T-wave alternans poorly prognostic in primary prophylactic ICD patients: a prospective EU-CERT-ICD study

Background

New methods to identify patients who truly benefit from primary prophylactic implantable cardioverter defibrillation (ICD) are urgently needed. T-wave alternans (TWA) represents a beat-to-beat fluctuation in the morphology of the ST-segment and T-wave. It has been shown to associate with arrhythmogenesis of heart and sudden cardiac death [1]. We hypothised that TWA might associate with benefit from ICD implantation in primary prevention.

Methods

In EU-CERT-ICD study, we prospectively enrolled 2327 primary prophylactic ICD candidates from 15 European countries. A 24-hours Holter-monitoring was taken from all recruited patients at enrolment. TWA was assessed from Holter-monitoring using MMA method with Getemed Cardioday software. To assess the benefit from ICD treatment, we used outcomes all-cause mortality, appropriate shock and survival benefit. We conducted Cox regression model, competing risk regression model and propensity score adjusted Cox regression model. TWA was assessed both as contiguous variable and with cut-off points <47 μV and <60 μV.

Results

Final cohort included 1,734 valid T-wave alternans samples, 1,211 patients with ICD and 523 control patients with conservative treatment, with mean follow-up time 2.3 years. TWA <60 μV predicted lower all-cause mortality in ICD patients in univariate cox regression model (HR 1.484, 95% CI 1.024–2.151, p=0.0374). In multivariate models, TWA did not predict death or appropriate shocks in ICD patients. In addition, TWA did not predict death in control patients. In propensity score adjusted Cox regression model, TWA did not predict ICD benefit.

Conclusion

T-wave alternans is poorly prognostic in primary prophylactic ICD patients. Altough it may predict life-threatening arrhythmias and sudden cardiac death in several patient populations, it cannot be used in assessing benefit from implantable cardioverter defibrillator in primary prevention among patients with ejection fraction ≤35%.

Funding Acknowledgement

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): European Community's 7th Framework Program FP7/2007-2013

Long-term comparison of contact force-guided versus conventional irrigated cool-tip circumferential pulmonary vein isolation of atrial fibrillation

Funding Acknowledgements

Type of funding sources: None.

Background

In atrial fibrillation (AF) patients, pulmonary vein isolation by means of catheter ablation (CA) is the most effective therapeutic option in order to maintain sinus rhythm. To improve successful PV isolation and effective lesion creation, contact force (CF)-sensing catheters were developed and have become routinely available. Previous studies did not always show superior clinical efficacy in comparison with non-CF CA. Moreover, data about long term clinical outcome are still lacking, especially by patients with persistent atrial fibrillation.

Purpose

The aim of the present study was to compare the outcome of CF-controlled ablation versus non-CF guided radiofrequency (RF) ablation of AF with regard to ablation characteristics and AF recurrence.

Methods

Consecutive patients, who underwent a mean 1.7±0.9 point-by-point RF CA for AF at our hospital between January of 2014 and October of 2017, were enrolled in the study. 354 patients were ablated without CF. After routine availability of CF catheters in October of 2016, 165 consecutive patients were ablated using CF. In case of crossover between the groups, follow up was censored. The primary endpoint was any recurrence documented as symptomatic or asymptomatic atrial tachycardia or atrial fibrillation >30 s after the 3-month blanking period. Secondary endpoints were procedural characteristics and periprocedural complications.

Results

62% of the enrolled patients had persistent AF. There were no significant differences in baseline characteristics (male gender 63% vs 62%, P=0.846; persistent AF 61% vs. 65%, P=0.496; BMI 29.0±5.2 vs 29.3±5.2 kg/m2, P=0.582; hypertension 76% vs 80%, P=0.369; coronary artery disease 14% vs 20%, P=0.076; left atrial diameter 43.3±7.0 vs 43.8±7.3 mm, P=0.386; diabetes 13% vs 10%, P=0.312; sleep apnoea 7% vs 10%, P=0.167) between the groups, except for older age in the CF group (62.8±10.0 vs 65.0±10.4 years, P=0.021).

In the first 12 months arrythmia-free survival was significantly higher in the CF group (Figure 1, Log-Rank (Mantel-Cox) P=0.049). Over 2.8 ± 1.8 years of follow-up, 47% of the patients in the CF group remained free of AF recurrence compared to 36% in the non-CF group (Log-Rank (Mantel-Cox) P=0.236). In multivariable Cox regression analysis using backward elimination, non-CF ablation was an independent risk factor for AF recurrence (HR=1.31; P=0.027) besides age (HR=1.023; P=0.001), persistent AF (HR=1.481; P=0.001), and left atrial diameter (HR=1.023; P=0.004). All other clinical factors were non-significant (Figure 2).

Total fluoroscopy time (27.6±16.0 vs. 14.4±7.9 min) and total procedure time (133.4±38.8 vs. 110.1±28.0 min) were significantly lower for CF guided CA (P<0.001). Complication rates did not differ between groups (P=0.123).

Conclusions

In our long-term single center study the AF recurrence rate was lower after CF PVI as compared to non-CF PVI.