T wave was similar in
T-wave was similar in seven patients. The terminal portion of the T-wave was negatively inverted compared with that at baseline in five patients on using ER-2000®. Representative example of sinus rhythm with T-wave discordance is shown in online Supplementary Fig. S3. T-wave morphology was different after wide QRS complex, which resulted from pacing or bundle branch block or aberrant conduction, because the polarity of wide QRS complex was usually different (see online Supplementary Fig. S4).
Discussion This study demonstrates that the accuracy of remote arrhythmia detection by ER-2000® is comparable to that of the standard 12-lead ECG. Lead II followed by lead V4 of the 12 leads are most comparable to the rhythm strip obtained by mode 1 of ER-2000®. However, the pacing blip was not well visualized. The exact QRS amplitude and T-wave morphology are modified especially after wide QRS complex compared to those of 12-lead ECG. ER-2000® has significant potential advantages over the conventional methods of detecting arrhythmia. Conventional methods include 12-lead ECG, Holter ECG, and other event monitoring systems. With ER-2000®, patients can carry the device with them and record rhythm strip conveniently and quickly whenever they Cyclosporin D experience symptoms related to cardiac arrhythmia. As such, the system has strong potential to increase the probability of detecting arrhythmias and help with disease management. Twenty-four-hour Holter monitoring has increasingly been utilized as a routine investigation for occult paroxysmal AF in patients with stroke and transient ischemic attack. However, its clinical utility remains controversial because the reported yield of 24-h Holter monitoring for detection of paroxysmal AF varies widely with ranges from 1% to 12% [1,4,5]. Therefore, outpatient cardiac telemetry with monitoring >21 days significantly increased the detection rate in a previous study . ER-2000® can record real-time continuous ECG data for up to 2500h. A long-term remote ECG monitoring offered by ER-2000® allows clarification of symptoms suggestive for arrhythmia, including occult paroxysmal AF, increasing the detection rate. Remote AF detection by a previously reported event recorder is predominantly accomplished by R-R interval analysis, because atrial signal recognition with conventional monitoring devices is difficult. As a result, some patients with organized AF or atrial flutter might be misdiagnosed. CardioBlip is a recently developed device using a portable wireless event recorder and provides signal reconstruction of a 12-lead waveform using 5 leads. Its potential for accurate assessment of atrial activity was demonstrated . Furthermore, ER-2000® clearly visualized similar atrial activity during AF rhythm compared to 12-lead ECG, and P-wave was clearly shown even during AT or APBs. Additionally, there was good concordance with respect to ventricular activity, suggesting that ER-2000® is also useful in detecting ventricular arrhythmia. ER-2000® can record a cardiac rhythm strip more simply, and can even record without connecting electrodes. Although the ER-2000® provides only one rhythm strip, the detection rate of a rhythm status was excellent. Although QRS and T-wave morphologies were slightly different, Discontinuous replication did not affect the diagnosis of arrhythmia. The primary limitation of ER-2000® is that there is only one lead presentation. Therefore, we could not perform a lead-by-lead analysis, and only the most similar lead was selected for comparison. QRS voltages were somewhat higher in V2-4 leads than in mode 1 of ER-2000®. Some discrepancy in QRS vector and amplitude might result from the simple method of connecting only three electrodes at the anterior chest, and the difference in electrode position. However, there was good overall concordance in QRS morphology, QRS directionality, and QRS duration. Pacing spike was not well visualized; however, we detected a pacing rhythm with similar wide QRS morphology. Major representative arrhythmias, including AF, AT, APBs, VPBs, and pacing rhythm that can cause palpitation, were well represented in both modes of ER-2000®. Most of all, we acquired 12-lead ECG and ER-2000® data simultaneously, allowing a direct comparison of the rhythm status. This pilot study demonstrates the accuracy and feasibility of ER-2000® in detecting arrhythmias. Limitations of the study include small sample size; however, we validated at least one case among each kind of major arrhythmias. Finally, while each mode of ER-2000® was recorded with 12-lead ECG simultaneously, modes 1 and 2 of ER-2000® had to, by definition, be taken separately.