Dual-Chamber Leadless Pacemaker

Lead of a pacemaker is often called as its Achilles Heel as most of the problems in a pacing system occur with the leads. Hence the quest for leadless pacemakers which are implanted within the heart through a delivery system. Single chamber leadless pacemakers have been around for quite some time. A new dual-chamber leadless pacing system has been tested successfully recently. It consists of two separate atrial and ventricular devices which communicate to maintain synchronous atrioventricular pacing and sensing. The first in-human evaluation of the new dual-chamber leadless pacemaker system showed reliable electrical performance through out the initial 6 month evaluation period [1].

The study had 381 patients in which dual-chamber leadless pacemaker systems were implanted successfully. Sinus node dysfunction in 65% and atrioventricular block in 30% were among the indications for pacing. Atrial device was implanted predominantly in the right atrial appendage anterior base. Ventricular devices were implanted predominantly in the mid-to-apical right ventricular septum. Pacing capture thresholds improved in both devices in the initial month. Sensed amplitudes also improved similarly. Stable impedances were noted for the atrial devices while it was reduced in ventricular devices. Electrical measurements remained fairly stable between 1-6 months post implant. Atrial pacing was delivered in 45.8% of the beats in those with sinus node dysfunction. It was also delivered in 18.7% of beats in those without sinus node dysfunction.

An earlier paper in NEJM had reported three month results of dual-chamber leadless pacemaker system [2]. Of the 300 patients in that report, 190 had sinus node dysfunction and 100 had atrioventricular block. Device was successfully implanted in 295 patients. There were a total of 35 device or procedure related serious adverse events in 29 patients. Evaluation period was three months and at least 70% atrioventricular synchrony was achieved in 97.3% of the patients.

References

1. Hindricks G, Doshi R, Defaye P, Exner DV, Reddy VY, Knops RE, Canby R, Shoda M, Bongiorni MG, Neužil P, Callahan T, Sundaram S, Badie N, Ip JE. Six-month Electrical Performance of the First Dual-Chamber Leadless Pacemaker. Heart Rhythm. 2024 Apr 30:S1547-5271(24)02525-6. doi: 10.1016/j.hrthm.2024.04.091. Epub ahead of print. PMID: 38697271.
2. Knops RE, Reddy VY, Ip JE, Doshi R, Exner DV, Defaye P, Canby R, Bongiorni MG, Shoda M, Hindricks G, Neužil P, Rashtian M, Breeman KTN, Nevo JR, Ganz L, Hubbard C, Cantillon DJ; Aveir DR i2i Study Investigators. A Dual-Chamber Leadless Pacemaker. N Engl J Med. 2023 Jun 22;388(25):2360-2370. doi: 10.1056/NEJMoa2300080. Epub 2023 May 20. PMID: 37212442.