Characterization of atrial flutter. Studies in man after open heart surgery using fixed atrial electrodes.

Abstract

SUMMARY Studies were performed using bipolar atrial wire electrodes to record atrial electrograms and to pace the atria in 27 patients who developed atrial flutter after open heart surgery. Two types of atrial flutter, classic or type I atrial flutter, and type II atrial flutter, were identified. Both types of atrial flutter were characterized by uniformity of the beat-to-beat atrial cycle length, morphology, polarity, and amplitude of the recorded bipolar atrial electrogram. Both types sometimes manifested a beat-to-beat electrical alternans, which in turn was sometimes associated with an alternans in beat-to-beat cycle length. ATRIAL FLUTTER is a supraventricular arrhythmia which has long been recognized in man,' although its underlying mechanism has not been explained. Based on the ECG, it has been characterized as a regular, rapid atrial rhythm, most often with an atrial rate close to 300 beats/min, with the upper and lower limits of its range uncertain and variously stated.2-8 At our institution, at the time of open heart surgery, bipolar wire electrodes are routinely placed on the right atrial epicardium for possible diagnostic or therapeutic use in the immediate postoperative period.9-12 Since many patients develop atrial flutter spontaneously during this latter period, this was an opportunity to use these electrodes to characterize and define this rhythm better while providing patient care. Methods Twenty-seven patients who developed atrial flutter in the immediate period after open heart surgery were studied. The atrial flutter was identified initially from a standard or monitored ECG, or from bipolar atrial electrograms recorded from a pair of atrial wire electrodes placed routinely 0.5-1.0 cm apart on the epicardial surface of the superior portion of the right atrium.9 12 The atrial electrograms were used to distinguish atrial flutter from atrial fibrillation when this differentiation was not clear from the ECG recording alone.'2 After identifying atrial flutter, bipolar atrial electrograms were recorded simultaneously with ECG leads II and IIII for as long as 15 minutes with an Electronics for Medicine Model DR-12 switched beam oscilloscopic recorder. In one patient, the recordings were made using a Medical Systems Corporation Model DU-35 three-channel ECG machine and in two patients using a Hewlett-Packard Model 1151B ECG machine. Then, the atria were paced rapidly at rates up to 600 beats/min in an attempt to interrupt the atrial flutter.10 11 All data were recorded on magnetic FM tape (Honeywell Model 5600) for later playback and analysis, except in three patients. In the 24 patients in whom recordings were made using the Electronics for Medicine DR-12 machine, allECGs and atrial electrograms were recorded between a bandpass of 0

A Mathematical Model of Human Atrioventricular Nodal Function Incorporating Concealed Conduction

“…4) (Task Force, 1993). The atrial rhythm during atrial flutter is not constant, but subject to small beat-tobeat cycle length variations possibly owing to the effects of ventricular contraction (Wells et al, 1979;Waxman et al, 1991;Pavri et al, 1999). A priori, it is not clear which atrial activations are conducted to the ventricles during the atrial flutter.…”

Diagnostic challenge of artifactual electrocardiographic tachyarrhythmias

“…Terms like uncommon or atypical flutter to describe forms of type II have been abandoned. Yet, the original classification of AFl into type I and II remains commonly used clinically [4]. Thus, the diagnosis of type II AFl in our case by general cardiologists is not surprising and likely to continue.…”

“…Regarding the terminology of AFl, the new classification of AFl based on mechanisms does not include terms such as type I and type II flutter because the mechanism of type II flutter is not fully understood [4][5][6]. Terms like uncommon or atypical flutter to describe forms of type II have been abandoned.…”

Atrial Flutter, Typical and Atypical: A Review

“…74 Pacing runs of 20-30 s are started at a rate 10 bpm higher than flutter, increasing in 10 bpm steps up to 400 bpm or until flutter is interrupted and sinus (or paced) atrial rhythm is established (see Figure 6). Pacing may induce AF or a faster flutter (type II flutter), 75 probably as an expression of functional re-entry 76 that tends to return to baseline flutter or change to AF. AF induced by pacing usually results in a lower ventricular rate and, not infrequently, terminates spontaneously into sinus rhythm.…”