Contributions of High Resolution Electrograms Memorized by DDDR Pacemakers in the Interpretation of Arrhythmic Events

Abstract

The accuracy of information retrievable from the memories of DDDR pacing systems has been limited by the absence of actual electrograms confirming the proper sensing of spontaneous cardiac activity versus that of extraneous signals. This study examined the diagnostic power of a new arrhythmia interpretation scheme, which includes the recording and storage of high resolution endocavitary atrial and ventricular electrograms (HREGM). HREGM stored in the memories of new generation pacemakers (PM) in response to nonsustained ventricular tachycardia (NSVT), sustained VT, and atrial arrhythmias were analyzed in a follow-up registry of 520 patients at 1 month, and 3 to 6 months after implantation of a PM for standard indications. For each sequence of stored HREGM, the accuracy of the PM response was examined, classified as accurate (true positive), versus inaccurate (false positive), versus undetermined, and the relative contribution of the HREGM in verifying the PM diagnosis was measured. During a follow-up of 4.9 +/- 2 months, 256 (49%) of the 520 patients had an event recorded, which was confirmed to be arrhythmic on the basis of HREGM. Overall, approximately 34% of atrialtachy response (ATR) episodes were confirmed to be appropriate. Similar percentages of episodes were prompted by oversensing of signals unrelated to cardiac arrhythmias, while nearly 12% of the episodes could not be clarified because of such brief duration as to preclude recording of their onset. Approximately one-third of NSVT, and one-half of VT detections were false positive. Ventricular oversensing, most often due to myopotential interference in presence of unipolar sensing, and atrial undersensing were both identified as sources of false-positive detections of ventricular events. The proportion of true-positive detections was significantly higher in the bipolar (83%) than unipolar configuration. Among 520 PM recipients, miscellaneous episodes of atrial arrhythmias were confirmed by HREGM in 37% of patients within 3 to 6 months of follow-up. Atrial fibrillation was confirmed in only 6% of patients, of whom over 50% already had histories of atrial fibrillation. The prevalence of unsuspected atrial arrhythmia in this unselected population was lower than previously reported.

Accuracy of Atrial Tachyarrhythmia Detection in Implantable Devices with Arrhythmia Therapies

“…Israel et al confirmed AT in 35% (83 of 235) of stored mode switch episodes in 46 patients (Pulsar VDD, Guidant) 12 . Defaye et al reported appropriate detection of atrial arrhythmias in 34% of 206 stored episodes from 70 of 520 patients using a variety of devices (Guidant Discovery 1274, Pulsar 972, Pulsar Max 1270) 13 . Bordacher et al 14 reported inappropriate mode switch detection due to FFRW oversensing in 20% of 3,511 mode‐switch episodes from 137 patients (Talent DR213 PM, ELA Medical, Montrouge, France).…”

Accuracy of the pacemaker event recorder versus Holter‐ECG to detect both symptomatic and asymptomatic ventricular arrhythmias

“…Current implantable pacemakers offer to the patients a better quality of life due to the existence of mathematical algorithms that aim to mimic the physiological behavior of the heart by individualized programming . They also provide the possibility of monitoring the patient’s cardiac rhythm through the intracavitary register of electrograms.…”

“…[1][2][3] The 24 hour Holter is aim to mimic the physiological behavior of the heart by individualized programming. [6][7][8][9] They also provide the possibility of monitoring the patient's cardiac rhythm through the intracavitary register of electrograms. Some authors call them as "intelligent pacemakers," because of their more precise information storage, such as electrocardiographic telemetry and event markers and counters.…”

Incidence of Atrial Tachyarrhythmias in Pacemaker Patients: Results from the Balanced Evaluation of Atrial Tachyarrhythmias in Stimulated Patients (BEATS) Study

“…However, data on the proportion of patients who develop ATs during therapy with a dual chamber pacemaker show a striking discrepancy. While studies, which assessed the AT incidence on the basis of ECG recordings at scheduled or unscheduled follow‐up visits, report an annual incidence of 0.4–14%, 1,3,4 studies assessing the same endpoint based on pacemaker memory data report an incidence of 23–69% 5–9 . This may be due to the low sensitivity of serial ECG recordings, or due to the low specificity of pacemaker memory data which may count atrial sensing errors as AT.…”

“…While studies, which assessed the AT incidence on the basis of ECG recordings at scheduled or unscheduled follow-up visits, report an annual incidence of 0.4-14%, 1,3,4 studies assessing the same endpoint based on pacemaker memory data report an incidence of 23-69%. [5][6][7][8][9] This may be due to the low sensitivity of serial ECG recordings, or due to the low specificity of pacemaker memory data which may count atrial sensing errors as AT. Therefore, the precise incidence of ATs in patients with dual-chamber pacemakers remains to be determined and poses a therapeutic dilemma; for instance, regarding the need of anticoagulation therapy.…”