The Effect of Open-Irrigated Radiofrequency Catheter Ablation of Atrial Fibrillation on Left Atrial Pressure and B-Type Natriuretic Peptide

Arrhythmic Risk Stratification in Cardiac Amyloidosis: A Review of the Current Literature

Cardiac amyloidosis is the most frequent infiltrative disease caused by the deposition of misfolded proteins in the cardiac tissue, leading to heart failure, brady- and tachyarrhythmia and death. Conduction disorders, atrial fibrillation (AF) and ventricular arrhythmia (VA) significantly impact patient outcomes and demand recognition. However, several issues remain unresolved regarding early diagnosis and optimal management. Extreme bradycardia is the most common cause of arrhythmic death, while fast and sustained VAs can be found even in the early phases of the disease. Risk stratification and the prevention of sudden cardiac death are therefore to be considered in these patients, although the time for defibrillator implantation is still a subject of debate. Moreover, atrial impairment due to amyloid fibrils is associated with an increased risk of AF resistant to antiarrhythmic therapy, as well as recurrent thromboembolic events despite adequate anticoagulation. In the last few years, the aging of the population and progressive improvements in imaging methods have led to increases in the diagnosis of cardiac amyloidosis. Novel therapies have been developed to improve patients' functional status, quality of life and mortality, without data regarding their effect on arrhythmia prevention. In this review, we consider the latest evidence regarding the arrhythmic risk stratification of cardiac amyloidosis, as well as the available therapeutic strategies.

Comparisons of procedural characteristics and clinical outcomes between SMARTTOUCH SURROUNDFLOW catheter and other catheters for atrial fibrillation radiofrequency catheter ablation: a systematic literature review

BACKGROUND

SMARTTOUCH SURROUNDFLOW (STSF) catheter is the new generation of SMARTTOUCH (ST) catheter with an upgraded irrigation system for radiofrequency catheter ablation (RFCA) in patients with atrial fibrillation (AF).

METHODS

This systematic literature review searched the major English and Chinese bibliographic databases from 2016 to 2022 for any original clinical studies assessing the STSF catheter for RFCA in AF patients. Meta-analysis with a random effects model was used for evidence synthesis.

RESULTS

Pooled outcomes from 19 included studies indicated that STSF catheter was associated with a significantly shorter procedure time (weighted mean difference (WMD): -17.4 min, p<0.001), shorter ablation time (WMD: -6.6 min, p<0.001) and lower catheter irrigation fluid volume (WMD: -492.7 mL, p<0.001) than ST catheter. Pooled outcomes from four included studies with paroxysmal AF patients reported that using the STSF catheter for RFCA was associated with a significantly shorter ablation time (WMD: -5.7 min, p<0.001) and a lower risk of 1-year postablation arrhythmia recurrence (rate ratio: 0.504, p<0.001) than the SURROUNDFLOW (SF) catheter. Significant reductions in procedure time and ablation time associated with the STSF catheter were also reported in the other four studies using non-ST/SF catheters as the control. Overall complications of STSF catheter and control catheters were comparable.

CONCLUSIONS

Using the STSF catheter was superior to using the ST catheter to conduct RFCA for AF by significantly reducing procedure time, ablation time, fluoroscopy time and irrigation fluid volume. The superiority of the STSF catheter over the SF catheter and other non-ST/SF catheters for RFCA needs further confirmation.

Atrial fibrillation ablation in patients with transthyretin cardiac amyloidosis

AIMS

Atrial fibrillation (AF) occurs in as many as 70% of patients with transthyretin cardiac amyloidosis (ATTR CA). The aim of our study was to investigate the impact of AF ablation on freedom from recurrent arrhythmia, hospitalization for AF or heart failure (HF), and mortality.

METHODS AND RESULTS

This was a retrospective observational cohort study of 72 patients with ATTR CA and AF, of whom 24 underwent AF ablation and were matched in a 2:1 manner based on age, gender, ATTR CA stage, New York Heart Association functional class, ejection fraction, and date of AF diagnosis with 48 patients with ATTR CA and AF undergoing medical management. During a mean follow-up of 39 ± 26 months, 10 (42%) patients remained free of recurrent arrhythmia following ablation. Ablation was significantly more effective in those with Stage I or II ATTR CA, with 9/14 (64%) patients with Stage I or II ATTR CA remaining free of recurrent arrhythmia compared to only 1/10 (10%) patients with Stage III disease (P = 0.005). Death occurred in 7 (29%) patients in the ablation group compared to 36 (75%) in the non-ablation arm (P = 0.01). Rates of ischaemic stroke were similar in both groups. Ablation was associated with a significant reduction in the frequency of hospitalization for HF/arrhythmia (1.7 ± 2.4 hospitalizations vs. 4 ± 3.5, P = 0.005). On Cox proportional hazards analyses, ablation was associated with improved survival (hazard ratio 0.38, 95% confidence intervals 0.17-0.86; P = 0.02).

CONCLUSION

Atrial fibrillation ablation is associated with reduced mortality in ATTR CA and is most effective when performed earlier during the disease process.

Venous access-site closure with vascular closure device vs. manual compression in patients undergoing catheter ablation or left atrial appendage occlusion under uninterrupted anticoagulation: a multicentre experience on efficacy and complications

AIMS

Manual compression (MC), widely used to achieve venous access haemostasis, needs prolonged immobilization and extended time-to-haemostasis. Vascular closure devices (VCD) have been reported to have significantly shorter time to haemostasis and ambulation in arterial access-site management. The current study aimed to evaluate the safety and efficacy as well as rate of urinary tract complications in patients receiving MC vs. VCD for venous access-site closure.

METHODS AND RESULTS

A total of 803 consecutive patients undergoing catheter ablation or left atrial appendage closure were classified into the VCD (n = 304) and the MC (n = 499) group, based on the methods used for haemostasis at the venous access site. Foley catheter was used for bladder-emptying in all MC cases and 15 VCD patients. At one site, VCD group patients with experience of MC in prior ablations were asked to describe their overall satisfaction level after comparing the past experience with the present. Haemostasis was achieved effectively in both populations. No VCD cases required >2 h bed rest, whereas 7 (1.4%) patients in the MC group needed prolonged immobilization (P = 0.04). Significantly higher incidence of access-site haematoma (P = 0.004) and urinary complications (P < 0.05) were observed in the MC group. Majority of VCD patients (68%) with prior experience of MC for haemostasis expressed satisfaction over the early ambulation and ability to void urine without bladder catheterization.

CONCLUSION

Vascular closure devices provided effective haemostasis, while reducing the access-site complications, ambulation time, and urinary complications.

Effect of catheter ablation on pre-existing abnormalities of left atrial systolic, diastolic, and neurohormonal functions in patients with chronic heart failure and atrial fibrillation

The critical role of the left atrium (LA) in cardiovascular homoeostasis is mediated by its reservoir, conduit, systolic, and neurohormonal functions. Atrial fibrillation is generally a reflection of underlying disease of the LA, especially in patients with heart failure. Disease-related LA remodelling leads to a decline in both atrial contractility and distensibility along with an impairment in the control of neurohormonal systems that regulate intravascular volume. Catheter ablation can lead to further injury to the atrial myocardium, as evidenced by post-procedural troponin release and tissue oedema. The cardiomyocyte loss leads to replacement fibrosis, which may affect up to 30-35% of the LA wall. These alterations further impair atrial force generation and neurohormonal functions; the additional loss of atrial distensibility can lead to a 'stiff LA syndrome', and the fibrotic response predisposes to recurrence of the atrial arrhythmia. Although it intends to restore LA systole, catheter ablation often decreases the chamber's transport functions. This is particularly likely in patients with long-standing atrial fibrillation and pre-existing LA fibrosis, especially those with increased epicardial adipose tissue (e.g. patients with obesity, diabetes and/or heart failure with a preserved ejection fraction). Although the fibrotic LA in these individuals is an ideal substrate for the development of atrial fibrillation, it may be a suboptimal substrate for catheter ablation. Such patients are not likely to experience long-term restoration of sinus rhythm, and catheter ablation has the potential to worsen their haemodynamic and clinical status. Further studies in this vulnerable group of patients are needed.

Influence of Left Atrial Appendage Amputation on Natriuretic Peptides-A Randomized Controlled Trial

BACKGROUND

Closure or amputation of the left atrial appendage (LAA) is a common therapy for atrial fibrillation (AF). As the LAA is a hormone-producing organ, however, amputation is still somewhat controversial. We examined patients after surgical AF therapy with or without LAA amputation to determine the influence of LAA amputation on pro-atrial natriuretic peptide (proANP) and B-type natriuretic peptide (BNP) plasma levels and on clinical severity of heart failure.

METHODS

Twenty-one consecutive patients were prospectively randomized to either undergo LAA amputation (n = 10) or no LAA amputation (n = 11) between 05/2015 and 10/2015. All patients underwent coronary and/or valve surgery and concomitant AF surgery with either cryoablation (n = 3) or radio frequency ablation (n = 17). ProANP and BNP levels were measured preoperatively and until 800 days postoperatively.

RESULTS

Baseline proANP values were comparable between the groups (without LAA amputation: 4.2 ± 2.1 nmol/L, with LAA amputation: 5.6 ± 3.6 nmol/L). Postoperatively, proANP levels rose markedly in both groups. Even after LAA amputation, proANP levels remained elevated for 7 days postoperatively but fell to baseline levels at day 31 and remained on baseline level at 800 days postoperatively. ProANP levels in the LAA amputation group (5.8-9.7 nmol/L) were not significantly lower than in the group without LAA amputation (9.2-14.1 nmol/L; p = 0.357). BNP levels also rose after surgery in both groups until day 7. At 800 days after surgery, BNP levels were back at baseline levels in both groups. Clinical follow-up at 2 years postoperatively showed no difference in heart failure symptoms or need for heart failure medication between the groups.

CONCLUSION

In contrast to commonly held beliefs about the endocrine and reservoir functions of the LAA, there seems to be no clinically relevant detrimental effect of LAA amputation on natriuretic peptide levels and severity of heart failure until up to 2 years postoperatively.

Neurohormonal Activation After Atrial Fibrillation Initiation in Patients Eligible for Catheter Ablation: A Randomized Controlled Study

BACKGROUND

Biomarker activation in atrial fibrillation (AF) has been widely studied, but the immediate effect of AF initiation remains unclear. We studied the effect of AF initiation on 2 cardiac biomarkers: the N-terminal fragment of the proB-type natriuretic peptide (NT-proBNP), the midregional fragment of the N-terminal of pro-atrial natriuretic peptide (MR-proANP), and 2 extracardiac biomarkers-the copeptin and the midregional portion of proadrenomedullin (MR-proADM).

METHODS AND RESULTS

This was a randomized controlled study, including 45 patients with AF who had been referred for radiofrequency ablation to the University Hospital, Linköping, Sweden, between February 2012 and April 2014. Freedom from AF during the 4 days prior to radiofrequency ablation was confirmed by transtelephonic ECGs. Biomarkers were collected from the femoral vein (fv), coronary sinus (CS), and left atrium (LA) prior to AF initiation (baseline) and 30 minutes later. The MR-proANP and NT-proBNP concentrations increased in the intervention group compared with the control group 30 minutes after the initiation of AF (MR-proANP: Pfv<0.001, PCS<0.001, PLA<0.001; NT-proBNP: PLA<0.001). Copeptin levels in patients without ischemic heart disease were decreased after the initiation of AF (Pfv=0.003, PCS=0.015, PLA=0.011).

CONCLUSIONS

AF is a strong stimulus that results in immediate activation of different biomarkers.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01553045.

Short-Term Influence of Radiofrequency Ablation on NT-proBNP, MR-proANP, Copeptin, and MR-proADM in Patients With Atrial Fibrillation: Data From the Observational SMURF Study

Background

There is limited knowledge on the short‐term influence of radiofrequency ablation (RFA) of atrial fibrillation (AF) on 2 cardiac biomarkers; the N‐terminal pro‐B‐type natriuretic peptide (NT‐proBNP) and the midregional fragment of the N‐terminal of pro‐ANP (MR‐proANP) and 2 extracardiac biomarkers; the c‐terminal provasopressin (copeptin) and the midregional portion of proadrenomedullin (MR‐proADM). There are also limited data concerning cardiac production of the latter two.

Methods and Results

We studied 192 consecutive patients eligible for RFA of AF referred to the University Hospital, Linköping, Sweden. NT‐proBNP, MR‐proANP, copeptin, and MR‐proADM levels were measured in peripheral blood, the coronary sinus (CS), and the left atrium before ablation, and in peripheral blood immediately and the day after RFA. The level of NT‐proBNP decreased the day after RFA in participants in AF at the time of RFA, compared to the participants in sinus rhythm who showed a slight increase (P<0.001). Furthermore, regardless of the actual rhythm, the level of MR‐proANP showed an increase immediately after RFA (P<0.001), followed by a decrease the day after ablation (P<0.001). Copeptin level showed a 6‐fold increase immediately after RFA compared to baseline (P<0.001), whereas MR‐proADM level increased the day after RFA (P<0.001). Levels of copeptin and MR‐proADM were not higher in the CS compared to peripheral blood.

Conclusions

RFA of AF is a strong stimulus with a significant and direct impact on different neurohormonal systems. We found no sign of a cardiac release of MR‐proADM or copeptin.

Clinical Trial Registration

URL: http://www.clinicaltrials.gov. Unique Identifier: NCT01553045.

Incidence and risk factors for symptomatic heart failure after catheter ablation of atrial fibrillation and atrial flutter

AIMS

To determine the incidence and risk factors for development of symptomatic heart failure (HF) following catheter ablation for atrial fibrillation (AF) and atrial flutter.

METHODS AND RESULTS

We prospectively enrolled consecutive patients undergoing pulmonary vein isolation (PVI) or cavotricuspid isthmus (CTI) ablation between November 2013 and June 2014. Post-discharge symptoms were assessed via telephone follow-up and clinic visits. The primary outcome was symptomatic HF requiring treatment with new/increased diuretic dosing. Secondary outcomes were prolonged index hospitalization and readmission for HF ≤30 days. Univariate and multivariable logistic regressions were used to assess the relationship between patient/procedural characteristic and post-ablation HF. Among 111 PVI patients [median age 62.0 years; left ventricular ejection fraction (LVEF) 55%], 29 patients (26.1%) developed symptomatic HF, 6 patients (5.4%) required prolonged index hospitalization, and 8 patients (7.2%) were readmitted for HF. In univariate analyses, persistent AF [odds ratio (OR) 2.97, P = 0.02], AF at start of the procedure (OR 2.99, P = 0.01), additional ablation lines (OR 11.07, P < 0.0001), and final left atrial pressure (OR 1.10 per 1 mmHg increase, P = 0.02) were associated with HF development. Peri-procedural diuresis, net fluid balance, and LVEF were not correlated. In multivariable analyses, only additional ablation lines (ORadj 9.17, P = 0.007) were independently associated with post-ablation HF. Six patients (16.7%) developed HF after CTI ablation.

CONCLUSION

A 26.1% of patients undergoing PVI and 16.7% of patients undergoing CTI ablation developed symptomatic HF when prospectively and uniformly assessed. 12.6% of patients experienced prolonged index hospitalizations or readmission for management of HF within 1 week after PVI. Improved understanding of risk factors for post-ablation HF may be critical in developing strategies to address during AF ablation.