Validation of leadless atrioventricular synchronous pacing with Holter-ECG: a pilot study

Abstract

Abstract Background The novel MICRA AV leadless pacemaker can provide atrioventricular (AV) synchronous pacing using an accelerometer-based atrial sensing algorithm. Purpose To describe the performance of MICRA AV pacemaker in a real-life setting and to determine the agreement between AV synchrony determined by the device counters and AV synchrony obtained by a 24 h ECG Holter test. Methods This pilot study included the first ten patients implanted with a MICRA AV leadless pacemaker at our institution. All implants were performed according to standard protocols and under deep sedation. A close follow-up was performed, and atrial sensing parameters were adjusted following AV synchrony given by the device counters. Patients underwent a 24 h ECG Holter test once AV synchrony remained stable for at least two months. The ECG Holter signal was analyzed in a blinded manner by an automatic delineation system based on the wavelet transform (Figure). This algorithm has a sensivity of 98.9% and a positive predictive value of 91.9% to detect p waves. Cardiac cycles were defined as synchronous if a QRS complex followed the P-wave by ≤300 ms, according to MARVEL 2 study criterion. AV synchrony obtained from the 24 h Holter test was compared with AV synchrony extracted from the device counters (AM-VP + AM-VS) during the same 24 h. Results From June to November 2020, 10 patients (7 males, mean age 83.5±5.4) were implanted with a MICRA AV leadless pacemaker (5 patients due to complete AV block and 5 patients due to second degree AV block). All devices were implanted after 1 deployment and no major complications appeared. Data related to implant parameters are displayed in Table 1. Device reprogramming was needed in all patients during follow-up. The 24 h ECG Holter monitoring was performed 141.4±45 days after the implant (mean time). Device settings and programming at Holter date is displayed in Table 1. Total ECG recorded time was 210.6 h and 915,488 cardiac cycles were analyzed. The mean percentage of synchronous cardiac cycles was 88.6±8.5% of total cycles while the mean AV synchrony determined by the device counters (AM-VP + AM-VS) during those 24 h was 89.8±5.5%. A good patient to patient correlation between these two measures was found (coefficient of intraclass correlation = 0.72). Conclusions We obtained high rates of AV synchrony with MICRA AV leadless pacemaker, in our short-term follow-up pilot study. Manual adjustment of the atrial sensing parameters, guided by the device counters, seems to be useful to obtain an optimal performance. Funding Acknowledgement Type of funding sources: None.