Home About us Contact
|
Home About us Contact | ||
|
|
||
Atrial Tachycardia (atrial + tachycardia)
Kinds of Atrial Tachycardia Terms modified by Atrial Tachycardia Selected AbstractsCharacteristics of Complex Fractionated Electrograms in Nonpulmonary Vein Ectopy Initiating Atrial Fibrillation/Atrial TachycardiaJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 12 2009LI-WEI LO M.D. Background: Nonpulmonary vein (PV) ectopy initiating atrial fibrillation (AF)/atrial tachycardia (AT) is not uncommon in patients with AF. The relationship of complex fractionated atrial electrograms (CFAEs) and non-PV ectopy initiating AF/AT has not been assessed. We aimed to characterize the CFAEs in the non-PV ectopy initiating AF/AT. Methods: Twenty-three patients (age 53 ± 11 y/o, 19 males) who underwent a stepwise AF ablation with coexisting PV and non-PV ectopy initiating AF or AT were included. CFAE mapping was applied before and after the PV isolation in both atria by using a real-time NavX electroanatomic mapping system. A CFAE was defined as a fractionation interval (FI) of less than 120 ms over 8-second duration. A continuous CFAE (mostly, an FI < 50 ms) was defined as electrogram fractionation or repetitive rapid activity lasting for more than 8 seconds. Results: All patients (100%) with non-PV ectopy initiating AF or AT demonstrated corresponding continuous CFAEs at the firing foci. There was no significant difference in the FI among the PV ostial or non-PV atrial ectopy or other atrial CFAEs (54.1 ± 5.6, 58.3 ± 11.3, 52.8 ± 5.8 ms, P = 0.12). Ablation targeting those continuous CFAEs terminated the AF and AT and eliminated the non-PV ectopy in all patients (100%). During a follow-up of 7 months, 22% of the patients had an AF recurrence with PV reconnections. There was no recurrence of any ablated non-PV ectopy during the follow-up. Conclusion: The sites of the origin of the non-PV ectopies were at the same location as those of the atrial continuous CFAEs. Those non-PV foci were able to initiate and sustain AF/AT. By limited ablation targeting all atrial continuous CFAEs, the AF could be effectively eliminated. [source] Successful Catheter Ablation and Documentation of the Activation and Propagation Pattern During a Left Atrial Focal Tachycardia in a Patient with Cor Triatriatum SinisterJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 9 2010KOICHIRO EJIMA M.D. Atrial Tachycardia in Cor Triatriatum. We report a case of an atrial tachycardia (AT) originating from the left atrium (LA) associated with cor triatriatum sinister. Electroanatomical mapping of the 2 subdivided chambers of the LA during the AT revealed a centrifugal activation pattern from the posterior wall of the accessory chamber near the left superior pulmonary vein. The propagation map on the CARTO system revealed that the AT wave front spread centrifugally over the "accessory chamber," turned around the edge of the membrane subdividing the LA, and then spread over the "main chamber." A single radiofrequency application successfully abolished the AT. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1050-1054, September 2010) [source] Distinguishing Far-Field Appendage from Local Pulmonary Vein Signal in the Left Upper Pulmonary Vein During Atrial TachycardiaJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 4 2010EDWARD DUNCAN Ph.D. First page of article [source] Origin of Atrial Tachycardia: The High Right Atrium or Right Superior Pulmonary Vein?JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 4 2009SHINYA KOWASE M.D. No abstract is available for this article. [source] Catheter Ablation of Peri-AV Nodal Atrial Tachycardia from the Noncoronary Cusp of the Aortic ValveJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 3 2008Ph.D, SAUMYA DAS M.D. Introduction: Atrial tachycardias (AT) originating from the anteroseptal region of the aortic root, near the atrioventricular node can be challenging to eliminate safely by catheter ablation. In this study, we examine the characteristics of anteroseptal ATs in a cohort of patients at our centers, and demonstrate the long-term efficacy and safety of targeting the arrhythmias from within the base of the noncoronary aortic valve cusp (NCC). Methods & Results: From among a cohort of 54 patients with symptomatic focal AT undergoing invasive electrophysiological evaluation, the point of earliest right atrial (RA) activation was at the peri-AV nodal region in 10 patients, just postero-superior to the His-bundle. Before further mapping, RA lesions placed in two patients were unsuccessful in eliminating the arrhythmia. Because of its proximity to the interatrial septum, the base of the NCC was mapped using a retrograde aortic approach, and revealed a point of early activation without the presence of a His potential. The arrhythmia terminated with <10 seconds of radiofrequency or cryothermal energy delivery and was successfully eliminated in 7 of 10 patients. Transient termination or acceleration of the AT was noted in the other three patients, prompting successful ablation from a left atrial septal position or a reattempt from a para-Hisian RA position. All patients have been arrhythmia free during follow-up (41 ± 12 months). Conclusions: Catheter ablation from within the base of the NCC represents a safe and effective means to eliminate focal AT arising from the peri-AV nodal region. [source] The VA Relationship After Differential Atrial Overdrive Pacing: A Novel Tool for the Diagnosis of Atrial Tachycardia in the Electrophysiologic LaboratoryJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 11 2007MITSUNORI MARUYAMA M.D. Introduction: Despite recent advances in clinical electrophysiology, diagnosis of atrial tachycardia (AT) originating near Koch's triangle remains challenging. We sought a novel technique for rapid and accurate diagnosis of AT in the electrophysiologic laboratory. Methods: Sixty-two supraventricular tachycardias including 18 ATs (10 ATs arising from near Koch's triangle), 32 atrioventricular nodal reentrant tachycardias (AVNRTs), and 12 orthodromic reciprocating tachycardias (ORTs) were studied. Overdrive pacing during the tachycardia from different atrial sites was performed, and the maximal difference in the postpacing VA intervals (last captured ventricular electrogram to the earliest atrial electrogram of the initial beat after pacing) among the different pacing sites was calculated (delta-VA interval). Results: The delta-VA intervals were >14 ms in all AT patients and <14 ms in all AVNRT/ORT patients, and thus, the delta-VA interval was diagnostic for AT with the sensitivity, specificity, and positive and negative predictive values all being 100%. When the diagnostic value of the delta-VA interval and conventional maneuvers were compared for differentiating AT from atypical AVNRT, both a delta-VA interval >14 ms and "atrial-atrial-ventricular" response after overdrive ventricular pacing during the tachycardia were diagnostic. However, the "atrial-atrial-ventricular" response criterion was available in only 52% of the patients because of poor ventriculoatrial conduction. Conclusions: The delta-VA interval was useful for diagnosing AT irrespective of patient conditions such as ventriculoatrial conduction. [source] Bepridil Reverses Atrial Electrical Remodeling and L-Type Calcium Channel Downregulation in a Canine Model of Persistent Atrial TachycardiaJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 7 2007KUNIHIRO NISHIDA M.D. Introduction: This study tested whether bepridil, a multichannel blocker, would reverse electrical remodeling induced by persistent atrial tachycardia. Methods and Results: Fourteen dogs were subjected to rapid atrial pacing at 400 bpm for 6 weeks after atrioventricular block was created to control the ventricular rate. During the study period, seven dogs were given placebo for 6 weeks (Control group), and seven were given placebo for 3 weeks, followed by 3 weeks of bepridil (10 mg/kg/day, Bepridil group). The atrial effective refractory period (ERP) and the inducibility and duration of atrial fibrillation (AF) were determined on a weekly basis. After 6 weeks, expression of L-type calcium channel ,1C messenger ribonucleic acid (mRNA) was quantified by real-time reverse transcription-polymerase chain reaction. In the Control group, ERP was shortened and the inducibility and duration of AF increased through the 6-week period. In the Bepridil group, the same changes occurred during the first 3 weeks, but were gradually reversed with bepridil. After 6 weeks, ERP was longer, AF inducibility was lower, and AF duration was shorter in Bepridil group than in the Control group. Expression of ,1C mRNA was decreased by 64% in the Control group (P < 0.05 vs sham), but in the Bepridil group, it was not different compared with the sham dogs. As a whole group of dogs, ERP was positively correlated with ,1C mRNA expression. Conclusion: Bepridil reverses the electrophysiological consequences of atrial remodeling to some extent and L-type calcium channel downregulation in a canine model of atrial tachycardia. [source] A Novel Pacing Maneuver to Localize Focal Atrial TachycardiaJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 1 2007F.R.A.C.P., UWAIS MOHAMED M.B.B.S. Background: Although focal atrial tachycardias cannot be entrained, we hypothesized that atrial overdrive pacing (AOP) can be an effective adjunct to localize the focus of these tachycardias at the site where the post-pacing interval (PPI) is closest to the tachycardia cycle length (TCL). Methods: Overdrive pacing was performed in nine patients during atrial tachycardia, and in a comparison group of 15 patients during sinus rhythm. Pacing at a rate slightly faster than atrial tachycardia in group 1 and sinus rhythm in group 2 was performed from five standardized sites in the right atrium and coronary sinus. The difference between the PPI and tachycardia or sinus cycle length (SCL) was recorded at each site. The tachycardia focus was then located and ablated in group 1, and the atrial site with earliest activation was mapped in group 2. Results: In both groups the PPI-TCL at the five pacing sites reflected the distance from the AT focus or sinus node. In group 1, PPI-TCL at the successful ablation site was 11 ± 8 msec. In group 2, PPI-SCL at the site of earliest atrial activation was 131 ± 37 msec (P < 0.001 for comparison). In groups 1 and 2, calculated values at the five pacing sites were proportional to the distance from the AT focus or sinus node, respectively. Conclusions: The PPI-TCL after-AOP of focal atrial tachycardia has a direct relationship to proximity of the pacing site to the focus, and may be clinically useful in finding a successful ablation site. [source] Focal Origin of Atrial Tachycardia in Dogs with Rapid Ventricular Pacing-Induced Heart FailureJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 10 2003GUILHERME FENELON M.D. Introduction: Dogs with rapid ventricular pacing-induced congestive heart failure (CHF) have inducible atrial tachycardia (AT), with a mechanism consistent with delayed afterdepolarization-mediated triggered activity. We assessed the hypothesis that AT has a focal origin. Methods and Results: Twenty-one CHF dogs undergoing 3 to 4 weeks of ventricular pacing at 235 beats/min were studied. Biatrial epicardial mapping of 20 sustained AT episodes (cycle length [CL], 175 ± 53 msec) in 5 dogs revealed an area of earliest activation in the right atrial (RA) free wall (13 episodes), RA appendage (4 episodes), or between the pulmonary veins (3 episodes). Total epicardial activation time during AT (73 ± 19 msec) was similar to that during sinus rhythm (72 ± 13 msec) and on average was <50% of the AT CL. Higher-density mapping of the RA free wall during 30 sustained AT episodes (163 ± 55 msec) in 9 dogs identified a site of earliest activation along the sulcus terminalis most frequently as a stable, focal activation pattern from a single site. Endocardial mapping of 49 sustained AT episodes (156 ± 27 msec) in 10 dogs revealed multiple sites of AT origin arising along the crista terminalis and pulmonary veins. Right and left ATs were terminated with discrete radiofrequency ablation, but other ATs remained inducible. A rapid, left AT generating an ECG pattern of atrial fibrillation was ablated inside the pulmonary vein. Conclusion: AT induced in this CHF model after 3 to 4 weeks of rapid ventricular pacing has an activation pattern consistent with a focal origin. Sites of earliest activation are distributed predominately along the crista terminalis and within or near the pulmonary veins. (J Cardiovasc Electrophysiol, Vol. 14, pp. ***-***, October 2003) [source] Characterization of Sustained Atrial Tachycardia in Dogs with Rapid Ventricular Pacing-Induced Heart FailureJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 5 2003Bruce S. Stambler M.D. Introduction: Atrial arrhythmias often complicate congestive heart failure (CHF). We characterized inducible atrial tachyarrhythmias and electrophysiologic alterations in dogs with CHF and atrial enlargement produced by rapid ventricular pacing. Methods and Results: Endocardial pacing leads were implanted in the right ventricle, right atrium, and coronary sinus in 18 dogs. The right ventricular lead was connected to an implanted pacemaker capable of rapid ventricular pacing. The atrial leads were used to perform electrophysiologic studies in conscious animals at baseline in all dogs, during CHF induced by rapid ventricular pacing at 235 beats/min in 15 dogs, and during recovery from CHF in 6 dogs. After20 ± 7 daysof rapid ventricular pacing, inducibility of sustained atrial tachycardia (cycle length120 ± 12 msec) was enhanced in dogs with CHF. Atrial tachycardia required a critical decrease in atrial burst pacing cycle length (,130 msec) for induction and often could be terminated by overdrive pacing. Calcium antagonists (verapamil, flunarizine, ryanodine) terminated atrial tachycardia and suppressed inducibility. Effective refractory periods at 400- and 300-msec cycle lengths in the right atrium and coronary sinus were prolonged in dogs with CHF. Atrial cells from dogs with CHF had prolonged action potential durations and reduced resting potentials and delayed afterdepolarizations (DADs). Mitochondria from atrial tissue from dogs with CHF were enlarged and had internal cristae disorganization. Conclusions: CHF promotes inducibility of sustained atrial tachycardia. Based on the mode of tachycardia induction, responses to pacing and calcium antagonists, and presence of DADs, atrial tachycardia in this CHF model has a mechanism most consistent with DAD-induced triggered activity resulting from intracellular calcium overload.(J Cardiovasc Electrophysiol, Vol. 14, pp. 499-507, May 2003) [source] Electrical Remodeling and Atrial Dilation During Atrial Tachycardia are Influenced by Ventricular Rate: Role of Developing TachycardiomyopathyJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 12 2001BAS A. SCHOONDERWOERD M.D. Atrial Remodeling in Tachycardiomyopathy. Introduction: Atrial fibrillation (AF) and congestive heart failure (CHF) are two clinical entities that often coincide. Our aim was to establish the influence of concomitant high ventricular rate and consequent development of CHF on electrical remodeling and dilation during atrial tachycardia. Methods and Results: A total of 14 goats was studied. Five goats were subjected to 3:1 AV pacing (A-paced group, atrial rate 240 beats/min, ventricular rate 80 beats/min). Nine goats were subjected to rapid 1:1 AV pacing (AV-paced group, atrial and ventricular rates 240 beats/min). During 4 weeks, right atrial (RA) and left ventricular (LV) diameters were measured during sinus rhythm. Atrial effective refractory periods (AERP) and inducibility of AF were assessed at three basic cycle lengths (BCL). After 4 weeks of rapid AV pacing, RA and LV diameters had increased to 151% and 113% of baseline, whereas after rapid atrial pacing alone, these parameters were unchanged. Right AERP (157 ± 10 msec vs 144 ± 16 msec at baseline with BCL of 400 msec in the A-paced and AV-paced group, respectively) initially decreased in both groups, reaching minimum values within 1 week. Subsequently, AERP partially recovered in AV-paced goats, whereas AERP remained short in A-paced goats (79 ± 7 msec vs 102 ± 12 msec after 4 weeks; P < 0.05). Left AERP demonstrated a similar time course. Inducibility of AF increased in both groups and reached a maximum during the first week in both groups, being 20% and 48% in the A-paced and AV-paced group, respectively. Conclusion: Nature and time course of atrial electrical remodeling and dilation during atrial tachycardia are influenced by concurrent high ventricular rate and consequent development of CHF. [source] Incidence and Clinical Significance of Inducible Atrial Tachycardia in Patients with Atrioventricular Nodal Reentrant TachycardiaJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 5 2001CHRISTIAN STICHERLING M.D. Significance of Atrial Tachycardia.Introduction: The purpose of this prospective study was to determine the prevalence and clinical significance of inducible atrial tachycardia in patients undergoing slow pathway ablation for AV nodal reentrant tachycardia who did not have clinically documented episodes of atrial tachycardia. Methods and Results: Twenty-seven (15%) of 176 consecutive patients who underwent slow pathway ablation for AV nodal reentrant tachycardia were found to have inducible atrial tachycardia with a mean cycle length of 351 ± 95 msec. The atrial tachycardia was sustained in 7 (26%) of 27 patients and was isoproterenol dependent in 20 patients (74%). The atrial tachycardia was not ablated or treated with medications, and the patients were followed for 9.7 ± 5.8 months. Six (22%) of the 27 patients experienced recurrent palpitations during follow-up. In one patient each, the palpitations were found to be due to sustained atrial tachycardia, nonsustained atrial tachycardia, recurrence of AV nodal reentrant tachycardia, paroxysmal atrial fibrillation, sinus tachycardia, and frequent atrial premature depolarizations. Thus, only 2 (7%) of 27 patients with inducible atrial tachycardia later developed symptoms attributable to atrial tachycardia. Conclusion: Atrial tachycardia may be induced by atrial pacing in 15% of patients with AV nodal reentrant tachycardia. Because the vast majority of patients do not experience symptomatic atrial tachycardia during follow-up, treatment for atrial tachycardia should be deferred and limited to the occasional patient who later develops symptomatic atrial tachycardia. [source] Temperature-Sensitive Focal Atrial Tachycardia in the Left AtriumJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 3 2000G. ANDRÉ NG M.B.CH.B., Ph.D. Temperature-Sensitive Focal Atrial Tachycardia. Temperature sensitivity has not been reported in focal atrial tachycardia. We describe a patient with a left atrial tachycardia whose tachycardia rate was affected by hot and cold drinks. The elTects were still evident after autonomic blockade. The arrhythmia focus was located at the entrance of the left upper pulmonary vein. Radiofrequency ablation was carried out, which proved to be difficult, but it was successful after several applications of energy, suggesting an epicardial location of the arrhytbmia focus. Sensitivity of atrial tachycardia rate to the temperature of food or drink ingested suggests a left atrial focus with a posterior and possibly epicardial location. [source] Atrial Tachycardia and "Kissing Catheters"JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 2 2000David S. Rosenbaum M.D. [source] Unusual ECG Pattern of Right Atrial Appendage Atrial Tachycardia in One Patient with Right PneumonectomyPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 5 2010KAZUYOSHI SUENARI M.D. The right atrial appendage atrial tachycardia (RAA AT) has been previously reported as a rare site in focal AT. We report a patient with a history of a right pneumonectomy who underwent catheter ablation of the AT originating from the RAA. This RAA AT showed unusual P-wave morphology compared with previous reports. We describe the RAA AT following right pneumonectomy using a NavX system (St. Jude Medical, St. Paul, MN, USA). (PACE 2010; e46,e48) [source] Prevalence and Characteristics of Left Atrial Tachycardia Following Left Atrial Catheter AblationPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 2007TORU HASHIMOTO M.D. Background: Left atrial tachycardia (AT) is a complication of left atrial catheter ablation (LACA) of atrial fibrillation (AF). However, its prevalence and characteristics have not been sufficiently clarified. Methods: We divided 121 patients who underwent LACA into 2 groups based on the results of AT occurrence after LACA (follow-up period; 12 ± 7 months): an AT+ group and AT, group. Results: New-onset left AT occurred in 30 patients (25%) 31 ± 51 days after LACA. Among the 26 patients with an early onset of AT, 4 underwent a second ablation for AT, and 21 became free of AT within 6 months without a repeat ablation procedure. Among the 4 patients with a late onset of AT (>2 months after the LACA), the tachycardia remitted without a repeat ablation procedure in a single patient within 6 months. Among 71 patients who underwent LACA with additional ablation lines, 22 (31%) developed new-onset left AT. Among 50 patients who underwent LACA alone, 8 (16%) developed new-onset left AT (P = 0.02). Conclusions: New-onset left AT is a frequent complication of LACA for AF, especially in men and in patients with a low left ventricular ejection fraction. Early (<2 months) onset AT does not require a repeat ablation because it often represents a transient phenomenon and disappears spontaneously. [source] Use of Intracardiac Echocardiography in Guiding Radiofrequency Catheter Ablation of Atrial Tachycardia in a Patient After the Senning OperationPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 11 2003ANITA KEDIA A patient with D-transposition of the great arteries developed drug refractory atrial tachycardia 12 years after a Senning operation. Electrophysiological study confirmed the presence of atrial baffle-tricuspid valve isthmus dependent reentrant intraatrial tachycardia. Intracardiac echocardiography facilitated initial identification of structures, catheter positioning, and identification of the atrial baffle-tricuspid valve isthmus. (PACE 2003; 26:2178,2180) [source] Sequential Ablation of Orthodromic Atrioventricular Tachycardia and Ectopic Atrial Tachycardia with a Single Application of Radiofrequency EnergyPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 1p1 2003NORIHIRO KOMIYA KOMIYA, N.,et al.: Sequential Ablation of Orthodromic Atrioventricular Tachycardia and Ectopic Atrial Tachycardia with a Single Application of Radiofrequency Energy. A 62-year-old woman with Wolff-Parkinson-White syndrome had two types of tachycardia; ectopic AT and orthodromic-type AVRT. A radiofrequency application 2 cm inside the coronary sinus ostium eliminated ectopic AT and accessory pathway conduction at once. (PACE 2003; 26[Pt. I]:108,109) [source] Atrial Tachycardia as the Presenting Sign of a Left Atrial Appendage AneurysmPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 2 2000ALAN B. WAGSHAL A patient presented with atrial tachycardia. The work-up, guided by the tachycardia morphology, led to the diagnosis of left atrial appendage aneurysm. Surgical removal of the atrial appendage resulted in cure of the tachycardia and associated symptoms. [source] P-P Cycle Alternans During Atrial Tachycardia:ANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 2 2000A Manifestation of Longitudinal Dissociation Within the Atrial Reentry Circuit Background: A-63 year-old man complaining of palpitations underwent a 24-hour ambulatory ECG monitoring that revealed the presence of recurrent episodes of nonsustained supraventricular tachycardia. Analysis of the tracings suggests an atrial origin of the arrhythmia. Tachycardias, quite regular at the beginning, suddenly showed a P-P cycle alternans, namely, P-P intervals alternately short and long. The evidence of two separate cycle ranges can be explained by the presence of a longitudinal dissociation within a discrete zone of the atrial circuit. [source] Atrial Tachycardias Encountered during and after Catheter Ablation for Atrial Fibrillation: Part I: Classification, Incidence, ManagementPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 3 2009GEORGE D. VEENHUYZEN M.D. First page of article [source] Ectopic Atrial Rhythm with Exit Block Following Catheter Ablation for Focal Atrial Tachycardias in a Patient with Prior Surgery for Atrial Septal DefectPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 6 2002KIMIE OHKUBO OHKUBO, K., et al.: Ectopic Atrial Rhythm with Exit Block Following Catheter Ablation for Focal Atrial Tachycardias in a Patient with Prior Surgery for Atrial Septal Defect. The patient was a 40-year-old woman with a history of surgery for atrial septal defect and catheter ablation for typical atrial flutter. An electrophysiological study was performed because she had palpitation and syncope. She had ectopic atrial rhythm originating from low lateral RA. Two focal atrial tachycardias ([1] superior vena cava-RA junction and [2] a low posteroseptal RA) were successfully ablated. Following catheter ablation for the second atrial tachycardia, she developed junctional rhythm because ectopic atrial rhythm showed exit block. However, atrial activation of junctional rhythm could conduct into the ectopic atrial rhythm focus and reset the rhythm when atrial activation of junctional rhythm reached the blocked line after atrial refractoriness by preceding ectopic atrial rhythm. [source] Characterization of Sustained Atrial Tachycardia in Dogs with Rapid Ventricular Pacing-Induced Heart FailureJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 5 2003Bruce S. Stambler M.D. Introduction: Atrial arrhythmias often complicate congestive heart failure (CHF). We characterized inducible atrial tachyarrhythmias and electrophysiologic alterations in dogs with CHF and atrial enlargement produced by rapid ventricular pacing. Methods and Results: Endocardial pacing leads were implanted in the right ventricle, right atrium, and coronary sinus in 18 dogs. The right ventricular lead was connected to an implanted pacemaker capable of rapid ventricular pacing. The atrial leads were used to perform electrophysiologic studies in conscious animals at baseline in all dogs, during CHF induced by rapid ventricular pacing at 235 beats/min in 15 dogs, and during recovery from CHF in 6 dogs. After20 ± 7 daysof rapid ventricular pacing, inducibility of sustained atrial tachycardia (cycle length120 ± 12 msec) was enhanced in dogs with CHF. Atrial tachycardia required a critical decrease in atrial burst pacing cycle length (,130 msec) for induction and often could be terminated by overdrive pacing. Calcium antagonists (verapamil, flunarizine, ryanodine) terminated atrial tachycardia and suppressed inducibility. Effective refractory periods at 400- and 300-msec cycle lengths in the right atrium and coronary sinus were prolonged in dogs with CHF. Atrial cells from dogs with CHF had prolonged action potential durations and reduced resting potentials and delayed afterdepolarizations (DADs). Mitochondria from atrial tissue from dogs with CHF were enlarged and had internal cristae disorganization. Conclusions: CHF promotes inducibility of sustained atrial tachycardia. Based on the mode of tachycardia induction, responses to pacing and calcium antagonists, and presence of DADs, atrial tachycardia in this CHF model has a mechanism most consistent with DAD-induced triggered activity resulting from intracellular calcium overload.(J Cardiovasc Electrophysiol, Vol. 14, pp. 499-507, May 2003) [source] Incidence and Clinical Significance of Inducible Atrial Tachycardia in Patients with Atrioventricular Nodal Reentrant TachycardiaJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 5 2001CHRISTIAN STICHERLING M.D. Significance of Atrial Tachycardia.Introduction: The purpose of this prospective study was to determine the prevalence and clinical significance of inducible atrial tachycardia in patients undergoing slow pathway ablation for AV nodal reentrant tachycardia who did not have clinically documented episodes of atrial tachycardia. Methods and Results: Twenty-seven (15%) of 176 consecutive patients who underwent slow pathway ablation for AV nodal reentrant tachycardia were found to have inducible atrial tachycardia with a mean cycle length of 351 ± 95 msec. The atrial tachycardia was sustained in 7 (26%) of 27 patients and was isoproterenol dependent in 20 patients (74%). The atrial tachycardia was not ablated or treated with medications, and the patients were followed for 9.7 ± 5.8 months. Six (22%) of the 27 patients experienced recurrent palpitations during follow-up. In one patient each, the palpitations were found to be due to sustained atrial tachycardia, nonsustained atrial tachycardia, recurrence of AV nodal reentrant tachycardia, paroxysmal atrial fibrillation, sinus tachycardia, and frequent atrial premature depolarizations. Thus, only 2 (7%) of 27 patients with inducible atrial tachycardia later developed symptoms attributable to atrial tachycardia. Conclusion: Atrial tachycardia may be induced by atrial pacing in 15% of patients with AV nodal reentrant tachycardia. Because the vast majority of patients do not experience symptomatic atrial tachycardia during follow-up, treatment for atrial tachycardia should be deferred and limited to the occasional patient who later develops symptomatic atrial tachycardia. [source] Catheter Ablation of Peri-AV Nodal Atrial Tachycardia from the Noncoronary Cusp of the Aortic ValveJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 3 2008Ph.D, SAUMYA DAS M.D. Introduction: Atrial tachycardias (AT) originating from the anteroseptal region of the aortic root, near the atrioventricular node can be challenging to eliminate safely by catheter ablation. In this study, we examine the characteristics of anteroseptal ATs in a cohort of patients at our centers, and demonstrate the long-term efficacy and safety of targeting the arrhythmias from within the base of the noncoronary aortic valve cusp (NCC). Methods & Results: From among a cohort of 54 patients with symptomatic focal AT undergoing invasive electrophysiological evaluation, the point of earliest right atrial (RA) activation was at the peri-AV nodal region in 10 patients, just postero-superior to the His-bundle. Before further mapping, RA lesions placed in two patients were unsuccessful in eliminating the arrhythmia. Because of its proximity to the interatrial septum, the base of the NCC was mapped using a retrograde aortic approach, and revealed a point of early activation without the presence of a His potential. The arrhythmia terminated with <10 seconds of radiofrequency or cryothermal energy delivery and was successfully eliminated in 7 of 10 patients. Transient termination or acceleration of the AT was noted in the other three patients, prompting successful ablation from a left atrial septal position or a reattempt from a para-Hisian RA position. All patients have been arrhythmia free during follow-up (41 ± 12 months). Conclusions: Catheter ablation from within the base of the NCC represents a safe and effective means to eliminate focal AT arising from the peri-AV nodal region. [source] Characteristics of Complex Fractionated Electrograms in Nonpulmonary Vein Ectopy Initiating Atrial Fibrillation/Atrial TachycardiaJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 12 2009LI-WEI LO M.D. Background: Nonpulmonary vein (PV) ectopy initiating atrial fibrillation (AF)/atrial tachycardia (AT) is not uncommon in patients with AF. The relationship of complex fractionated atrial electrograms (CFAEs) and non-PV ectopy initiating AF/AT has not been assessed. We aimed to characterize the CFAEs in the non-PV ectopy initiating AF/AT. Methods: Twenty-three patients (age 53 ± 11 y/o, 19 males) who underwent a stepwise AF ablation with coexisting PV and non-PV ectopy initiating AF or AT were included. CFAE mapping was applied before and after the PV isolation in both atria by using a real-time NavX electroanatomic mapping system. A CFAE was defined as a fractionation interval (FI) of less than 120 ms over 8-second duration. A continuous CFAE (mostly, an FI < 50 ms) was defined as electrogram fractionation or repetitive rapid activity lasting for more than 8 seconds. Results: All patients (100%) with non-PV ectopy initiating AF or AT demonstrated corresponding continuous CFAEs at the firing foci. There was no significant difference in the FI among the PV ostial or non-PV atrial ectopy or other atrial CFAEs (54.1 ± 5.6, 58.3 ± 11.3, 52.8 ± 5.8 ms, P = 0.12). Ablation targeting those continuous CFAEs terminated the AF and AT and eliminated the non-PV ectopy in all patients (100%). During a follow-up of 7 months, 22% of the patients had an AF recurrence with PV reconnections. There was no recurrence of any ablated non-PV ectopy during the follow-up. Conclusion: The sites of the origin of the non-PV ectopies were at the same location as those of the atrial continuous CFAEs. Those non-PV foci were able to initiate and sustain AF/AT. By limited ablation targeting all atrial continuous CFAEs, the AF could be effectively eliminated. [source] Acute atrial arrhythmogenesis in murine hearts following enhanced extracellular Ca2+ entry depends on intracellular Ca2+ storesACTA PHYSIOLOGICA, Issue 2 2010Y. Zhang Abstract Aim:, To investigate the effect of increases in extracellular Ca2+ entry produced by the L-type Ca2+ channel agonist FPL-64176 (FPL) upon acute atrial arrhythmogenesis in intact Langendorff-perfused mouse hearts and its dependence upon diastolic Ca2+ release from sarcoplasmic reticular Ca2+ stores. Methods:, Confocal microscope studies of Fluo-3 fluorescence in isolated atrial myocytes were performed in parallel with electrophysiological examination of Langendorff-perfused mouse hearts. Results:, Atrial myocytes stimulated at 1 Hz and exposed to FPL (0.1 ,m) initially showed (<10 min) frequent, often multiple, diastolic peaks following the evoked Ca2+ transients whose amplitudes remained close to control values. With continued pacing (>10 min) this reverted to a regular pattern of evoked transients with increased amplitudes but in which diastolic peaks were absent. Higher FPL concentrations (1.0 ,m) produced sustained and irregular patterns of cytosolic Ca2+ activity, independent of pacing. Nifedipine (0.5 ,m), and caffeine (1.0 mm) and cyclopiazonic acid (CPA) (0.15 ,m) pre-treatments respectively produced immediate and gradual reductions in the F/F0 peaks. Such nifedipine and caffeine, or CPA pre-treatments, abolished, or reduced, the effects of 0.1 and 1.0 ,m FPL on cytosolic Ca2+ signals. FPL (1.0 ,m) increased the incidence of atrial tachycardia and fibrillation in intact Langendorff-perfused hearts without altering atrial effective refractory periods. These effects were inhibited by nifedipine and caffeine, and reduced by CPA. Conclusion:, Enhanced extracellular Ca2+ entry exerts acute atrial arrhythmogenic effects that is nevertheless dependent upon diastolic Ca2+ release. These findings complement reports that associate established, chronic, atrial arrhythmogenesis with decreased overall inward Ca2+ current. [source] Scn3b knockout mice exhibit abnormal sino-atrial and cardiac conduction propertiesACTA PHYSIOLOGICA, Issue 1 2010P. Hakim Abstract Aim:, In contrast to extensive reports on the roles of Nav1.5 , -subunits, there have been few studies associating the , -subunits with cardiac arrhythmogenesis. We investigated the sino-atrial and conduction properties in the hearts of Scn3b,/, mice. Methods:, The following properties were compared in the hearts of wild-type (WT) and Scn3b,/, mice: (1) mRNA expression levels of Scn3b, Scn1b and Scn5a in atrial tissue. (2) Expression of the ,3 protein in isolated cardiac myocytes. (3) Electrocardiographic recordings in intact anaesthetized preparations. (4) Bipolar electrogram recordings from the atria of spontaneously beating and electrically stimulated Langendorff-perfused hearts. Results:,Scn3b mRNA was expressed in the atria of WT but not Scn3b,/, hearts. This was in contrast to similar expression levels of Scn1b and Scn5a mRNA. Immunofluorescence experiments confirmed that the ,3 protein was expressed in WT and absent in Scn3b,/, cardiac myocytes. Lead I electrocardiograms from Scn3b,/, mice showed slower heart rates, longer P wave durations and prolonged PR intervals than WT hearts. Spontaneously beating Langendorff-perfused Scn3b,/, hearts demonstrated both abnormal atrial electrophysiological properties and evidence of partial or complete dissociation of atrial and ventricular activity. Atrial burst pacing protocols induced atrial tachycardia and fibrillation in all Scn3b,/, but hardly any WT hearts. Scn3b,/, hearts also demonstrated significantly longer sinus node recovery times than WT hearts. Conclusion:, These findings demonstrate, for the first time, that a deficiency in Scn3b results in significant atrial electrophysiological and intracardiac conduction abnormalities, complementing the changes in ventricular electrophysiology reported on an earlier occasion. [source] Electrophysiologic and electrocardiographic characteristics of focal atrial tachycardia arising from superior tricuspid annulusINTERNATIONAL JOURNAL OF CLINICAL PRACTICE, Issue 7 2008J. X. Yin Summary Objectives:, This study describes the electrophysiologic and electrocardiographic characteristics of focal atrial tachycardia (AT) arising from superior tricuspid annulus in six (1.9%) patients of a consecutive series of 320 patients. Methods:, Six patients (mean age 42 ± 22 years) with a mean cycle length of 326 ms of a consecutive series of 320 patients undergoing radiofrequency ablation for focal AT were mapped. Results:, During electrophysiologic study, tachycardia could be induced in five patients with programmed atrial extrastimuli while a spontaneous onset and offset with ,warm-up and cool-down' phenomenon was seen in the other patient. During tachycardia, P-wave morphology in Lead I, II, III and aVF was upright in all the six patients. The precordial leads were dominantly negative or isoelectric in V1,V2 and positive in V5,V6 with a transition at V3 or V4. Moreover, the tachycardia was sensitive to intravenous administration of adenosine triphosphate in five of six patients. Conclusions:, Radiofrequency ablation was performed successfully in all patients (mean 4.5 ± 1.2 applications). No recurrence of AT was observed after a mean follow-up of 8 ± 6 months. Thus, AT arising from superior tricuspid annulus is rare. Radiofrequency ablation of this kind of AT is safe and effective. [source] Electrophysiologic characteristics and radiofrequency ablation of focal atrial tachycardia arising from para-Hisian regionINTERNATIONAL JOURNAL OF CLINICAL PRACTICE, Issue 3 2007Y. Zhou Summary This study describes the electrophysiologic characteristics and radiofrequency ablation of focal atrial tachycardia (AT) arising from para-Hisian region in 14 (6.0%) patients of a consecutive series of 224 patients patients. Inverted or biphasic P wave in V1 and uncharacteristic P wave in inferior leads were observed during tachycardia, suggesting that there isn't a characteristic P-wave morphology for para-Hisian AT. During electrophysiological study, tachycardia could be induced with programmed atrial extrastimuli in 11 patients while a spontaneous onset and offset with ,warm-up and cool-down' phenomenon were seen in other three patients. Moreover, the tachycardias were sensitive to intravenous administration of adenosine triphosphate in all patients. On the basis of these findings, the mechanism is suggestive of triggered activity or micro-reentry, but automaticity cannot be conclusively excluded. Radiofrequency energy was delivered to the earliest site of atrial activation during AT. Ablating energy was carefully titrated, starting at 5 W and increasing gradually upto a maximum of 40 W, to achieve the ceasing of tachycardia. The long-term outcome was a 100% success rate in these 14 patients and there were no irreversible complications associated with ablation. Thus, the mapping and ablation of focal AT arising from para-Hisian region is safe and effective, delivery of radiofrequency energy in a titrated manner and continuous monitoring of atrioventricular (AV) conduction advocated to minimise the risk of damage to the anterograde AV conduction. [source] | ||||||||||