Clinical value of routine predischarge testing after ICD-implantation

After implantation of a cardioverter/defibrillator (ICD) predischarge testing is often performed to ensure appropriate therapy function. Nevertheless there is no proven evidence for the necessity of this examination. In this retrospective single-centre analysis we investigated the clinical value of routine predischarge testing.

Predischarge testing was performed in 161 patients 6+/-2 days after primary implantation of an ICD. There were no complications related to ICD-testing. In 17 of 161 patients (11%) there was at least one pathological finding. In 4 of 17 patients we observed a defibrillation energy requirement (DER) with a safety margin of less than 10J. In two of these patients an early lead repositioning was undertaken and in two patients reversal of the shock polarity was used to achieve an adequate DER. In 13 of 17 patients we detected a distinct deviation of pacing thresholds or R-wave sensing amplitudes. In two of these patients an early electrode repositioning was performed because of lead displacement. In the remaining 11 patients we found an adequate DER at first, whereas in two patients a further lead repositioning was still necessary during follow-up. In 144 of 161 patients (89%) predischarge testing was without pathological findings. None of these patients needed revision of the ICD-lead during a mean follow-up of 24+/-13 months.

Abnormal measurements during predischarge testing are not rare findings in ICD-recipients. Noninvasive methods cannot rule out inadequate defibrillation function. A normal predischarge test seems to be a reliable predictor for a stable electrode function during the first years of follow-up.