Early mortality and complications following first-time catheter ablation of atrial fibrillation in a nationwide cohort

Funding Acknowledgements

Type of funding sources: None.

Background

Atrial fibrillation (AF) is the most common clinical arrhythmia. Pulmonary vein isolation (PVI) by catheter ablation has become a cornerstone in the treatment of AF. Serious complications to PVI have been reported to be at an acceptable level and risk of death after AF ablation is low.

Purpose

In a contemporary nationwide cohort of patients undergoing first-time PVI by catheter ablation, we wanted to investigate the 30-day mortality after ablation, and to examine risk and potential risk factors of PVI-related complications.

Methods

Population-based cohort study in patients who underwent first-time PVI by catheter ablation between 2011-2018 identified from the National Danish Ablation Registry. Primary outcome was early post-procedural mortality, defined as death of any cause within 30 days of index PVI procedure, or in connection to a hospitalization started within 30 days. Secondary outcomes were all-cause rehospitalization and complication, including postoperative infection, cardiac, vascular, neurological, vascular, and pulmonary complications within 30 days. Data on mortality and complications were collected from national health and administrative registries. Binary regression was used to estimate risk ratio (RR) with 95% confidence intervals (CI) for association between selected predictors and any complication, and adjusted gender, age, BMI, prior ablation, calendar period (ablation from 2011-2013, 2014-2016, and >2016).

Results

We included 8560 patients. Median age was 62, 66% were men, 12% had a history of heart failure, and median CHA2DS2VASc score was 1 (Interquartile range [IQR]; 1-2). Charlton Comorbidity index (CCI) was none in 66%, moderate in 29% and severe in 5%. A total of 10 (0.12%) patients died within 30 days of ablation, of which 4 patients died during initial hospitalization. Median time to death was 20 (IQR, 12 to 29) days. Patients who died were more likely to have experienced a procedure-related complication (40% vs. 4%, P<0.001). Procedure-related complications occurred in 298 (3.5%), and the risk was 4.4%, 3.0% and 3.3% in the time periods between 2011-2013, 2014-2016 and >2016, respectively. Most common complications were postoperative infection (26%), cardiac complication (26%), and vascular complications (18%). Complication risk was increased in patients with higher age (aRR, 65-74 year; 1.67 [1.32-2.11] and >74 years; 2.48 [1.60-3.84]), moderate CCI (aRR 1.45 [1.14-1.83]), cardiovascular disease (aRR 1.52 [1.09-2.11]) and antithrombotic treatment (aRR 1.41 [1.05-1.89]). After first-time PVI, 1.963 (23%) patients were re-hospitalized within 30 days, and most common primary discharge diagnoses were AF (87%) and direct cardioversion was performed in 765 (39%) patients.

Conclusion

In a nationwide cohort of patients who underwent first-time PVI, number of deaths within 30 days of ablation was low (0.12%). Risk of complication was low and 23% of the patients were re-hospitalized within 30 days.

Recurrence rates of atrial fibrillation ablation according to body mass Index, a nationwide, registry-based danish study

Funding Acknowledgements

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Novo Nordisk supported the project.

Background

The proportion of people with obesity is rapidly rising, and the number of overweight patients undergoing ablation for atrial fibrillation (AF) is also increasing. The link between body mass index (BMI), and AF prevalence is well-established but the impact of BMI on the risk of recurrent AF after ablation is less elucidated. Therefore, data pertaining to recurrence rates of ablations according to BMI in large, unselected cohorts of patients is still warranted.

Purpose

To examine the risk of recurrent AF after AF ablation by BMI.

Method

Using Danish nationwide registries, all Danish patients above 18 years who underwent first-time AF ablation from January 1st 2010 to December 31st 2018 were identified and included at the date of ablation. The patients were categorized by BMI; underweight: < 18.5 kg/m2; normal weight: 18.5-24 kg/m2; overweight 25-29 kg/m2; obese 30-34 kg/m2; morbidly obese > 34 kg/m2. Recurrent AF was defined using a composite endpoint comprising claimed prescriptions of anti-arrhythmic drugs, hospital admissions due to AF, re-ablation, or electrical cardioversions. The cumulative incidence of recurrent AF by BMI at 1- and 5-year follow-up after a blanking period of 90 days, was estimated using the Aalen-Johansen estimator, takin death as competing risk in to account. The relative rates of recurrent AF by BMI were examined using Cox models adjusted for sex, age, procedure-year, heart failure, ischemic heart disease, chronic obstructive pulmonary disease, chronic kidney disease, hypertension, and diabetes.

Results

The study cohort consisted of 9,229 patients. Median age [IQR] decreased from 64 [60, 75] in the normal weight group to 60 [53, 66] in the morbidly obese. The number of patients with a CHA2DS2-VASc score of 2 or more increased from 48% in normal-weight to 65% in morbidly obese. Use of amiodarone increased by BMI category, while the use of Class 1C anti-arrhythmic medication remained stable.

Figures 1 and 2 show the 1- and 5-year cumulative incidence of recurrent AF, Hazard Ratios (HR), and 95% Confidence Intervals (CI 95%) stratified by BMI categories and depict that the risk of recurrent AF increased incrementally and significantly in overweight groups compared to normal weight patients, both in 1- and 5-year follow-up. Underweight patients demonstrated non-significantly increased risk of recurrent AF, both in 1- and 5-year follow-up.

Conclusion

In this large nationwide study examining recurrent AF post AF ablation, we found that recurrence rates of AF increased incrementally according to BMI, both in short- and long-term follow-up. Therefore, aggressive weight management in overweight patients could potentially provide substantial benefits and improve short- and long-term outcomes after ablation.

Left atrial function assessed by speckle tracking echocardiography predicts atrial fibrillation burden after catheter ablation independently of reconduction: a RACE-AF echocardiographic sub-study

Funding Acknowledgements

Type of funding sources: None.

Background

Left atrial (LA) function assessed by 2D speckle tracking echocardiography (STE) has demonstrated to be a useful predictor of recurrence of atrial fibrillation (AF) following catheter ablation (CA). Pulmonary vein reconduction (PVR) is one of the most important causes of recurrent paroxysmal AF (PAF) after ablation. The purpose of this study was to evaluate the association between AF burden (% of time in AF) following CA and LA strain measurements independently of PVR.

Methods

This prospective study included 66 patients with PAF who underwent CA (mean age 60 ± 8 years, 65% male). STE was performed during sinus rhythm prior to CA. AF burden was recorded by continuous rhythm monitoring using implantable loop recorders during a follow-up period of 4-6 months, excluding a blanking period of 3 months. After follow-up, all patients underwent an invasive assessment of pulmonary vein isolation to test for PVR. Multivariable linear regression analysis was used to assess the association between AF burden and peak atrial longitudinal reservoir strain (PALS), peak atrial contraction strain (PACS) and peak atrial conduit strain (PCS).

Results

Prior to CA, median AF burden was 3.8% (IQR: 0.5, 17). During follow-up, 37 patients (56%) were free of AF while median AF burden was 0.7% (IQR: 0.2, 1.6) in patients with an AF burden of more than 0%. A total of 35 patients (54%) were found to have PVR after ablation. Patients with AF recurrence had significantly lower PACS compared to patients with no AF during follow-up (10% ± 6% vs. 14% ± 5%, p = 0.004). No differences in PALS and PCS were observed. Increased PACS remained independently associated with low AF burden following CA after multivariable adjustments for clinical characteristics, comorbidities, and PVR (β=-0.262, p = 0.049) (Figure 1). PALS and PCS did not remain significantly associated with AF burden.

Conclusion

Increased PACS is strongly associated with low AF burden after CA even after adjusting for PVR. This suggests that an analysis of LA function could be useful to stratify patients prior to CA and improve treatment strategies.

Abstract Figure.

Captopril does not blunt the sympathoadrenal response to cigarette smoking in normotensive humans

The aim of this study was to assess whether an interaction exists between the renin-angiotensin system and the sympathetic nervous system at the level of the adrenal medulla during smoking in normal humans. Thirteen habitual smoking volunteers were studied in a randomized, single-dose, double-blind, cross-over fashion using 50 mg captopril vs placebo followed by smoking of two high nicotine content cigarettes within 15 min. Blood samples were obtained at frequent intervals before, during and after smoking. We found that the increase in plasma adrenaline concentration during cigarette smoking was modest. There was no difference between captopril treatment as compared to placebo. Thus, the adrenaline response to cigarette smoking was not blunted by acute blockade of angiotensin II generation. A significant increase in heart rate, and blood pressure was found as well. No increase in plasma noradrenaline concentration was found. Plasma renin concentration increased significantly during captopril treatment, whereas it decreased throughout the study period in the placebo phase. Plasma angiotensin II concentration decreased in both the captopril treatment and the placebo phase throughout the study period, but this was more pronounced during captopril treatment. In conclusion, cigarette smoking-induced activation of the sympathetic nervous system was not blunted by acute ACE-inhibition by captopril. This indicates that angiotensin II does not facilitate smoking-induced activation of sympathoadrenal activity in humans.