|
Accuracy of an automatic and patient-triggered long-term solid memory ambulatory cardiac event recorder
Frédéric
Roche, Jean-Michel Gaspoz, Vincent Pichot, Frédéric Costes, Karl Isaaz,
Chantal Ferron, Christian Roche, André Geyssant, Jean-René Lacour et Jean-Claude Barthélémy
Université Jean Monnet, Saint Etienne, France.
The American Journal of Cardiology, 1997, 80:1095-1098
Rare cardiac arrhythmic events have been recognized as independant predictors of severe casualties (1) and, more importantly, of sudden cardiac death (2), in the context of syncope, which accounts for 3.5% of emergency room visits (3) (4). The diagnosis of these cardiac events has been enhanced by event recorders (5) (10). They allow longer monitoring than standard Holter systems, but have mainly been limited up to now by the fact that all recordings had to be patient-triggered. This standard patient-triggered recording mode has been shown to document 70% of symptoms, particularly syncope, but only 52% of serious arrhythmias (5) (7) (10).
Clinical evaluation of the R.TEST Evolution was carried out on a first group of 103 patients recovering from a recent myocardial infarction, as well as in a second group including 35 symptomatic patients with palpitations, dizziness, syncope, or recent stroke attacks, and, finally, in a third group of 12 patients evaluated during a reference exercise test to detect myocardial ischemia.
Figure 1.
Heart rate trend of a patient having two brief episodes of atrial fibrillation revealed,
at the same time, an abrupt thickening of the shadowed part of the trend line
which represents the successive individual RR lengths, and an abrupt increase
of the thin black line superimposed over the shadowed part,
which represents the mean heart rate.
Comparison with standard 24-hour Holter recordings
Pauses and episodes of bradycardia runs were all detected by the R.TEST Evolution with, however, some overdetection. For "grouped" events at the supraventricular level, the sensitivity was 70%, but all patients having permanent or paroxysmal atrial fibrillation were recognized (Figure 1). For "grouped" events at the ventricular level (Figure 2), the sensitivity of the R.TEST Evolution was 86%; one patient with episodes of ventricular tachycardia was not detected, due to the limitation inherent to a one-lead system. However, a visual pre-test control could give the physician the opportunity to chose an appropriate lead placement. However, a lower specificity was observed mainly for isolated supraventricular or ventricular events.
Figure 2.
ECG tracings of a non sustained VT recorded by the R.TEST Evolution (upper panel)
and the reference Holter system (lower panel). The slight difference in morphology
is explained by lead position.
Symptomatic patients
In patients with palpitations or other symptoms, cardiac event recorders have recently been shown to be more efficient and more cost effective in their diagnosing capabilities than 48-hour Holter recorders (9). In this study, long-term recording with the automatic mode revealed significant events in 6 out of the 35 patients with a variety of symptoms, who represented 17.1% of the cohort: 2 patients required permanent pacemaker implantation, 2 others an antiarrhythmic treatment adaptation for life-threatening arrhythmias and in the last 2, the origin of a recent stroke was revealed as previously undisclosed episodes of paroxysmal atrial fibrillation. No patient-triggered recordings gave any further information.
Myocardial ischemic ST Segment changes
Compared to that of a control stress test system during simultaneous recordings, there was a correct identification of patients presenting with a significant down-sloping of the ST segment depression during exercise.
Comparison with others event-recorders
When compared with other event-recorders, the R.TEST Evolution offers several technical differences. The most important is added automatic arrhythmia detection which is a striking "progres" as this feature should help to detect more arrhythmic events as those which are symptomatic or "come" during the night, and more particularly in the 20% of patients who are inconsistent in their use of patient-triggered recordings, especially the elderly (5). In addition, the seven-day autonomy of the R.TEST Evolution could help recognize an ætiology still undisclosed after electrophysiologic studies, or tilt-table testing (7) (11). Transtelephonic capabilities are included, which have been shown to allow documentation of arrhythmias in 66% of symptomatic patients within one week, and in 95% of patients within five weeks (6).
In conclusion
This 45-gram one-lead patient-triggered and automatic event-recorder with a 20-minute solid state memory allows monitoring of arrhythmic events of major clinical relevance, particularly in patients at risk of severe arrhythmic events inconsistent in their use of patient-triggered recordings. Furthermore, the patient-triggered mode allows to explain rare events such as syncope, feelings of weakness or faintness, palpitations, and stroke. In both automatic and patient-triggred modes, which can run simultaneously, the long-term autonomy of the R.TEST Evolution represents a "definite" clinical advantage, especially when investigating patients with rare events.
(1).
Rehm CG, et al. Am Surg 1995;61:1006-1008
(2). Kapoor WN. Medicine (Baltimore) 1990;69:160-175
(3). Hori S. Keio J Med 1994;43:185-191
(4). Kapoor WN. JAMA 1992;268:2553-2560
(5). Linzer M, et al. Am J Cardiol 1990;66:214-219
(6). Reiffel JA, et al. J Electrocardiol 1991;24:165-168
(7). Linzer M, et al. Am Heart J 1988;116:1632-1634
(8). Brown AP, et al. Br Heart J 1987;58:251-253
(9). Kinlay S, et al. Ann Intern Med 1996;124:16-20
(10). Zimetbaum P, et al. Am J Cardiol 1997;79:371-372
(11). Prystowsky EN, et al. Mod Conc Cardiovasc Dis 1991;60:49-53
TOP OF PAGE
|
