Dormant PV Research Articles

Safety and Efficacy of a Novel Approach to Pulmonary Vein Isolation Using Prolonged Apneic Oxygenation

BackgroundImproved ablation catheter–tissue contact results in more effective ablation lesions. Respiratory motion causes catheter instability, which impacts durable pulmonary vein isolation (PVI). ObjectivesThis study sought to evaluate the safety and efficacy of a novel ablation strategy involving prolonged periods of apneic oxygenation during PVI. MethodsWe conducted a multicenter, prospective controlled study of 128 patients (mean age 63 ± 11 years; 37% women) with paroxysmal atrial fibrillation undergoing PVI. Patients underwent PVI under general anesthesia using serial 4-minute runs of apneic oxygenation (apnea group; n = 64) or using standard ventilation settings (control group; n = 64). Procedural data, arterial blood gas samples, catheter position coordinates, and ablation lesion characteristics were collected. ResultsBaseline characteristics between the 2 groups were similar. Catheter stability was significantly improved in the apnea group, as reflected by a decreased mean catheter displacement (1.55 ± 0.97 mm vs 2.25 ± 1.13 mm; P < 0.001) and contact force SD (4.9 ± 1.1 g vs 5.2 ± 1.5 g; P = 0.046). The percentage of lesions with a mean catheter displacement >2 mm was significantly lower in the apnea group (22% vs 44%; P < 0.001). Compared with the control group, the total ablation time to achieve PVI was reduced in the apnea group (18.8 ± 6.9 minutes vs 23.4 ± 7.8 minutes; P = 0.001). There were similar rates of first-pass PVI, acute PV reconnections and dormant PV reconnections between the two groups. ConclusionsA novel strategy of performing complete PVI during apneic oxygenation results in improved catheter stability and decreased ablation times without adverse events. (Radiofrequency Ablation of Atrial Fibrillation Under Apnea; NCT04170894)

Optimized lesion size index (o-LSI): A novel predictor for sufficient ablation of pulmonary vein isolation.

BackgroundAlthough the lesion size index (LSI) has been well established, it is sometimes difficult to achieve first‐pass pulmonary vein isolation (PVI) and to avoid acute pulmonary vein reconnections, even with LSI‐guided procedures. The purpose of this study was to assess the predictive accuracy of a novel parameter, the optimized lesion size index (o‐LSI), to perform PVI.MethodsThe voltage maps created by the Advisor™ high‐density (HD) grid catheter before PVI in 35 atrial fibrillation (AF) patients were examined for an association between the voltage amplitude and insufficient ablation sites (IAS), which were defined as either (i) spontaneous reconnection sites, (ii) dormant PV conduction sites unmasked with 20 mg of adenosine triphosphate disodium hydrate (ATP) injection, or (iii) PV‐LA gap sites after the initial PVI.ResultsIAS was observed in 25/1417 of the total ablation sites. IAS was significantly associated with higher bipolar voltage areas (4.20 ± 2.68 vs 2.43 ± 1.93 mV, P < .0001) but not with LSI. A novel index, o‐LSI (defined as LSI/bipolar voltage), was significantly lower in IAS than in others (1.14 [0.82, 1.81] vs 2.35 [1.31, 4.80] LSI/mV). By receiver operating characteristic analysis, an o‐LSI of 2.04 was the best cutoff value for the prediction of IAS (88% sensitivity and 55% specificity, P < .0001, areas under the curve: 0.742).ConclusionLow o‐LSI was strongly associated with IAS, potentially providing a novel index to improve first‐pass PV isolation.

The modified ablation index: a novel determinant of acute pulmonary vein reconnections after pulmonary vein isolation.

Although pulmonary vein isolation (PVI) guided by the ablation index (AI) has been well-developed, acute PV reconnections (PVRs) still occur. This study aimed to compare the prognostic performance of the modified AI and its optimal cut-off value for the prediction of acute PVRs to ensure durable PVI. Three-dimensional left atrium (LA) voltage maps created before an extensive encircling PVI in 64 patients with atrial fibrillation (AF) (45 men, 62 ± 10years) were examined for an association between electrogram voltage amplitude recorded from the PV-LA junction and acute post-PVI PVRs (spontaneous PVRs and/or ATP-provoked dormant PV conduction). Acute PVRs were observed in 22 patients (34%) and 33 (3%) of the 1012 PV segments. Acute PVRs were significantly associated with segments with higher bipolar voltage zones (3.23 ± 1.17 vs. 1.97 ± 1.20mV, P < 0.0001), lower mean AI values (449 [428-450] vs. 460 [437-486], P = 0.05), and radiofrequency lesion gaps ≥ 6mm (48 vs. 32%, P = 0.04), but not with contact force, force-time integral, or power. We created the modified AI calculated as AI/LA bipolar voltage, and found it to be significantly lower in areas with acute PVRs than in those without (152 [109-185] vs. 256 [176-413]AU/mV, P < 0.0001). Univariate analysis showed the prognostic performance of the modified AI, with an area under the curve of 0.801 (0.775-0.825), to be the highest of all the significant parameters. Low values of the novel modified AI on the PV-encircling ablation line were strongly associated with acute PVRs.

No association between dormant conduction sites and pulmonary vein reconnection sites in late atrial fibrillation recurrence after catheter ablation

ObjectiveDespite use of provocation testing to unmask dormant left atrium (LA)-PV conduction after index pulmonary vein isolation (PVI) for atrial fibrillation (AF), AF recurrence still occurs, with PV reconnection as the main cause. In an effort to answer the question whether freedom from AF recurrence can be achieved by ablation that targets sites of dormant conduction, we compared sites of dormant conduction against sites of PV reconnection identified at the time of repeat ablation for AF recurrence. Materials and methodsThe study group comprised 46 patients (30 men/16 women, aged 58.7±10.3 years) with AF (paroxysmal: n=37, persistent: n=9) who underwent repeat ablation for AF recurrence 12.3 (7.4–29.7) months after the index ablation procedure. Ipsilateral PVs were divided into 8 segments each (736 total segments), and the relation between dormant conduction sites and PV reconnection sites was determined per segment. ResultsDormant LA-PV conduction was unmasked and ablated in 22 (47.8%) of the 46 patients at sites within 43 (5.8%) of the 736 PV segments. Late PV reconnection was found within 122 (17%) of the 736 PV segments at the time of re-ablation for AF recurrence. Only 22 (18%) of these 122 PV segments corresponded to dormant conduction sites identified during the index procedure. ConclusionAlthough additional ablation to eliminate dormant PV conduction unmasked during the index ablation procedure is performed, the majority of PVs that show reconduction at the time of treatment for clinical AF recurrence are PVs that have not shown dormant conduction.

High-voltage zones within the pulmonary vein antra: Major determinants of acute pulmonary vein reconnections after atrial fibrillation ablation.

Recurrence of atrial fibrillation (AF) after pulmonary vein isolation (PVI) is mainly due to PV reconnections. Patient-specific tissue characteristics that may contribute remain unidentified. This study aimed to assess the relationship between the bipolar electrogram voltage amplitudes recorded from the PV-left atrial (LA) junction and acute PV reconnection sites. Three-dimensional LA voltage maps created before an extensive encircling PVI in 47 AF patients (31 men; mean age 62±11years) were examined for an association between the EGM voltage amplitude recorded from the PV-LA junction and acute post-PVI PV reconnections (spontaneous PV reconnections and/or ATP-provoked dormant PV conduction). Acute PV reconnections were observed in 17 patients (36%) and in 24 (3%) of the 748 PV segments (16 segments per patient) and were associated with relatively high bipolar voltage amplitudes (3.26±0.85 vs. 1.79±1.15mV, p<0.0001) and a relatively low mean force-time integral (FTI) (428±56 vs. 473±76gs, p=0.0039) as well as FTI/PV-LA bipolar voltage (137 [106, 166] vs. 295 [193, 498] gs/mV, p<0.0001). An analysis of the receiver operating characteristic curves revealed a high prognostic performance of the LA bipolar voltage and FTI/PV-LA bipolar voltage for acute PV reconnections (areas under the curve: 0.86 and 0.89, respectively); the best cutoff values were >2.12mV and ≤183gs/mV, respectively. The PV-LA voltage on the PV-encircling ablation line and FTI/PV-LA voltage were related to the acute post-PVI PV reconnections. A more durable ablation strategy is warranted for high-voltage zones.

The role of adenosine challenge in catheter ablation for atrial fibrillation: A systematic review and meta-analysis

AimsAdenosine may unmask dormant PV conduction and facilitate consolidation of PV isolation. We performed a meta-analysis to determine the impact of adenosine administration on clinical outcomes in patients undergoing PVI. MethodsReferences and electronic databases reporting AF ablation and adenosine following PVI were searched through to 22nd November 2015. The impact of adenosine on freedom from AF was assessed in twenty publications after radiofrequency ablation (RFA), and in four publications after cryoablation to achieve PVI. Relative risks were calculated and combined in a meta-analysis using random effects modeling. ResultsIn patients undergoing RFA with adenosine challenge, there was a significant reduction in freedom from AF in patients with versus without adenosine induced reconnection (RR 0.86; 95%CI 0.77–0.98; p=0.02) particularly if no further ablation was performed (RR 0.66; 95%CI 0.50–0.87; p<0.01). There was no difference when comparing outcomes in studies of routine adenosine challenge vs no adenosine (RR 1.07; 95%CI 0.93–1.22; p=0.36). There was a non-significant trend to an increase in freedom from AF in patients receiving routine adenosine challenge (RR 1.18 95%CI 0.99–1.42; p=0.07) in non-randomized studies using cryoablation. ConclusionAdenosine induced PV reconnection following PVI is associated with a significant increase in AF recurrence, particularly if the reconnection sites are not targeted for ablation. The routine use of adenosine may be beneficial in AF ablation if given early post-PVI, at sufficient dose and reconnection is ablated.

Adenosine triphosphate-guided pulmonary vein isolation for atrial fibrillation: the UNmasking Dormant Electrical Reconduction by Adenosine TriPhosphate (UNDER-ATP) trial.

Most of recurrent atrial tachyarrhythmias after pulmonary vein isolation (PVI) for atrial fibrillation (AF) are due to reconnection of PVs. The aim of the present study was to evaluate whether elimination of adenosine triphosphate (ATP)-induced dormant PV conduction by additional energy applications during the first ablation procedure could reduce the incidence of recurrent atrial tachyarrhythmias. We randomly assigned 2113 patients with paroxysmal, persistent, or long-lasting AF to either ATP-guided PVI (1112 patients) or conventional PVI (1001 patients). The primary endpoint was recurrent atrial tachyarrhythmias lasting for >30 s or those requiring repeat ablation, hospital admission, or usage of Vaughan Williams class I or III antiarrhythmic drugs at 1 year with the blanking period of 90 days post ablation. Among patients assigned to ATP-guided PVI, 0.4 mg/kg body weight of ATP provoked dormant PV conduction in 307 patients (27.6%). Additional radiofrequency energy applications successfully eliminated dormant conduction in 302 patients (98.4%). At 1 year, 68.7% of patients in the ATP-guided PVI group and 67.1% of patients in the conventional PVI group were free from the primary endpoint, with no significant difference (adjusted hazard ratio [HR] 0.89; 95% confidence interval [CI] 0.74-1.09; P = 0.25). The results were consistent across all the prespecified subgroups. Also, there was no significant difference in the 1-year event-free rates from repeat ablation for any atrial tachyarrhythmia between the groups (adjusted HR 0.83; 95% CI 0.65-1.08; P = 0.16). In the catheter ablation for AF, we found no significant reduction in the 1-year incidence of recurrent atrial tachyarrhythmias by ATP-guided PVI compared with conventional PVI.

The effects of standard electrical PV isolation vs. “pace and ablate” on ATP-provoked PV reconnections

Catheter ablation procedures for atrial fibrillation (AF) often involve circumferential pulmonary vein isolation (PVI). Lack of reliable identification of conduction gaps along the ablation line necessitates additional ablation within previous lesion sets. We conducted a retrospective comparative study to determine the best PVI strategy for prevention of PV reconnections. We compared the outcomes of PVI performed in two groups of patients with AF: those in whom a three-dimensional mapping system and irrigated tip radiofrequency catheter were used to electrically isolate the ipsilateral PVs (31 patients, electrical isolation group) and those in whom "pace and ablate" was performed in the PV antra until pacing at 10 mA and 2 ms no longer captured the atrial myocardium along the ablation line (31 patients, pace and ablate group). A bolus administration of 30 mg of adenosine triphosphate (ATP) revealed dormant PV reconnections more frequently in the electrical isolation group than in the pace and ablate group (28 [90%] of 31 patients vs. 16 [52%] of 31 patients, p = 0.0005). After re-isolation of the sites of dormant PV conduction, the post-ablation recurrence rates at 1 year were similar (26 vs. 26%, p = 1.000). Electrical PVI can usually be achieved without complete circumferential ablation. However, the isolated PVs often show dormant conduction. These findings support the hypothesis that reversible tissue injury contributes to PVI that may be acute but not necessarily durable. Similar outcomes between the two ablation strategies suggest that ATP provocation tests remain necessary to unmask dormant PV conduction.

Abstract 9461: Prevalence and Characteristics of Spontaneous and Adenosine-Induced Acute PV Reconnection Associated With IV Corticosteroid Use During Pulmonary Vein Isolation

Background: Atrial fibrillation (AF) recurrence after pulmonary vein isolation (PVI) is associated with PV to left atrium re-conduction. Intraprocedural corticosteroids may limit RF-induced tissue edema and prevent post-ablation inflammatory responses. We prospectively evaluated the impact of pre-ablation IV corticosteroids on the prevalence of spontaneous and adenosine-induced acute PV reconnection following PVI and on long-term success rates after ablation. Methods: Prior to wide circumferential PVI 45 patients received a single IV bolus of 250 mg of hydrocortisone immediately following transseptal access (steroid group), whereas another 45 consecutive patients underwent standard PVI without IV hydrocortisone (non-steroid group). Post PVI, acute PV reconnection was systematically assessed in each PV (prevalence and location) using a circular mapping catheter during a 20-min waiting period (spontaneous PV reconnection), followed by provocation with IV adenosine (dormant conduction). All patients were followed at 3, 6, and 12 months. Results: Spontaneous PV reconnection during the 20-min waiting period was observed in 9% of PVs (31/358), with no significant difference between the 2 groups (5.5% steroid vs 11.4% non-steroid; p=0.10). Dormant conduction was unmasked in a significantly higher proportion of PVs in the steroid group when compared to the non-steroid group (32.8% of PVs [60/183] vs. 21.1% of PVs [37/175] P=0.03). On multivariate GEE analysis, steroid use remained independently associated with dormant PV conduction (P=0.03). There was no difference in the segmental distribution of reconnection between the two groups. The one-year freedom from recurrent AF did not differ between groups (P=0.37). Radiofrequency time was significantly longer in the steroid group (58±21 vs. 48±18 minutes, P=0.006), whereas procedure duration and fluoroscopy time were comparable (p=0.55, and p=0.44). Conclusions: A single bolus of hydrocortisone 250 mg IV prior to PVI results in greater RF requirements for PV isolation and higher prevalence of dormant PV conduction unmasked by adenosine without affecting long-term outcomes. The utility of these approaches requires evaluation in a long-term prospective randomized study.

Corticosteroid use during pulmonary vein isolation is associated with a higher prevalence of dormant pulmonary vein conduction

Atrial fibrillation (AF) recurrence after pulmonary vein isolation (PVI) is associated with PV to left atrium reconduction. The purpose of this study was to prospectively determine if the use of intraprocedural corticosteroids to limit the extent of tissue edema and/or inflammation alters the prevalence of spontaneous and adenosine-induced acute PV reconnection after PVI. Prior to wide circumferential PVI, 45 patients received a single intravenous (IV) bolus of hydrocortisone 250 mg immediately after transseptal access (steroid group). Another 45 consecutive patients underwent standard PVI without IV hydrocortisone (nonsteroid group). After PVI, all patients underwent adenosine testing to unmask dormant conduction. Patients were followed at 3, 6, and 12 months. Dormant conduction was unmasked in a significantly higher proportion of PVs in the steroid group compared with the nonsteroid group (32.8% of PVs [60/183] vs 21.1% of PVs [37/175], P = .03). On multivariate generalized estimating equation analysis, steroid use remained independently associated with dormant PV conduction (P = .03). There was no difference in the segmental distribution of reconnection between the 2 groups. The 1-year freedom from recurrent AF did not differ between groups (P = .37). Radiofrequency time was significantly longer in the steroid group (58 ± 21 minutes vs 48 ± 18 minutes, P <.01), whereas procedure duration and fluoroscopy time were comparable (P = .55 and P = .44, respectively). A single bolus of hydrocortisone 250 mg IV prior to PVI results in greater radiofrequency requirements for PVI and a higher prevalence of dormant PV conduction unmasked by adenosine. The utility of these approaches requires evaluation in a long-term prospective randomized study.

The Role of Adenosine Following Pulmonary Vein Isolation in Patients Undergoing Catheter Ablation for Atrial Fibrillation: A Systematic Review

Pulmonary vein reconnection is a major limitation of pulmonary vein isolation (PVI) for symptomatic atrial fibrillation (AF). Adenosine may unmask dormant PV conduction and facilitate consolidation of PV isolation. We performed a systematic review of the literature to determine the impact of routine adenosine administration on clinical outcomes in patients undergoing PVI. References and electronic databases reporting AF ablation and adenosine following PVI were searched through to 31 July 2012. Six studies included 544 patients to assess the impact of catheter ablation to target adenosine-induced PV reconnection on AF ablation outcome and 3 studies included 612 patients to assess the impact of adenosine testing on AF ablation outcome. Relative risks were calculated and combined in a meta-analysis using random effects modeling. Routine adenosine testing for PV reconnection with additional targeted ablation resulted in a significant increase in freedom from AF post-PVI (RR 1.25; 95% CI 1.12-1.40; P < 0.001). However, within the group of patients undergoing adenosine testing, those with reconnection identified a population with a trend to reduction in freedom from AF despite the use of further targeted ablation in the reconnection group (RR 0.91 with 95% CI 0.81-1.03; P = 0.15). Routine adenosine testing is associated with an improvement in freedom from AF post-PVI. Paradoxically acute adenosine-induced PV reconnection may portend a greater likelihood of AF recurrence despite additional ablation. Randomized controlled trials are required to determine the role of adenosine testing post-PVI.

Trends in Cardiac Radiofrequency Ablation: A Single Centre Experience

Introduction: Pulmonary vein reconnection is a major limitation of pulmonary vein isolation (PVI) for symptomatic atrial fibrillation (AF). Adenosine may unmask dormant PV conduction and facilitate consolidation of PV isolation. We performed a systematic review of the literature to determine the impact of routine adenosine administration on clinical outcomes in patients undergoing PVI. Methods: References and electronic databases reporting AF ablation and adenosine following PVI were searched through to 31st July 2012. Six studies included 544 patients to assess the impact of catheter ablation to target adenosine induced PV reconnection on AF ablation outcome and three studies included 612 patients to assess the impact of adenosine testing on AF ablation outcome. Relative risks were calculated and combined in a meta-analysis using random effects modelling. Results: Routine adenosine testing for PV reconnection with additional targeted ablation resulted in a significant increase in freedom from AF post PVI (RR 1.25; 95% CI 1.12–1.40; p< 0.001). However, within the group of patients undergoing adenosine testing, those with reconnection identified a population with a trend to reduction in freedom from AF despite the use of further targeted ablation in the reconnection group (RR 0.91 with 95% CI 0.81–1.03; p= 0.15). Conclusion: Routine adenosine testing is associated with an improvement in freedom from AF post PVI. Paradoxically acute adenosine induced PV reconnection may portend a greater likelihood of AF recurrence despite additional ablation. Randomised controlled trials are required to determine the role of adenosine testing post PVI.

The Role of Lead Integrity Alerts and Remote Monitoring in Reducing Morbidity Associated With the St Jude Medical Riata ICD Lead

Introduction: Pulmonary vein reconnection is a major limitation of pulmonary vein isolation (PVI) for symptomatic atrial fibrillation (AF). Adenosine may unmask dormant PV conduction and facilitate consolidation of PV isolation. We performed a systematic review of the literature to determine the impact of routine adenosine administration on clinical outcomes in patients undergoing PVI. Methods: References and electronic databases reporting AF ablation and adenosine following PVI were searched through to 31st July 2012. Six studies included 544 patients to assess the impact of catheter ablation to target adenosine induced PV reconnection on AF ablation outcome and three studies included 612 patients to assess the impact of adenosine testing on AF ablation outcome. Relative risks were calculated and combined in a meta-analysis using random effects modelling. Results: Routine adenosine testing for PV reconnection with additional targeted ablation resulted in a significant increase in freedom from AF post PVI (RR 1.25; 95% CI 1.12–1.40; p< 0.001). However, within the group of patients undergoing adenosine testing, those with reconnection identified a population with a trend to reduction in freedom from AF despite the use of further targeted ablation in the reconnection group (RR 0.91 with 95% CI 0.81–1.03; p= 0.15). Conclusion: Routine adenosine testing is associated with an improvement in freedom from AF post PVI. Paradoxically acute adenosine induced PV reconnection may portend a greater likelihood of AF recurrence despite additional ablation. Randomised controlled trials are required to determine the role of adenosine testing post PVI.

The Role of Adenosine following Pulmonary Vein Isolation in Patients Undergoing Catheter Ablation for Atrial Fibrillation: A Systematic Review

A Systematic Review of Adenosine in AF Ablation Introduction Pulmonary vein reconnection is a major limitation of pulmonary vein isolation (PVI) for symptomatic atrial fibrillation (AF). Adenosine may unmask dormant PV conduction and facilitate consolidation of PV isolation. We performed a systematic review of the literature to determine the impact of routine adenosine administration on clinical outcomes in patients undergoing PVI. Methods References and electronic databases reporting AF ablation and adenosine following PVI were searched through to 31 July 2012. Six studies included 544 patients to assess the impact of catheter ablation to target adenosine-induced PV reconnection on AF ablation outcome and 3 studies included 612 patients to assess the impact of adenosine testing on AF ablation outcome. Relative risks were calculated and combined in a meta-analysis using random effects modeling. Results Routine adenosine testing for PV reconnection with additional targeted ablation resulted in a significant increase in freedom from AF post-PVI (RR 1.25; 95% CI 1.12–1.40; P < 0.001). However, within the group of patients undergoing adenosine testing, those with reconnection identified a population with a trend to reduction in freedom from AF despite the use of further targeted ablation in the reconnection group (RR 0.91 with 95% CI 0.81–1.03; P = 0.15). Conclusion Routine adenosine testing is associated with an improvement in freedom from AF post-PVI. Paradoxically acute adenosine-induced PV reconnection may portend a greater likelihood of AF recurrence despite additional ablation. Randomized controlled trials are required to determine the role of adenosine testing post-PVI.

Adenosine testing after cryoballoon pulmonary vein isolation improves long-term clinical outcome

Adenosine infusion after pulmonary vein isolation (PVI) with radiofrequency energy reveals dormant muscular sleeves and predicts atrial fibrillation (AF) recurrence. The aim of our study was to determine whether adenosine could reveal dormant PV sleeves after cryoballoon isolation and study its effect on long-term recurrence of AF. Patients with paroxysmal AF underwent cryoballoon PVI. After PVI, adenosine 25mg was infused to test for dormant muscular sleeves in each vein. If reconnection under adenosine was shown, further cryoballoon ablation was performed until no more reconnection occurred. Follow-up was performed with ECG, 24-h Holter recording, and a symptom questionnaire at three monthly intervals. Transtelephonic Holter monitoring was performed for 1month before and 3months after PVI. Patients who underwent cryoballoon PVI without adenosine administration were used as controls for comparison. In the study group (n = 34, 24 males), adenosine revealed dormant sleeves in 9/132 (8%) veins, and 7/34 (21%) patients. All but one vein was further treated until the dormant sleeves were isolated. During a mean follow-up of 520 ± 147days, 23/34 (68%) patients were free of AF without antiarrhythmic drugs (AADs). In the control group (n = 65, 46 males), 29/65 (46%) were free of AF without AADs. There were significantly less AF recurrences in the study group (p = 0.04). Adenosine administration after cryoballoon PVI reveals dormant muscular sleeves in 21% of patients. Clinical follow-up shows that adenosine testing is effective in reducing AF recurrence after cryoballoon ablation.

Adenosine Following Pulmonary Vein Isolation to Target Dormant Conduction Elimination (ADVICE): Methods and Rationale

BackgroundPulmonary vein (PV) isolation (PVI) has emerged as an effective therapy for paroxysmal atrial fibrillation (AF). However, AF recurs in up to 50% of patients, generally because of recovery of PV conduction. Adenosine given during the initial procedure may reveal dormant PV conduction, thereby identifying the need for additional ablation, leading to improved outcomes. The Adenosine Following Pulmonary Vein Isolation to Target Dormant Conduction Elimination (ADVICE) study is a prospective multicentre randomized trial assessing the impact of adenosine-guided PVI in preventing AF recurrences. MethodsPatients undergoing a first PVI procedure for paroxysmal AF will be recruited. After standard PVI is completed, all patients will receive intravenous adenosine in an attempt to unmask dormant conduction. If dormant conduction is elicited, patients will be randomized to no further ablation (control group) or additional adenosine-guided ablation until dormant conduction is abolished. If no dormant conduction is revealed, randomly selected patients will be followed in a registry. The primary outcome is time to first documented symptomatic AF recurrence. Assuming that dormant conduction is present in 50% of patients post PVI and symptomatic AF recurs in 45% of controls, 244 patients with dormant conduction will be required to obtain > 90% power to detect a difference of 20%. Thus, a total of 488 patients will be enrolled and followed for 12 months. ConclusionThe ADVICE trial will assess whether a PVI strategy incorporating elimination of dormant conduction unmasked by intravenous adenosine will decrease the rate of recurrent symptomatic AF compared with standard PVI.

ATP‐Induced Dormant Pulmonary Veins Originating from the Carina Region After Circumferential Pulmonary Vein Isolation of Atrial Fibrillation

Elimination of transient pulmonary vein recurrences (dormant PVs) induced by an ATP injection and ablation at the PV carina region is an effective strategy for atrial fibrillation (AF) ablation. The relationship between dormant PVs and the PV carina region has not been evaluated. A total of 212 consecutive symptomatic AF patients underwent circumferential PV electrical isolation (CPVEI) with a double lasso technique. They were divided into 2 groups in a retrospective review; Group 1: those given an ATP injection during an intravenous isoproterenol infusion after the CPVEI (n = 106), and Group 2: those in which it was not given after the CPVEI (n = 106). Radiofrequency energy was applied at the earliest dormant PV activation site identified using a Lasso catheter on the CPVEI line and then PV carina region if it was ineffective. After a successful PVEI, 54 patients (51%) in Group 1 had PV reconnections during an ATP injection. Acute PVEI sites were observed on the carina region within the CPVEI line in the right PVs (16%) and left PVs (10%). Dormant PVs were reisolated at the carina region in the right PVs (23%) and left PVs (26%). The distribution of the dormant PV sites, except for the RIPV, significantly differed from that of the acute PVEI sites (P < 0.05). Further, AF recurred significantly in the Group 2 patients as compared to those in Group 1 during 16 +/- 6.1 months of follow-up (P < 0.05). PV carina region origins may partly be responsible for an acute PVEI and potential recurrences.

Promoting photovoltaic electricity usage in developing countries — Experience from Ghana

The awareness of PV systems as a means to provide electricity for remote small towns and villages with small electrical loads has long been recognised. That PV electricity is not widely patronised by the potential end-users can be attributed to lack of awareness of the existence of the technology and the high initial cost of systems which necessarily has to be paid up front. It is argued that demonstration PV systems can be used to awaken awareness. This will open up the dormant large PV market waiting to be tapped in the developing countries, and this will be the benefit of the PV manufacturers who can take advantage of the economies of scale to reduce PV systems production cost and, therefore, a reduced selling price. Suggestions are also made for financing the purchase of PV systems by end-users in the developing countries.