BACKGROUND: The clinical utilization of leadless pacemakers (LPs) as an alternative to traditional transvenous pacemakers is likely to increase with the advent of dual-chamber LP systems. Since device retrieval to allow LP upgrade or replacement will become an important capability, the first such dual-chamber, helix-fixation LP system (Aveir DR; Abbott, Abbott Park, IL) was specifically designed to allow catheter-based retrieval. In this study, the preclinical performance and safety of retrieving chronically implanted dual-chamber LPs was evaluated. METHODS: Atrial and ventricular LPs were implanted in the right atrial appendage and right ventricular apex of 9 healthy ovine subjects. After ≈2 years, the LPs were retrieved using a dedicated transvenous retrieval catheter (Aveir Retrieval Catheter; Abbott) by snaring, docking, and unscrewing from the myocardium. Comprehensive necropsy/histopathology studies were conducted to evaluate device- and procedure-related outcomes. RESULTS: At a median of 1.9 years postimplant (range, 1.8-2.6), all 18 of 18 (100%) LPs were retrieved from 9 ovine subjects without complications. The median retrieval procedure duration for both LPs, from first-catheter-in to last-catheter-out, was 13.3 minutes (range, 2.5-36.4). Postretrieval, all right atrial, and right ventricular implant sites demonstrated minimal tissue disruption, with intact fibrous tissue limited to the distal device body. No significant device-related trauma, perforation, pericardial effusion, right heart or tricuspid valve injury, or chronic pulmonary thromboembolism were observed at necropsy. CONCLUSIONS: This preclinical study demonstrated the safe and effective retrieval of chronically implanted, helix-fixation, dual-chamber LP systems, paving the way for clinical studies of LP retrieval.
- MeSH
- design vybavení MeSH
- fibrilace síní * MeSH
- kardiostimulátor * MeSH
- lidé MeSH
- lipopolysacharidy MeSH
- ovce domácí MeSH
- ovce MeSH
- srdeční komory MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
BACKGROUND: Dual-chamber leadless pacemakers (LPs) require robust communication between distinct right atrial (RA) and right ventricular (RV) LPs to achieve atrioventricular (AV) synchrony. OBJECTIVE: The purpose of this preclinical study was to evaluate a novel, continuous implant-to-implant (i2iTM) communication methodology for maintaining AV-synchronous, dual-chamber DDD(R) pacing by the 2 LPs. METHODS: RA and RV LPs were implanted and paired in 7 ovine subjects (4 with induced complete heart block). AV synchrony (% AV intervals <300 ms) and i2i communication success (% successful i2i transmissions between LPs) were evaluated acutely and chronically. During acute testing, 12-lead electrocardiographic and LP diagnostic data were collected from 5-minute recordings, in 4 postures and 2 rhythms (AP-VP and AS-VP, or AP-VS and AS-VS) per subject. Chronic i2i performance was evaluated through 23 weeks postimplant (final i2i evaluation period: week 16-23). RESULTS: Acute AV synchrony and i2i communication success across multiple postures and rhythms were median [interquartile range] 100.0% [100.0%-100.0%] and 99.9% [99.9%-99.9%], respectively. AV synchrony and i2i success rates did not differ across postures (P = .59, P = .11) or rhythms (P = 1, P = .82). During the final i2i evaluation period, the overall i2i success was 98.9% [98.1%-99.0%]. CONCLUSION: Successful AV-synchronous, dual-chamber DDD(R) leadless pacing using a novel, continuous, wireless communication modality was demonstrated across variations in posture and rhythm in a preclinical model.
BACKGROUND: Leadless pacemakers (LPs) can mitigate conventional pacemaker complications related to the transvenous leads and subcutaneous pocket surrounding the pulse generator. Although single-chamber leadless pacing has been established, multichamber pacing requires wireless bidirectional communication across multiple LPs to maintain synchrony. This preclinical study demonstrates the chronic performance of implant-to-implant (i2i) communication that achieves synchronous, dual-chamber pacing with 2 LPs. METHODS: The i2i communication modality employs subthreshold electrical signals conducted between implanted LPs through the blood and myocardial tissue on a beat-by-beat basis. Right atrial and right ventricular LPs were implanted in 9 ovine subjects. The i2i transmission performance was evaluated 13 weeks after implant. RESULTS: Right atrial and right ventricular LPs were implanted successfully and without complication in 9 ovine subjects. A total of 8715±457 right atrial-to-right ventricular and right ventricular-to-right atrial transmissions were sent per hour, with a success rate of 99.2±0.9%. Of periods with i2i communication failure when DDD pacing was not possible, 97.3±1.8% were resolved within 6 s. CONCLUSIONS: For the first time, synchronized, dual-chamber pacing has been demonstrated in a chronic preclinical feasibility study by 2 leadless pacemakers using beat-to-beat, wireless communication, achieving a success rate of 99.2%.
BACKGROUND: Complications associated with transvenous pacemakers, specifically those involving the lead or subcutaneous pocket, may be avoided with leadless pacemakers (LPs). The safety and efficacy of single-chamber right ventricular LPs have been demonstrated, but their right atrium (RA) use poses new design constraints. OBJECTIVES: The purpose of this study was to evaluate the implant success, electrical performance, and safety of a novel RA LP design in benchtop and preclinical studies. METHODS: A new LP was designed with a dual-helix fixation mechanism specific to the RA anatomy. A 12-week preclinical ovine study was conducted to evaluate implant success, electrical performance, mechanical stability, and safety in vivo, with supporting benchtop measurements to quantify the mechanical forces needed for device retrieval and dislodgment. RESULTS: LPs were successfully implanted in all 10 ovine subjects with no complications. The pacing capture threshold improved significantly over time from implant to week 12 (1.1 ± 0.7 V vs 0.4 ± 0.2 V, P = .008). Sensing amplitudes and pacing impedances were stable from implant to week 12 (4.8 ± 1.8 mV vs 6.0 ± 1.9 mV, P = .160; and 393 ± 77 Ω vs 398 ± 65 Ω, P = .922, respectively). Gross pathology and microscopic histology revealed no adverse interactions and no evidence of device dislodgment or clinically significant myocardial perforation. Benchtop ex vivo porcine atrial tissue measurements revealed greater pull forces required to dislodge the LP vs transvenous active fixation lead (0.42 ± 0.18 lbf vs 0.29 ± 0.08 lbf, P = .020), and greater rotational forces required for deliberate extraction (0.28 ± 0.04 lbf vs 0.14 ± 0.07 lbf, P <.001). CONCLUSION: The novel atrial LP demonstrated successful implantation, with acceptable electrical performance, mechanical stability, and safety in a 12-week preclinical study.
- MeSH
- design vybavení MeSH
- kardiostimulace umělá MeSH
- kardiostimulátor * MeSH
- lidé MeSH
- lipopolysacharidy * MeSH
- ovce MeSH
- prasata MeSH
- protézy a implantáty MeSH
- srdeční síně MeSH
- výsledek terapie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
