Counterclockwise Atrial Flutter Research Articles

Ablation of Atrial Flutter in a Patient with a Tricuspid Valve Replacement after Endocarditis

Myocardial scars from heart surgery are a source of tachycardia, eventually causing late morbidity and sudden death. In general, catheter ablation has been shown to be an effective therapy for various rhythm disorders, but it has been rarely described after atrioventricular valve replacement. We report on a 45-year-old man who developed atrial flutter after implantation of a tricuspid valve bioprosthesis. An electrophysiological investigation revealed typical type-I counterclockwise atrial flutter that was successfully terminated by catheter ablation. A sinus rhythm was restored and remained stable during the course of treatment; the valvular function was not diminished. It is demonstrated that safe mapping and ablation of typical atrial flutter is possible after a tricuspid valve replacement.

Not so innocent bystander(s)

A patient with atrial flutter, intermittent non-sustained wide complex tachycardia and 1:1 AV conduction is reported. Electrophysiology testing showed counterclockwise isthmus-dependent right atrial flutter with conduction via the AV node and an innocent bystander left lateral accessory pathway. This explained the observed intermittent wide complex tachycardia. After successful bidirectional cavotricuspid isthmus conduction block, a sustained wide complex tachycardia with identical counterclockwise right atrial activation and rate occurred. This was due to antidromic AV re-entrant tachycardia with innocent bystander activation of the right atrium mimicking atrial flutter. Accessory pathway ablation effectively stopped tachycardia.

Assessment of Clockwise Cavotricuspid Isthmus Block Based on Conduction Times during Transient Entrainment: A Prospective Study

In typical counterclockwise atrial flutter (AFL), the route of impulse propagation to anteroinferior right atrium (AIRA) during transient entrainment (TE) from the coronary sinus (CS) is expected to be similar to that during pacing from the same CS site during sinus rhythm (SR) when cavotricuspid isthmus (CTI) block has occurred. This could be used to identify CTI block during ablation procedures. Thirty-six patients with AFL (cycle length [CL], 240 +/- 25 ms) underwent CTI ablation during AFL. CS pacing was performed at a CL of 20 ms less than AFL CL before ablation (n = 36), and at several CL during SR with conduction through the CTI (n = 21) and after CTI block (n = 36). TE with orthodromic activation of AIRA occurred in all 36 patients. Conduction time from CS to AIRA during TE (T-entr, 199 +/- 29 ms) was significantly longer than during pacing in SR (T-CTI) at the same rate not only with CTI conduction (T-CTI-C, 135 +/- 24 ms, P < 0.001), but also with CTI block (T-CTI-B, 186 +/- 24 ms, P < 0.01). T-entr did not correlate with T-CTI-C, but there was an excellent correlation between T-entr and T-CTI-B (r = 0.874, P < 0.001). A "TE index" that corrected T-CTI for individual T-entr identified CTI block with 97% sensitivity and 91% specificity. T-CTI at low rates differed from T-CTI at high rates but correlated significantly with them. Comparison of conduction times during TE from the CS and during pacing from the same site and rate in SR can help to establish whether clockwise CTI block has been achieved in patients with typical AFL.

Mechanisms of atypical flutter wave morphology in patients with isthmus-dependent atrial flutter

Sixty-three episodes of isthmus-dependent atrial flutter (AFL) in 55 patients were studied to characterize variations in flutter wave morphology and to investigate the mechanisms of the atypical flutter waves on surface ECG. The activation patterns of coronary sinus (CS) and their relationship with flutter wave morphology on the ECG were analyzed. In 46 episodes of counterclockwise AFL (CCW-AFL), there were four types of flutter waves on ECG. Typical and atypical flutter waves were found in 47.8% and 13.0% of the episodes, respectively. Atypical flutter waves had broad positive terminal portion or entirely positive wave in the inferior leads and in V(1), with a distal-to-proximal or fused activation pattern in the CS, and an average activation time of 21.3 +/- 11.4 ms. In 17 episodes of clockwise AFL (CW-AFL), typical and atypical flutter waves were identified in 41.2% and 41.2%, respectively. Atypical flutter waves had negative waves in the inferior ECG leads and in V1, a proximal-to-distal activation pattern in the CS, and an average activation time of 42.4 +/- 14.4 ms. We conclude that atypical flutter waves are common in the isthmus-dependent AFL. The clockwise or counterclockwise conduction in the right atrium, and the activation patterns or conduction sequences between the right and the left atrium, are associated with the variations in the flutter wave morphology on body surface ECG.

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

To investigate the activation patterns and conduction velocity (CV) in the posterolateral right atrial (RA) wall during typical counterclockwise atrial flutter (AFL) using an electroanatomic mapping system. During typical AFL in 25 patients, the transverse conduction pattern and CV were classified and calculated. The line blocking transverse conduction was defined by the conduction pattern and double potentials recorded during mapping. There were 3 types (including 2 subtypes) of transverse conduction pattern based on the conduction blocks across the posterolateral RA in a line between the superior and inferior venae cava. Trans-cristal conduction activation in a horizontal direction was seen in all but 4 patients. The CV in the gap area was 0.59+/-0.21 m/s. Three types of transverse conduction pattern were observed during trans-ctristal conduction and the trans-ctristal CV was relatively slower than that in other parts of the RA, except for the isthmus.

Abstract 2644: High Prevalence of a Novel Conduction Pattern Around the Coronary Sinus in Cavotricuspid Isthmus Dependent Right Atrial Flutter

Objective : We tested our hypothesis that, in atrial flutter (AFL) dependent on the cavotricuspid isthmus (CTI), lower loop reentry (LLR) is the common pathway route at the coronary sinus (CS) posterior site, and thus, dual loop reentry (DLR) is a common circular pattern. Methods and result s: We studied 25 patients with CTI-dependent AFL, 16 with chronic counterclockwise atrial flutter (CCW-AFL) and 9 with clockwise atrial flutter (CW-AFL) and determined the precise reentry circuitry, especially for conduction patterns around the CS orifice, using electroanatomical mapping. We measured post pacing interval and tachycardia cycle length during entrainment from sites within the flutter circuit. In 16 of the 25 CCW-AFL patients, the CS anterior pacing site was within the AFL circuit in 13. The CS anterior pacing site was within the AFL circuit in 6 of the 9 CW-AFL patients. In 8 each of 16 CCW-AFL and 9 CW-AFL patients, both the CS anterior and posterior sites were within the AFL circuit. Results of 3-Dimensional (3D) activation mapping suggest that all of these patients had a DLR circuit, and that CS posterior conduction broke through the eustachian valve/ridge. Conclusion : CS posterior conduction consisted of the flutter circuit and appeared to be critical for maintaining AFL. Almost all AFL patients had DLR formed within the LLR or the superior RA circuit constituted from CS posterior conduction and in the anterior loop around the tricuspid annulus.

Change in Atrial Flutter Wave Morphology—Insight into the Sources of Electrocardiographic Variants in Common Atrial Flutter

Whether the activation sequence of the right or left atrium plays a role in the morphology of the flutter wave in common atrial flutter is not completely understood. We present two patients with common counterclockwise atrial flutter in whom changes in the left atrial activation sequence produced significant changes in flutter wave polarity (+ to - and - to -/+ biphasic) without a change in the activation sequence within the right atrium. These cases highlight the possible role of alterations of the interatrial connections in the genesis of atypical manifestations of common atrial flutter.

Atrial Tachycardia Arising From the Right Atrial Inferoseptum Masquerading as Common Atrial Flutter

Radiofrequency catheter ablation was performed in 2 patients with atrial tachycardia (AT). In both cases the AT originated from the inferoseptal portion of the right atrium, and the cycle length was 210 ms. The surface ECG demonstrated common counterclockwise atrial flutter, probably caused by functional block in the clockwise direction at the cavo-tricuspid isthmus and posterior right atrium with rapid activation of the origin. Although rare (2%), AT originating from the inferoseptum of the right atrium should be considered when the surface ECG exhibits common atrial flutter.

P4-108: Reentrant atrial tachycardia from coronary sinus os simulating counterclockwise atrial flutter

Counterclockwise Atrial Flutter (AFl) is the most frequent Cavo-Tricuspid Isthmus-dependant AFl. Entrainment maneuvers from around the Tricuspid Annulus (TA) can verify the reentrant nature and the circuit of the AFl. However, the Entrainment must be performed from at least two different points of the TA, in order to rule out other forms of Atrial Tachycardia (AT) where the reentrant circuit can contain part of the TA and which can be misinterpreted as AFl if the entrainment is performed only in that shared portion of the TA.

P3-57: Comparison of the conduction velocity and conducting area between the counter clockwise and clockwise atrial flutters using electroanatomical mapping system

There is still controversy about the difference of the conduction velocity (CV) around the tricuspid valve annulus (TVA) between the counter clockwise (CCW) atrial flutter (AFl) and the clockwise (CW). Therefore, this study was undertaken to evaluate the CV around the TVA and conducting area per milli-second (CA) of right atrium (RA) using the electroanatomical mapping system (CARTO).

Usefulness of the polarity in high-density wide range-filtered bipolar mapping to detect isthmus block during radiofrequency ablation of typical atrial flutter

The atrial activation sequence around the tricuspid annulus (TA) cannot always be used to establish whether complete block has been achieved across the cavotricuspid isthmus (CTI) during radiofrequency ablation (RFCA) for typical counterclockwise atrial flutter (CCW-AFL). We examined whether a change in the polarity of the atrial high-density wide range-filtered bipolar electrograms recorded near the ablation line is an accurate indicator of complete CTI block. Nineteen patients with CCW-AFL underwent RFCA. Electrograms were recorded around the TA with duodecapolar conventional (2mm x 8mm x 2mm spacing) and high-density (2-mm spacing) Halo catheters. The bipolar electrograms on the high-density Halo catheter recorded from a series of adjacent electrode pairs positioned just lateral to the ablation line were filtered at a bandpass setting of 0.05-500 Hz. The activation sequence on the conventional Halo catheter during coronary sinus pacing (CSp) and inferolateral TA pacing, and the bipolar electrograms on the high-density Halo catheter during CSp were determined before and after RFCA. The final complete CTI block was verified by the presence of widely split double electrograms > or =100 msec along the ablation line. The final complete CTI block was achieved in all the 19 patients. Before RFCA, the polarity of bipolar electrograms was predominantly negative during CCW-AFL and positive during CSp. In 18 of the 19 patients, the bipolar electrograms exhibited the CCW activation and a negative polarity during CSp only after complete CTI block. In one of those 18 patients, additional applications of RFCA changed the polarity of bipolar electrograms positive to negative although the conventional Halo electrogram activation sequence suggested complete CTI block during CSp. In seven patients, who had transverse conduction across the crista terminalis during CSp, the conventional Halo electrogram activation sequence suggested an incomplete CTI block. However, in six of those seven patients, the CCW activation had a predominantly negative polarity of the bipolar electrograms. In one of those seven patients, complete CTI block was unable to be detected even using the high-density Halo catheter. These data demonstrate that the high-density wide range-filtered mapping can identify the CTI block in undetectable cases of complete CTI block or incomplete CTI block by the conventional method. The polarity of the bipolar electrograms recorded just lateral to the ablation line during CSp after RFCA of AFL may be used as a simple and an accurate indicator of complete CTI block.

Modes of Initiation of Two Types of Atrial Reentry in a Patient with Typical Atrial Flutter: Isthmus-dependent Micro-reentry versus Macro-reentry

We studied the modes of initiation of two types of atria] reentrant tachycardias (i.e., microreentry isthmus tachycardia and counterclockwise atrial flutter) in a 39‐year‐old male with typical atrial flutter. Rapid atrial pacing from proximal coronary sinus at a cycle length of 220 msec initiated micro‐reentry isthmus tachycardia (non‐sustained), while rapid atrial pacing at a cycle length of 210 msec initiated sustained atrial flutter circulating counterclockwise around the tricuspid annulus. It was suggested that initiation of the counterclockwise atrial flutter was associated with a pacing‐induced conduction block in the entire width of the isthmus, whereas initiation of the micro‐reentry isthmus tachycardia was associated with a pacing‐induced conduction block in a limited segment of the isthmus (i.e., partial isthmus block).

Coexistence of Intracardiac Atrial Flutter and Extracardiac Fibrillation

This report describes the coexistence of fibrillatory activity limited to an isolated left common pulmonary vein trunk with typical counterclockwise isthmus-dependent right atrial flutter in a patient undergoing a pulmonary vein isolation procedure.

Counterclockwise atrial flutter in dextrocardia

A 57-year-old woman with history of flutter had a surface ECG suggestive of clockwise (CW) atrial flutter with positive F waves in leads II, III, and aVF and negative F wave in lead V1 (Figure 1). The complete absence of an R wave in lead I was noted. Chest x-ray film demonstrated dextrocardia. Echocardiography established complete situs inversus with otherwise normal intracardiac anatomy.

Mechanism of Atrial Flutter Occurring Late After Orthotopic Heart Transplantation with Atrio‐atrial Anastomosis

We sought to better define the electrophysiologic mechanism of atrial flutter in patients after heart transplantation. Atrial flutter is a recognized problem in the post-cardiac transplant population. The electrophysiologic basis of atrial flutter in this patient population is not completely understood. Six patients with cardiac allografts and symptoms related to recurrent atrial flutter underwent diagnostic electrophysiologic study with electroanatomic mapping and radiofrequency catheter ablation. Comparison was made with a control non-transplant population of 11 patients with typical counterclockwise right atrial flutter. In each case, mapping showed typical counterclockwise activation of the donor-derived portion of the right atrium, with concealed entrainment shown upon pacing in the cavotricuspid isthmus (CTI). The anastomotic suture line of the atrio-atrial anastomosis formed the posterior barrier of the reentrant circuit. Ablation of the electrically active, donor-derived portion of the CTI was sufficient to terminate atrial flutter and render it noninducible. Comparison with the control population showed that the electrically active portion of the CTI was significantly shorter in patients with transplant-associated flutter and that ablation was accomplished with the same or fewer radiofrequency lesions. Atrial flutter in cardiac transplant recipients is a form of typical counterclockwise, isthmus-dependent flutter in which the atrio-atrial anastomotic suture line forms the posterior barrier of the reentrant circuit. Ablation in the donor-derived portion of the CTI is sufficient to create bidirectional conduction block and eliminate this arrhythmia. Ablation or surgical division of the donor CTI at the time of transplantation could prevent this arrhythmia.

Modes of Initiation of Two Types of Atrial Reentry in a Patient with Typical Atrial Flutter: Isthmus-dependent Micro-reentry versus Macro-reentry

We studied the modes of initiation of two types of atria] reentrant tachycardias (i.e., microreentry isthmus tachycardia and counterclockwise atrial flutter) in a 39-year-old male with typical atrial flutter. Rapid atrial pacing from proximal coronary sinus at a cycle length of 220 msec initiated micro-reentry isthmus tachycardia (non-sustained), while rapid atrial pacing at a cycle length of 210 msec initiated sustained atrial flutter circulating counterclockwise around the tricuspid annulus. It was suggested that initiation of the counterclockwise atrial flutter was associated with a pacing-induced conduction block in the entire width of the isthmus, whereas initiation of the micro-reentry isthmus tachycardia was associated with a pacing-induced conduction block in a limited segment of the isthmus (i.e., partial isthmus block).

Use of a New Non‐Fluoroscopic Three‐Dimensional Mapping System in Type I Atrial Flutter Ablation

We studied 40 patients who underwent cavo-tricuspid isthmus ablation for typical counterclockwise atrial flutter with cooled tip catheters between 2001 and 2003. Complete bi-directional isthmus block was created in all patients. A new, three-dimensional (3D), non-fluoroscopic mapping system was used in 20 patients (test group), and conventional fluoroscopy in 20 others (conventional group), using anatomic and electrophysiologic criteria in both groups. We measured the total procedure, ablation procedure, and overall fluoroscopy times, and the total number of radiofrequency (RF) applications delivered in the two groups. The overall fluoroscopy time was shorter in the test group (mean 8.8 minutes, range 2-17 minutes) than the conventional group (29.7 minutes, range 12-57 minutes; P < 0.001). Though the overall procedure time was similar in both groups (92.5 +/- 28.6 minutes vs 106.5 +/- 20.9 minutes; P = 0.067) the ablation duration (25.1 +/- 6.6 minutes versus 43.3 +/- 19.6 minutes; P = 0.0051) and the total RF applications (10.6 +/- 9.4 versus 16.4 +/- 9.4; P = 0.044) were smaller in the test group. The use of a new, 3D non-fluoroscopic mapping system markedly reduced the fluoroscopy exposure during typical atrial flutter ablation. It was also associated with a significant reduction in ablation time and in the number of RF applications. Since atrial flutter ablation is one of the most frequently performed procedures, this system may significantly reduce the overall amount of radiation exposure in high-volume laboratories.

Pulmonary vein stenosis after radiofrequency pulmonary vein isolation for atrial fibrillation

A 52-year-old man presented to our institution because of recurrent episodes of atrial fibrillation and counterclockwise atrial flutter, refractory to medical therapy with different regimens including amiodarone, and after several cardioversions to restore in sinus rhythm. Coronary artery stenosis was ruled out invasively. Left and right ventricular function were normal at rest and during bicycle exercise. Preinterventional nuclear magnetic resonance imaging (MRI) and transesophageal echocardiography (TEE) showed 4 pulmonary veins (Figure 1, A) with normal left atrial inflow. The patient underwent radiofrequency (RF) isolation of the 2 left pulmonary veins and the upper right pulmonary vein in combination with a right atrial isthmus ablation in July 2001, and a reintervention because of recurrent atrial fibrillation including reisolation of all 4 pulmonary veins until December 2001. MRI (Figure 1, A) and TEE (Figure 1, B to E) during follow-up demonstrated progressive narrowing of the left upper pulmonary vein until January 2003 with turbulent left atrial inflow (Figure 1, C to E) as compared with the normal inflow pattern (Figure 1, B and C) of the lower left pulmonary vein. Because of normal hemodynamic findings (pulmonary artery mean pressure: 14 mm Hg) on a repeated measurement and absence of any symptoms, the patient is still under close observation without any need for revascularization of the stenosed pulmonary vein. In a similar case, however, venous congestion and recurrent hemoptysis from the upper left pulmonary lobe made surgical reconstruction of the upper left pulmonary vein necessary.

Typical counterclockwise atrial flutter occurring despite absence of the inferior vena cava

A 74-year-old man with a structurally normal heart presented with typical atrial flutter, after treatment of atrial fibrillation with propafenone. Catheterization and computed tomographic imaging revealed absence of the inferior vena caval segment that normally traverses the liver to enter the right atrium. Abdominal venous return occurred via the hemi-azygous vein, draining into the superior vena cava. Hepatic veins inserted postero-inferiorly into the right atrium. Pacing atrial myocardium between the hepatic veins and the tricuspid valve resulted in concealed entrainment. Radiofrequency catheter ablation directed (via a superior approach from the right internal jugular vein) to this extraordinary “isthmus” abolished atrial flutter. The implications of this congenital abnormality on posterior barriers maintaining the atrial flutter circuit are discussed.

Lower loop reentry as a mechanism of clockwise right atrial flutter.

Right atrial reentrant tachycardia resulting from lower loop reentry (LLR) around the inferior vena cava (IVC) has been described recently. However, all reported cases of LLR in the literature have negative flutter waves on the inferior surface ECG leads similar to that of counterclockwise typical atrial flutter around the tricuspid annulus (TA). Right atrial flutter with positive flutter waves in the inferior ECG leads has been assumed to rotate as a single reentrant activation wave front around the TA, and the role of LLR in those patients is not known. Twelve consecutive patients with flutter wave morphology on surface ECG consistent with clockwise atrial flutter were studied. The endocardial activation pattern recorded from conventional multipolar electrode catheters was characteristic of clockwise atrial flutter around the TA. Entrainment pacing in all 12 patients and 3D activation sequence mapping in 7 patients, however, revealed clockwise LLR involving the lower right atrium around the IVC in 7 patients, figure-of-8 double-loop reentry around both the IVC and TA in 4, and single reentrant loop around the TA in 1. Linear radiofrequency ablation in the isthmus between the TA and IVC (TI isthmus) terminated the tachycardia in all patients. Surface ECG flutter wave morphology and limited recording intracardiac sites proved insufficient to delineate the precise mechanism of the TI isthmus-dependent clockwise right atrial flutters. Most right atrial flutters with positive flutter wave on surface ECG may be supported by a reentrant circuit around the IVC or a figure-of-8 double-loop reentry involving both the IVC and TA.