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PubMed2002

Double potential interval and transisthmus conduction time for prediction of cavotricuspid isthmus block after ablation of typical atrial flutter.

BACKGROUND: Complete bi-directional isthmus block is the endpoint of typical atrial flutter ablation. The purpose of this study was to investigate the feasibility of the local double potential (DP) interval and the change in transisthmus conduction time for predicting complete isthmus block after ablation of the cavotricuspid isthmus. METHODS: The study population consisted of 32 patients with typical atrial flutter after a procedure of radiofrequency (RF) ablation of the cavotricuspid isthmus (16 had incomplete block and 16 had complete block). The transisthmus conduction time was determined during pacing from the proximal coronary sinus and low lateral right atrium before and after RF ablation. The DP interval close to the ablation line was evaluated after final RF energy application. RESULTS: In the counterclockwise direction, transisthmus conduction time had an increase of 37 +/- 25.4% and 127.3 +/- 35.5% (P < 0.001), and the DP interval was 63.3 +/- 8.7 ms and 120 +/- 17.4 ms (P < 0.001) after achievement of incomplete and complete block, respectively. The sensitivity, specificity, positive and negative predictive values of an increase in the transisthmus conduction time > or =50% were 100%, 81%, 84% and 100%, respectively; those of DP interval > or =100 ms were 100%. In the clockwise direction, transisthmus conduction time had an increase of 38.8 +/- 28.6% and 135.7 +/- 63.6% (P < 0.001), and the DP interval was 63.6 +/- 13.8 ms and 127.7 +/- 27.1 ms (P < 0.001) after achievement of incomplete and complete block, respectively. The sensitivity, specificity, positive and negative predictive values of an increase in the transisthmus conduction time > or =50% were 100%, 67%, 83% and 100%, respectively; those of the DP interval > or =100 ms were 100%. CONCLUSIONS: The transisthmus conduction time > or =50% increase or DP interval > or =100 ms was feasible to predict complete bi-directional isthmus block.

Action Potentials↗
PubMed1993

[The electrophysiological diagnosis and surgical treatment of atrial flutter].

From 1982 to the late 1990 thirty-three patients with tachysystolic atrial fibrillation refractory to preventive antiarrhythmic therapy were examined and operated on. Invasive electrophysiological investigation was a must in the preoperative examination. The "entrainment" and "adaptation" effects of the refractory periods of different parts of the atria were estimated depending on the duration of the basic cycle of pacing. After provoking atrial flutter paroxysm the place of the early appearance of A spike was determined and endocardial mapping was performed. During intraoperative mapping, the data of low-amplitude and fragmented activity were processed by a computer; the sequence of electric activation of the atria was determined on flutter. 20 transthoracic operations with extracorporeal circulation were made. Of these, there were 7 operations of laser or cryogenic isolation of the AB node, 30 of laser photo ablation, and 9 of cryodestruction of the arrhythmogenic areas. In a female patient, resection of the terminal crest and sinoatrial node followed by implantation of a pacemaker was performed in the AAI mode. Closed operations involved both transvenous electrodestruction of the arrhythmogenic areas (5 patients) and destruction of the His bundle with the development of complete transverse block and implantation of the pacemaker in the VVI mode. The best results were attained in young persons with Type I idiopathic atrial flutter where areas of fragmented and low-amplitude activity could be accurately specified.

Adolescent↗
PubMed1998

Isolated neonatal atrial flutter: clinical features, prognosis and therapy.

BACKGROUND: Concern exists in literature about the clinical course, the best acute and chronic treatment and the prognosis of idiopathic neonatal atrial flutter. The aim of our study was to evaluate this in a population of our patients with this type of arrhythmia. METHODS: Six infants (3 M, 3 F, mean age 42 +/- 62 days, range 1-150) affected with atrial flutter without structural heart disease were studied and then acutely and chronically treated. The effectiveness of chronic antiarrhythmic treatment was evaluated with Holter monitoring every 3 months for the first year of life and with transesophageal atrial pacing. RESULTS: Mean arrhythmia cycle length was 180 +/- 34 ms with atrioventricular conduction ratio ranging between 1:1 and 3:1. Two patients with clinical signs of heart failure were successfully treated with DC shock. Transesophageal overdrive atrial pacing was successfully used in one patient treated with i.v. propafenone without benefit. In the remaining three patients, cardioversion was achieved with amiodarone after digoxin had failed in all three and propafenone had failed in two of them. To prevent recurrences, we treated four patients with amiodarone, one with amiodarone combined with propranolol and one with digoxin. During the follow-up (22 +/- 11 months), neither arrhythmia recurrences nor side-effects of the therapy occurred. CONCLUSIONS: Neonatal atrial flutter is an arrhythmia with significant acute morbidity but an excellent long-term prognosis. Electrical cardioversion is the first-choice treatment when the arrhythmia is not well-tolerated hemodynamically, while class III antiarrhythmic drugs such as amiodarone should be preferred in the other cases.

Amiodarone↗
PubMed1986

Noninvasive conversion of atrial flutter using a multiprogrammable DDD pulse generator.

A patient with sick sinus syndrome and resistant paroxysmal atrial flutter was treated with amiodarone and implanted with a Medtronic 7005 DDD pacemaker. Following discontinuation of amiodarone, an episode of sustained atrial flutter was converted to sinus rhythm by noninvasive rapid atrial pacing in the outpatient clinic. This case illustrates one of the many capabilities for arrhythmic intervention using currently available implanted pacemakers.

Amiodarone↗
PubMed1994

Overdrive pacing for atrial flutter.

To determine the incidence and predictors of conversion to normal sinus rhythm, a total of 124 procedures using a standard pacing protocol were performed in 101 consecutive inpatients referred for pace termination of atrial flutter. Normal sinus rhythm was achieved in 75 pace termination procedures (60%), including 10 in which atrial fibrillation occurred initially and later converted spontaneously. Sustained atrial fibrillation was provoked in 39 procedures, and atrial flutter persisted in 10. Clinical and laboratory parameters, including use of antiarrhythmic drugs, were not helpful in predicting the outcome of pacing. Of 17 patients undergoing repeat pacing for recurrent flutter, concordant results were obtained in only 4. It is concluded that: (1) overdrive pacing is only a moderately effective means of restoring sinus rhythm in patients with atrial flutter, although some change in rhythm occurs in the vast majority; (2) pacing-induced atrial fibrillation may be unstable and spontaneously converts to sinus rhythm in > 20% of cases; (3) there are no clinically useful predictors of success; (4) antiarrhythmic drugs do not facilitate pacing-induced conversion to sinus rhythm; and (5) failure to convert to sinus rhythm with 1 episode of flutter does not preclude success on subsequent occasions.

Aged↗
PubMed2005

Cryothermal ablation treatment of atrial flutter--experience with a new 9 French 8 mm tip catheter.

BACKGROUND: Cardiac cryoablation has been used to successfully treat a variety of arrhythmias. OBJECTIVE: This study documents our experience with a new 9 French (FR) 8 mm cryocatheter for ablation treatment of symptomatic atrial flutter. METHODS: A total of 77 consecutive patients with symptomatic atrial flutter were treated. Electrophysiological studies (EPS) were performed with diagnostic catheters and ablation was performed with a 9FR, 8 mm tip, quadripolar cryocatheter (Freezor MAX catheter, CryoCath Technologies Inc., Kirkland, Canada). Cryoablation at -75 degrees C for 8 minutes was performed, beginning at the inferior rim of the coronary sinus (CS) os and creating a posterior line to the Eustachian ridge. Safety, bidirectional isthmus block at intervention, and recurrence at 3 months post procedure were assessed. RESULTS: There were no adverse events reported. All patients remained free of discomfort on cryoenergy delivery. The acute success rate at intervention was 96% for all patients and 100% for those with common atrial flutter. Follow-up data from 47 patients showed 33 (70%) patients without conduction recurrence on repeat EPS at 3 months. Although, 1 (2%) patient had both symptom and conduction recurrence. Data available from 53 acutely successful patients at 6 month clinical follow-up showed that 48 (91%) patients were asymptomatic and 5 (9%) patients had recurrence documented by ECG and/or patient diary records. CONCLUSIONS: Our experience with a new 9FR, 8 mm tip, quadripolar cryocatheter yielded a high success rate at intervention and an excellent safety profile. Although repeat EPS at 3 months post ablation identified conduction recurrence in 30% of patients, at 6 month clinical follow-up only 9% of patients had recurrence. Further monitoring is necessary to assess whether the relatively low recurrence rate observed at 6 month clinical follow-up is maintained over the long term.

Atrial Flutter↗
PubMed2005

Ibutilide--recent molecular insights and accumulating evidence for use in atrial flutter and fibrillation.

Ibutilide is a 'pure' class III antiarrhythmic drug, used intravenously against atrial flutter and fibrillation. At a cellular level it exerts two main actions: induction of a persistent Na+ current sensitive to dihydropyridine Ca2+ channel blockers and potent inhibition of the cardiac rapid delayed rectifier K+ current, by binding within the channel pore cavity upon channel gating. Ibutilide has been shown to terminate atrial flutter and fibrillation in animal studies, with some risk of ventricular pro-arrhythmia. Experimental models of hypertrophy/heart failure show altered sensitivity to ibutilide, with increased dispersion of repolarisation and incidence of pro-arrhythmia. Patient trials show that ibutilide is effective at terminating atrial arrhythmias when given alone, and that it can increase effectiveness and reduce energy requirements of electrical cardioversion. The risk to patients of polymorphic ventricular tachycardia necessitates careful patient selection and monitoring during and after treatment. An ibutilide analogue, trecetilide, requires further investigation but may offer a less readily metabolised and pro-arrhythmic alternative to ibutilide.

Animals↗
PubMedDate not supplied

Pseudoconduction of atrial flutter of a recipient atrium.

A nine-year-old girl had an episode of atrial flutter and a nonsustained wide QRS tachycardia during her initial hospitalization after orthotopic heart transplantation. Evaluation of her ECG and telemetric tracing revealed atrial flutter of the recipient atrium and sinus rhythm of the donor atrium. The wide QRS tachycardia was an accelerated ventricular rhythm that was also found on subsequent 24-hour ambulatory ECG monitoring. Timely recognition of recipient atrial arrhythmias prevents inappropriate clinical intervention.

Atrial Flutter↗
PubMed2005

Comparative efficacy of monophasic and biphasic waveforms for transthoracic cardioversion of atrial fibrillation and atrial flutter.

BACKGROUND: Transthoracic cardioversion fails to restore sinus rhythm in 6% to 33% of patients with atrial fibrillation. This study sought to determine the relative efficacy of biphasic waveforms compared with monophasic waveforms in the treatment of atrial arrhythmias. METHODS: A total of 912 patients underwent 1022 transthoracic cardioversions between May 2000 and December 2001. A monophasic damped sine waveform was used in the first 304 cases, and a rectilinear biphasic defibrillator was used in the next 718 cases. RESULTS: Use of a biphasic waveform was associated with 94% success in conversion to sinus rhythm compared with 84% with a monophasic waveform (P < .001). The cumulative energy required to restore sinus rhythm was lower with biphasic shocks in both atrial fibrillation and atrial flutter groups (554 +/- 413 J for monophasic vs 199 +/- 216 J for biphasic shocks in the atrial fibrillation group, P < .001; 251 +/- 302 J vs 108 +/- 184 J, respectively, in the atrial flutter group, P < .001). In a multivariate analysis, use of a biphasic shock was associated with a 3.9-fold increase in success of cardioversion. CONCLUSION: When used to cardiovert atrial arrhythmias, the rectilinear biphasic waveform was associated with higher success rates and lower cumulative energies than the monophasic damped sine waveform.

Aged↗
PubMed2006

Right ventricular pacing to assess transisthmus conduction in patients undergoing isthmus-dependent atrial flutter ablation: a new useful technique?

BACKGROUND: Successful radiofrequency (RF) ablation of typical, isthmus-dependent atrial flutter requires establishment and confirmation of bidirectional conduction block across the cavotricuspid isthmus. Low atrial pacing usually is performed from the bipoles of the 20-pole Halo catheter, septal and lateral to the cavotricuspid isthmus ablation line. However, occasionally this is difficult because of high pacing thresholds and/or saturation of the atrial electrograms recorded near the pacing catheter. OBJECTIVES: The purpose of this study was to assess if right ventricular (RV) pacing and resulting retrograde atrial activation can be used to assess conduction block from the septum to the lateral wall in a clockwise direction. METHODS: Thirty-five consecutive male patients (mean age 64 +/- 10 years; mean ejection fraction 42 +/- 13%; mean left atrial dimension 44 +/- 6 mm) with typical isthmus-dependent atrial flutter were studied. The following electrophysiology catheters were used: 20-pole catheter along the tricuspid annulus, quadripolar catheters at the His and/or RV apex, and 8-mm ablation catheter. Following RF ablation of the cavotricuspid isthmus, bidirectional conduction block was confirmed in all 35 patients by pacing at a cycle length of 600 ms from bipoles septal and lateral to the cavotricuspid isthmus ablation line. Conduction times from pacing artifact to adjacent bipolar atrial electrograms and reversal of atrial activation pattern were analyzed. RV pacing was performed and retrograde atrial activation pattern assessed. If retrograde AV nodal conduction was absent, isoproterenol was infused intravenously at 2 microg/min, and RV pacing was repeated. The conduction time between the double potentials across the cavotricuspid isthmus ablation line was measured. RESULTS: Mean conduction times across the isthmus during septal (S), lateral (L), and RV pacing were 145 +/- 21 ms, 144 +/- 24 ms, and 129 +/- 20 ms, respectively. Retrograde AV nodal conduction was present in 34 of 35 patients (isoproterenol 8 patients). Evidence of conduction block by a clear change in activation pattern across the isthmus was seen during RV pacing in 33 of 35 patients with bidirectional conduction block. CONCLUSION: RV pacing is a simple and easy maneuver that can be performed to assess isthmus conduction in most patients.

Atrial Flutter↗
PubMed2001

Role of transisthmus conduction intervals in predicting bidirectional block after ablation of typical atrial flutter.

INTRODUCTION: Complete bidirectional cavotricuspid isthmus block is the endpoint for ablation of typical atrial flutter. The purpose of this study was to determine whether the extent of prolongation of the transisthmus interval after ablation predicts complete bidirectional block. METHODS AND RESULTS: Fifty-seven consecutive patients underwent 60 ablation procedures for isthmus-dependent atrial flutter. The clockwise and counterclockwise transisthmus intervals were determined before and after ablation during pacing from the low lateral right atrium and the coronary sinus. Bidirectional block was achieved with ablation in 55 (96%) of 57 patients. The transisthmus intervals before ablation and after complete transisthmus block were 100.3 +/- 21.1 msec and 195.8 +/- 30.1 msec, respectively, in the clockwise direction (P < 0.0001), and 98.2 +/- 24.7 msec and 185.7 +/- 33.9 msec, respectively, in the counterclockwise direction (P < 0.0001). An increase in the transisthmus interval by > or = 50% in both directions after ablation predicted complete bidirectional block with 100% sensitivity and 80% specificity. The positive and negative predictive values were 89% and 100%, respectively. The diagnostic accuracy of a > or = 50% prolongation in the transisthmus interval was 92%. CONCLUSION: Prolongation of the transisthmus interval by > or = 50% in the clockwise and counterclockwise directions is associated with a high degree of diagnostic accuracy and an excellent negative predictive value in determining complete bidirectional transisthmus block. This may be a useful and simple adjunctive criterion for assessment of complete transisthmus conduction block.

Aged↗
PubMed1992

Recurrent atrial flutter in apical hypertrophic cardiomyopathy.

Palpitations are a symptom often reported by patients with apical hypertrophic cardiomyopathy (HCM), yet the arrhythmias associated with this type of HCM have not been studied adequately. Herein, a case of persistently recurrent atrial flutter in a 63-year-old Greek man with apical HCM is presented. Synchronized direct-current shocks were used twice during his hospitalization in order to convert atrial flutter to sinus rhythm. No definite precipitating factor for the induction of atrial flutter was identified.

Amiodarone↗
PubMed1995

Safety and efficacy of intravenous diltiazem in atrial fibrillation or atrial flutter.

This study examines the efficacy of various doses of intravenous diltiazem to control the ventricular response during atrial fibrillation or atrial flutter. Control of the ventricular response of patients with atrial fibrillation and a rapid ventricular response can provide patients with relief of symptoms and improve hemodynamics. Eighty-four consecutive patients with atrial fibrillation or atrial flutter, or both, received an intravenous bolus dose of diltiazem followed by a continuous infusion of diltiazem at 5, 10, and 15 mg/hour. The mean ventricular response and blood pressure were monitored. Overall, 94% of patients (79 of 84) responded to the bolus dose with a > 20% reduction in heart rate from baseline, a conversion to sinus rhythm, or a heart rate < 100 beats/min. Seventy-eight patients received the continuous infusion. After 10 hours of infusion, 47% of patients (confidence interval [CI]: 36%, 59%) had maintained response with the 5 mg/hour infusion, 68% (CI: 57%, 79%) maintained response after the infusion was titrated to 10 mg/hour, and 76% (CI: 66%, 85%) after titration from the 5 and 10 mg/hour infusion to the 15 mg/hour dose. For the 3 diltiazem infusions studied, mean (+/- SD) heart rate was reduced from a baseline value of 144 +/- 14 beats/min to 98 +/- 19, 107 +/- 25, 107 +/- 22, 101 +/- 22, 91 +/- 17, and 88 +/- 18 beats/min at infusion times 0, 1, 2, 4, 8, and 10 hours, respectively. By the end of the infusion, 18% of patients (14 of 78) had conversion to sinus rhythm.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1989

Transesophageal atrial pacing: a first-choice technique in atrial flutter therapy.

Here we report on a study of 181 episodes of spontaneous atrial flutter (AF) (mean atrial cycle length 250 +/- 32 msec) treated by transesophageal atrial pacing (TAP) in 138 patients (92 men and 46 women; mean age 59.5 +/- 12.6 years). TAP was effective in 163 episodes (90%); sinus rhythm resumption was immediate in 36 (19.9%) and followed a short period of atrial fibrillation in 64 (35.3%); in 63 episodes (34.8%) a stable atrial fibrillation was obtained. TAP was unsuccessful in 18 cases (10%). All the patients tolerated the procedure well. A statistical elaboration with the Fisher exact test did not evidence a correlation between efficacy and age, sex, atrial cycle length, or underlying heart disease but showed a significant correlation between efficacy and AF duration of less than 1 day (p less than 0.05) and absence of antiarrhythmic pharmacologic pretreatment (p less than 0.01). These data strongly support the immediate first-choice use of TAP in AF therapy.

Adult↗
PubMed2004

Effect of chronic amiodarone therapy on excitable gap during typical human atrial flutter.

INTRODUCTION: Class I antiarrhythmic drugs increase duration of the excitable gap (EG) during typical atrial flutter whereas intravenous class III drugs decrease the EG. The effect of chronic oral amiodarone therapy on the EG is unknown. METHODS AND RESULTS: EG was prospectively determined by introducing a premature stimulus and analyzing the response pattern during typical atrial flutter in 30 patients without antiarrhythmic drugs and in 20 patients under chronic oral amiodarone therapy. EG was calculated by the difference between the longest coupling interval leading to resetting and the effective atrial refractory period (EARP). A fully EG was defined by the portion of EG where the response curve of the return cycles was flat. A partially EG was defined by the portion of EG where the return cycle increases while coupling interval decreases. A resetting response curve was constructed by plotting the duration of the return cycle against the value of the coupling interval. Cycle length (CL; 222 +/- 17 vs 267 +/- 20 msec, P < 0.0001), EARP (128 +/- 16 vs 152 +/- 18 msec, P < 0.0001), and EG (54 +/- 19 vs 70 +/- 21 msec, P = 0.01) were significantly longer in patients taking amiodarone than in controls. Compared to CL, the relative part of the EARP (57 +/- 7 vs 57 +/- 6%, P = 0.96) and EG (24 +/- 7 vs 26 +/- 8%, P = 0.41) were comparable in both groups. The fully EG was larger in patients under chronic amiodarone therapy than in controls (39 +/- 21 vs 26 +/- 20 msec, P = 0.03). Neither duration of the partially EG (28 +/- 15 vs 31 +/- 15 msec, P = 0.42) nor slope of the ascending portion of the resetting response curve (1.15 +/- 0.5 vs 1.13 +/- 0.4 msec/msec, P = 0.71) differed between the two groups. CONCLUSION: EG in patients under chronic amiodarone therapy is significantly larger than in controls, mainly because of a longer fully EG. This observation may be explained by opposite effects on conduction velocity and refractoriness.

Administration, Oral↗
PubMed2000

Impact of transisthmus linear ablation of typical atrial flutter on coronary sinus activation time.

Complete or incomplete bidirectional isthmus conduction block after linear ablation of atrial flutter is difficult to interpret without detailed multiple electrodes mapping along the tricuspid annulus and the low right atrial isthmus area. The influence of isthmus block on the intraatrial septal and coronary sinus activation has not been assessed by endocardial mapping. This study was designed to analyze the intraartial and interatrial activation times in a retrospective fashion to investigate (1) whether isthmus conduction block can change the coronary sinus activation sequence during low lateral right atrial pacing, and (2) the correlation between change of coronary sinus activation time and isthmus conduction block. Sixty-five consecutive patients (mean age, 57 +/- 18 years) with clinically documented typical atrial flutter were studied. A 20-pole "Halo" catheter was placed around the tricuspid annulus including the entire low right atrial isthmus to verify complete bidirectional isthmus block. Activation time from ostium to distal coronary sinus (OCS-->DCS), and interatrial septum and isthmus activation times during right atrial pacing were analyzed and compared before and after incomplete or complete isthmus block. Complete bidirectional isthmus block was achieved in 50 (77%) patients. During low lateral right atrial pacing, linear ablation at low right atrial isthmus results in a significant delay of activation in all coronary sinus recording sites with greater extent at the ostium area without influence on interatrial septum activation in complete and incomplete isthmus conduction block. The difference of the OCS-->DCS interval before and after ablation, delta (OCS-->DCS), was well correlated with results of isthmus conduction block and significantly longer in patients with complete than those with incomplete isthmus block (34 +/- 11 vs 11 +/- 8 ms, P < 0.001), thereby allowing a value of 20 ms as a discriminative parameter to differentiate incomplete (< 20 ms) from complete (> or = 20 ms) isthmus counterclockwise conduction block with a sensitivity of 96% and a specificity of 88%. In conclusion, creation of a line of block at the inferior vena cava-tricuspid annulus isthmus could change coronary sinus activation sequence during low lateral right atrial pacing in sinus rhythm. The change of coronary sinus activation time after linear ablation, delta (OCS-->DCS), was well correlated with isthmus conduction block by using a value > or = 20 ms to discern complete counterclockwise isthmus block.

Adolescent↗
PubMed1990

Circus movement atrial flutter in the canine sterile pericarditis model. Activation patterns during initiation, termination, and sustained reentry in vivo.

The mechanisms of single-loop reentry in a syncytium without anatomically predetermined pathways have not been shown. Using a "jacket electrode" with 111 bipolar electrodes in a nylon matrix, we mapped in situ the atrial epicardial surface during atrial flutter in dogs with sterile pericarditis. Of 21 episodes of reentrant atrial flutter, only four showed double-loop ("figure-eight") reentry, whereas in 17 episodes a single loop was present. During initiation of single-loop reentry, an arc of functional block extended to the atrioventricular (AV) ring. This forced activation to proceed as a single wave around the free end of the arc, before breaking through the arc close to the AV ring. Activation continued as one loop around an arc close to the AV ring (in eight episodes) or around a combined functional and anatomic obstacle (in nine episodes) when the arc joined an atrial vessel. A zone of slow conduction was consistently bordered by the arc of block and the AV ring or by the anatomic obstacle and the AV ring. Spontaneous termination occurred when conduction failed in this area and the arc rejoined the AV ring. High-density recordings (2 mm) along the arc of block showed double potentials separated by an isoelectric interval, interpreted as local activation and electrotonus due to activation on the opposite side of the arc. Histologically, a diffuse inflammatory reaction involved 50-80% of the atrial wall. A transitional layer of myocardial bundles with preserved cross striation, but separated by edema and inflammatory cells, was enclosed between an epicardial layer of fragmented myocytes and an endocardial layer of grossly intact myocardium. There were no distinctive features at sites of functional conduction block or slowed conduction. In conclusion, single-loop reentry is the common pattern during atrial flutter in this model. Its induction depends on an interaction of the AV ring, a functional arc of block, and a zone of slow conduction. The location of the inferior vena cava predisposes the lower right atrium to this type of reentry.

Animals↗