Ablation index predicts outcomes of catheter ablation of focal atrial tachycardia: results of a multicenter study

Funding Acknowledgements

Type of funding sources: None.

Background

Ablation index (AI) is a radiofrequency energy lesion quality marker integrating power, contact force, and time, which was recently shown to be linked to successful catheter ablation (CA) of atrial fibrillation, atrial flutter, and premature ventricular complexes. The possible role of AI as a predictor of outcomes after CA of focal atrial tachycardia (AT) has not been explored so far.

Purpose

To evaluate the role of AI as a predictor of arrhythmia-free survival after CA of focal AT.

Methods

We retrospectively enrolled forty-five consecutive patients undergoing CA for focal AT in four referral Italian electrophysiology laboratories. Clinical and procedural information were collected. For each patient, maximum and mean (by averaging maximum AI values for each radiofrequency ablation lesion) values of AI were measured. Focal AT-free survival was the primary outcome, and was assessed with repeated Holter monitors or cardiac implantable electronic devices, when available. The Shapiro-Wilk’s test was used to check continuous variables for normality; non-normal variables were expressed as median (1st-3rd quartile), whereas categorical variables were reported as counts and percentages. The primary outcome was assessed in a time-to-event fashion, with the Kaplan-Meier method, and the role of AI as a predictor of focal AT recurrence was tested with univariable Cox proportional hazard regression. Furthermore, differences in AI values between patients experiencing a primary outcome event and patients not experiencing a primary outcome event were analyzed with the Student t test. Discrimination ability of AI was measured with area under the receiver operating characteristic curve, and the optimal AI cutoff value was identified with Youden’s index. An alpha level <0.05 was considered statistically significant, and the software RStudio (RStudio Inc., Boston, MA) was used for statistical analysis.

Results

CA was acutely effective in every patient; however, 20% (n=9) of the study population had a focal AT recurrence over a median follow-up of 288 (160-560) days. Both maximum and mean AI values were significantly higher among patients without AT recurrences (maximum AI=568±91, mean AI=426±105) than in patients with AT relapses (maximum AI=447±142, mean AI=352±76, p=0.036 and p=0.028, respectively). All other procedural parameters were similar between the two groups. In a time-to-event analysis, only maximum AI was significantly associated with survival free from AT recurrence (p=0.001, Figure), whereas mean AI was not (p=0.08). By receiver operating characteristic (ROC) curve analysis, the optimal maximum AI cutoff for predicting effective CA according to Youden’s index was 461 (sensitivity, 0.89; specificity, 0.56).

Conclusion

We observed a strong association between maximum AI and outcomes, suggesting that maximum AI may be regarded as a quantitative marker of successful CA of focal AT.

Clinical risk factors associated with ventricular fibrillation during first ST-elevation myocardial infarction

Funding Acknowledgements

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): European Union’s Horizon 2020 research and innovation programme under acronym ESCAPE-NET, registered under grant agreement No 733381

Introduction

Sudden cardiac death (SCD) remains a major public health issue. Most cases in the general population are caused by ischemic heart disease, and often occur in patients without known ischemic heart disease. The assessment of risk factors may point to novel causal pathways or new targets for intervention and risk prediction of SCD.

Objective

The aim of this study was to evaluate the effect of family history of sudden death, prior history of atrial fibrillation (AF), and anterior infarct location on ECG on the development of ventricular fibrillation (VF) during first ST-elevation myocardial infarction (STEMI).

Methods

We performed individual participant data meta-analyses of three European case-control studies including first STEMI patients (aged 18-80 years) with VF (cases) and without VF (controls) before revascularization (GEVAMI, AGNES, and PREDESTINATION). Analyses were done using fixed-effect, inverse variance weighted meta-analysis and multivariable logistic regression. Potential confounding variables were identified using causal diagrams and missing data were handled with multiple imputation for each cohort separately.

Results

We included 1664 cases and 2497 controls (median age (IQR) = 59 (51-67) years, 20% females) in the analyses. After adjusting for potential confounding, we found an independent and additive association between the three exposures and VF (see picture): for family history of sudden death odds ratio (OR) 1.59 (95% confidence interval: 1.37-1.85), for AF OR 2.41 (1.49-3.89), and for anterior myocardial infarction OR 1.50 (1.32-1.71). Further investigation indicated increased effect of family history with multiple sudden deaths in the family, a stronger effect of AF on VF developing within the first minutes of symptoms, and the effect of anterior infarctions being modified by enzymatically determined infarct size. The three risk factors showed an additive effect: with one factor present OR 1.59 (1.38-1.84), two factors OR 2.41 (1.95-2.99), and all three factors OR 5.49 (1.43-21.1). Complete case analysis gave similar results for all analyses.

Conclusions

Family history of sudden death, history of AF, and anterior infarct location with significant interaction with enzymatic infarct size were all independently and additively associated with an increased risk of VF in patients with a first STEMI.

P227 DOES NITROPRUSSIDE TEST BEHAVE AD AN INCREMENTAL PROGNOSTIC FACTOR IN SELECTION OF PATIENTS CANDIDATE TO LVAD IMPLANTATION?

Background

Left ventricular assist device in the last two decades has been used to improve survival and quality of life of patients suffering from heart failure, regardless presence of concomitant pulmonary hypertension. Most patients showed improvement in pulmonary pressure. Current clinical practice lacks a reliable method for prediction of reverse remodelling and prognosis.

Aim

of this study is to investigate the possible role of nitroprusside test as prognostic factor in candidates to LVAD implantation.

Methods

We conducted a monocentric prospective observational study analysing 31 consecutive patients implanted with LVAD between July 2013 and October 2021 that underwent right heart catheterization and nitroprusside test before implantation. Basal and nitroprusside–obtained hemodynamic parameters were subsequently correlated with the primary outcome, defined as the composite of death and episodes of right ventricular failure.

Results

Mean age of study population was 58,6 ± 7,97 years, 12,9% were female. Most prevalent INTERMACS class was 3 and mean EF was 18 ± 4,92 %. Mean follow–up was 31,3 ± 20,4 months, during which 11 death and 14 episodes of RVF occurred. At basal hemodynamic assessment, patients with pulmonary vascular resistance above 3 WU had a significant higher rate of events (50% vs 9%, Likelihood ratio 5.7, p = 0.029). No hemodynamic parameter measured after nitroprusside infusion was found to predict survival or episode of RVF.

Conclusion

In this exploratory study we have shown that nitroprusside infusion does not add further prognostic information when compared with basal hemodynamic parameters.

Echocardiographic-derived Pulmonary Artery Pulsatility Index: towards non-invasive evaluation of right ventricular function

Funding Acknowledgements

Type of funding sources: None.

Background. Pulmonary artery pulsatility index (PAPi)(1) is a powerful predictor of right ventricular failure in patients with acute inferior myocardial infarction(2) and in patients with heart failure undergoing LVAD implantation(3). PAPi derivation requires invasive right heart catheterism (RHC), thus limiting availability and seriate assessment of right ventricular function.

Purpose. Aim of the study was to evaluate accuracy and agreement of echocardiographic derived PAPi (ePAPi) compared to right heart catheterism derived PAPi in heart failure with reduced ejection fraction (HFrEF) patients.

Methods. ePAPi was defined as the ratio of pulmonary artery pulse pressure (sPAP – dPAP) to right atrial pressure (RAP). Systolic pulmonary artery pressure (sPAP) was determined from tricuspid regurgitation (TR) velocity using the simplified Bernoulli equation(4): sPAP = 4 x (peak TR jet velocity)2 + RA pressure. Diastolic pulmonary artery pressure (dPAP) was calculated as: dPAP = 4 x (end-diastolic pulmonary regurgitant velocity)2 + RA pressure. Simplified ePAPi, defined as peak TR pressure to RA pressure ratio was also investigated. Pearson and Spearman correlation tests were performed. A Bland-Altman plot analysis was performed to assess agreement between ePAPi and invasive PAPi. ROC curves were made to assess ePAPi accuracy in identifying patients with low PAPi (defined as PAPi < 2 and PAPi < 3.65).

Results. 66 HFrEF patients (age 59 ± 10 years, 63% males, mean EF: 35 ± 9%) underwent RHC and blinded echocardiogram in a single center Cardiology Departement. Mean invasive derived PAPi was 4.4 ± 3.6, while ePAPi was 3.9 ± 2.3. ePAPi showed an excellent correlation with invasive PAPi (Pearson r: 0.80, p < 0.001; Spearman rho: 0.83, p < 0.001) and good agreement as shown in Bland Altman plot (figure 1). In ROC analysis, ePAPi accurately identified patients with low hemodynamic PAPi < 2 (Sensibility: 100%; Specificity: 87.2%; AUC: 0.97; Youden criterion: ePAPi < 2.3) and PAPi < 3.65 (Sensibility: 81.8%; Specificity: 84%; AUC: 0.89; Youden criterion: ePAPi < 3.6)(figure 2). Simplified ePAPi also showed good correlation and agreement (Pearson r: 0.58, p < 0.001; Spearman rho: 0.81, p < 0.001).

Conclusions. In patients with HFrEF, echocardiographic derived PAPi showed a good agreement and correlation with invasive derived PAPi. ePAPi was also accurate in identifying patients with low PAPi values associated with poor outcomes and may be of interest for non-invasive right ventricular function seriate assessment. Further studies are needed to investigate prognostic implications. Abstract Figure.  Abstract Figure 2