Dual loop reentrant tachycardia with a combination of a localized reentry and a macro-reentry.
ABSTRACT: A 78-year-old woman presented 2 years after mitral valve replacement for rheumatic mitral stenosis with cardioversion-resistant atrial tachycardia (AT). Dual-loop AT was identified by activation mapping with the Rhythmia™ system (Boston Scientific, Marlborough, MA, USA) and confirmed by entrainment-mapping; one circuit with localized re-entry turned around the scar on the posterior left atrium and the other circuit, which was macro re-entrant, turned around the left superior pulmonary vein (LSPV) using the PV-carina, the ridge beween the left atrial appendage and the LSPV, and the roof. The two wavefronts fused on the posterior wall close to the LSPV. Radiofrequency ablation of an area of slow conduction on the posterior wall changed the tachycardia to roof-dependent AT which was then terminated by completion of a roof line. .
Project description:A 66-year-old male had an atrial tachycardia (AT) during a first extensive pulmonary vein (PV) isolation (PVI) of persistent atrial fibrillation. Activation mapping during the AT using Rhythmia (Boston Scientific, Marlborough, MA, USA) exhibited a centrifugal pattern with the earliest activation at the left-sided carina, and conduction towards the inferior left atrium (LA) over the left PVI line. The post-pacing interval was similar to the tachycardia cycle length (TCL) upon entrainment from the LA roof, left-sided carina, and anterior, inferior, and septal LA, but was longer than the TCL upon entrainment from the left superior PV and lateral and posterior LA. These findings suggested the presence of a macroreentrant AT circuit with epicardial conduction from the roof toward the inferior LA via the left-sided carina over the PVI line and propagation to the anterior LA through the septum. A radiofrequency application at the left-sided carina terminated the AT. This case suggested a rare type of PV-gap reentrant AT with multiple epicardial conduction gaps by high-resolution activation mapping and entrainment pacing, which may have been associated with non-transmural radiofrequency lesions along the PVI line. Further, the origin of the residual epicardial gaps may have been subepicardial myocardial strands or the Marshall ligament. <<b>Learning objective:</b> Pulmonary vein (PV)-gap reentrant atrial tachycardias (ATs) generally have conduction gaps on the previous PV isolation lines. However, this case had a variant of PV-gap reentrant AT with multiple epicardial conduction gaps, without any endocardial gaps on the PV isolation line. High-resolution activation mapping during PV pacing and the AT in combination with entrainment pacing may facilitate an identification of residual epicardial connections associated with the PV-gap reentrant AT circuits.>.
Project description:Pulmonary vein isolation (PVI) with radiofrequency ablation (RFA) is the cornerstone of atrial fibrillation (AF) therapy, but few strategies exist for when it fails. To guide RFA, phase singularity (PS) mapping locates reentrant electrical waves (rotors) that perpetuate AF. The goal of this study was to test existing and develop new RFA strategies for terminating rotors identified with PS mapping. It is unsafe to test experimental RFA strategies in patients, so they were evaluated in silico using a bilayer computer model of the human atria with persistent AF (pAF) electrical (ionic) and structural (fibrosis) remodeling. pAF was initiated by rapidly pacing the right (RSPV) and left (LSPV) superior pulmonary veins during sinus rhythm, and rotor dynamics quantified by PS analysis. Three RFA strategies were studied: (i) PVI, roof, and mitral lines; (ii) circles, perforated circles, lines, and crosses 0.5-1.5 cm in diameter/length administered near rotor locations/pathways identified by PS mapping; and (iii) 4-8 lines streamlining the sequence of electrical activation during sinus rhythm. As in pAF patients, 2 ± 1 rotors with cycle length 185 ± 4 ms and short PS duration 452 ± 401 ms perpetuated simulated pAF. Spatially, PS density had weak to moderate positive correlations with fibrosis density (RSPV: r = 0.38, p = 0.35, LSPV: r = 0.77, p = 0.02). RFA PVI, mitral, and roof lines failed to terminate pAF, but RFA perforated circles and lines 1.5 cm in diameter/length terminated meandering rotors from RSPV pacing when placed at locations with high PS density. Similarly, RFA circles, perforated circles, and crosses 1.5 cm in diameter/length terminated stationary rotors from LSPV pacing. The most effective strategy for terminating pAF was to streamline the sequence of activation during sinus rhythm with >4 RFA lines. These results demonstrate that co-localizing 1.5 cm RFA lesions with locations of high PS density is a promising strategy for terminating pAF rotors. For patients immune to PVI, roof, mitral, and PS guided RFA strategies, streamlining patient-specific activation sequences during sinus rhythm is a robust but challenging alternative.
Project description:Transseptal catheterization has become part of the interventional electrophysiologist?s technical armamentarium since the development of left atrial catheter ablation and percutaneous technologies for treating mitral and aortic valve disease. Although frequently performed, the procedure?s most feared complication is aortic root penetration. Focal atrial tachycardia has been described as the most common late sequela of surgical valve replacements. We present a complicated case involving the inadvertent delivery of an 8 French sheath across the noncoronary cusp during radiofrequency catheter ablation for left atrial tachycardia originating from the mitral annulus in a patient with prior mitral valve replacement.
Project description:The purpose of this study was to evaluate ultra high density-activation sequence mapping (UHD-ASM) for ablating atypical atrial flutters.For 23 patients with 31 atypical atrial flutters (AAF), we created UHD-ASM.Demographics age?=?65.3?±?8.5 years, male?=?78%, left atrial size?=?4.66?±?0.64 cm, redo ablation 20/23(87%). AAF were left atrial in 30 (97%). For each AAF, 1273?±?697 points were used for UHD-ASM. Time to create and interpret the UHD-ASM was 20?±?11 min. For every AAF, the entire circuit was identified. Thirty (97%) were macroreentry. AAF cycle length was 267?±?49 ms, and the circuit length was 138?±?38 mm (range 35-187). Macroreentry atrial flutters took varied pathways, but each had an area of slow conduction (ASC) averaging 16?±?6 mm (range 6-29) in length. Entrainment was not utilized. We targeted the ASC and ablation terminated AAF directly in 19/31 (61.3%) and altered AAF activation in 7/31 (22.6%), all of which terminated directly with additional mapping/ablation. AAF degenerated to atrial fibrillation in 2/31 (6.5%) with RF and could not be reinduced after ASC ablation. Median time from initial ablation to AAF termination was 64 s. Thus, 28/31 (90.3%) terminated with RF energy and/or could not be reinduced after ASC ablation. At 1 year of follow-up, 77% were free of atrial tachycardia or atrial flutter and 61% were free of all atrial arrhythmias.Using rapidly acquired UHD-ASM, the entire AAF circuit as well as the target ASC could be identified. Most AAF were left atrial macroreentry. Ablation of the ASC or microreentry focuses directly terminated or eliminated AAF in 90.3% without the need for entrainment mapping.
Project description:A 73-year-old woman was admitted for atrial tachycardia (AT) ablation. The activation map and pacing study indicated that the AT propagated around the left pulmonary vein and that the Marshall bundle (MB) bypassed the scar area of the left pulmonary vein ridge and mitral isthmus. The Rhythmia Mapping System revealed double potentials propagated along the assumed position of the MB. The mapping system includes a confidence mask that can be used to visually identify low-confidence areas of the map based upon extremely low-voltage signals. Given the low-voltage area in the endocardial side, the epicardial conduction was emphasized.
Project description:A 67-year-old man underwent left atrial appendage (LAA) exclusion concomitant with mitral valve surgery and radiofrequency ablation maze procedure. On transoesophageal echocardiography anticipating ablation for left atrial tachycardia, an echodense thrombus was visualised in the LAA location with apparent intracavitary extension into the left atrium. Based on CT imaging findings, the echo represented thrombosis of a large left atrial appendage with probable extension into the left atrium.
Project description:Background:Micro-reentry tachycardia usually emerges in scar tissues related to post-atrial fibrillation ablation and cardiomyopathy. It is difficult to identify the micro-reentry circuit accurately by conventional mapping method. Case summary:A 74-year-old man presented with paroxysmal atrial tachycardia (AT) presenting as palpitations. He was evaluated by an electrophysiological examination using a high-density CARTO mapping system. The mapping results showed the AT with a cycle length of 184 ms was focused on his right atrial fossa ovalis (FO). In this small area, the high-density mapping demonstrated a significant micro-reentrant tachycardia. Radiofrequency ablation at the centre of the micro-reentrant circuit successfully terminated the AT. No recurrences were observed during a 12-month follow-up. Discussion:This case demonstrated a micro-reentrant AT originates from the FO without cardiomyopathy or previous ablation with specific loops. This is an unusual location for AT though and can cause difficulty for operators if it terminates or is non-sustained. High-density mapping using a PentaRay catheter can effectively characterize micro-reentrant circuits and determine the real target for ablation therapy.
Project description:Abstract <h4>Background</h4> An increasing number of catheter ablations are performed for symptomatic tachyarrhythmias and commonly involve the left atrium, increasing the risk of catheter interaction with the mitral valve (MV) complex. Mitral valve trauma at the time of atrial fibrillation (AF) ablations remains a rare yet emergent situation that requires prompt diagnosis and management to prevent the long-term sequelae of heart failure secondary to MV dysfunction. <h4>Case summary</h4> We present a case of a 69-year-old female with symptomatic paroxysmal AF and atrial flutter who underwent a combined ablation procedure. During the pulmonary vein isolation procedure, the mapping catheter became entangled within the MV apparatus but was freed. She presented to our hospital 2 weeks later with dyspnoea, lethargy, and a cough. Clinical examination revealed a pansystolic murmur and right moderate pleural effusion. Transthoracic echocardiogram (TTE) demonstrated a flail posterior MV leaflet with severe eccentric mitral regurgitation (MR). She underwent urgent valve repair at the regional cardiothoracic centre. Upon review 2 months later, she was symptom free with surveillance TTE demonstrating a preserved left ventricular systolic function with a trace of MR. <h4>Discussion</h4> Mitral valve injury secondary to catheter entrapment at the time of left-sided ablations is a rare yet serious complication and can present as an emergent situation requiring prompt recognition and early surgical management to salvage valve and cardiac function.
Project description:It is not clear whether bidirectional block (BDB) of linear ablations reduces atrial fibrillation (AF) recurrence after radiofrequency catheter ablation. We hypothesized that BDB of linear ablation has prognostic significance after radiofrequency catheter ablation for persistent AF.Among 1793 consecutive patients in the Yonsei AF ablation cohort, this observational cohort study included 398 patients with persistent AF (75.6% male; age, 59.8±10.3 years) who underwent catheter ablation with a consistent ablation protocol of the Dallas lesion set: circumferential pulmonary vein isolation; cavotricuspid isthmus ablation (CTI); roof line (RL); posterior-inferior line (PIL); and anterior line (AL). BDB rates of de novo ablation lines were 100% in circumferential pulmonary vein isolation, 100% in CTI, 84.7% in RL, 44.7% in PIL, and 63.6% in AL. During 29.0±18.4 months of follow-up, 31.7% (126/398) of the patients showed clinical recurrence. Left atrial posterior wall (LAPW) isolation (BDBs of RL and PIL) was independently associated with lower clinical AF/atrial tachycardia recurrence (hazard ratio, 0.68; 95% CI, 0.47-0.98; P=0.041; log-rank, P=0.017), whereas BDBs of RL or AL were not (log-rank, P=0.178 for RL; P=0.764 for AL). Among 52 patients who underwent repeat procedures (23.0±16.1 months after de novo procedure), the BDB maintenance rates for CTI, RL, PIL, and AL were 94.2% (49 of 52), 63.5% (33 of 47), 62.1% (18 of 29), and 61.8% (21 of 34), respectively.Although PIL crosses the esophageal contact area, LAPW isolation is important for better clinical outcome in catheter ablation with a linear ablation strategy for patients with persistent AF.
Project description:Left ventricular aneurysms are a frequent and serious complication following acute transmural myocardial infarction and are most commonly located at the ventricular apex. The majority of these patients presents with severe mitral insufficiency, congestive heart failure, systemic embolism and sudden cardiac death. Giant aneurysms occurring in a submitral position between anterior and posterior papillary muscles on the lateral ventricular wall constitute a minor entity and those leaving the mitral apparatus intact are extremely rare.Herein, we report the case of a 57 y/o Caucasian male patient with a past medical history of coronary artery disease and myocardial infarction with a giant left ventricular aneurysm measuring 15x10x8 cm in diameter. Despite the size of the aneurysm and its close topographical relation to the posterior mitral annulus the mitral apparatus was intact with a competent valve and normal left atrial size. He underwent successful surgical ventricular restoration.