was then crossed into the LA using the fluoroscopic landmark of the guide wire and the ICE imaging. The sheath was then advanced along the ICE catheter via the transseptal puncture (TSP) and the procedure continued. Follow-up compputed tomography imaging was obtained at 4-8 weeks. RESULTS: Each group consisted of 25 patients. There were no significant differences in baseline characteristics. All procedures were performed successfully under conscious sedation and ICE guidance. There was a significant reduction in the overall procedure time, fluoroscopy time, and time for transseptal puncture to ICE in LA. There was no difference in the size of the acute residual interatrial shunt, as measured via ICE, or the size and presence of iatrogenic ASD at follow-up. CONCLUSION: Balloon dilation of TSP is safe and is associated with increased efficiency in ICE-guided LAAO procedures.

Atrial fibrillation ablation in heart failure patients: Where do we stand in 2023? - State of the art review.

Atrial fibrillation (AF) and heart failure are common overlapping cardiovascular disorders. Despite important therapeutic advances over the past several decades, controversy persists about whether a rate control or rhythm control approach constitutes the best option in this population. There is also considerable debate about whether antiarrhythmic drug therapy or ablation is the best approach when rhythm control is pursued.  A brief historical examination of the literature addressing this issue will be performed. An analysis of several important clinical outcomes observed in the prospective, randomized studies, which have compared AF ablation to non-ablation treatment options, will be discussed. This review will conclude with recommendations to guide clinicians on the status of AF ablation as a treatment option when considering management options in heart failure patients with atrial fibrillation.

Insights into new-onset atrial fibrillation following open heart surgery and implications for type II atrial flutter.

AIMS: Postoperative atrial fibrillation (POAF), new-onset AF after open heart surgery (OHS), is thought to be related to pericarditis. Based on AF studies in the canine sterile pericarditis model, we hypothesized that POAF in patients after OHS may be associated with a rapid, regular rhythm in the left atrium (LA), suggestive of an LA driver maintaining AF. The aim of this study was to test the hypothesis that in patients with POAF, atrial electrograms (AEGs) recorded from at least one of the two carefully selected LA sites would manifest a rapid, regular rhythm with AEGs of short cycle length (CL) and constant morphology, but a selected right atrial (RA) site would manifest AEGs with irregular CLs and variable morphology. METHODS AND RESULTS: In 44 patients undergoing OHS, AEGs recorded from the epicardial surface of the RA, the LA portion of Bachmann's bundle, and the posterior LA during sustained AF were analysed for regularity of CL and morphology. Sustained AF occurred in 15 of 44 patients. Atrial electrograms were recorded in 11 of 15 patients; 8 of 11 had rapid, regular activation with constant morphology recorded from at least one LA site; no regular AEG sites were present in 3 of 11 patients. CONCLUSIONS: Atrial electrograms recorded during sustained POAF frequently demonstrated rapid, regular activation in at least one LA site, consistent with a driver maintaining AF.

Variable clinical features and ablation of manifest nodofascicular/ventricular pathways.

BACKGROUND: Manifest nodofascicular/ventricular (NFV) pathways are rare. METHODS AND RESULTS: From 2008 to 2013, 4 cases were identified with manifest NFV pathways from 3 centers. The clinical findings and ablation sites are reported. All 4 cases presented with a wide complex tachycardia but with different QRS morphologies. Case 1 showed a left bundle branch block/superior axis, case 2 showed a right bundle branch block/inferior axis, case 3 showed a left bundle branch block/inferior axis, and case 4 showed a narrow QRS tachycardia and a wide complex tachycardia with a left bundle branch block/inferior axis. Three of the 4 tachycardias had atrioventricular dissociation ruling out extranodal accessory pathways, including atriofascicular pathways. Programmed extrastimuli showed evidence of a decremental accessory pathway in 3 of the 4 cases. Coexisting tachycardia mechanisms were seen in 3 of the 4 cases (atrioventricular nodal reentry tachycardia [2] and atrioventricular reentrant tachycardia [1]). Ablation in the slow pathway region eliminated the NFV pathway in 3 (transient in 1) with the other responding to surgical closure of a large atrial septal defect. The NFV pathway was a critical part of the tachycardia circuit in 1 and proved to be a bystander in the other 3 cases. CONCLUSIONS: Manifest NFV pathways presented with variable QRS expression dependent on the ventricular insertion site and often coexisted with other tachycardia mechanisms (atrioventricular nodal reentry tachycardia and atrioventricular reentrant tachycardia). In most cases, the atrial insertion of the pathway was in or near the slow pathway region. The NFV pathways were either critical to the tachycardia circuit or served as bystanders.

Ranolazine terminates atrial flutter and fibrillation in a canine model.

BACKGROUND: Ranolazine has been shown to have antiarrhythmic properties. OBJECTIVE: We tested the hypothesis that intravenous ranolazine would terminate induced atrial flutter (AFL) or atrial fibrillation (AF) in the canine sterile pericarditis model. METHODS: In 6 dogs with sterile pericarditis, we performed electrophysiological measurements of the atrial effective refractory period (AERP) and conduction time (CT) while pacing from the right atrial appendage, Bachmann bundle, and the posteroinferior left atrium at cycle lengths (CLs) of 400, 300, and 200 ms before and after the administration of ranolazine. In 13 induced episodes of AFL (n = 9) and AF (n = 4), ranolazine was administered intravenously as a 3.2 mg/kg bolus, followed by a maintenance infusion of 0.17 mg/(kg·min). Six episodes (4 AFL and 2 AF) were induced in the open-chest state to perform simultaneous, multisite (486 electrodes), epicardial mapping of the arrhythmia and its termination. RESULTS: Ranolazine terminated 7 of 9 AFL and 3 of 4 AF episodes. Ranolazine significantly prolonged the AFL CL by a mean of 43 ms (P < .001) and the AF CL by a mean of 34 ms (P < .01). The AERP was prolonged (P < .05 overall), and the atrial capture threshold increased minimally (P < .01 for all). Ranolazine prolonged CTs (P < .01 overall). During open-chest, multisite mapping, block in the region of slow conduction in the reentrant circuit terminated AFL and interruption of the regular driver terminated AF. CONCLUSION: Ranolazine terminated AFL/AF in our canine sterile pericarditis model by interrupting the regular driver. Ranolazine was found to significantly prolong the AERP, CT, and tachycardia CLs.

New alternative anticoagulants in atrial fibrillation: the move beyond warfarin.

Given the increasing prevalence of atrial fibrillation, the need for safe and effective stroke prophylaxis will continue to rise. Warfarin has been around for many years and has proven efficacy in preventing stroke, but it has major limitations due to its variable dosing, food and drug interactions, and requirement for regular monitoring. Newer agents which include dabigatran, rivaroxaban, and apixaban have recently or will soon be available and may provide an improved efficacy in stroke prevention, an improved safety profile, and improved user-friendliness. Dabigatran was the first of the agents to be widely available, and in the RE-LY study, dabigatran (150 mg dose) showed superiority to warfarin in preventing ischemic stroke and a significant reduction in intracranial bleeding. Rivaroxaban was studied in the ROCKETAF trial, and with once daily dosing, it showed noninferiority to warfarin in preventing stroke with a significant reduction in intracranial bleeding. The ARISTOTLE trial showed apixaban was superior to warfarin for stroke prevention, significantly reduced all major bleeding, and resulted in a significant reduction in all-cause mortality. While all three trials have important limitations, they were very large randomized trials with more than 14,000 patients each and show a clear overall net clinical benefit when compared with warfarin. Key features of the drugs as well as an individual's preferences and stability on warfarin will help guide the ultimate drug choice for any given patient, but these newer anticoagulant agents are likely to usher in a new era in stroke prevention in atrial fibrillation.

Extensive nonbacterial thrombotic endocarditis isolated to the tricuspid valve in primary antiphospholipid syndrome.

Nonbacterial thrombotic endocarditis is a condition characterized by noninfectious valvular vegetations and is associated with numerous conditions, including the antiphospholipid syndrome. Although vegetations most frequently affect the left-sided valves, isolated involvement of the right-sided valves rarely occurs. Ideal management of the lesions, from both medical and surgical perspectives, is not well defined. The authors report the case of a patient who presented with clinically symptomatic isolated tricuspid valve and right atrial nonbacterial thrombotic endocarditis due to primary antiphospholipid syndrome, who was subsequently managed with diuretics and anticoagulation and has remained clinically stable.

Complex motor function in humans: validating and extending the postulates of Alexandr R. Luria.

OBJECTIVE: We used functional brain imaging to reevaluate Luria's postulates and to elaborate the neural circuitry underlying performance of complex motor tasks. BACKGROUND: The anatomic organization and physiologic functioning of the normal human motor system have great significance for understanding motor dysfunction and remediation in neurology. Working with victims of penetrating head injuries, noted Russian neuropsychologist Aleksandr R. Luria designed several tests of fine motor control to understand their difficulties with complex voluntary movements. This led to his postulates that such function involves the premotor cortices and their interaction with the parietal lobe. METHOD: Six healthy young adults performed the hand imitation, fist-scissors-gun, and piano key tasks during blood oxygen level-dependent functional magnetic resonance imaging at 3 T. RESULTS: All 3 tasks revealed activation of both premotor and parietal cortices. Furthermore, while hand Imitation relied more on the ventral premotor area and right parietal lobe, fist-scissors-gun and piano key relied more on the supplementary motor cortex. CONCLUSIONS: We postulate that differences in task-dependent activations across these tasks relate to degrees of sequential movement, pacing, and imitation. These results uphold Luria's original hypotheses, and extend that work by providing a further characterization of the motor areas involved in complex motor behaviors.