Prospective study of interleukin-6 and the risk of malignant ventricular tachyarrhythmia in ICD-recipients--a pilot study.

OBJECTIVE

We investigated the relationship between interleukin-6 (IL-6) and the risk of experiencing spontaneous ventricular tachyarrhythmia (VT/VF) in patients with an implantable cardioverter-defibrillator (ICD).

BACKGROUND

Cytokine levels predict outcome in patients with advanced heart failure and are elevated in patients with coronary artery disease (CAD). Regarding heart rhythm disturbances, proinflammatory activity could predict the occurrence of atrial fibrillation. There is no data on cytokine levels and the risk of spontaneous VT/VF.

METHODS

IL-6 serum concentrations were determined at baseline and follow-up in 47 consecutive ICD-patients with CAD and idiopathic dilated cardiomyopathy (IDC). Data were prospectively correlated with VT/VF-incidence.

RESULTS

Thirty-six patients (76.6%) suffered from CAD and 11 (23.4%) from IDC. Mean serum concentrations of IL-6 at baseline and at 9 months follow-up were 6.12+/-4.98 and 4.63+/-6.97. 88 spontaneous VT/VF-events occurred in 13/47 patients (27.7%). Patients with VT/VF had significantly higher IL-6 levels as compared to patients without VT/VF (8.96+/-5.97 vs. 5.04+/-4.16pg/ml at baseline (p =0.03), 7.8+/-4.88 vs. 3.42+/-6.32pg/ml at follow-up (p =0.01)).

CONCLUSIONS

Elevated IL-6 serum concentrations were prospectively associated with an increased risk of spontaneous VT/VF-events in ICD-patients with CAD or IDC. These preliminary findings support a possible association of proinflammatory activity and an increased susceptibility to spontaneous VT/VF-events.