Pulmonary vein isolation for atrial fibrillation: Does ablation technique influence outcome?

BACKGROUND

Over the last 20 years various techniques have been developed striving for safer and more durable pulmonary vein isolation (PVI). The three most commonly used tools are pulmonary vein ablation catheter (PVAC) and cryoballoon ('single-shot' techniques), and point-by-point (PBP) radiofrequency ablation using 3D electroanatomical mapping (EAM).

OBJECTIVE

Evaluate the safety and efficacy of the different techniques in an unselected population undergoing de-novo ablation for persistent or paroxysmal atrial fibrillation (AF) at Royal Papworth Hospital (RPH).

METHOD

Retrospective, single-centre study of consecutive AF ablations at RPH between March 2017 and April 2018. Demographic, procedural and outcome data were analysed.

RESULTS

Over the study period 329 first-time PVI procedures were performed. 37.4% were performed using PBP, 39.8% using cryoballoon and 22.8% using PVAC. There was no significant difference in age or sex between different ablation technique groups. 238 procedures were performed for paroxysmal AF and 91 for persistent AF. A higher proportion of the persistent cases were performed using point-by-point techniques compared to paroxysmal cases (58.2% vs 29.0%, p < 0.05). Procedural times were significantly longer in the group undergoing PBP ablation compared to cryoballoon or PVAC. However, there was no statistically significant difference in 12-month freedom from symptomatic AF or procedural complications between the groups.

CONCLUSIONS

PBP, PVAC and cryoballoon AF ablation all appeared equally efficacious in an unselected population, though PVAC and cryoballoon procedures were shorter. All procedures were associated with a low adverse event rate. Prospective examination is required to substantiate this finding.

Prevalence and clinical impact of atrioventricular conduction disease in patients with idiopathic pulmonary arterial hypertension

Background

Although bradycardia-related sudden death is common in patients with idiopathic pulmonary arterial hypertension (IPAH), the prevalence and prognostic significance of atrioventricular (AV) conduction disease in this patient group is not well-established.

Objectives

– Determine the prevalence of AV conduction disorders in patients with IPAH

– Investigate the relationship between AV block and functional outcomes and mortality.

Method

12-lead electrocardiograms (ECGs) of patients with IPAH were analysed. Patients were categorised according to the presence or absence of AV block. Demographic, pulmonary haemodynamic, cardiac structural characteristics and expression of genes associated with cardiac conduction were compared and functional and mortality outcomes analysed between groups.

Student's t-tests and χ2 tests were used to compare data. Survival was estimated using Kaplan-Meier analyses. Initial exploratory covariates were included in a univariate analysis and those terms with P-value of &lt;0.1 were then used to generate a Cox proportional-hazards multivariate model.

Results

135 IPAH patients (mean age 55±16 years, 28.1% male) were eligible for analysis. Median follow up was 9 years (interquartile range 4–14 years).

AV block was seen in 34.8% of patients with IPAH compared to 10.8% of matched comparators (p&lt;0.001), drawn from patients attending hospital for non-PAH related reasons.

IPAH patients with conduction disease were more likely to be older (59±16 vs 53±17 years, p=0.038). AV block was associated with more severe right ventricular (RV) basal dilatation (5.1±1.0 vs 4.3±0.7cm, p=0.013) and worse RV function (fractional area change 26±9% vs 31±9%, p=0.14). Pulmonary haemodynamics, right atrial size and resting and exertional oxygen saturations were not significantly different. Expression of HCN1, HCN2, SCN1B, SCN5A, CAV1, and KCN2 genes in peripheral blood from a subcohort was similar between those with and without AV block.

Lower 6 minute walk distances (344±153 vs 408±140m, p=0.035) and worse CAMPHOR scores across all 3 domains were seen in those with AV block (figure 1), and mortality was significantly higher (36.2 vs 13.6%, p=0.002) (figure 2). On multivariate analysis the presence of bundle branch block (BBB) was independently associated with a 2.1-fold increased risk of death (95% CI 1.89–4.85, p=0.045).

Conclusions

AV conduction disorders are more prevalent in IPAH than the general population, and are associated with worse prognosis and functional status. Prospective study is required to validate this finding.

In our cohort AV block could not be explained by hypoxia, differences in pulmonary haemodynamics nor, in a small subgroup, by differential expression of specific transmembrane ion channels implicated in cardiac conduction. More detailed investigation into causal mechanisms of AV block in IPAH could establish whether improved prognosis could be achieved by treatment of AV block.

Funding Acknowledgement

Type of funding sources: None. Figure 1Figure 2

Pulmonary vein isolation for AF: does technique influence outcome?

Funding Acknowledgements

Type of funding sources: None.

Background

Over the last 20 years various techniques have been developed striving for safer and more durable pulmonary vein isolation (PVI). The three most commonly used tools are pulmonary vein ablation catheter (PVAC) and cryoballoon (‘single-shot’ techniques), and point-by-point (PBP) radiofrequency ablation using 3D electroanatomical mapping (EAM).

Objective

Evaluate the safety and efficacy of the different techniques in an unselected population undergoing de-novo ablation for persistent or paroxysmal atrial fibrillation (AF) at a single high-throughput centre.

Method

Retrospective, single-centre study of consecutive AF ablations between March 2017 and April 2018. Demographic, procedural and outcome data were analysed.

Results

Over the study period 329 first-time PVI procedures were performed. 37.4% were performed using PBP, 39.8% using cryoballoon and 22.8% using PVAC. There was no significant difference in age or sex between different ablation technique groups. 238 procedures were performed for paroxysmal AF and 91 for persistent AF. A higher proportion of the persistent cases were performed using point-by-point techniques compared to paroxysmal cases (58.2% vs 29.0%, p &lt; 0.05).

Procedural times were significantly longer in the group undergoing PBP ablation compared to cryoballoon or PVAC. However, there was no statistically significant difference in 12-month freedom from symptomatic AF or procedural complications between the groups.

Conclusions

PBP, PVAC and cryoballoon AF ablation all appeared equally efficacious in an unselected population, though PVAC and cryoballoon procedures were shorter. All procedures were associated with a low adverse event rate. Prospective examination is required to substantiate this finding. Table 1CARTOn= 123Cryoballoonn= 131PVACn = 75p-valueAge/years61.7 ± 9.259.5 ± 10.661.7 ± 9.70.14Male92 (74.8)88 (67.2)49 (61.3)0.80Paroxysmal AF70 (56.9)106 (78.6)62 (82.7)0.14Cardiovascular risk factors Hypertension Diabetes Ischaemic heart disease Cerebrovascular disease Heart failure Dyslipidaemia73 (59.3)23 (18.7)40 (32.5)2 (1.6)0 (0) 12 (9.8)79 (60.3)19 (14.5)45 (34.4)0 (0)1 (0.8)16 (12.2)43 (57.3)16 (21.3)22 (29.3)1 (1.3)0 (0)10 (13.3) 0.58 0.24 0.62 - - 0.71Left atrial diameter/cm4.2 ± 0.74.1 ± 0.73.9 ± 1.00.69Procedure time/mins191.3 ± 39126.7 ± 24117.4 ± 30&lt;0.056 month success Paroxysmal Persistent50/66 (75.8)32/51 (62.7)78/103 (75.7)18/24 (75.0)48/61 (78.6)10/12 (83.3) 0.99 0.80Complications9 (7.3)3 (2.3)1 (1.3)0.07Patient demographics, procedural characteristics and outcomes for Carto, cryoballoon and PVAC cases. Values presented as mean ± SD or n (%)Abstract Figure. Time to arrhythmia recurrence