Results
Over the study period, 631 patients underwent CRT-D therapy and were included in the analysis. In most cases (73.7%), the high-voltage lead was implanted via the cephalic vein (cephalic group). Both groups were pre-dominantly male (82.1% vs 78.3%, respectively, p=0.28) of a similar age (69.7 ± 11.5 years vs 68.7 ± 11.9, respectively, p=0.33) and had a left sided implant (96.3% vs 97%, p=0.7) for primary prevention (91.2% vs 94%, p=0.26). Co-morbidities in both groups were fairly similar (table 1 ) although chronic kidney disease was more prevalent in the cephalic group (16.6% vs 9.6%, respectively, p=0.03). The mean follow-up period was 4.75 ± 2.4 years. The overall lead failure rate in this study was 0.33%/year.
During the study period, 20 patients required revision or replacement of the RV lead. Of these, 6 (30%) patients had an infection indication, including erosion, local infection, and systemic sepsis. Early lead replacement for displacement or cardiac perforation accounted for 4 (20%) cases and the remaining 10 (50%) were premature lead failures.
High-voltage lead failure was rare; failure occurred at a rate of 0.4% per year in the cephalic group and 0.14% per year in the non-cephalic group (p=0.34; figure 1 ). The number of shock coils, the number of concomitant leads implanted with the defibrillator lead and the ICD lead tip position within the right ventricle did not affect lead longevity (figure 1 ). However, ICD leads implanted in female patients for CRT-D, were more likely to experience premature failure (p=0.01) (figure 2 ).