Single-Dose Intraprocedural Steroid Administration Does Not Impact Early Atrial Fibrillation Recurrence

PURPOSE

To evaluate the effect of single-dose intravenous dexamethasone on atrial fibrillation (AF) recurrence following radiofrequency catheter ablation.

METHODS

A cohort of 84 adult patients (> 18 years) underwent catheter ablation at Mayo Clinic Rochester from January to March 2019. Only first-time ablation patients were included, with all re-do ablations excluded to minimize heterogeneity. Administration of intraoperative dexamethasone 4 mg or 8 mg was determined by chart review from the procedure. At our institution, intraoperative intravenous steroids are administered for postoperative nausea and vomiting (PONV) prophylaxis at the discretion of the anesthesiologist. AF recurrence was determined by ECG or cardiac monitoring within 3 months or between 3 and 12 months post-ablation with an in-person follow-up visit.

RESULTS

A total of 31 (36.9%) patients received intravenous dexamethasone compared to 54 (63.1%) who did not (approximating a 2:1 comparison group). The incidence of documented AF or atrial flutter, lasting greater than 30 s, within the first 3 months post-ablation was 29.0% in the dexamethasone group versus 24.5% in the non-dexamethasone group (p value 0.80). AF or atrial flutter recurrence at 3-12 months post-ablation was 3.2% in the dexamethasone group compared to 9.4% in the non-dexamethasone group (p value 0.41).

CONCLUSION

These data suggest that intraoperative intravenous dexamethasone administered during AF ablation for postoperative nausea and vomiting prophylaxis may not have a significant effect on AF recurrence rates.

The Blinding Period Following Ablation Therapy for Atrial Fibrillation: Proarrhythmic and Antiarrhythmic Pathophysiological Mechanisms

Atrial fibrillation (AF) causes heart failure, ischemic strokes, and poor quality of life. The number of patients with AF is estimated to increase to 18 million in Europe in 2050. Pharmacological therapy does not cure AF in all patients. Ablative pulmonary vein isolation is recommended for patients with drug-resistant symptomatic paroxysmal AF but is successful in only about 60%. In patients in whom ablative therapy is successful on the long term, recurrence of AF may occur in the first weeks to months after pulmonary vein ablation. The early recurrence (or delayed cure) of AF is not understood but forms the basis for the generally accepted 3-month blinding (or blanking) period after ablation therapy, which is not included in the evaluation of the eventual success rate of the procedures. The underlying pathophysiological processes responsible for early recurrence and the delayed cure are unknown. The implicit assumption of the blinding period is that the AF mechanism in this period is different from the ablation-targeted AF mechanism (ectopy from the pulmonary veins). In this review, we evaluate the temporary and long-lasting pro- and antiarrhythmic effects of each of the pathophysiological processes and interventions (necrosis, ischemia, oxidative stress, edema, inflammation, autonomic nervous activity, tissue repair, mechanical remodeling, and use of antiarrhythmic drugs) occurring in the blinding period that can modulate AF mechanisms. We propose that stretch-reducing ablation scar is a permanent antiarrhythmic mechanism that develops during the blinding period and is the reason for delayed cure.

The Efficacy of Anti-inflammatory Agents in the Prevention of Atrial Fibrillation Recurrences

Several studies have indicated an association between inflammation and the recurrence of Atrial Fibrillation (AF), especially after ablation, which is a therapeutic option leading to local inflammation. On the other hand, each AF can lead to another AF, as a general rule. Thus, preventing recurrences of AF is extremely important for patient outcomes. In this paper, we attempted to review the effect of medicinal agents with anti-inflammatory properties on the prevention of AF recurrence. There are several randomized controlled trials (RCTs) and meta-analyses on the prevention of AF recurrence using agents with anti-inflammatory properties, which include steroids, colchicine, statins, and n-3 fatty acids (n-3 FA). Clinical trials evaluating the efficacy of anti-inflammatory drugs in preventing the recurrence of AF led to inconsistent results for corticosteroids, statins and n-3 FAs. These results may be related to the fact that inflammation is not the only factor responsible for triggering recurrences of AF. For example, the presence of structural, mechanical and electrical remodeling could potentially be the most important factors that trigger recurrences of AF but these factors have not been addressed in most of the reported studies. Therefore, future clinical trials are needed to compare the efficacy of anti-inflammatory drugs in AF patients with, or without other factors. For colchicine, a potent anti-inflammatory drug, there are limited studies. However, all the studies investigating colchicine in the context of AF were consistent and promising, especially when colchicine was used on a short-term basis following ablation in patients with paroxysmal AF. Therefore, colchicine could be a promising candidate for further clinical studies involving recurrent AF.

Anti-inflammatory drugs in the prevention of post-operative atrial fibrillation: a literature review

Atrial fibrillation (AF) is a serious and common complication following heart surgery. Cardiac surgery triggers inflammation in the heart and makes it susceptible to the incidence of AF. Therefore, anti-inflammatory drugs may reduce the rate of AF incidence in the post-surgery conditions. Immunosuppressant agents, steroidal anti-inflammatory drugs (corticosteroids), non-aspirin non-steroid anti-inflammatory drugs (NSAIDs), colchicine and omega-3 unsaturated fatty acids (n-3 UFA) are drugs with well-known anti-inflammatory properties. The efficacy, safety and other aspects of using these drugs in the prevention of post-operative AF (POAF) have been reviewed here. Studies evaluating the efficacy of colchicine have shown that it could be effective in the prevention of POAF. However, there is a need for additional studies to find a colchicine regimen with optimal efficacy and higher tolerability. The use of corticosteroids may also be of value based on the most of meta-analyses. In the case of n-3 polyunsaturated fatty acids and NSAIDs, current data fail to support their efficacy in POAF prevention. Moreover, perioperative administration of NSAIDs may be associated with some severe safety considerations. Immunosuppressant agents have not been used for the prevention of POAF. Further studies are needed to find the most effective strategy for POAF prevention with the least safety considerations and the highest health benefits.

Use of Oral Steroid and its Effects on Atrial Fibrillation Recurrence and Inflammatory Cytokines Post Ablation - The Steroid AF Study

Background

Use of corticosteroids before and after atrial fibrillation (AF) ablation can decrease acute inflammation and reduce AF recurrence.

Purpose

To assess the efficacy of oral prednisone in improving the outcomes of pulmonary vein isolation with radiofrequency ablation and its effect on inflammatory cytokine.

Methods

A total of 60 patients with paroxysmal AF undergoing radiofrequency ablation were randomized (1:1) to receive either 3 doses of 60 mg daily of oral prednisone or a placebo. Inflammatory cytokine levels (TNF-α, IL-1, IL6, IL-8) were measured at baseline, prior to ablation, immediately after ablation, and 24 hours post ablation. Patients underwent 30 day event monitoring at 3 months, 6 months and 12 months post procedure.

Results

Immediate post ablation levels of inflammatory cytokines were lower in the steroid group when compared to the placebo group; IL-6: 9.0 ±7 vs 15.8 ±13 p=0.031; IL-8: 10.5 ±9 vs 15.3 ±8; p=0.047 respectively. Acute PV reconnection rates during the procedure (7/23% vs 10/36%; p = 0.39), and RF ablation time (51±13 vs 56±11 min, p = 0.11) trended to be lower in the placebo group than the steroid group. There was no difference in the incidence of early recurrence of AF during the blanking period and freedom from AF off AAD at 12 months between both groups (5/17% vs 8/27%; p = 0.347 and 21/70% vs 18/60%; p=0.417 in placebo and steroid groups respectively).

Conclusion

Although oral corticosteroids have significant effect in lowering certain cytokines, it did not impact the clinical outcomes of AF ablation.

Comparison of two different doses of single bolus steroid injection to prevent atrial fibrillation recurrence after radiofrequency catheter ablation

PURPOSE

Steroids may play a role in preventing the early recurrence of atrial fibrillation (AF) after radiofrequency catheter ablation (RFCA). However, optimal doses and route of steroid delivery have not yet been determined. This study evaluated the effect of two different doses of a single bolus injection of steroids on AF recurrence after RFCA.

MATERIALS AND METHODS

Of 448 consecutive AF patients who underwent RFCA, a single steroid bolus was injected into 291 patients. A low-dose steroid group (n=113) received 100 mg of hydrocortisone and a moderate-dose steroid group (n=174) received 125 mg of methylprednisolone. We used propensity-score matching to select patients as follows: control (n=95), low-dose (n=95), and moderate-dose steroid groups (n=97).

RESULTS

Pericarditis developed in 1 (1.1%) control patient, 2 (2.1%) low-dose patients and 0 moderate-dose patients. Maximum body temperature and C-reactive protein were significantly decreased in the moderate-dose steroid group compared to the other groups (p<0.01). The number of patients of early AF recurrence (≤3 months) did not differ among three groups. Early recurrence was 24 (25%) in the control, 24 (25%) in the low-dose and 25 (26%) in the medium-dose groups (p=0.99). Compared with control group, low-dose or moderate-dose steroid treatment did not effectively decrease mid-term (3-12 months) AF recurrence [22 (23%) vs. 23 (24%) vs. 18 (19%); p=0.12].

CONCLUSION

A single injection of moderate-dose steroid decreased inflammation. However, single bolus injections of low-dose or moderate-dose steroids were not effective in preventing immediate, early or midterm AF recurrence after RFCA.

Time course of inflammation, myocardial injury, and prothrombotic response after radiofrequency catheter ablation for atrial fibrillation

BACKGROUND

Inflammation has been linked to the genesis of stroke in atrial fibrillation (AF) and is implicated in early recurrent arrhythmia after AF ablation. We aimed to define the time course of inflammation, myocardial injury, and prothrombotic markers after radiofrequency ablation for AF and its relation to AF recurrence.

METHODS AND RESULTS

Ninety consecutive AF patients (53% paroxysmal) undergoing radiofrequency ablation were recruited. High-sensitivity C-reactive protein (hs-CRP), Troponin-T, creatine kinase-MB, fibrinogen, and D-Dimer concentrations were measured at baseline, at 1, 2, 3, 7 days, and at 1 month after ablation. AF recurrence was documented at 3 days and at 1, 3, and 6 months follow-up. Troponin-T and creatine kinase-MB peaked at day 1 after procedure (both P<0.05). Hs-CRP peaked at day 3 after procedure (P<0.05). Fibrinogen (P<0.05) and D-Dimer (P<0.05) concentrations were significantly elevated at 1 week after procedure. Ln hs-CRP elevation correlated with Ln Troponin-T and fibrinogen elevation. The extent of Ln hs-CRP, Ln Troponin-T, and fibrinogen elevation predicted early AF recurrence within 3 days after procedure (P<0.05, respectively), but not at 3 and 6 months.

CONCLUSIONS

Patients undergoing radiofrequency ablation for AF exhibit an inflammatory response within 3 days. The extent of inflammatory response predicts early AF recurrence but not late recurrence. Prothrombotic markers are elevated at 1 week after ablation and may contribute to increased risk of early thrombotic events after AF ablation.

Are the virtual lines created with the EnSite electroanatomical mapping system really continuous?

BACKGROUND

EnSiteNavx electroanatomic mapping system is widely used in radiofrequency (RF) atrial fibrillation ablation, helping the creation of linear lesions. However, the correspondence of the virtual line created by EnSite with the pathological lesion has not yet been evaluated.

OBJECTIVE

to assess the continuousness of Ensite-guided virtual lines in a swine model.

METHODS

we performed RF ablation linear lesions (8mm and irrigated catheters tips) in both atria of 14 pigs (35 Kg) guided by the EnSite. The animals were sacrificed 14 days post-ablation for macroscopic and histological analysis.

RESULTS

a total of 23 lines in the right atrium and 21 lines in the left atrium were created in 14 animals. The medium power, impedance and temperature applications were 56 W, 54 ºC and 231 Ω for the 8mm tip, and 39 W, 37 ºC, 194 Ω for the irrigated tip catheter, respectively. All (100%) lines were identified on the epicardial and endocardial surfaces, denoting transmurality. At macroscopic examination, lesions were extensive and pale, continuous, with 3.61 cm long and 0.71 cm deep. The transmurality of the lesions was confirmed by microscopy. There was a correlation in the location of the lines at the virtual map and the anatomical lesions in 21 of 23 (91.3%) of the right atrium and 19/21 (90.4%) of the left atrium.

CONCLUSION

In this model, the lines created in the virtual map by EnSiteNavX system correspond to continuous transmural linear lesions in anatomical specimen, suggesting that this method is suitable for linear ablation of atrial fibrillation.