Home  About us  Contact
 

Atrial Activation Sequence (atrial + activation_sequence)

Distribution by Scientific Domains
Medical Sciences100%

Selected Abstracts

Atrial Activation Sequence During Junctional Tachycardia Induced by Thermal Stimulation of Koch's Triangle in Canine Blood-Perfused Atrioventricular Node Preparation

PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 5 2002
ATSUSHI IWASA
IWASA, A., et al.: Atrial Activation Sequence During Junctional Tachycardia Induced by Thermal Stimulation of Koch's Triangle in Canine Blood-Perfused Atrioventricular Node Preparation. Junctional tachycardia is observed during radiofrequency ablation of the slow pathway. The authors investigated the atrial activation sequence during junctional tachycardia induced with thermal stimulation in canine blood-perfused atrioventricular node (AVN) preparation. The canine heart was isolated (n = 7) and cross-circulated with heparinized arterial blood of the support dog. The activation sequence in the region of Koch's triangle (15 × 21 mm) was determined by recording 48 unipolar electrograms. Atrial sites anterior to the coronary sinus ostium (site AN), close to the His-potential recording site (site N) and superior to site N (site F), were subjected to a continuous temperature rise from 38°C to 50°C with a heating probe. The temperature of the tissue adjacent to the heating site was monitored simultaneously. Junctional tachycardia at a rate of 92 ± 12 beats/min with the His potential preceding the atrial one in the His-bundle electrogram was induced during thermal stimulation at site AN (temperature 42.1°C ± 0.9°C) in all seven preparations, whereas junctional tachycardia was induced during stimulation at site N in one and at site F in none. In each case, the temperature rose only at the site of stimulation. The earliest activation site during junctional tachycardia induced by site AN stimulation was at the His-potential recording site in five preparations and the middle of Koch's triangle in the other two. After creating an obstacle between sites AN and N, atrial tachycardia at a rate of 85 ± 11 beats/min was induced during site AN stimulation. The earliest activation site during this tachycardia was site AN. Thus, junctional tachycardia induced by thermal stimulation was suggested to originate from the AN thermal stimulation site. The impulse from the stimulation site appeared to conduct via the posterior input to the compact AVN and junctional tachycardia was generated. When the posterior input was interrupted, atrial tachycardia was generated. [source]

Conduction Properties of the Crista Terminalis and Its Influence on the Right Atrial Activation Sequence in Patients with Typical Atrial Flutter

PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 2 2002
HIROSHIGE YAMABE
YAMABE, H., et al.: Conduction Properties of the Crista Terminalis and Its Influence on the Right Atrial Activation Sequence in Patients with Typical Atrial Flutter. The conduction properties of the crista terminalis (CT) and its influence on the right atrial activation sequence were analyzed in 14 patients with typical atrial flutter (AF). Atrial mapping was performed with 35 points of the right atrium during typical AF and during atrial pacing performed after linear ablation of inferior vena cava-tricuspid annulus (IVCTA) isthmus. Atrial pacing was delivered from the septal isthmus at cycle lengths of 600 ms and the tachycardia cycle length (TCL). The right atrial activation sequence and the conduction interval (CI) from the septal to lateral portion of the IVC-TA isthmus were analyzed. During AF, the conduction block line (CBL) (detected by the appearance of double potentials along the CT and craniocaudal activation on the side anterior to CT) was observed along the CT in all patients. The TCL and CI during AF were 254 ± 19 and 207 ± 14 ms, respectively. During pacing at a cycle length of 600 ms, the CBL was observed along the CT in four patients, however, a short-circuiting activation across the CT was observed in the remaining ten patients. The CI during pacing at 600 ms was 134 ± 38 ms, shorter than that during AF (P < .0001). During pacing at the TCL, the CBL was observed along the CT in all patients. The presence of the CBL along the CT prevented a short-circuiting activation across the CT and resulted in the same right atrial activation as observed during AF. With the formation of the CBL, the CI significantly increased to 206 ± 17 ms and was not different from that during AF. These data suggest that the conduction block along the CT is functional. It was presumed that presence of conduction block at the CT has some relevance to the initiation of typical AF though it was not confirmed. [source]

A Single Pulmonary Vein as Electrophysiological Substrate of Paroxysmal Atrial Fibrillation

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 11 2006
HE HUANG M.D.
Introduction: It has been demonstrated that pulmonary veins (PVs) play an important role in initiation and maintenance of paroxysmal atrial fibrillation (AF). However, it is not clearly known whether a single PV acts as electrophysiological substrate for paroxysmal AF. Methods and Results: This study included five patients with paroxysmal AF. All patients underwent complete PV isolation with continuous circular lesions (CCLs) around the ipsilateral PVs guided by a three-dimensional mapping system. Irrigated radiofrequency (RF) delivery was performed during AF on the right-sided CCLs in two patients and on the left-sided CCLs in three patients. The incomplete CCLs resulted in a change from AF to atrial tachycardia (AT), which presented with an identical atrial activation sequence and P wave morphology. Complete CCLs resulted in AF termination with persistent PV tachyarrhythmias within the isolated PV in all five patients. PV tachyarrhythmia within the isolated PV was PV fibrillation from the left common PV (LCPV) in two patients, PV tachycardia from the right superior PV (RSPV) in two patients, and from the left superior PV in one patient. All sustained PV tachyarrhythmias persisted for more than 30 minutes, needed external cardioversion for termination in four patients and a focal ablation in one patient. After the initial procedure, an AT from the RSPV occurred in a patient with PV fibrillation within the LCPV, and was successfully ablated. Conclusion: In patients with paroxysmal AF, sustained PV tachyarrhythmias from a single PV can perpetuate AF. Complete isolation of all PV may provide good clinical outcome during long-term follow-up. [source]

Electrogram Polarity and Cavotricuspid Isthmus Block During Ablation of Typical Atrial Flutter

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 4 2001
HIROSHI TADA M.D.
Electrogram Polarity in Atrial Flutter Ablation.Introduction: The atrial activation sequence around the tricuspid annulus has been used to assess whether complete block has been achieved across the cavotricuspid isthmus during radiofrequency ablation of typical atrial flutter. However, sometimes the atrial activation sequence does not clearly establish the presence or absence of complete block. The purpose of this study was to determine whether a change in the polarity of atrial electrograms recorded near the ablation line is an accurate indicator of complete isthmus block. Methods and Results: Radiofrequency ablation was performed in 34 men and 10 women (age 60 ± 13 years [mean ± SD]) with isthmus-dependent, counterclockwise atrial flutter. Electrograms were recorded around the tricuspid annulus using a duodecapolar halo catheter. Electrograms recorded from two distal electrode pairs (E1 and E2) positioned just anterior to the ablation line were analyzed during atrial flutter and during coronary sinus pacing, before and after ablation. Complete isthmus block was verified by the presence of widely split double electrograms along the entire ablation line. Complete bidirectional isthmus block was achieved in 39 (89%) of 44 patients. Before ablation, the initial polarity of E1 and E2 was predominantly negative during atrial flutter and predominantly positive during coronary sinus pacing. During incomplete isthmus block, the electrogram polarity became reversed either only at E2, or at neither E1 nor E2. In every patient, the polarity of E1 and E2 became negative during coronary sinus pacing only after complete isthmus block was achieved. In 4 patients (10%), the atrial activation sequence recorded with the halo catheter was consistent with complete isthmus block, but the presence of incomplete block was accurately detected by inspection of the polarity of E1 and E2. Conclusion: Reversal of polarity in bipolar electrograms recorded just anterior to the line of isthmus block during coronary sinus pacing after ablation of atrial flutter is a simple, quick, and accurate indicator of complete isthmus block. [source]

Atrial Activation Sequence During Junctional Tachycardia Induced by Thermal Stimulation of Koch's Triangle in Canine Blood-Perfused Atrioventricular Node Preparation

PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 5 2002
ATSUSHI IWASA
IWASA, A., et al.: Atrial Activation Sequence During Junctional Tachycardia Induced by Thermal Stimulation of Koch's Triangle in Canine Blood-Perfused Atrioventricular Node Preparation. Junctional tachycardia is observed during radiofrequency ablation of the slow pathway. The authors investigated the atrial activation sequence during junctional tachycardia induced with thermal stimulation in canine blood-perfused atrioventricular node (AVN) preparation. The canine heart was isolated (n = 7) and cross-circulated with heparinized arterial blood of the support dog. The activation sequence in the region of Koch's triangle (15 × 21 mm) was determined by recording 48 unipolar electrograms. Atrial sites anterior to the coronary sinus ostium (site AN), close to the His-potential recording site (site N) and superior to site N (site F), were subjected to a continuous temperature rise from 38°C to 50°C with a heating probe. The temperature of the tissue adjacent to the heating site was monitored simultaneously. Junctional tachycardia at a rate of 92 ± 12 beats/min with the His potential preceding the atrial one in the His-bundle electrogram was induced during thermal stimulation at site AN (temperature 42.1°C ± 0.9°C) in all seven preparations, whereas junctional tachycardia was induced during stimulation at site N in one and at site F in none. In each case, the temperature rose only at the site of stimulation. The earliest activation site during junctional tachycardia induced by site AN stimulation was at the His-potential recording site in five preparations and the middle of Koch's triangle in the other two. After creating an obstacle between sites AN and N, atrial tachycardia at a rate of 85 ± 11 beats/min was induced during site AN stimulation. The earliest activation site during this tachycardia was site AN. Thus, junctional tachycardia induced by thermal stimulation was suggested to originate from the AN thermal stimulation site. The impulse from the stimulation site appeared to conduct via the posterior input to the compact AVN and junctional tachycardia was generated. When the posterior input was interrupted, atrial tachycardia was generated. [source]

Conduction Properties of the Crista Terminalis and Its Influence on the Right Atrial Activation Sequence in Patients with Typical Atrial Flutter

PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 2 2002
HIROSHIGE YAMABE
YAMABE, H., et al.: Conduction Properties of the Crista Terminalis and Its Influence on the Right Atrial Activation Sequence in Patients with Typical Atrial Flutter. The conduction properties of the crista terminalis (CT) and its influence on the right atrial activation sequence were analyzed in 14 patients with typical atrial flutter (AF). Atrial mapping was performed with 35 points of the right atrium during typical AF and during atrial pacing performed after linear ablation of inferior vena cava-tricuspid annulus (IVCTA) isthmus. Atrial pacing was delivered from the septal isthmus at cycle lengths of 600 ms and the tachycardia cycle length (TCL). The right atrial activation sequence and the conduction interval (CI) from the septal to lateral portion of the IVC-TA isthmus were analyzed. During AF, the conduction block line (CBL) (detected by the appearance of double potentials along the CT and craniocaudal activation on the side anterior to CT) was observed along the CT in all patients. The TCL and CI during AF were 254 ± 19 and 207 ± 14 ms, respectively. During pacing at a cycle length of 600 ms, the CBL was observed along the CT in four patients, however, a short-circuiting activation across the CT was observed in the remaining ten patients. The CI during pacing at 600 ms was 134 ± 38 ms, shorter than that during AF (P < .0001). During pacing at the TCL, the CBL was observed along the CT in all patients. The presence of the CBL along the CT prevented a short-circuiting activation across the CT and resulted in the same right atrial activation as observed during AF. With the formation of the CBL, the CI significantly increased to 206 ± 17 ms and was not different from that during AF. These data suggest that the conduction block along the CT is functional. It was presumed that presence of conduction block at the CT has some relevance to the initiation of typical AF though it was not confirmed. [source]

Predicting the Arrhythmogenic Foci of Atrial Fibrillation Before Atrial Transseptal Procedure:

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 7 2000
Implication for Catheter Ablation
Arrhythmosenic Foci of Atrial Fibrillation. Introduction: Use of endocardial atrial activation sequences from recording catheters in the right atrium. His bundle, and coronary sinus to predict the location of initiating foci of atrial fibrillation (AF) before an atrial transseptal procedure has not been reported. The purpose of the present study was to develop an algorithm using endocardial atrial activation sequences to predict the location of initiating foci of AF before transseptal procedure. Methods and Results: Seventy-five patients (60 men and 15 women, age 68 ± 12 years) with frequent episodes of paroxysmal AF were referred for radiofrequency ablation. By retrospective analysis, characteristics of the endocardial atrial activation sequences of right atrial, His-bundle, and coronary sinus catheters from the initial 37 patients were correlated with the location of initiating foci of AF, which were confirmed by successful ablation. The endocardial atrial activation sequences of the other 38 patients were evaluated prospectively to predict the location of initiating foci of AF before transseptal procedure using the algorithm derived from the retrospective analysis. Accuracy of the value <0 msee (obtained by subtracting the time interval between high right atrium and His-bundle atrial activation during atrial premature beats from that obtained during sinus rhythm) for discriminating the superior vena cava or upper portion of the crista terminalis from the pulmonary vein (PV) foci was 100%. When the interval between atrial activation ostial and distal pairs of the coronary sinus catheter of the atrial premature beats was <0 msec, the accuracy for discriminating left PV foci from right PV foci was 92% in the 24 foci from the left PVs and 100% in the 19 foci from the right PVs. Conclusion: Endocardial atrial activation sequences from right atrial, His-bundle, and coronary sinus catheters can accurately predict the location of initiating foci of AF before transseptal procedure. This may facilitate mapping and radiofrequency ablation of paroxysmal AF. [source]