Background:
Ventricular leadless pacemakers eliminate transvenous leads and subcutaneous device pockets and are increasingly used in contemporary clinical practice. However, currently available systems differ substantially in device design, fixation mechanism, delivery system, and implantation workflow. In particular, helix-fixated and tine-based ventricular leadless pacemaker systems may be associated with different procedural requirements, fluoroscopy exposure, and acute electrical performance. Direct comparative data between these two fixation concepts remain limited.
Methods:
This multicentre observational cohort study included consecutive adult patients undergoing ventricular leadless pacemaker implantation at two tertiary care centres between June 2015 and September 2025. Patients received either a helix-fixated or a tine-based ventricular leadless pacemaker at the discretion of the treating physician. Baseline clinical characteristics, pacing indications, procedural parameters, acute electrical measurements, and procedural safety outcomes during the index hospitalization were analysed. The primary procedural parameters included total procedure time and fluoroscopy time. Acute complications were defined as adverse events occurring during the implantation procedure or index hospitalization.
Results:
A total of 324 patients were included, of whom 90 received a helix-fixated and 234 a tine-based ventricular leadless pacemaker. Median age was 81 [75–86] years, and 36.4% of patients were female. Baseline characteristics were largely comparable between groups, although coronary artery disease was more frequent in the tine-based group, whereas heart failure was more common in the helix-fixated group. The most frequent indications for pacing included atrial fibrillation with slow ventricular response, atrioventricular conduction disease, and sinus node disease.
Procedure time was significantly longer with the helix-fixated system compared with the tine-based system: 44.5 [30.5–61.5] vs. 34.0 [23.0–50.0] min; p<0.001. Fluoroscopy time was also significantly longer in the helix-fixated group: 7.2 [4.0–11.5] vs. 3.0 [2.0–5.9] min; p<0.001. Acute electrical parameters differed between fixation concepts. The helix-fixated system showed longer pulse width, lower R-wave sensing amplitudes, and lower impedance compared with the tine-based system. Acute procedural complications were infrequent and did not differ significantly between groups: 3.3% vs. 2.1%; p=0.690. No procedure-related deaths occurred, and no patient required emergency cardiac surgery during the index hospitalization.
Conclusion:
In this real-world multicentre cohort, helix-fixated and tine-based ventricular leadless pacemaker systems demonstrated low and comparable acute complication rates. While helix-fixated implantation was associated with longer procedure and fluoroscopy times as well as distinct acute electrical measurements, the potential impact of these differences on long-term device performance and clinical outcomes remains to be determined.
