Secretoneurin plasma levels are decreased after catheter ablation for atrial fibrillation, patients with AF produce lower SN levels than healthy individuals

Secretoneurin (SN) is a novel biomarker with potential use in cardiovascular medicine. The main effect of SN is mediated through its inhibition of calmodulin-dependent kinase II (CaMKII), which influences calcium handling[1], plasma SN levels differ in ischemic vs. dilated cardiomyopathy [2]. We aim to associate the levels of SN pre- and postprocedurally and according to the type of atrial fibrillation (AF).

We prospectively enrolled patients indicated for catheter ablation (CA) for AF, sequentially sampled patients for SN before, during and after CA for AF. We also sampled healthy individuals as controls. SN was analysed from venous, left atrial and coronary sinus (CS) blood by the use of the ELISA method. Values are expressed as means±SD, variables are compared by standard statistical methods.

A total of 104 patients (59.4% male) with AF aged 64±10.4, with BMI 30.1±5 and 34 healthy individuals (38% male) were included in the analysis. SN plasma levels were significantly lower 32.3±15.1 after the procedure (SN2) as compared to levels before (SN1) 38.4±17.5 pmol/L (P=0.02, Fig.1). SN was not associated with any marker of cardiac injury or overload, echocardiographic parameters, or ablation characteristics (P=NS), even though Troponin I was significantly increased after the procedure (P<0.0001, Fig.2). Left atrial SN was numerically higher 40.9±19.1 than SN sampled from CS 32.9±13 (P=NS).The SN levels in our patients with AF were generally lower than in healthy individuals (50.7±15.3 pmol/L) before (P=0.0004) as well as after the procedure (P=0.0001).

Catheter ablation of AF leads to a decrease in SN plasma levels even though markers of cardiac injury are increased. Patients with AF irrespective of actual rhythm produce lower levels of SN than healthy individuals.