The implanted defibrillator: relation of defibrillating lead configuration and clinical variables to defibrillation threshold

• Published in: Journal of the American College of Cardiology 1985-12, Vol.6 (6), p.1315-1321
• Main Authors: Troup, Paul J., Chapman, Peter D., Olinger, Gordon N., Kleinman, Leonard H.
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Aged; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Arrhythmias, Cardiac - therapy; Biological and medical sciences; Coronary Disease - therapy; Electric Countershock - methods; Electrodes; Emergency and intensive cardiocirculatory care. Cardiogenic shock. Coronary intensive care; Female; Humans; Intensive care medicine; Male; Medical sciences; Middle Aged
• ISSN: 0735-1097; 1558-3597
• DOI: 10.1016/S0735-1097(85)80219-9

Forty-two defibrillating lead systems for the automatic implantable defibrillator were implanted and tested in 41 patients. Two basic lead configurations were used: 1) spring-patch, consisting of a transvenous superior vena cava spring electrode as the anode and an apical or left lateral ventricular patch electrode (either small [13.9 cm2] or large [27.9 cm2]) as the cathode; and 2) patchpatch, consisting of an anterior right ventricular patch as the anode and a posterior left ventricular patch as the cathode. Of the 42 lead systems, 10 were springpatch and 32 were patch-patch combinations. The defibrillation threshold for the patch-patch combinations (9.8 ± 6.5 J, mean ± standard deviation) was significantly (p < 0.01) lower than that for the spring-patch combinations (19.1 ± 10.3 J). Subgroup analysis revealed the lowest defibrillation thresholds for patch-patch combinations with at least one large patch. Total surface area of defibrillating leads was strongly negatively correlated with the defibrillation threshold (p < 0.005). Analysis of the relation of clinical variables to defibrillation threshold revealed that only amiodarone therapy was independently associated with a significantly (p < 0.05) higher defibrillation threshold. Thus, surface area of the defibrillating leads is a critical determinant of the defibrillation threshold for the implanted defibrillator. Patch-patch lead systems with at least one large patch may provide an increased safety margin for defibrillation. Conversely, amiodarone therapy is associated with higher defibrillation thresholds and may decrease the margin of safety.