Background:

Difference between cardiac troponin T (cTnT), creatinine kinase (CK) and CK isoenzyme MB (CK-MB) concentrations before and after catheter ablation reflects the extent of the myocardial lesion created. Pulsed field ablation (PFA) is a novel, nonthermal ablation modality that preferentially ablates myocardial tissue, with minimal collateral effect on surrounding tissues. Therefore, there is no necessity to reduce the ablation power. In preclinical studies, it has been demonstrated that PFA can create deeper and larger myocardial lesions. However, the amount of myocardial damage due to pulmonary vein isolation (PVI) using PFA is unknown. The aim of the study was to investigate the 30-day kinetics of cTnT, CK and CK-MB after PFA-ablation for paroxysmal atrial fibrillation (PAF).

Methods:

In patients with symptomatic PAF, PVI using PFA (Farapulse, Inc.) was perfomed. Using a multispline catheter, biphasic pulse trains with a power of 1,900 V were applied. A minimum of 8 ablation applications per pulmonary vein was required. In all procedures, extensive high-density pre- and post-ablation 3D electroanatomical bipolar voltage maps (Biosense Webster, Inc.) were performed to document acute PVI and the extend of the ablation lesions. Blood samples analyzing CK, CK-MB and cTnT were obtained before PVI and 6h, 24h, 48h and 30 days after PVI. The reference ranges for the cardiac enzymes were: <14 ng/l for cTnT, <190 U/l for CK and <25 U/l for CK-MB. Data of the cardiac enzymes are presented as median and interquartile range [IQR]. 

Results:

In 30 patients (mean age 63 ± 10 years; 47% male; CHA₂DS₂-VASc-Score 2 [IQR 1-3]), uncomplicated PFA was performed, with all PVs acutely isolated. Six hours post ablation, significantly higher cTnT levels (1,790 ng/l [1,427-2,088], compared to 7.5 ng/l [7-8.5] at baseline) were measured, with declining levels at 24h and 48h, respectively (1,705 ng/l [1,508-2,200] and 993ng/l [804-1,125]). Similar kinetics for CK and CK-MB were measured, however the increase was less pronounced (for CK: 102 U/l [68-139] vs. 630 U/l [495-772] vs. 453 U/l [343-578] vs. 228 U/l [138-425] at baseline, 6h, 24h and 48h, respectively and for CK-MB: 13 U/l [11-14] vs. 80 U/l [64-96] vs. 41 U/l [36-48] vs. 16 U/l [15-18] at baseline, 6h, 24h and 48h, respectively). Thirty days post ablation cTnT, CK and CK-MB reached baseline levels (8 ng/l [7-11], 101 U/l [75-156] and 13 U/l [12-15], respectively). See figure 1 for curves of kinetic data.

Conclusions:

This was the first study to evaluate the kinetics of cTnT, CK and CK-MB after PVI using PFA for PAF. The degree of cTnT increase is much more pronounced than for CK and CK-MB. The maximum peak for all parameters is 6 hours after the ablation with a 240-fold increase for cTnT and a 6-fold increase for both CK and CK-MB. Thirty days after PFA ablation, there were no signs of sustained cardiac injury, enzyme levels were normalized. To assess cardiac enzymes kinetics as a non-invasive marker to predict the outcome of cardiac ablation using PFA, long-term follow-up is needed.

Figure 1:

Thirty-day kinetic data curves of cTnT, CK and CK-MB after PVI using PFA for PAF. Data are shown as median( ng/l for c TnT and U/l for CK and CK-MB).