scholarly journals Automatic Activity Arising in Cardiac Muscle Sleeves of the Pulmonary Vein

Biomolecules ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 23
Author(s):  
Pierre Bredeloux ◽  
Come Pasqualin ◽  
Romain Bordy ◽  
Veronique Maupoil ◽  
Ian Findlay

Ectopic activity in the pulmonary vein cardiac muscle sleeves can both induce and maintain human atrial fibrillation. A central issue in any study of the pulmonary veins is their difference from the left atrial cardiac muscle. Here, we attempt to summarize the physiological phenomena underlying the occurrence of ectopic electrical activity in animal pulmonary veins. We emphasize that the activation of multiple signaling pathways influencing not only myocyte electrophysiology but also the means of excitation–contraction coupling may be required for the initiation of triggered or automatic activity. We also gather information regarding not only the large-scale structure of cardiac muscle sleeves but also recent studies suggesting that cellular heterogeneity may contribute to the generation of arrythmogenic phenomena and to the distinction between pulmonary vein and left atrial heart muscle.

2009 ◽  
Vol 297 (1) ◽  
pp. H102-H108 ◽  
Author(s):  
Nicolas Doisne ◽  
Véronique Maupoil ◽  
Pierre Cosnay ◽  
Ian Findlay

Ectopic activity in cardiac muscle within pulmonary veins (PVs) is associated with the onset and the maintenance of atrial fibrillation in humans. The mechanism underlying this ectopic activity is unknown. Here we investigate automatic activity generated by catecholaminergic stimulation in the rat PV. Intracellular microelectrodes were used to record electrical activity in isolated strips of rat PV and left atrium (LA). The resting cardiac muscle membrane potential was lower in PV [−70 ± 1 (SE) mV, n = 8] than in LA (−85 ± 1 mV, n = 8). No spontaneous activity was recorded in PV or LA under basal conditions. Norepinephrine (10−5 M) induced first a hyperpolarization (−8 ± 1 mV in PV, −3 ± 1 mV in LA, n = 8 for both) then a slowly developing depolarization (+21 ± 2 mV after 15 min in PV, +1 ± 2 mV in LA) of the resting membrane potential. Automatic activity occurred only in PV; it was triggered at approximately −50 mV, and it occurred as repetitive bursts of slow action potentials. The diastolic membrane potential increased during a burst and slowly depolarized between bursts. Automatic activity in the PV was blocked by either atenolol or prazosine, and it could be generated with a mixture of cirazoline and isoprenaline. In both tissues, cirazoline (10−6 M) induced a depolarization (+37 ± 2 mV in PV, n = 5; +5 ± 1 mV in LA, n = 5), and isoprenaline (10−7 M) evoked a hyperpolarization (−11 ± 3 mV in PV, n = 7; −3 ± 1 mV in LA, n = 6). The differences in membrane potential and reaction to adrenergic stimulation lead to automatic electrical activity occurring specifically in cardiac muscle in the PV.


EP Europace ◽  
2020 ◽  
Vol 22 (Supplement_1) ◽  
Author(s):  
A P Martin ◽  
M Fowler ◽  
N Lever

Abstract Background Pulmonary vein isolation using cryotherapy is an established treatment for the management of patients with paroxysmal atrial fibrillation. Ablation using the commercially available balloon cryocatheter has been shown to create wide antral pulmonary vein isolation. A novel balloon cryocatheter (BCC) has been designed to maintain uniform pressure and size during ablation, potentially improving contact with the antral anatomy. The extent of ablation created using the novel BCC has not previously been established. Purpose To determine the anatomical extent of pulmonary vein isolation using electroanatomical mapping when performing catheter ablation for paroxysmal atrial fibrillation using the novel BCC. Methods Nine consecutive patients underwent pre-procedure computed tomography angiography of the left atrium to quantify the chamber dimensions. An electroanatomical map was created using the cryoablation system mapping catheter and a high definition mapping system. A bipolar voltage map was obtained following ablation to determine the extent of pulmonary vein isolation ablation. A volumetric technique was used to quantify the extent of vein and posterior wall electrical isolation in addition to traditional techniques for proving entrance and exit block. Results All patients had paroxysmal atrial fibrillation, mean age 56 years, 7 (78%) male. Electrical isolation was achieved for 100% of the pulmonary veins; mean total procedure time was 109 min (+/- 26 SD), and fluoroscopy time 14.9 min (+/- 2.4 SD). The median treatment applications per vein was one (range one - four), and median treatment duration 180 sec (range 180 -240). Left atrial volume 32 mL/m2 (+/- 7 SD), and mean left atrial posterior wall area 22 cm2 (+/- 4 SD). Data was available for quantitative assessment of the extent of ablation for eight patients. No lesions (0 of 32) were ostial in nature. The antral surface area of ablation was not statistically different between the left and right sided pulmonary veins (p 0.63), which were 5.9 (1.6 SD) and 5.4 (2.1 SD) cm2 respectively. In total 50% of the posterior left atrial wall was ablated.  Conclusion Pulmonary vein isolation using a novel BCC provides a wide and antral lesion set. There is significant debulking of the posterior wall of the left atrium. Abstract Figure.


2021 ◽  
Vol 42 (Supplement_1) ◽  
Author(s):  
M Boussoussou ◽  
B Vattay ◽  
B Szilveszter ◽  
M Kolossvary ◽  
M Vecsey-Nagy ◽  
...  

Abstract Introduction The CLOSE protocol is a novel contact-force guided technique for enclosing pulmonary veins in patients with atrial fibrillation (AF). Consistency and lesion contiguity are essential factors for procedural success. We sought to determine whether left atrial (LA) wall thickness (LAWT) and pulmonary vein (PV) dimensions as assessed by coronary CT angiography (CTA) could influence the efficacy of successful first-pass isolation using the CLOSE protocol. Methods In a single center, prospective study we enrolled 94 patients with symptomatic, drug-refractory AF who underwent pre-ablation left atrial CTA and initial radiofrequency catheter ablation between 2019.01–2020.09. The LA was divided into 11 regions when assessing LAWT. Additionally, the diameter and area of the PV orifices were obtained. First pass isolation was recorded separately for the right and left PVs. After the first pass ablation circles were ready, additional ablations were applied in those cases where first pass isolation was not achieved, to reach complete PV isolation. Predictors of successful first pass isolation were determined using logistic regression models that included anthropometrical, echocardiographic and CTA derived parameters. Results A total of 94 patients were included in the analysis with mean CHA2DS2-VASc score of 2.1±1.5 (mean age 62.4±12.6 years, 39.5% female). 61.7% were paroxysmal, 38.3 were persistent AF patients. Mean procedure times were 81.2±19.3 minutes. Complete isolation of all four PVs was achieved in 100% of patients. First-pass isolation rate was 76%, 71% and 54%, for the right PVs, left PVs and all four PVs, respectively. No difference was found regarding comorbidities and imaging parameters between those with and without first pass isolation. LAWT (mean of all 11 regions or separately) had no effect on the procedural outcome (all p>0.05). Out of all assessed parameters, only RSPV diameter was associated with right sided successful PVI on first pass isolation (p=0.04, OR 1.01). Conclusion The use of CLOSE protocol in AF patients resulted in high periprocedural success rate in terms of first pass isolation, independently from the thickness of the LA wall. RSPV diameter could influence the results of first pass isolation. FUNDunding Acknowledgement Type of funding sources: None.


Author(s):  
Naama R. Bogot ◽  
Amir Elami ◽  
Dorith Shaham ◽  
Philip M. Berman ◽  
Jacob Sosna ◽  
...  

Objective The Cox-Maze procedure using cryoablation results in transmural lesions, which follow the lesion pattern of the cut-and-sew Cox-Maze procedure. The purpose of our study was to evaluate the effect of the Cox-Maze procedure on left atrial and pulmonary vein size using computed tomography angiogram (CTA). An additional aim was to evaluate pulmonary vein anatomic variability. Methods Six patients (four women and two men; ages 39–63 years, mean age 54.3) underwent chest CTA 1 day before and 38 to 104 days (mean 62.6 days) after the cryosurgical Cox-Maze procedure. Measurements of pulmonary vein ostia and left atrial cranio-caudal, left-to-right and anterior-posterior diameters were derived by consensus. The change in diameters after therapy was compared using the Wilcoxon nonparametric test for paired measurements. Four patients (1 woman and 3 men; age 57–73 years; mean age 59) were evaluated with postoperative CTA alone 296–530 days (mean 447) after surgery, for the development of postoperative pulmonary vein stenosis. A single patient underwent preoperative CTA, but surgery was not performed. Pulmonary venous anatomy was recorded in all 11 patients. Results Sinus rhythm was restored in all operated patients. No focal ostial stenosis of the pulmonary veins was observed. The quantitative assessment in the six patients with preoperative and postoperative studies disclosed only slight changes in pulmonary vein diameter with either reduction or dilatation of no more than 20% from baseline (P > 0.05). There was a consistent trend toward decrease in left atrial dimensions, which did not reach statistical significance. Six patients (55%) had standard pulmonary venous anatomy and five patients (45%) had at least one variation in their pulmonary vein anatomy. Conclusions In this study, we found that a very intensive cryoablation protocol around the pulmonary veins did not result in pulmonary vein stenosis. In addition, a relatively high incidence of anatomic variations of the pulmonary veins was documented.


2011 ◽  
Vol 152 (34) ◽  
pp. 1374-1378
Author(s):  
Eszter Mária Végh ◽  
Gábor Széplaki ◽  
Szabolcs Szilágyi ◽  
István Osztheimer ◽  
Tamás Tahin ◽  
...  

A 29-year-old male was admitted to our outpatient clinic because of palpitation and documented narrow QRS arrhythmia. Based on the ECG, supraventricular tachycardia was diagnosed, electrophysiological examination was indicated and ablation therapy was recommended. During positioning of the catheter the patient developed arrhythmia. On the coronary sinus catheter the activation spread from distal to proximal electrodes, suggesting left atrial origin. During atrial entrainment pacing long return cycle was observed and distal coronary sinus pacing resulted in a 15 ms longer cycle length than the arrhythmia. Therefore, the left atrial origin of the arrhythmia was confirmed and double transseptal puncture was performed. Lasso and irrigated tip catheter were introduced into the left atrium and electroanatomical mapping was performed with CARTO3 system. After electroanatomical mapping the origin of tachycardia was located proximally in the left superior pulmonary vein. Ablation was started at the earliest activation point, where acceleration was observed and the arrhythmia stopped after the first ablation. Pulmonary vein isolation was completed, and bidirectional block could be confirmed. After 30 minutes the arrhythmia was not inducible. During follow-up, Holter-examination was negative and the patient remained asymptomatic. The pulmonary vein tachycardia is a supraventricular arrhythmia that can occur at any age, but the diagnosis based on the ECG is not always simple. Detailed electroanatomical mapping is very important in the diagnosis of this type of arrhythmia, although it can be verified with conventional electrophysiological methods as well. Focal ablation may be a therapeutic option; however, total isolation of pulmonary veins can be more effective. Orv. Hetil., 2011, 152, 1374–1378.


EP Europace ◽  
2003 ◽  
Vol 4 (Supplement_2) ◽  
pp. B11-11
Author(s):  
M. Casella ◽  
G. Fassini ◽  
S. Riva ◽  
F. Giraldi ◽  
N. Trevisi ◽  
...  

Author(s):  
James S. Gammie ◽  
G Kwame Yankey ◽  
Timothy Nolan ◽  
Z. Jon Wu ◽  
Timm Dickfeld ◽  
...  

Objective Clinical experience with endocardial cryoablation for the surgical treatment of atrial fibrillation has demonstrated safety and efficacy. Direct access to the left atrium via a thoracoscopic or pericardial approach with a balloon-tipped cryoablation catheter might facilitate endocardial cryoablation on the beating heart. We investigated the ability of a novel cryoballoon to produce endocardial pulmonary vein ostial cryolesions on the beating heart in a large-animal model. Methods Six sheep underwent small left thoracotomy. A 10.5F catheter with a 23-mm cryoballoon was inserted directly into the left atrium under fluoroscopic and intracardiac echo (ICE) guidance. Cryoablation of the pulmonary vein ostia was performed. Animals were killed at 14 days. Pulmonary venous electrical isolation was assessed immediately before the animals were killed. Results All animals survived balloon cryoablation with no periprocedural complications. Balloon occlusion was well tolerated hemodynamically, with minimal change in blood pressure (–4 ± 6 mm Hg systolic BP) and no change in heart rate. ICE demonstrated an absence of intracardiac air or ice embolization during ablation. Mean balloon temperature was −67 ± 8°C. All animals were neurologically intact after the procedure. Five of 6 (83%) veins exhibited circumferential exit block. Phrenic nerve function was intact in all animals. On gross inspection, all lesions were circumferential and continuous without evidence of endocardial thrombus. Pathology confirmed circumferential transmurality in all treated veins. Conclusions Direct left atrial access cryoballoon ablation was effective for isolating pulmonary veins. This technology may be an important component of a minimally invasive beating heart CryoMaze procedure for the treatment of atrial fibrillation.


2015 ◽  
Vol 3 (9) ◽  
pp. 49
Author(s):  
Sharmila Sehli ◽  
David M Donaldson

A 52-year-old man with symptomatic paroxysmal atrial fibrillation was offered an atrial fibrillation (AF) ablation procedure. His echocardiogram indicated that he had no structural heart disease. A cardiac computed tomographic (CT) scan showed enlargement of the right pulmonary veins, absence of the left pulmonary veins, a prominent left atrial appendage, and a hypoplastic left lung. Cardiac CT with an electroanatomic mapping system confirmed a prominent left atrial appendage and the absence of the left pulmonary veins. Due to the limited number of patients with this condition, information about ablation remains very limited, and his ablation was deferred. Unilateral pulmonary vein atresia is a rare condition in adults which results from failure of incorporation of the common pulmonary vein into the left atrium. This case demonstrates the clinical importance of preprocedural imaging prior to AF ablation.


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