Implantable cardioverter defibrillator shocks are prospective predictors of anxiety.

OBJECTIVES To examine the temporal contingency of anxiety and implantable cardioverter defibrillator (ICD) therapy (anti-tachycardia-pacing and shocks to prevent ventricular tachycardia and/or fibrillation). BACKGROUND It is under debate whether anxiety is a precursor and/or consequence of ICD-therapy. METHODS In a prospective longitudinal study, fifty-four patients undergoing first-time ICD-implantation were assessed for anxiety, frequency of ICD-shocks and anti-tachycardia-pacing up to two days before ICD-implantation (T0) and twelve months later (T1). RESULTS Anxiety at T0 did not predict frequency of ICD-shocks at T1, but ICD-shocks significantly predicted increased anxiety at T1. In contrast, anxiety at T0 and T1 was unrelated to frequency of anti-tachycardia-pacing. Effects remained stable when we controlled for potentially confounding variables (e.g. age, sex, cardiac health and depression at T0). CONCLUSION Our findings indicate that repeated ICD-shocks are a cause of anxiety in ICD-patients rather than a consequence, thus shock frequency should be minimized.