Cor Vasa 2004, 45(7):331-337

Oscilloscopic analysis of the defibrillation discharge for detecting implanted defibrillation lead integrity defects in experiment

Jan Bytešník^1,*, Vlastimil Vančura¹, Marie Kocinová², Věra Lánská², Petr Volík³, Libert Malina³

¹ Klinika kardiologie

² Oddělení lékařské statistiky, Institut klinické a experimentální medicíny

³ Biotronik Praha, Praha, Česká republika

Aim of study:
To assess the contribution of oscilloscopic recordings of the defibrillation discharge to detecting an implanted defibrillation lead defect in an experimental model, and to compare any differences in the course of test discharges with an energy of 1 J and 30 J.


Material and method:
Nine minipigs had endocardial SPS 75 UP/BP (Biotronik, Berlin, Germany) or Kainox RV 75 (Biotronik, Berlin, Germany) leads implanted transvenously into the apical region of the right ventricle with a Phylax 06 (Biotronik, Berlin, Germany) cardioverter-defibrillator (ICD) placed subcutaneously in the left pectoral region. Discharges of 1 J and 30 J were registered and analyzed using oscilloscopy in the presence of an intact lead system and subsequently in model defects involving contact between the lead and the ICD, lead insulation and partial or complete fracture in front of its entry into the trimmed vein.

Results:
When compared with baseline, testing a 30 J discharge in the presence of a fractured lead whose fragments remained in contact, the reduction of leading edge voltage of phase 1 (50.6 ± 42.6 V vs. 79.3 ± 41.8 V; p < 0.01) and phase 2 (-23.0 ± 17.6 V vs. -35.7 ± 15.8 V; p < 0.1) of the biphasic discharge were seen. These findings were consistent with an increase in total defibrillation lead impedance. No significant change was observed when using the recommended low-energy discharge (1 J in this particular case) to test the integrity of the lead defibrillation system. No diagnostic changes were likewise noted in the presence of a less significant damage to the lead system.

Conclusion:
Oscilloscopic registration and analysis of the defibrillation discharge may help detect a major defect of a defibrillation lead of the implantable cardioverter-defibrillator in cases where a change in total impedance was conclusive. Alterations in the amplitude, breadth and shape of the 30 J biphasic discharge furnish more detailed information on the change in the impedance of a damaged defibrillation lead. This finding could be used for oscilloscopic analysis of the defibrillation discharge in clinical testing of implantable cardioverter-defibrillator integrity.

Keywords: Implantable cardioverter-defibrillator; Defibrillation lead defect; Oscilloscopic analysis; Biphasic impulse

Published: July 1, 2004  Show citation