From the Guidelines
Atrial noise reversion episodes on Abbott pacemakers are a protective mechanism that prevents inappropriate tracking of non-cardiac signals, which could lead to rapid ventricular pacing and potentially life-threatening complications, such as stroke or systemic embolism, as seen in patients with atrial high-rate episodes 1.
The primary goal of this mechanism is to maintain appropriate heart rates and protect the patient from harmful rapid pacing. When the pacemaker detects rapid, non-physiologic signals on the atrial lead, it initiates this safety mechanism to switch from an atrial tracking mode to a non-tracking mode.
- The pacemaker will automatically return to its programmed mode once the noise or interference subsides.
- These episodes are recorded in the device's diagnostics and can be reviewed during routine device checks.
- Frequent atrial noise reversion episodes may indicate lead issues, such as insulation breaks, conductor fractures, or electromagnetic interference from external sources, which can increase the risk of stroke or systemic embolism, as seen in the ASSERT trial, where atrial high-rate episodes were associated with a >5-fold increase in subsequent diagnosis of atrial arrhythmia on ECG and a 1.60% per year rate of stroke or systemic embolism 1.
Key characteristics of atrial high-rate episodes, such as those detected by implanted devices, are still being studied to further clarify the relationship between stroke risk and these episodes 1. However, it is essential to evaluate the atrial lead integrity and consider lead replacement if necessary, especially if a patient experiences symptoms during these episodes or if they occur frequently. Understanding these episodes is crucial for proper pacemaker management and patient safety, as it can help prevent morbidity, mortality, and reduce the risk of stroke or systemic embolism.
From the Research
Atrial Noise Reversion Episodes on Abbott Pacemakers
- Atrial noise reversion episodes on Abbott pacemakers refer to a phenomenon where the pacemaker switches to asynchronous pacing mode due to rapid cardiac activity or other electrical abnormalities 2, 3.
- This can occur in patients with atrial fibrillation, where the pacemaker's ventricular refractory period is shorter than the patient's ventricular cycle length, triggering noise reversion 2.
- Studies have shown that Abbott pacemakers are associated with a higher risk of lead abnormalities, including lead noise with normal impedance, which can contribute to atrial noise reversion episodes 3.
- Paradoxical atrial undersensing is another phenomenon that can occur in dual-chamber pacemakers, where high atrial sensing levels can lead to false atrial noise reversion and loss of mode switch behavior 4, 5.
- Noise reversion can be diagnosed by telemetering the pacemaker marker channel during ventricular arrhythmias and can be prevented or minimized by programming short ventricular refractory periods or using pacemakers with short retriggerable refractory periods 6.
- The incidence of paradoxical atrial undersensing is approximately 13% when using very high atrial sensing levels, and decreasing the atrial sensing level can resolve the issue in most cases 4.