ICG which simply and non invasively
ICG, which simply and non-invasively measures changes in thoracic impedance generated by fluctuating blood volumes during the cardiac cycle, allows for the calculation of stroke volume, CO, and other derived parameters. In recent years, the accuracy of ICG has been greatly improved by the advent of real-time beat-to-beat blood pressure monitoring, obtaining results equivalent to those of conventional invasive methods [17–19].
Conflict of interest
Introduction Cardiac arrhythmia is a serious Tedizolid HCl condition causing morbidity and mortality. Twelve-lead electrocardiography (ECG) remains the gold standard for the diagnosis of arrhythmias. However, intermittent arrhythmia may not be detected using standard ECG. Twenty-four-hour to 7-day Holter monitoring increases the chance of arrhythmia diagnosis , and implantable loop recorders are especially suitable for identifying undetected sources of a suspected cardiac syncope or arrhythmia when cardiac events are infrequent [2,3]. However, limitations exist, delaying both the diagnosis of arrhythmia and treatment decisions. ER-2000® (Boryung Soo & Soo Ltd., Seoul, Republic of Korea) is a portable wireless ECG monitor that provides a real-time rhythm strip by two different methods. We performed this study to evaluate the feasibility and accuracy of ER-2000® in the remote detection of arrhythmia by comparing it to the current gold standard, 12-lead ECG. We hypothesized that the arrhythmia detection rate using ER-2000® is comparable to that of a 12-lead ECG.
Materials and methods
Results Twelve-lead ECG revealed normal sinus rhythm in three patients, sinus tachycardia in one, atrial fibrillation (AF) in two, atrial tachycardia (AT) in one, first degree atrioventricular block in one, pacing rhythm in two who underwent permanent pacemaker implantation, AF with intermittent ventricular pacing in one, complete right bundle branch block (RBBB) in one, J-wave elevation in one, narrow QRS tachycardia in one, atrial premature beat (APB) in one, ventricular premature beat (VPB) in one and narrow QRS tachycardia with intermittent aberrant conduction in one. Significant findings comparing the data obtained by ER-2000® and 12-lead ECG are summarized in Table 1. The accuracy of rhythm diagnosis obtained by the two different modes of ER-2000® was accurate compared to that obtained by the 12-lead ECG in all patients, except in patient 3 in whom ER-2000® showed one APB while 12-lead ECG showed sinus rhythm (Fig. 2). P-wave was clearly identified by using ER-2000® and the morphology was similar with that in the 12-lead ECG in most cases. Even fibrillatory wave was well matched in patients with AF (Fig. 3). AT can also be diagnosed correctly by inverted P-wave morphology obtained by using ER-2000®. The P-wave was inverted in II, III, and aVF, and positive in aVR and aVL in patient 7 who showed atrial tachycardia on 12-lead ECG. The P-wave was also clear and inverted in mode 1 of ER-2000®. Unfortunately, AT was terminated during recording by mode 2 of ER-2000® (Fig. 4). However, P-wave was unclear in mode 1 and mode 2 of ER-2000® while first degree AV block was shown in patient 8 on 12-lead ECG (see online Supplementary Fig. S1). Therefore, the diagnosis of a first degree AV block might be missed on ER-2000®. Lead II (35.3%) followed by lead V4 (23.5%) among 12 leads showed the most similar QRS pattern with the rhythm strip obtained using mode 1 of ER-2000®. QRS morphology was usually similar; however, amplitude of R- or S-waves was different in four patients. Paced QRS duration was similar and notching was present in both methods; however, QRS polarity was different. Mode I of ER-2000® revealed rSR′, qR, and QR patterns in patients with ventricular pacing rhythm (patients 9, 10, and 11, respectively), while 12-lead ECG revealed QS patterns in all patients. In addition, pacing spike was not visible on ER-2000®. A representative example of ventricular pacing rhythm is shown in Fig. 5. This patient (patient 9) underwent implantation of VVI mode pacemaker and 12-lead ECG showed ventricular pacing rhythm with dissociated P-wave. In patients with RBBB (patient 12), the rhythm strip obtained using mode 1 of ER-2000® revealed similar QRS widening; however, the rhythm strip obtained by mode 2 of ER-2000® did not show definite QRS widening. The morphology was Rs in mode 1 of ER-2000® but Rsr′ pattern in lead V2 despite similar QRS widening (see online Supplementary Fig. S2). J-wave elevation was obviously observed in mode 1 of ER-2000®; however, the J-wave was much smaller than that of lead III (1.5mV vs. 4.5mV). J point elevation was significant in lead III (4.5mV), but not observed on using ER-2000®. The rhythm strip obtained by using mode 2 of ER-2000® showed incomplete RBBB with coved-type ST elevation such as the Brugada pattern (Fig. 6). The R-R interval was accurate in patients with narrow QRS tachycardia with a heart rate of 120 beats per minute and QRS alternans is obvious in data obtained by both methods (Fig. 7). Coupling interval of VPB obtained using both methods was the same and VPB was differentiated from sinus rhythm by wide QRS morphology (Fig. 8).