Recent research suggests that atrial high frequency episodes (AHRE) detected by devices are associated with more than twice the risk of cardiovascular and overall mortality, even in patients without prior atrial fibrillation (AF), atrial flutter (AFL), or atrial tachycardia (AT).
Cardiac implantable electronic devices (CIEDs) with continuous rhythm monitoring, including implantable cardioverterdefibrillators (ICDs) and cardiac resynchronization therapy-defibrillators (CRT-Ds), enable the detection of often asymptomatic, short episodes of AT/AF, referred to as AHRE or subclinical atrial fibrillation.
„Previous studies have confirmed that patients with AHRE have a higher risk of clinical atrial fibrillation, heart failure, and thromboembolism,“ said study author Shu Zhang, MD, PhD, from the State Key Laboratory of Cardiocular Disease, Arrhythmia Center, National Center for Cardiovascular Diseases, Fuwai Hospital, Chinese Academy of Medical Sciences, and Peking Union Medical College in Beijing, shared with Medscape. „These findings could potentially lead to a poor long-term prognosis.“
In fact, a retrospective analysis of patients with CIEDs found that patients with AHRE had a significantly higher risk of cardiovascular disease (hazard ratio [HR] 2.40) and overall mortality (HR, 2.31) after adjustment.
The study was published online on December 11 in the Canadian Journal of Cardiology.
Consider Additional Screening
Researchers analyzed archived data from the Patient Registry „Safety and Efficacy of Biotronik Home Monitoring System in Cardiac Implantable Electronic Device“ for patients with ICD or CRT-D implantation and no history of atrial fibrillation, AFL, or AT.
The primary endpoint of the study was cardiovascular mortality, and the secondary endpoint was overall mortality.
During an average follow-up period of 4.2 years, there were 87 (25.4%) deaths, of which 61 (70.1%) were due to a cardiovascular cause. Of these deaths, 44 (35.5%) were among 124 patients with AHRE, a significantly higher proportion than those without AHRE (43 patients, 19.6%).
Furthermore, a multivariate analysis showed that patients with AHRE had a significantly higher risk of cardiovascular (HR: 2.40) and overall mortality (HR: 2.31) after adjustment for relevant variables.
Patients with AHRE were grouped based on the longest AHRE duration, and it was found that those with medium and high burden AHRE had a higher risk of cardiovascular and overall mortality compared to those with low burden AHRE.
Based on the increased risks associated with AHRE, the researchers recommended considering anticoagulation and additional ECG or Holter screening based on the patient’s AHRE burden and stroke risk factors.
Unknown Confounders, Variables
Commenting on the study for Medscape Medical News, José Joglar, MD, Professor of Cardiac Electrophysiology at UT Southwestern Medical Center in Dallas, noted that prolonged AHREs are considered precursors of atrial fibrillation, supporting the study’s findings.
However, he cautioned that the study had certain limitations, as an observational study, there were many unknown confounders and variables that were not considered.
In conclusion, he emphasized the need for more detailed data to understand the underlying conditions or risk factors that trigger prolonged AHREs and ensure proper investigation and treatment for patients.
For now, physicians should be aware that persistent AHREs are precursors of atrial fibrillation, and patients should be examined, monitored, and treated for underlying conditions,“ Joglar concluded.
This study was supported by the Beijing Municipal Science and Technology Commission. Zhang and Joglar declare no competing interests.