Transseptal puncture for left atrial ablation: risk factors for cardiac tamponade and a proposed causative classification system

Aims

Cardiac tamponade is a high morbidity complication of transseptal puncture (TSP). We examined the associations of TSP‐related cardiac tamponade (TRCT) for all patients undergoing left atrial ablation at our center from 2016 to 2020.

Methods and Results

Patient and procedural variables were extracted retrospectively. Cases of cardiac tamponade were scrutinized to adjudicate TSP culpability. Adjusted multivariate analysis examined predictors of TRCT. A total of 3239 consecutive TSPs were performed; cardiac tamponade occurred in 51 patients (incidence: 1.6%) and was adjudicated as TSP‐related in 35 (incidence: 1.1%; 68.6% of all tamponades). Patients of above‐median age [odds ratio (OR): 2.4 (1.19–4.2), p = .006] and those undergoing re‐do procedures [OR: 1.95 (1.29–3.43, p = .042] were at higher risk of TRCT. Of the operator‐dependent variables, choice of transseptal needle (Endrys vs. Brockenbrough, p > .1) or puncture sheath (Swartz vs. Mullins vs. Agilis vs. Vizigo vs. Cryosheath, all p > .1) did not predict TRCT. Adjusting for operator, equipment and demographics, failure to cross the septum first pass increased TRCT risk [OR: 4.42 (2.45–8.2), p = .001], whilst top quartile operator experience [OR: 0.4 (0.17–0.85), p = .002], transoesophageal echocardiogram [TOE prevalence: 26%, OR: 0.51 (0.11–0.94), p = .023], and use of the SafeSept transseptal guidewire [OR: 0.22 (0.08–0.62), p = .001] reduced TRCT risk. An increase in transseptal guidewire use over time (2016: 15.6%, 2020: 60.2%) correlated with an annual reduction in TRCT (R² = 0.72, p < .001) and was associated with a relative risk reduction of 70%.

Conclusions

During left atrial ablation, the risk of TRCT was reduced by operator experience, TOE‐guidance, and use of a transseptal guidewire, and was increased by patient age, re‐do procedures, and failure to cross the septum first pass.

P504VT ablation outcomes and predictors in a UK population- validating existing predictors and novel markers

Background

Radiofrequency catheter ablation (CA) can reduce ventricular tachycardia (VT) burden and registry data suggests an improvement in mortality. However, there is significant heterogeneity in patient morbidity and VT phenotype. A risk prediction model derived from observational data has suggested pre-procedural left ventricular (LV) function, age and underlying ischaemic cardiomyopathy are associated with greater post-procedural mortality. Validation of proposed factors in clinical practice is required to facilitate comprehensive pre-procedural risk stratification and inform decision making.

Purpose

To determine whether proposed pre-procedural predictors of mortality after VTCA are valid in a UK population and explore any association with other predictors.

Method

Patients undergoing VTCA at a tertiary electrophysiology centre between 06/07/16 and 31/07/19 were included. Pre-specified characteristics and mortality follow-up data were analysed from electronic health records. Cox regression analysis was undertaken to determine association with mortality.

Results

161 patients with mean age of 63 ±15.9 years underwent VTCA of whom 133 (83%) were male. During the follow-up  period (16 months, 13-24; median, 1st-3rd quartile) 16 patients died. No deaths occured in the 27 (16%) patients with structurally normal hearts. Chronic kidney disease (CKD) stage III-IV (HR 14.73 [4.9-44.4]), LV ejection fraction &lt;35% (HR 7.13 [1.59-31.88]), underlying ischaemic cardiomyopathy (HR 6.17 [1.37-27.85]), LV internal diameter (LVID) (1.08 [1.02-1.15]) and age (HR 1.08 [1.02-1.14]) were associated with significantly greater mortality risk (Table 1) (Figure 1).

Conclusion

Proposed risk stratifying factors are validated in our UK centre’s experience. Additionally, CKD and baseline LVID appear to be associated with mortality in our population and warrant further study.

Risk factor Hazard ratio Lower confidence interval Upper confidence interval P-value Atrial fibrillation (yes/no) 0.14 0.02 1.11 0.06 Age (years) 1.08 1.02 1.14 &lt;0.01 Diabetes (yes/no) 2.43 0.85 6.92 0.10 Chronic kidney disease (yes/no) 14.73 4.88 44.41 &lt;0.01 Ischaemic cardiomyopathy (yes/no) 6.17 1.37 27.85 0.02 LV EF &lt;35% (yes/no) 7.13 1.59 31.88 &lt;0.01 LV internal diameter (mm) 1.08 1.02 1.15 &lt;0.01 Procedural urgency (urgent/elective) 1.12 0.57 2.20 0.75 Table 1: Association between baseline risk factors and mortality risk after VT catheter ablation

Abstract Figure 1: Kaplan-Meier survival curves

Outcome of ACHD patients with non-inducible versus inducible IART undergoing cavo-tricuspid isthmus ablation: the role of empiric ablation

PURPOSE

Catheter ablation for supraventricular tachycardia (SVT) in adults with congenital heart disease (ACHD) is an important therapeutic option. Cavo-tricuspid isthmus (CTI)-dependent intraatrial re-entrant tachycardia (IART) is common. However, induction of sustained tachycardia at the time of ablation is not always possible. We hypothesised that performing an empiric CTI line in case of non-inducibility leads to good outcomes. Long-term outcomes of empiric versus entrained CTI ablation in ACHD patients were examined.

METHODS

Retrospective, single-centre, case-control study over 7 years. Arrhythmia-free survival after empiric versus entrained CTI ablation was compared.

RESULTS

Eighty-seven CTI ablations were performed in 85 ACHD patients between 2010 and 2017. The mean age of the cohort was 43 years and 48% were male. Underlying aetiology included ASD (31%), VSD (11.4%), AVSD (9.1%), AVR (4.8%), Fallot's (18.4%), Ebstein's (2.3%), Fontan's palliation (9.2%) and atrial switch (13.8%). CTI-dependent IART was entrained in 59 patients whereas it was non-inducible in 28. The latter had an empiric CTI ablation. Forty-three percent of procedures were performed under general anaesthesia. There were no reported procedural complications. There was no significant difference in the mean procedure or fluoroscopy times between the groups (empiric vs entrained CTI; 169.1 vs 183.3 and 28.1 vs 19.9 min). Arrhythmia-free survival was 64.3% versus 72.8% (p value 0.44) in the empiric and entrained groups at 21 months follow-up.

CONCLUSIONS

Long-term outcomes after empiric and entrained CTI ablation for IART in ACHD patients are comparable. This is a safe and effective therapeutic option. In the case of non-inducibility of IART, an empiric CTI line should be considered in this cohort.

Impact of attributed audit on procedural performance in cardiac electrophysiology catheter laboratory

PURPOSE

Audit has played a key role in monitoring and improving clinical practice. However, audit often fails to drive change as summative institutional data alone may be insufficient to do so. We hypothesised that the practice of attributed audit, wherein each individual's procedural performance is presented will have a greater impact on clinical practice. This hypothesis was tested in an observational study evaluating improvement in fluoroscopy times for AF ablation.

METHODS

Retrospective analyses of fluoroscopy times in AF ablations at the Barts Heart Centre (BHC) from 2012-2017. Fluoroscopy times were compared pre- and post- the introduction of attributed audit in 2012 at St Bartholomew's Hospital (SBH). In order to test the hypothesis, this concept was introduced to a second group of experienced operators from the Heart Hospital (HH) as part of a merger of the two institutions in 2015 and change in fluoroscopy times recorded.

RESULTS

A significant drop in fluoroscopy times (33.3 ± 9.14 to 8.95 ± 2.50, p < 0.0001) from 2012-2014 was noted after the introduction of attributed audit. At the time of merger, a significant difference in fluoroscopy times between operators from the two centres was seen in 2015. Each operator's procedural performance was shared openly at the audit meeting. Subsequent audits showed a steady decrease in fluoroscopy times for each operator with the fluoroscopy time (min, mean±SD) decreasing from 13.29 ± 7.3 in 2015 to 8.84 ± 4.8 (p < 0.0001) in 2017 across the entire group.

CONCLUSIONS

Systematic improvement in fluoroscopy times for AF ablation procedures was noted byevaluating individual operators' performance. Attributing data to physicians in attributed audit can promptsignificant improvement and hence should be adopted in clinical practice.