Abstract 738: Role of the Pulmonary Veins in Experimental Paradigms of Remodeling- Basic Science Associated Atrial Fibrillation

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Masao Sakabe ◽  
Kristina Lemola ◽  
Katsuyoshi Chiba ◽  
Grigorios Katsouras ◽  
Akiko Shiroshita-Takeshita ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Pulmonary Veins ◽  
Rate Adaptation ◽  
Ventricular Rate ◽  
Atrial Remodeling ◽  
List Type ◽  
Ablation Therapy ◽  
Before And After ◽  
The Mean

Background : Pulmonary vein (PV) activity is crucial in some forms of clinical atrial fibrillation (AF), particularly paroxysmal lone AF. The precise importance of PVs in AF associated with structural heart disease is less clear. Some evidence suggests that PVs may be important for AF in experimentally-remodeled atrial substrates, e.g. atrial-tachycardia remodeling (ATR) and congestive heart failure (CHF)-induced structural remodeling, but contradictory findings also exist. This study assessed the role of PVs in canine remodeling-associated AF by evaluating the changes induced by PV-LA disconnection via encircling epicardial ablation. Methods: AF was induced before and after complete isolation of all PVs in dogs with: ATR induced by atrial tachypacing (400 bpm x 1 wk; with AV block and 80 bpm ventricular pacing to control ventricular rate, n=5); and CHF induced by ventricular tachypacing (VTP, 240 bpm x 2 wks, n=7). Electrophysiological measurements and AF mapping with 240 unipolar atrial electro-grams in both atria and all PVs were also obtained before and after PV isolation. Results ATR reduced atrial ERPs and ERP rate adaptation. The shortest AF cycle length (AFCL) in each ATR dog was recorded from PVs (mean 84±3 ms), but the mean AFCL in each of the PVs (range 97–103 ms) was not different from the mean AFCL at LA sites (98 –103 ms). PV ablation did not affect AF duration in ATR dogs (mean 284±265 pre- vs. 304±225 s post-ablation, P=NS), nor did it significantly alter RA or LA AFCL. In CHF dogs, ERPs and ERP rate adaptation were preserved. The shortest AFCL was recorded in PVs in 2 dogs (108,112 ms) and in the left side of Bachmann’s bundle in 3 (97–117 ms). PV ablation failed to alter AF duration in CHF dogs (mean 778±203 pre- vs. 644±206 s post-ablation), and increased AFCL in RA and LA slightly (10 –15%) but not significantly. Conclusions : Uncoupling of the PVs from the LA fails to significantly affect the AF substrate in 2 clinically-relevant animal paradigms of AF-promoting atrial remodeling. These findings suggest that in the presence of a favorable atrial substrate for AF the PVs are not needed for AF maintenance, and are consistent with clinical observations that complete PV isolation may not be essential for effective ablation therapy of all groups of AF patients.

Intraoperative CARTO Mapping for Atrial Fibrillation Ablation in Patients Undergoing Cardiac Surgery

2021 ◽  
Author(s):  
Sara Rita Vacirca
Keyword(s):  
Atrial Fibrillation ◽  
Cardiac Surgery ◽  
Heart Surgery ◽  
Pulmonary Veins ◽  
Open Heart Surgery ◽  
Atrial Fibrillation Ablation ◽  
Surgical Ablation ◽  
Before And After ◽  
The Mean ◽  
Exit Block

Objective: Intraoperative CARTO Mapping for Atrial Fibrillation ablation in cardiac surgery. Background: Surgical ablation of Atrial Fibrillation is usually performed without mapping. The study aims to determine if intraoperative CARTO can be useful to guide the ablating procedure. Methods and Findings: Fourteen patients with symptomatic and drug-refractory concomitant AF were operated on in 2003 and 2004. CARTO mapping was performed before and after surgical bipolar radio-frequency ablation. Application of energy was repeated when residual electrical activity was detected at the pulmonary veins-atrial junction. Pacing wires were applied on right and left pulmonary veins distally to the ablation line to confirm the exit block. The mapping protocol was completed in 12 patients. Acute left atrium-pulmonary vein isolation was achieved after single or double energy application in 2/12 (16.6%) and 9/12 (75%) patients, respectively. The mean duration of the mapping and ablation procedure was 67 minutes. At discharge, PV isolation persisted in 10 patients: exit block was confirmed by the absence of pacing through the pulmonary veins electrodes. After a mean follows up of 181 months, no further recurrent AF events were registered in 9/12 (69.2%) patients. Conclusions: CARTO system is useful during open-heart surgery to guide the ablating strategy.

scholarly journals The Intrinsic Autonomic Nervous System in Atrial Fibrillation: A Review

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Bo He ◽  
Benjamin J. Scherlag ◽  
Hiroshi Nakagawa ◽  
Ralph Lazzara ◽  
Sunny S. Po
Keyword(s):  
Atrial Fibrillation ◽  
Catheter Ablation ◽  
Clinical Evidence ◽  
Critical Role ◽  
Pulmonary Veins ◽  
Atrial Remodeling ◽  
Success Rates ◽  
Minimally Invasive Surgical ◽  
Wolff Parkinson White Syndrome

The procedure of catheter ablation for the treatment of drug resistant atrial fibrillation (AF) has evolved but still relies on lesion sets intended to isolate areas of focal firing, mainly the myocardial sleeves of the pulmonary veins (PVs), from the rest of the atria. However the success rates for this procedure have varied inversely with the type of AF. At best success rates have been 20 to 30% below that of other catheter ablation procedures for Wolff-Parkinson-White syndrome, atrioventricular junctional re-entrant tachycardia and atrial flutter. Basic and clinical evidence has emerged suggesting a critical role of the ganglionated plexi (GP) at the PV-atrial junctions in the initiation and maintenance of the focal form of AF. At present the highest success rates have been obtained with the combination of PV isolation and GP ablation both as catheter ablation or minimally invasive surgical procedures. Various lines of evidence from earlier and more recent reports provide that both neurally based and myocardially based forms of AF can separately dominate or coexist within the context of atrial remodeling. Future studies are focusing on non-pharmacological, non-ablative approaches for the prevention and treatment of AF in order to avoid the substantive complications of both these regimens.

Abstract 741: Atrial Fibrillation Begets Atrial Fibrillation: Acute Autonomic Remodeling Leads to Enhanced Inducibility for Atrial Fibrillation

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Zhibing Lu ◽  
Benjamin J Scherlag ◽  
Guo-Dong Niu ◽  
Jiaxiong Lin ◽  
Muhammad Ghias ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Pulmonary Veins ◽  
Atrial Pacing ◽  
Time Period ◽  
Before And After ◽  
Rapid Pacing ◽  
Group 2 ◽  
Window Of Vulnerability ◽  
Group 1

Introduction: There have been many forms of remodeling reported to play a role in the concept of “atrial fibrillation (AF) begets atrial fibrillation.” The role of intrinsic cardiac nervous system (ICNS) in this remodeling process was evaluated in this study. Methods: Continuous rapid pacing (1200 bpm, 2× threshold, TH) was performed at the left atrial appendage to maintain AF. Group 1 (N=7): 6-hours of pacing followed by ganglionated plexi (GP) ablation, both left and right side; Group 2 (N=7): GP ablation followed by 6-hours of pacing. At 2x and 10x TH, the effective refractory period (ERP) and window of vulnerability (WOV), i.e., longest-shortest coupling of premature stimulus which induced AF in milliseconds (ms), were measured at the left atrium, right atrium and pulmonary veins (PVs) every hour during the 6-hours of pacing before and after GP ablation. Results: In group 1 (rapid pacing with GP intact) ERP progressively shortened in the first two hours and then stabilized both at 2×TH and 10×TH (Figure 1A ), however, WOV progressively widened throughout the time period (Figure 1B ). After GP ablation, ERP was significantly longer than prior to ablation and AF could not be induced (WOV=0, p<0.01) at any pacing site at either 2×TH or 10×TH (Figure 1B ). In group 2 (initial GP ablation), ERP exhibited a slightly increasing trend as the pacing time increased. AF could not be induced in 6/7 dogs during the 6-hour pacing, and was inducible in 1/7 with a cumulative WOV of only 10 ms. Conclusion: The ICNS is crucial for the process of “AF begets AF” in the acute stages of remodeling by rapid atrial pacing.

Ventricular Rate During Atrial Fibrillation Before and After Slow-Pathway Ablation

Circulation ◽  
1996 ◽  
Vol 94 (5) ◽  
pp. 1023-1026 ◽  
Author(s):  
S. Adam Strickberger ◽  
Raul Weiss ◽  
Emile G. Daoud ◽  
Rajiva Goyal ◽  
Frank Bogun ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Ventricular Rate ◽  
Slow Pathway ◽  
Slow Pathway Ablation ◽  
Before And After

scholarly journals Persistent Atrial Fibrillation: The Role of Left Atrial Posterior Wall Isolation and Ablation Strategies

2021 ◽  
Vol 10 (14) ◽  
pp. 3129
Author(s):  
Riyaz A. Kaba ◽  
Aziz Momin ◽  
John Camm
Keyword(s):  
Atrial Fibrillation ◽  
Left Atrial ◽  
Pulmonary Veins ◽  
Treatment Strategies ◽  
Persistent Atrial Fibrillation ◽  
Posterior Wall ◽  
Cardiovascular Death ◽  
Good Effect ◽  
Complex Forms

Atrial fibrillation (AF) is a global disease with rapidly rising incidence and prevalence. It is associated with a higher risk of stroke, dementia, cognitive decline, sudden and cardiovascular death, heart failure and impairment in quality of life. The disease is a major burden on the healthcare system. Paroxysmal AF is typically managed with medications or endocardial catheter ablation to good effect. However, a large proportion of patients with AF have persistent or long-standing persistent AF, which are more complex forms of the condition and thus more difficult to treat. This is in part due to the progressive electro-anatomical changes that occur with AF persistence and the spread of arrhythmogenic triggers and substrates outside of the pulmonary veins. The posterior wall of the left atrium is a common site for these changes and has become a target of ablation strategies to treat these more resistant forms of AF. In this review, we discuss the role of the posterior left atrial wall in persistent and long-standing persistent AF, the limitations of current endocardial-focused treatment strategies, and future perspectives on hybrid epicardial–endocardial approaches to posterior wall isolation or ablation.

Effect of thromboxane antagonists on ozone-induced airway responses in dogs

1990 ◽  
Vol 69 (3) ◽  
pp. 880-884 ◽  
Author(s):  
G. L. Jones ◽  
C. G. Lane ◽  
P. M. O'Byrne
Keyword(s):  
Airway Hyperresponsiveness ◽  
The Other ◽  
Receptor Antagonists ◽  
Thromboxane Receptor ◽  
Before And After ◽  
The Mean ◽  
Airway Responses ◽  
Control Infusion

Airway hyperresponsiveness after inhaled ozone in dogs may occur as a result of thromboxane release in the airway. In this study, two thromboxane receptor antagonists, L-655,240 and L-670,596, were used in doses that inhibit the response to an inhaled thromboxane mimetic, U-46619, to determine further the role of thromboxane in ozone-induced airway hyperresponsiveness. Dogs were studied on 2 days separated by 1 wk. On each day, the dogs inhaled ozone (3 ppm) for 30 min. On one randomly assigned day, 10 dogs received an infusion of L-655,240 (5 mg.kg-1.h-1) and 5 dogs received an infusion of L-670,596 (1 mg.kg-1.h-1); on the other day dogs received a control infusion. Airway responses to doubling doses of acetylcholine were measured before and after inhalation of ozone and were expressed as the concentration of acetylcholine giving a rise in resistance of 5 cmH2O.l-1.s from baseline (acetylcholine provocation concentration). The development of airway hyperresponsiveness after ozone was not inhibited by the thromboxane antagonists. The mean log difference in the acetylcholine provocative concentration before and after ozone on the L-655,240 treatment day was 0.62 +/- 0.12 (SE) and on the control day was 0.71 +/- 0.12 (P = 0.48); on the L-670,596 treatment day the mean log difference was 0.68 +/- 0.15 (SE) and on the control day it was 0.75 +/- 0.19 (P = 0.45). These results do not support an important role for thromboxane in causing ozone-induced airway hyperresponsiveness.

Role of the Ambulatory Assessed Apnea-Hypopnea Index for Predicting Recurring Atrial Fibrillation After Ablation Therapy

2021 ◽  
Author(s):  
Teresa Trenkwalder ◽  
Christian Grebmer ◽  
Madeleine Tydecks ◽  
Patrick Blažek ◽  
Marc Kottmaier ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Apnea Hypopnea Index ◽  
Ablation Therapy

scholarly journals A novel individualized strategy for cryoballoon catheter ablation in patients with paroxysmal atrial fibrillation

2019 ◽  
Author(s):  
Jun Ding ◽  
Jing Xu ◽  
Wei Ma ◽  
Bingwei Chen ◽  
Peigen Yang ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Left Atrial ◽  
Dwell Time ◽  
Pulmonary Veins ◽  
Group Versus ◽  
Conventional Group ◽  
Optimal Dosage ◽  
Total Procedure Time ◽  
The Mean

Abstract Background : The optimal dosage for cryoablation of atrial fibrillation (Cryo-AF) is still unknown. To evaluate the efficacy of an individualized freeze duration, we compared the clinical outcome of patients treated with a time-to-pulmonary vein isolation (TT-PVI) or temperature-guided ablation protocol to the outcome of patients treated with a conventional ablation protocol. Methods: A total of 164 consecutive patients were included in the study. One method employed was a conventional dosing protocol (at least 2 applications of 180 seconds each)(the Cryo-AF Conventional group n=84), and the second method had a shorter protocol that was based on the TT-PVI or achievement of -40°C within 60 seconds (the Cryo-AF Dosing group n=80). Results: We treated 656 pulmonary veins (PVs) with 1420 cryotherapy applications. The mean number of applications per patient was 8.7±0.8, with no difference between groups (Cryo-AF Conventional , 8.7±0.8 versus Cryo-AF Dosing ,8.6±0.8; P =0.359). The Cryo-AF Dosing group required significantly less total cryotherapy application time (990.60±137.77versus 1501.58±89.60 seconds; P <0.001) and left atrial dwell time (69.91±6.91 versus 86.48±7.03 minutes; P <0.001) than the Cryo-AF Conventional group. Additionally, the Cryo-AF Dosing group required significantly less total procedure time (95.03±6.50 versus 112.43±7.11 minutes; P <0.001). We observed acute ATP-induced or spontaneous vein electric reconnections in 13 veins (1.98%) after 20 minutes. The reconnection rates between the Cryo-AF Conventional and Cryo-AF Dosing groups were similar in that 2.98% and 0.94% of the initially isolated veins were reconnected, respectively, ( P =0.061). There was no difference in the recurrence rate of free atrial arrhythmia after a 1-year follow-up, which were 78.75% in the Cryo-AF Dosing group versus 78.57% in the Cryo-AF Conventional group ( P =0.978). Conclusion: A novel Cryo-AF dosing protocol guided by temperature or the TT-PVI can be used to individualize an ablation strategy. This new protocol can lead to a significant reduction in duration of the procedure, the cryoenergy dosage and the left atrial dwell time. The procedure had equal safety and similar acute and 1-year follow-up outcomes compared to the conventional approach.

Effect of Narrow- band UVB on serum and tissue vitamin D level in vitiligo

QJM ◽  
2021 ◽  
Vol 114 (Supplement_1) ◽  
Author(s):  
Ali Abdulkareem Al-Shabkhon ◽  
Adel Ahmed Halim Emam ◽  
Ahmed Abd Elfattah Afify
Keyword(s):  
Vitamin D ◽  
Case Control Study ◽  
Narrow Band ◽  
Tissue Level ◽  
Before And After ◽  
Duration Of Disease ◽  
The Mean ◽  
Tissue Vitamin ◽  
Control Study

Abstract Background Immunologic background of vitiligo, role of vitamin D on its pathogenesis, role of NB-UVB on its treatment and its stimulatory effect NB-UVB on VDR expression are challenging area of research. The current study will focus on evaluating the effect of NB-UVB on serum and tissue level of vitamin D in vitiligo patients and correlating it with the degree of improvement. Aim of the study The aim of the present study is to evaluate and compare the serum and tissue vitamin D level in vitiligo patients before and after NB- UVB therapy and correlate them together and with the degree of improvement. Patients and methods A case-control study included 16 vitiligo patients and 16 age and sex matched healthy controls. All patients will be examined by one dermatologist (demonstrating the extent of depigmentation according to rule of nines), and photographs will be taken before and after phototherapy to be evaluated by two different dermatologists to document the extent of repigmentation. Estimation of serum level of vitamin D by ELISA Results Five of the 15 patients achieved more than 55% repigmentation; the mean duration of disease was 13 months. The remaining 10 patients had 30% - 40% repigmentation.

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