[Comparison of basic electrical features of ICD defibrillating leads implanted to right ventricular apex or right...

Automatic implantable cardioverter-defibrillators (ICDs) are nowadays an essential tool for reducing mortality due to sudden cardiac death. Technological advances in the miniaturization of devices and lead fixation, and the development of surgical techniques has led to more frequent implantation of the defibrillation leads outside the right ventricular apex (RVA), especially in those patients requiring cardiac pacing, as data from large clinical trials showed that chronic RVA pacing is harmful, especially in heart failure subjects, who are an important target for the ICD. Very few studies have been published comparing the electrical characteristics of leads placed in the RVA versus those implanted outside the RVA, mainly to right ventricular outflow tract of the heart (RVA), hence any subsequent analysis of this issue seems to be a valuable addition to the available information in this topic. The aim of this study was to compare the electrical parameters of ICD leads implanted into the right ventricular apex (RVA), to those placed in one of the alternative sites: the right ventricular outflow tract (RVOT), or the area of the interventricular septum (RVS).

Retrospective analysis of medical data from a single centre (teaching hospital), which included 132 patients with ICD implanted in 2010-2011, both in primary and secondary prevention of sudden cardiac death. We compared the most important electrical parameters of the ICD system, as the resistance of the pacing system, resistance of high-voltage coil, the amplitude of the sensed beats and pacing threshold. In addition, we compared the time of implantation, X-ray fluoroscopy time and X-ray exposure.

There were no statistically significant differences between the two analysed groups in terms of pacing-system resistance (601.012 vs. 602.7omega, p = 0,499), high-energy coil resistance (63.7omega vs. 67.22, p = 0,201), amplitude of sensed R-waves (14,6mV vs. 15.3mV, p = 0, 710) and the pacing threshold energy (0,368 microJ vs. 0.259 microJ, p = 0,803). Also the duration of implantation (123, 3 min vs. 123, 9 min, p = 0,940), fluoroscopy time (11,0 minutes vs. 8,6 minutes, p = 0,06) and dose exposure (1594, 5cGy/cm2 vs. 2094, 4cGy/cm2, p = 0,069) were comparable in both groups.

Implantation of ICD leads to the RVOT/RVS is a safe procedure, and the basic electrical parameters of such systems are comparable to ICDs with lead implanted to the RVA.