Evidence of a reentry circuit in the common type of atrial flutter in man.

Abstract

SUMMARY To investigate the mechanism of atrial flutter (AF) in humans, we studied 13 patients during episodes of spontaneous common AF, with simultaneous multiple atrial endocavitary recordings and atrial programmed stimulation. In all patients, low paraseptal atrial activation preceded high right atrial activation, and the latter preceded mid-or low lateral right atrial activation (recorded in five patients). Programmed atrial stimulation resulted in early reset of the AF cycle, with an unchanged poststimulation AF activation pattern. The poststimulation cycle recorded from an even potential to the site of stimulation was always shorter than the basic flutter cycle length. The poststimulation cycle recorded at the site of stimulation was always equal to or longer than the flutter cycle length.These results strongly favor the existence of a reentry circuit to which the extrastimulus has access. We recently documented induction and termination of episodes of common AF in man by programmed atrial stimulation.'6 17 Although this strongly favors reentry, it is not a definitive demonstration of it, because a triggered activity cannot be excluded.'8 We studied the effects of programmed atrial stimulation on the basic AF cycle in man, and observed that the poststimulation cycle, recorded at the stimulation point, was equal to the basic AF cycle in some cases.'6 17In this paper we report the results of studies using simultaneous multiple atrial endocavitary recordings and atrial programmed stimulation. Materials and MethodsThe study population consisted of 13 patients, 11 males and two females, ages 32-72 years (mean 54.3 years).The underlying heart disease was coronary atherosclerotic heart disease in five patients, idiopathic cardiomyopathy in five and mitral valvular disease in two. One patient had no clinical evidence of heart disease except for the arrhythmia ( After diazepam, 10 mg i.m., at least two quadripolar catheters (1 cm between electrodes) were inserted for atrial endocavitary recordings and stimulation. Initially, all patients had one catheter positioned in the low paraseptal atrium (low right septal wall in eight and proximal coronary sinus in five) and another in the high right atrium (lateral wall in 10 and septal wall in three). These two sites were named points 1 and 2, respectively. The different catheter positions were chosen so as to attain a firm position with good atrial potentials and atrial capture during stimulation.Programmed atrial stimulation was first performed at point 2, with a coupling interval progressively decreased by 10 msec until the atrial refractory period was attained. If the interruption or transformation of the arrhythmia was unsuccessful, the coupling interval of this extrastimulus was fixed at a slightly higher value than that of the effective atrial refractory period; a second extrastimulus was then given at progressively decreasing coupling intervals. In case offailure, a third extrastimulus was given in the same way.In five cases, the same pattern of stimulation was repe...

Ablação do flutter atrial típico: estudo prospectivo e randomizado do cateter irrigado fechado versus cateter com eletrodo distal de 8 mm

“…Typical atrial flutter is a macroreentrant atrial tachycardia with electrical activation through the cavotricuspid isthmus (CTI) 1 , which is a critical part of this circuit 1 . According to the electrophysiological mechanism and the anatomical structure, atrial flutter is classified as typical or reverse-typical depending on, respectively, the counterclockwise or clockwise direction of the activation wave through the CTI 2 .…”

Activation Patterns and Conduction Velocity in Posterolateral Right Atrium During Typical Atrial Flutter Using an Electroanatomic Mapping System

“…2 The cavotricuspid isthmus is an essential part of the typical AFL circuit and has been identified as the area of slow conduction. 3,4 To date, it has been assumed that activation of typical AFL rotates around the TA, and it is considered that an electrical barrier to transverse conduction exists throughout the posterolateral area of the RA, from the SVC to the IVC. 5,6 However, it has been shown recently that blocking does not occur in that entire region.…”

Ventricular beats induce variations in cycle length of rapid (type II) atrial flutter in humans. Evidence of leading circle reentry.

“…6 The diagnosis of rapid atrial flutter was based on (1) organized, rhythmical atrial waves (variation in cycle length <10%), (2) an atrial rate of spontaneous flutter above 320 beats per minute, and (3) in case the arrhythmia was induced by rapid atrial pacing performed to interrupt spontaneous common atrial flutter, any type of arrhythmia was considered rapid atrial flutter that showed organized electrical activity as an atrial rate above that of the original arrhythmia. The morphology of the F wave was not considered discriminant.…”