Clinical and electrophysiologic characteristics of antidromic tachycardia in children with Wolff-Parkinson-White syndrome

Background: Antidromic reciprocating tachycardia (ART) is a rare form of wide complex tachycardia in children with Wolff‐Parkinson‐White syndrome (WPW). The incidence and electrophysiologic characteristics of ART in children with WPW have not been well described. Methods: A multicenter retrospective analysis of all patients with WPW undergoing electrophysiology (EP) study from 1990 to 2009 was performed. Patients with clinical or inducible ART were included. Results: A total of 1,147 patients with WPW underwent EP study and 30 patients had ART (2.6%) and were the subject of this analysis. The mean age was 16 ± 3 years, weight was 65 ± 16 kg, and tachycardia cycle length was 305 ± 55 ms. There were two patients (7%) with congenital heart disease (both with Ebstein's anomaly). Four patients (13%) had more than one accessory pathway (AP). The location of the AP was left sided in 53% of patients and right sided in 47%, with septal location and left lateral pathways most commonly involved. AP conduction was found to be high risk in 17 patients (57%). Ablation was not attempted in two patients (7%) due to proximity to the HIS and risk of heart block. Ablation was acutely successful in 93% of the patients in whom it was attempted. Conclusions: ART is a rare finding in children undergoing EP study. Over half of the patients with ART were found to be high risk and multiple AP were uncommon. Unlike the adult population, ART occurred commonly with septal APs. PACE 2012; 35:480–488)     

Initial results of linear duty-cycled radiofrequency for atypical flutter and atrial tachycardia

Background: Duty‐cycled radiofrequency (DCRF) is increasingly used for ablation of atrial fibrillation (AF). Many patients also have atrial flutter (AFL). Recently, a linear multielectrode has been shown to create linear block at the cavotricuspid isthmus and in the left atrium (LA). Objective: To map and ablate atypical AFL and atrial tachycardias (ATs) in the right and LA using a linear multielectrode with DCRF. Methods: The linear multielectrode delivers DCRF at 20–45 W maximum in 1:1 unipolar/bipolar temperature‐controlled mode. Target temperatures were manually titrated to 60 °C in the LA, if power >5W indicated adequate passive cooling. Results: A total of 76 AT/AFL were targeted in 57 patients. Acute success was reached in 14/15 (93%) right AT, in 17/22 (77%) left atrial roof AFL, in 5/6 (83%) septal AFL, in 9/9 (100%) other left atrial AT, but only in 8/23 (35%) AFL from the mitral isthmus (which rose to 13/23 [57%] with additional use of irrigated radiofrequency). Nevertheless, freedom of AF/AFL 10 ± 6 months after a single procedure was documented in 92% of right AT, 71% of roof AFL, 73% for mitral AFL, and 60% of septal or other LA AT/AFL. No char formation was noted. However, frequent induction of AF and one case of asystole occurred during delivery of DCRF in a pacemaker patient. Conclusion: The linear multielectrode allows mapping and ablation of atypical AFL/AT. Freedom of AF/AT was reached in 60%–92% depending on localization and number of arrhythmias. Technical modifications will improve safety and efficacy. (PACE 2011; 34:1128–1137)     

Electrophysiology of inducible atrial flutter in patients with atrioventricular nodal reentrant tachycardia

An association between atrial flutter and atrioventricular nodal reentrant tachycardia (AVNRT) has been observed, but the underlying mechanisms are poorly defined. This issue was therefore investigated by comparing the electrophysiological properties of AVNRT patients with and without inducible atrial flutter and those of patients with a history of flutter. Twenty-nine patients with clinically documented atrial flutter and 104 with AVNRT were studied. Atrial flutter was induced in 38 (37%) AVNRT patients during standardized electrophysiological testing before radiofrequency ablation. The atrial relative refractory periods in AVNRT patients with inducible flutter (260 +/- 30 ms) were significantly shorter than those of either patients with a history of flutter (282 +/- 30 ms; P = 0.02) or AVNRT patients without inducible flutter (284 +/- 38 ms; P = 0.006). The atrial effective refractory periods in AVNRT patients with inducible flutter (205 +/- 31 ms) were shorter than in AVNRT patients without inducible flutter (227 +/- 40 ms; P = 0.01). The maximum AH interval during premature atrial stimulation in patients with clinical flutter (239 +/- 94 ms) was shorter than in AVNRT patients either with (290 +/- 91 ms; P = 0.04) or without inducible flutter (313 +/- 101 ms; P = 0.002). However, no significant differences were found in the maximum AH interval achieved during incremental atrial pacing among different groups. Our data show that a non-clinical flutter could more often be induced in those who had short atrial refractoriness. Despite their anatomical proximity, the slow pathway conduction of AVNRT and the isthmus slow conduction of flutter may be related to different mechanisms.     

Effect of landiolol hydrochloride, an ultra-short-acting beta 1-selective blocker, on supraventricular tachycardia, atrial fibrillation and flutter after pulmonary resection

What is known and objective: Supraventricular tachycardia is a common complication after pulmonary resection. The objective of this study was to investigate the efficacy of landiolol hydrochloride, an ultra‐short‐acting β1‐blocker, in patients with post‐operative supraventricular tachycardia after pulmonary resection. Methods: The response to continuous intravenous infusion of landiolol was evaluated in 25 patients who developed post‐operative atrial fibrillation or atrial flutter after major pulmonary resection. Four patients had preoperative rate‐controlled chronic atrial fibrillation. The heart rate and blood pressure were compared before and after infusion of landiolol. Side effects and recurrence of supraventricular tachycardia after termination of landiolol infusion were also monitored. Results and discussion: The heart rate was reduced from 135 ± 24 bpm before landiolol infusion to a plateau rate of 85 ± 19 bpm during infusion (P < 0·0001). Heart rate reduction occurred in all but two patients. Conversion to normal sinus rhythm from supraventricular tachycardia occurred in 14 patients (56%). Recurrence of supraventricular tachycardia after stopping landiolol infusion was observed in 17 patients (68%), but all patients without preoperative AF were cured of post‐operative AF. There were no detectable side effects, including no adverse influence on the circulatory and respiratory systems. What is new and conclusion: Continuous intravenous infusion of landiolol was found to be effective and safe for supraventricular tachycardia after pulmonary resection.     

Conduction properties of the crista terminalis in patients with atrial flutter due to amiodarone therapy for atrial fibrillation

Some patients with atrial fibrillation (AF) treated by antiarrhythmic drugs (AAD) can develop typical atrial flutter, but the mechanism is not clear. This study included 21 patients with AF. Group I (n = 7) had typical atrial flutter due to amiodarone therapy. Group II (n = 7) did not develop atrial flutter after amiodarone treatment. Group III (n = 7) did not receive AAD treatment. A 7 Fr, 20-pole electrode catheter was placed along the CT identified by fluoroscopy and intracardiac echocardiography. After restoration of the sinus rhythm, decremental pacing near the CT was performed until 2 to 1 atrial capture. Complete transverse conduction block was defined as the appearance of double potentials with opposite activation sequence along the CT. Focal transverse conduction delay was defined as the appearance of double potentials at > or = 2 recording sites. Focal transverse conduction delay was observed during pacing at the cycle length of 693 +/- 110 ms in group I, 360 +/- 97 ms in group II and 343 +/- 109 ms in group III (P = 0.001). Complete transverse conduction block was observed during pacing at the cycle length of 391 +/- 118 ms in group I and 231 +/- 23 ms in group II (P = 0.001), but not in group III. In conclusion, focal transverse conduction delay in the CT was common in patients with AF. A predisposition to the line of the conduction block in the CT might contribute to the conversion of AF to typical atrial flutter due to amiodarone therapy.     

Different clinical courses and predictors of atrial fibrillation occurrence after transisthmic ablation in patients with preablation lone atrial flutter, coexistent atrial fibrillation, and drug induced atrial flutter

The aim of this prospective study was to compare the long-term follow-up after transisthmic ablation of patients with preablation lone atrial flutter, coexistent AF, and drug induced atrial flutter to determine if postablation AF followed a different clinical course and displayed different predictors in these groups. The study evaluated 357 patients who underwent transisthmic ablation for typical atrial flutter. These were divided into four groups according to their preablation history. Group A included patients with typical atrial flutter and without preablation AF (n=120, 33.6%). Group B included patients with preablation AF and spontaneous atrial flutter (n=132, 37.0%). Group C patients had preablation AF and atrial flutter induced by treatment with IC drugs (propafenone or flecainide) (n=63, 17.6%) Group D included patients with preablation AF and atrial flutter induced by treatment with amiodarone (n=42, 11.8%). During a mean follow-up of 15.2 double dagger 10.6 months (range 6-55 months) AF occurred more frequently in groups B (56.1%) and C (57.1%) patients than in groups A (20.8%, P <0.0001) and D (31.0%, P <0.0001) patients. The results of multivariate analysis revealed that different clinical and echocardiographical variables were correlated with postablation AF occurrence in the different groups. Patients with atrial flutter induced by amiodarone have a significantly lower risk of postablation AF than patients with spontaneous atrial flutter and AF, and those with atrial flutter induced by IC drugs. Different clinical and echocardiographical variables predict postablation AF occurrence in different subgroups of patients.     

Right atrial tachycardia in a patient with severe atrial conduction disturbances and an anatomically normal heart

We describe a case of abnormal right atrial (RA) conduction in a patient with atrial tachycardia (AT) but no history of structural heart disease or cardiac surgery. Following ablation of AT, the patient experienced typical atrial flutter (AFL) and a postcardioversion ECG suggestive of low atrial rhythm. Repeat EPS and three-dimensional electroanatomic activation mapping showed unusual RA activation during SR. This case illustrates the possibility that abnormal intraatrial conduction may lead to unusual patterns of activation in the RA which can serve as a necessary substrate for the initiation and maintenance of macro-reentry circuits.     

Left atrial tachycardia after right atrial separation for chronic atrial fibrillation with atrial septal defects

A right atrial separation procedure was performed for the ablation of chronic atrial fibrillation in four cases, concomitant with the repair of the atrial septal defect. After the operation, chronic atrial fibrillation disappeared in three of them and left atrial tachycardia occurred in the other one. Left atrial tachycardia is an arrhythmia encountered after a right atrial separation procedure.     

Decremental ramp atrial extrastimuli pacing protocol for the induction of atrioventricular nodal re-entrant tachycardia and other supraventricular tachycardias

AIM: The primary aim of this study was to evaluate the utility of decremental ramp atrial extrastimuli pacing protocol (PRTCL) for induction of atrioventricular nodal re-entrant tachycardia (AVNRT), and other supraventricular tachycardias (SVTs), compared to standard (STD) methods. METHODS: The study cohort of 121 patients (age 57.51 +/- 14.02 years) who presented with documented SVTs and/or symptoms of palpitations and dizziness, and underwent invasive electrophysiological evaluation was divided into Group I (AVNRT, n = 42) and Group II (Control, n = 79). The PRTCL involved a train of six atrial extrastimuli, delivered in a decremental ramp fashion. The STD methods included continuous burst and rapid incremental pacing up to atrioventricular (AV) block cycle length, and single and occasionally double atrial extrastimuli. Prolongation in the Atrio-Hisian (Delta-AH) intervals achieved by both methods were compared, as were induction frequencies. RESULTS: In Group I, three categories of responses--(1) induction of AVNRT, (2) induction of echo beats only, and (3) none--were observed in 29 (69%), 11 (26%), and 2 (5%) patients with the PRTCL, when compared with 14 (33%), 16 (38%), and 12 (29%) patients with STD methods in the baseline state without the use of pharmacological agents. The Delta-AH intervals for each of these three categories were larger using PRTCL versus STD methods; 293.3 +/- 95.2 ms versus 192.9 +/- 61.4 ms (P < 0.005), 308.6 +/- 68.5 ms versus 189. 9 +/- 64.9 ms (P < 0.0005), and 203.0 +/- 86.3 ms versus 145.8 +/- 58.9 ms (P = NS), respectively. In Group II, in one patient with dual AV nodal physiology but no clinical tachycardia, the PRTCL induced nonsustained (12 beats) AVNRT. Additionally, in this group, both PRTCL and STD methods induced atrial tachycardia in two patients and orthodromic AV re-entrant tachycardia in one patient. CONCLUSION: Decremental ramp atrial extrastimuli pacing PRTCL demonstrates a superior response for induction of typical AVNRT as compared to STD techniques. Because of easy and reliable induction of AVNRT and echo beats by the PRTCL, we recommend it as a method to increase the likelihood of induction of AVNRT. For induction of other SVTs, the PRTCL and the STD methods are comparable.     

Method of atrioventricular programming in atrial flutter in patients with biventricular pacemaker

BACKGROUND: Atrial flutter is a common cause of exacerbation of congestive heart failure (CHF). Typically, during atrial tachycardia, pacemakers, both dual and biventricular, are programmed to ignore atrial tracking. Virtually all current pacemakers and defibrillators use a programmable mode switch algorithm to switch between atrial tracking modes (DDD, DDDR) to nontracking modes (DDIR, DDI, VVI) during episodes of atrial tachycardia. METHODS: In this report, we describe a novel method of atrioventricular (AV) pacemaker programming in four patients with atrial flutter and CHF who remained symptomatic postbiventricular pacemaker implantation. All patients had chronic atrial flutter upon interrogation; adjustment of AV delay and postventricular atrial refractory period (PVARP) was performed to enable sensing of every second to fourth atrial flutter beat by the atrial lead. Mode switch was turned "OFF" in all points, and lower and upper rate limits were set to 50 and 100 bpm. Once sequential early and late diastolic filling was seen on mitral inflow pulsed-wave (PW) Doppler, further adjustment of AV delay and PVARP was performed until the highest and broadest atrial velocity occurred on mitral inflow PW Doppler. RESULTS: All patients developed improvement in aortic ejection duration and peak ejection velocity during AV optimization. Repeat ECG in these patients at 8 months, 7 days, 2 days, and 2 months postoptimization showed no change in P and QRS relationship. All patients developed improvement in CHF symptoms postbiv pacemaker optimization. CONCLUSION: In symptomatic patients with CHF and stable atrial flutter who have a biventricular pacemaker, atrial mechanical contribution to cardiac output can be achieved by adjusting PVARP and AV delay during echo-guided pacemaker programming.     

Basket catheter localization of the origin of atrial tachycardia with atypical morphology after atrial flutter ablation

Atrial activation from a site in the low lateral right atrium will typically proceed in a superior direction. We present a case of a low lateral right atrial tachycardia with a surface electrocardiographic P wave morphology that appeared to have an inferiorly directed axis. The tachycardia occurred 2 years after successful atrial flutter ablation. The use of a multipolar basket catheter allowed confirmation of the focal origin of the tachycardia, permitted its rapid localization, facilitated catheter ablation, and provided clues to atrial activation that helped describe the appearance of the P wave.     

Electrophysiologic characteristics of the sinus venosa in patients with typical atrial flutter

BACKGROUND: The sinus venosa is a posterior barrier of typical atrial flutter. However, its electrophysiology has not been studied. METHODS AND RESULTS: The study population included 20 patients with typical atrial flutter (Group 1) and 20 patients with paroxysmal supraventricular tachycardia (Group 2). The noncontact mapping system was used to evaluate the electrophysiology of the sinus venosa (SV) during coronary sinus (CS) and low right atrial (LRA) pacing and atrial activation during typical atrial flutter. The results showed 12 of Group 1 patients (60%) had two lines of block, one in the CT and the other in the SV. The virtual electrograms in the CT and SV showed double potentials. Eight patients (40%) had only one line of block in the CT. During atrial pacing at the cycle length of 500 ms, nine of Group 1 patients had a line of block on the SV. None of the Group 2 patients had a line of block. During atrial pacing at the CL of 300 ms, 12 of Group 1 patients had a line of block on the SV. Eight of Group 1 patients had transverse conduction through the SV during atrial pacing. None of the Group 2 had a line of block. CONCLUSIONS: This study showed that the SV formed the posterior line of block in 60% of the patients with typical atrial flutter. Fixed conduction block and rate-dependent conduction block in the SV may be involved in the pathogenesis of typical AFL.     

Macroreentrant atrial flutter around a common atrioventricular canal in an infant with complicated congenital heart anomaly

This report describes a 2-year-old male infant after repair of complicated congenital heart anomalies including common atrioventricular canal (CAVC), in which macroreentrant atrial flutter around the CAVC was demonstrated by electroanatomic mapping (CARTO) using a single catheter. Radiofrequency catheter ablation at the isthmus between the CAVC and the inferior vena cava eliminated the atrial flutter successfully.     

Prospective evaluation of catheter ablation in patients with implantable cardioverter defibrillators and multiple inappropriate ICD therapies due to atrial fibrillation and type I atrial flutter

The high incidence of inappropriate therapies due to drug refractory supraventricular tachycardia remains a major unsolved problem of the ICD. Most of the inappropriate therapies for supraventricular tachycardia are caused by AF and type I atrial flutter with rapid ventricular response. The purpose of this prospective study was to determine the usefulness of AVN modulation or ablation for rapid AF and ablation of the tricuspid annulus-inferior vena cava (TA-IVC) isthmus for type I atrial flutter in ICD patients with frequent inappropriate ICD interventions. Eighteen consecutive patients were enrolled in this study. Twelve patients received a mean of 34 +/- 36 antitachycardia pacing (ATP) and 41 +/- 32 shock therapies for rapid AF during 49 +/- 39 months, and 6 patients a mean of 111 +/- 200 ATP and 11 +/- 8 shock therapies for type I atrial flutter during 52 +/- 37 months preceding ablation procedure. Modification of the AVN was successful in 10 (83%) of 12 AF patients, in 2 (17%) patients ablation of the AVN was performed. A complete TA-IVC isthmus block was achieved in 5 (83%) of 6 atrial flutter patients. Three (25%) AF patients had 11 +/- 24 recurrences of ATP and 0.4 +/- 1.1 shock therapies for rapid AF during 15 +/- 7 months. None of the atrial flutter patients had recurrences of inappropriate therapies for type I atrial flutter during 14 +/- 8 months, but two (33%) patients had inappropriate ICD therapies for type II atrial flutter or rapid AF. There was an overall mean incidence of 18 +/- 22 inappropriate ICD therapies per 6 months before and 4 +/- 9 per 6 months after the ablation procedure (P < 0.05). In conclusion, radiofrequency catheter modification or ablation of the AVN for rapid AF and ablation for atrial flutter type I are demonstrated to be highly effective in the majority of ICD patients with drug refractory multiple inappropriate ICD therapies.     

Efficacy and safety of ibutilide for cardioversion of atrial flutter and fibrillation in patients receiving amiodarone or propafenone

AIM: The effectiveness and safety of ibutilide (IB) use in patients receiving amiodarone or propafenone for atrial flutter (AFL) and atrial fibrillation (AF) were compared to IB alone. METHODS AND RESULTS: In 104 consecutive patients with AF (65%) or AFL (35%), receiving amiodarone (n = 46), propafenone (n = 30), or no specific antiarrhythmic drug (n = 28), IB was given for cardioversion. Fifteen patients in amiodarone group were loaded with 1.2 g intravenously before IB administration. The mean duration of arrhythmia episode was 23 +/- 65 days, while 85% of patients had structural heart disease. The left ventricle ejection fraction was 57 +/- 10% and the left atrium size was 4.2 +/- 0.6 cm. The conversion efficacy did not differ among groups (62% for amiodarone vs 55% for propafenone vs 64% for IB alone). The QTc intervals were significantly prolonged, at 10 minutes and 30 minutes after IB administration, in amiodarone group (from 449 +/- 88 to 496 +/- 92 ms, 508 +/- 52 ms; P = 0.001) and in the group where IB was used alone (from 434 +/- 45 to 517 +/- 74 ms, 492 +/- 65 ms; P < 0.001), while it remained unchanged in propafenone group (from 464 +/- 52 to 471 +/- 80 ms, 489 +/- 93 ms; P = 0.536). The only predictor of conversion was the presence of AFL (P = 0.009). Five patients developed ventricular tachycardias after IB administration (two in propafenone, one in amiodarone, and two in IB group). CONCLUSIONS: The use of IB in patients receiving amiodarone or propafenone for AFL or AF is equally effective and safe as the use of IB alone. The presence of AFL is the stronger predictor factor for cardioversion.