Ablation in Atrial Fibrillation with Ventricular Pacing Results in Similar Catheter Stability and Arrhythmia Recurrence Compared to Ablation in Sinus Rhythm with Atrial Pacing

Abstract Background Slowing electrical conduction by cooling the myocardium can be used for defibrillation. We previously demonstrated the efficacy of a small cold device placed in oblique sinus (OS) in terminating atrial fibrillation (AF). However, the parameters needed to achieve effective atrial defibrillation are unknown. Purpose Assess effect of the size of cooled myocardium on frequency of AF termination in acute canine animal models. Methods Sternotomy was performed under general anesthesia in 10 acute canine experiments. AF was induced using rapid atrial pacing and intra-myocardial epinephrine and acetylcholine injections. Once AF sustained for at least 30s, either a cool (7–9°C) or placebo (body temperature) device was placed in the OS. Four device sizes were tested; ½X½, ¾X¾, and 1X1 inch devices and two ¾X¾ inch devices placed side by side simultaneously. Time to AF termination was recorded. Chi-squared or Fisher's exact test were used to compare the frequency of arrhythmia termination with cooling versus placebo. Results A total of 166 applications were performed (89 cool vs 77 placebo) in 10 animal experiments. Overall, AF terminated in 82% of the cooling applications vs. 67.5% of placebo (P=0.03, Figure 1). For the ½X½ inch device 88% of cold applications restored sinus rhythm vs. 63.6% for placebo (P=0.05). The frequency of sinus restoration for cold ¾X¾, 1X1 and two ¾X¾ side by side devices was 86.7%, 83.3% and 70% respectively. Time to sinus restoration when achieved was within three minutes was also not significantly changed. Conclusion Placing a cool device in the oblique sinus can terminate AF and efficacy is not affected by the size of device. Funding Acknowledgement Type of funding source: Private grant(s) and/or Sponsorship. Main funding source(s): MediCool Technologies

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Thoracic vein ablation terminates chronic atrial fibrillation in dogs

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00595.2003 ◽

2004 ◽

Vol 286 (6) ◽

pp. H2072-H2077 ◽

Cited By ~ 13

Author(s):

Angela M. Park ◽

Chung-Chuan Chou ◽

Paul C. Drury ◽

Yuji Okuyama ◽

Anish Peter ◽

...

Keyword(s):

Atrial Fibrillation ◽

Sinus Rhythm ◽

Superior Vena Cava ◽

Superior Vena ◽

Vena Cava ◽

Chronic Atrial Fibrillation ◽

Atrial Pacing ◽

Bipolar Electrodes ◽

Cycle Lengths ◽

Activation Cycle

The thoracic vein hypothesis of chronic atrial fibrillation (AF) posits that rapid, repetitive activations from muscle sleeves within thoracic veins underlie the mechanism of sustained AF. If this is so, thoracic vein ablation should terminate sustained AF and prevent its reinduction. Six female mongrel dogs underwent chronic pulmonary vein (PV) pacing at 20 Hz to induce sustained (>48 h) AF. Bipolar electrodes were used to record from the atria and thoracic veins, including the vein of Marshall, four PVs, and the superior vena cava. Radio frequency (RF) application was applied around the PVs and superior vena cava and along the vein of Marshall until electrical activity was eliminated. Computerized mapping (1,792 electrodes, 1 mm resolution) was also performed. Sustained AF was induced in 30.6 ± 6.5 days, and ablation was done 17.3 ± 8.5 days afterward. Before ablation, the PVs had shorter activation cycle lengths than the atria, and rapid, repetitive activations were observed in the PVs. All dogs converted to sinus rhythm during ( n = 4 dogs) or within 90 min of completion of RF ablation. Rapid atrial pacing afterward induced only nonsustained (<60 s) AF in all dogs. Average AF cycle lengths after reinduction were significantly ( P = 0.01) longer (183 ± 31.5 ms) than baseline (106 ± 16.2 ms). There were no activation cycle length gradients after RF application. We conclude that thoracic vein ablation converts canine sustained AF into sinus rhythm and prevents the reinduction of sustained AF. These findings suggest that thoracic veins are important in the maintenance of AF in dogs.

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Implication of ventricular pacing burden and atrial pacing therapies on the progression of atrial fibrillation: A systematic review and meta-analysis of randomized controlled trials

Heart Rhythm ◽

10.1016/j.hrthm.2019.02.020 ◽

2019 ◽

Vol 16 (8) ◽

pp. 1204-1214 ◽

Cited By ~ 2

Author(s):

Dian A. Munawar ◽

Rajiv Mahajan ◽

Thomas A. Agbaedeng ◽

Anand Thiyagarajah ◽

Darragh J. Twomey ◽

...

Keyword(s):

Atrial Fibrillation ◽

Systematic Review ◽

Randomized Controlled Trials ◽

Meta Analysis ◽

Controlled Trials ◽

Atrial Pacing ◽

Ventricular Pacing ◽

Randomized Controlled

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Loss of atrial contractility is primary cause of atrial dilatation during first days of atrial fibrillation

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00581.2004 ◽

2004 ◽

Vol 287 (5) ◽

pp. H2324-H2331 ◽

Cited By ~ 30

Author(s):

Ulrich Schotten ◽

Sunniva de Haan ◽

Hans-Ruprecht Neuberger ◽

Sabine Eijsbouts ◽

Yuri Blaauw ◽

...

Keyword(s):

Atrial Fibrillation ◽

Sinus Rhythm ◽

Right Atrium ◽

Contractile Function ◽

Atrial Pressure ◽

Right Atrial ◽

Atrial Pacing ◽

Rapid Pacing ◽

The Mean ◽

The Right

Atrial fibrillation (AF) induces a progressive dilatation of the atria which in turn might promote the arrhythmia. The mechanism of atrial dilatation during AF is not known. To test the hypothesis that loss of atrial contractile function is a primary cause of atrial dilatation during the first days of AF, eight goats were chronically instrumented with epicardial electrodes, a pressure transducer in the right atrium, and piezoelectric crystals to measure right atrial diameter. AF was induced with the use of repetitive burst pacing. Atrial contractility was assessed during sinus rhythm, atrial pacing (160-, 300-, and 400-ms cycle length), and electrically induced AF. The compliance of the fibrillating right atrium was measured during unloading the atria with diuretics and loading with 1 liter of saline. All measurements were repeated after 6, 12, and 24 h of AF and then once a day during the first 5 days of AF. Recovery of the observed changes after spontaneous cardioversion was also studied. After 5 days of AF, atrial contractility during sinus rhythm or slow atrial pacing was greatly reduced. During rapid pacing (160 ms) or AF, the amplitude of the atrial pressure waves had declined to 20% of control. The compliance of the fibrillating atria increased twofold, whereas the right atrial pressure was unchanged. As a result, the mean right atrial diameter increased by ∼12%. All changes were reversible within 3 days of sinus rhythm. We conclude that atrial dilatation during the first days of AF is due to an increase in atrial compliance caused by loss of atrial contractility during AF. Atrial compliance and size are restored when atrial contractility recovers after cardioversion of AF.

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Abstract 5665: Assessment of Noninducibility after Catheter Ablation for Atrial Fibrillation: High Dose Isoproterenol vs Rapid Atrial Pacing

Circulation ◽

10.1161/circ.118.suppl_18.s_980-b ◽

2008 ◽

Vol 118 (suppl_18) ◽

Author(s):

Thomas Crawford ◽

Jean F Sarrazin ◽

Michael Kuhne ◽

Nagib Chalfoun ◽

Darryl Wells ◽

...

Keyword(s):

Atrial Fibrillation ◽

Catheter Ablation ◽

Sinus Rhythm ◽

Antiarrhythmic Drugs ◽

High Dose ◽

Atrial Pacing ◽

Target Sites ◽

Isoproterenol Infusion ◽

Complex Fractionated Atrial Electrograms

Background: Noninducibility of atrial fibrillation (AF) after catheter ablation of paroxysmal AF (PAF) identifies patients who are more likely to remain in sinus rhythm (SR). However, it is not clear whether assessment of noninducibility by rapid atrial pacing (RAP) is incremental to high dose isoproterenol (ISO) infusion. Methods and Results: There were 65 patients (age=56±13 years) with PAF who presented in sinus rhythm for catheter ablation. ISO was administered in escalating doses of 5/10/15/20 μg/min every 2 minutes prior to ablation. AF (or frequent PACs in 4) was inducible in 61/65 patients (94%) at a mean dose of 15±6 μg/min. Antral pulmonary vein (PV) isolation (APVI) was performed in all patients with complete isolation of all PVs. If AF did not terminate during APVI, complex fractionated atrial electrograms (CFAEs) were targeted in the left atrium (16) or coronary sinus (2) until AF terminated or all target sites were ablated. AF terminated during ablation in 41/65 (63%). Following conversion to sinus rhythm, 54 of the 61 patients (89%) who were initially inducible with ISO became noninducible during ISO re-challenge. Among these 54 patients who were noninducible by ISO, rapid atrial pacing (RAP) down to a cycle length of 180 ms (≥5 times) induced sustained AF (>60 seconds) in 17 patients (31%). At a mean follow-up of 9±4 months after a single ablation procedure, 35/54 patients (65%) who were noninducible by ISO and 2/7 patients (29%) who were inducible were in sinus rhythm without antiarrhythmic drugs. However, 11/17 patients (65%) who were inducible by RAP and 26/37 (70%) who were noninducible by RAP were in sinus rhythm without antiarrhyhtmic drug therapy (P=0.8). Conclusions: Noninducibility of AF in response to high dose isoproterenol infusion identifies patients who are more likely to remain in sinus rhythm after catheter ablation. Rapid atrial pacing may still result in induction of AF in 30% of patients who are noninducible by isoproterenol. However, inducibility of AF by rapid atrial pacing in patients who are noninducible by isoproterenol appears to be a nonspecific observation.

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