Long-term performance of left ventricular leads in cardiac resynchronisation therapy

Background Cardiac resynchronisation therapy (CRT) confers symptomatic and survival benefits in chronic heart failure with reduced ejection fraction (HFrEF). There remains a paucity of data on long-term performance of left ventricular (LV) leads, particularly with newer quadripolar lead designs. Methods This single-centre study utilised an electronic, outpatient HFrEF database to identify CRT recipients (2008-2014). The primary endpoint was temporal trend in LV pacing thresholds during follow-up. Secondary outcomes were complications relating to acute or chronic lead failure and device-related infections. Results Two hundred eighty patients were included, with mean (+/- SD) age of 74.2 years (+/- 9.0) and median follow-up of 7.6 years (interquartile range 4-9). Mean LV threshold was 1.37 V (+/- 0.73) at implant and remained stable over the study period. No differences were observed based upon lead manufacturer. Compared to non-quadripolar leads (n = 216), those of quadripolar designs (n = 64) had a lower threshold at 6 months (1.20 vs 1.37 V;P = .04) and at the end of the study period (1.32 vs 1.46 V;P = .04). Patients with HFrEF of ischaemic aetiology had higher thresholds at implant (1.46 vs 1.34 V;P = .05), and this persisted until the end of follow-up (1.49 vs 1.34 V;P = .03). There was low incidence of acute (0.71%; 2/280) and chronic lead failure (1.79%; 5/280), with four cases (1.43%) of device infection. Conclusions LV leads in the context of CRT have excellent chronic stability and low rates of adverse events. Those with newer quadripolar lead designs have lower thresholds at initial follow-up and in the longer term.