New insights into typical atrial flutter ablation: extra-isthmus activation time on the flutter wave is predictive of extra-isthmus conduction time after isthmus block.

PURPOSE: Catheter ablation of typical atrial flutter (AFl) is succesful if double electrograms on the ablation line are widely separated. Nevertheless, a small interval may also be compatible with complete isthmus block. Predicting such a situation may avoid useless additionnal radiofrequency (RF) applications. We postulated that measuring the extra-isthmus activation time (EIAT) on the counterclockwise (CCW) flutter wave is correlated with the extra-isthmus conduction time after a proven block. METHODS: Files of 76 patients (71 males, 71 ± 12 years) ablated for typical CCW AFl were reviewed. Ten had 2/1 conduction prohibiting reliable measurement. Three patients with proven crista terminalis shunt were also excluded. In the remaining 63 patients, EIAT was measured on the surface ECG before the first RF pulse from the beginning of the negative deflection of the F wave in lead III to the end of the positive deflection (or beginning of the plateau). After successful ablation and completion of block, right atrial (RA) CCW (during low septal pacing), and clockwise (CW) (during low lateral pacing) activation times were measured. RESULTS: Flutter cycle length was 247 ± 34 ms and EIAT was 142 ± 25 ms. A bidirectionnal isthmus block was obtained in all patients after an RF delivery time of 623 ± 546 s. At a pacing cycle length of 681 ± 71 ms, RA CCW and CW activation times were 147 ± 23 and 139 ± 26 ms, respectively. There was a good correlation between EIA, RA CCW (r = 0.75, p < 0.0001), and CW (r = 0.69, p = 0.0002) activation times. CONCLUSION: EIAT on the flutter wave is an easy and feasible measure. It is correlated with extra-isthmus RA conduction time after block completion. EIAT can be used as a measure to predict the post cavo-tricuspid isthmus block RA activation time.

Characteristics of recurrent clockwise atrial flutter after previous radiofrequency catheter ablation for counterclockwise isthmus-dependent atrial flutter.

AIMS: Isthmus-dependent (ID) clockwise (CW) atrial flutters (AFl) are rare in comparison with counterclockwise (CCW) AFl. Little is known about clinical and electrophysiological characteristics of CW AFl occurring after previous radiofrequency (RF) catheter ablation of CCW AFl. We sought to compare CW AFl de novo vs. CW AFl occurring after previous CCW AFl RF ablation. METHODS AND RESULTS: A total of 246 procedures of RF catheter ablation for AFl from January 2009 to January 2011 were reviewed. Clinical and electrophysiological data were analysed. Patients were excluded if they were in sinus rhythm at the beginning of the procedure, if they had concomitant/previous atrial fibrillation ablation, or if AFl was not ID. Twenty-seven patients presented CW AFl (10.9% of all ID AFl), including 10 CW AFl occurring after a previous RF catheter ablation for CCW AFl. Mean time for recurrence after the previous procedure of CCW AFl RF ablation was 3.5 years. They were younger (61.6 ± 11 years) than patients with CW AFl de novo (74.0 ± 7.2 years; P = 0.005). Bidirectional isthmus block was obtained in all patients. There was a significant difference in terms of double potential separation after ablation (155 ± 31 ms for CW AFl de novo vs. 111 ± 7 ms for recurrent CW AFl; P = 0.028). No differences were observed concerning CHADS score, AFl cycle length, and electrocardiogram typical pattern for CW AFl between the two groups. CONCLUSION: Patients with CW AFl occurrence after CCW AFl RF catheter ablation are younger than patients with CW AFl de novo. They also have a smaller interspike interval after block completion.

Hepatico-tricuspid isthmus ablation for typical-like atrial flutter by femoral approach in absence of the inferior vena cava: use of magnetic navigation and three-dimensional mapping with image integration.

The previously unknown congenital absence of inferior vena cava, an otherwise benign condition, may create difficulties for catheter ablation of arrhythmias. We describe a case of a typical-like atrial flutter, in which magnetic navigation was important for conserving the femoral approach. Electroanatomic mapping with image integration helped define the critical isthmus between the ostia of the suprahepatic veins and the tricuspid valve.

Atrial fibrillation disorganization is reduced by catheter ablation: a standard ECG study.

Selection of candidates to catheter ablation (CA) of long-lasting persistent atrial fibrillation (AF) is challenging, since success is not guaranteed. In this study, we put forward an automated method for noninvasively evaluating the reduction of the complexity of the AF organization following CA. Complexity is meant as the amount of disorganization observed on the ECG, supposed to be directly correlated to the number and interactions of atrial wavefronts. By means of PCA, the complexity of the AF organization is evaluated quantitatively from a 12-lead ECG recording. Preliminary results show that CA is able to reduce the complexity of AF organization in the atrial wavefront pattern propagation, despite the persistence of AF in most cases. This can be viewed as a first clinical validation of this parameter. Whether AF complexity and its reduction by CA are predictive of long-term outcome is thus still to be determined.

Slow pathway radiofrequency ablation in patients with AVNRT: junctional rhythm is less frequent during magnetic navigation ablation than with the conventional technique.

INTRODUCTION: The occurrence of accelerated junctional rhythm (JR) during radiofrequency ablation of the slow pathway in patients with atrioventricular nodal reentrant tachycardia (AVNRT) is frequent. The aim of the present study was to compare the occurrence of JR during magnetic remote catheter ablation to the conventional manual ablation. METHODS AND RESULTS: Twenty six patients (males: seven; age: 51 + or - 15 years) underwent slow pathway ablation with magnetic navigation (MN) system (Niobe, Stereotaxis Inc., St. Louis, MO, USA) and were compared to a control group of 11 patients (males: three; age: 53 + or - 16 years) treated with conventional manual ablation. A 4-mm nonirrigated tip catheter was used in both groups with a maximum of 30 W and 60 degrees C. Acute success was obtained in all patients. In the MN group, three patients out of 24 had no junctional beat (JB) at all and seven patients had 10 or less JB. In contrast, in the conventional group no patient had less than 10 JB. The mean number of JB in the MN group was 66 + or - 94.9 (0-410) and 200 + or - 243.1 (43-914) in the control group (P = 0.019). In the MN group one patient had a first-degree atrioventricular block. No other complication occurred. CONCLUSIONS: Magnetic remote catheter ablation of AVNRT is effective and is associated with less JB than the manual conventional technique. Therefore, JB may not be considered as a mandatory indicator for successful AVNRT ablation with MN system.

Thromboaspiration of left atrial clot during ablation of atrial fibrillation.

We describe a case during which a left atrial thrombus was visualized within the left atrium attached to a circular catheter during an atrial fibrillation ablation procedure. This was managed by successful thromboaspiration using a steerable sheath, preventing a potential serious complication.

Robotic magnetic navigation for ablation of human arrhythmias: initial experience.

BACKGROUND: Magnetic navigation system (MNS) (Niobe, Stereotaxis, Saint-Louis, Missouri, USA) allows remote control of a radiofrequency ablation catheter using a steerable magnetic field and a catheter advancement system. AIMS: We report our initial experience of ablation of human arrhythmias using the MNS. METHODS: Eighty-four patients (mean age 54+/-17years; 39 women) had an electrophysiologic study followed by ablation with the MNS using non-irrigated 4, 8 and 3.5mm-tip catheters with three distal magnets. All patients were symptomatic, with commonly-accepted indications for ablation: atrioventricular nodal re-entrant tachycardia (AVNRT; n=37); typical atrial flutter (n=15); accessory pathway (n=12); atypical atrial flutter (n=7); ventricular tachycardia (n=7); atrial tachycardia (n=3); paroxysmal atrial fibrillation (n=3). Electroanatomical mapping was used for atrial flutter, atrial fibrillation, atrial tachycardia and ventricular tachycardia procedures (29 patients, 34%). RESULTS: Ablation was performed successfully in 69 (82%) patients. In 15 patients (18%), MNS technique was unsuccessful: seven typical atrial flutters, four accessory pathways, two left atrial flutters after atrial fibrillation ablation, one ventricular tachycardia and one AVNRT; in all these cases except one typical atrial flutter and two left atrial flutters, success was obtained by switching to the manual technique by means of an irrigated catheter. Total fluoroscopy time was 14+/-11minutes; operator exposure fluoroscopy time was 1.5+/-0.6minutes; procedure time was 169+/-72minutes. CONCLUSION: MNS ablation is a feasible treatment for various human arrhythmias, with a high success rate. Mapping with a magnetic catheter is safe. However, magnetic ablation of typical atrial flutter remains challenging, probably because of insufficient pressure for cavotricuspid isthmus ablation.

[Typical atrial flutter: history, mechanisms and radiofrequency "ablation"]. / Le flutter auriculaire typique: histoire, mécanismes et "ablation" par la technique de radiofréquence.

yipical atrial flutter can now be permanently cured by a single session of radiofrequency ablation, a non pharmacological technique. The term "atrial flutter" is in fact somewhat confusing. A review of the history of this form of tachycardia shows that atrial flutter is indeed a multiple entity. While the reentrant nature of atrial flutter has long been known, most cardiologists refer to the typical ECG aspect and right atrial macro reentry circuit with counterclockwise rotation, as described by Puech. It is now possible to classify these flutters according to their electrocardiographic aspect and electrophysiological mechanisms. This article describes the diagnostic signs of typical flutter, and provides a detailed description of the most frequently used radical therapy, namely catheter ablation of the cavotricuspidian isthmus. This technique delivers radiofrequency pulses, under continuous local temperature monitoring, in order to permanently interrupt conduction in this structure. Outcome is assessed with the pacing technique and local electrocardiography. In experienced hands the immediate success rate is very high, late recurrence is rare, and complications are virtually absent.

Catheter ablation of recipient right ventricular tachycardia after heterotopic heart transplantation.

Ventricular tachycardia after heart transplantation. A case is reported of ventricular tachycardia (VT) in a 62-year-old male after heterotopic heart transplantation, who occasionally had attacks of palpitation. Surface electrocardiogram suggested VT arising from the recipient heart. Intracardiac electrograms and entrainment mapping confirmed macroreentrant VT located in the recipient right ventricle. Radiofrequency ablation using an electroanatomical mapping system (CARTO, Biosense Webster, Diamond Bar, CA, USA) successfully eliminated VT.

Radiofrequency ablation of ventricular fibrillation and multiple right and left atrial tachycardia in a patient with Brugada syndrome.

Brugada syndrome is a well-known form of idiopathic ventricular fibrillation (VF). Few data suggest that this arrhythmia may be triggered by ventricular premature beats (VPBs), and an association with other arrhythmia such as monomorphic ventricular tachycardia (VT) or supraventricular tachycardia (SVT) has been reported. In a highly symptomatic 18-year-old-male patient with this syndrome, frequent episodes of VF, fast polymorphic VT, and fast monomorphic sustained regular tachycardia were observed. The tachycardia episodes were classified as VT or VF and as a consequence received appropriate therapies with the implanted cardioverter defibrillator (ICD). Precipitating VPBs that were stored in the ICD memory and on the electrocardiogram (ECG) exhibited the same morphology as frequent isolated VPBs. During the electrophysiological study, right and left atrial tachycardia (AT) with one-to-one atrioventricular conduction were also induced and successfully ablated. VF was ablated using the same noncontact mapping (NCM) system triggering VPBs from right ventricular outflow tract (RVOT).

[Cardioversion in atrial fibrillation]. / Cardioversion dans la fibrillation atriale.

For cardioversion of atrial fibrillation 2 techniques are available: pharmacological and electrical. Pharmacological cardioversion is effective, especially when the duration of arrhythmia is shorter than 7 days. In contrast, for long duration of fibrillation electrical external cardioversion is the technique of choice. The success rate ranges from 64 to 96%. The development of new defibrillators delivering biphasic waveforms is associated with an increase in the success rate of cardioversion. For patients where external cardioversion has failed, internal cardioversion should be proposed. One major concern is prevention of embolic complications. For this purpose 2 strategies are equally effective: 1.3-week anticoagulation with warfarin; 2. short-duration (2 days) heparin treatment is sufficient if the presence of a left atrial thrombus has been ruled out with a transoesophageal echocardiocardiogram.

Biphasic versus monophasic shock waveform for conversion of atrial fibrillation: the results of an international randomized, double-blind multicenter trial.

OBJECTIVES: This study compared a biphasic waveform with a conventional monophasic waveform for cardioversion of atrial fibrillation (AF). BACKGROUND: Biphasic shock waveforms have been demonstrated to be superior to monophasic shocks for termination of ventricular fibrillation, but data regarding biphasic shocks for conversion of AF are still emerging. METHODS: In an international, multicenter, randomized, double-blind clinical trial, we compared the effectiveness of damped sine wave monophasic versus impedance-compensated truncated exponential biphasic shocks for the cardioversion of AF. Patients received up to five shocks, as necessary for conversion: 100 J, 150 J, 200 J, a fourth shock at maximum output for the initial waveform (200 J biphasic, 360 J monophasic) and a final cross-over shock at maximum output of the alternate waveform. RESULTS: Analysis included 107 monophasic and 96 biphasic patients. The success rate was higher for biphasic than for monophasic shocks at each of the three shared energy levels (100 J: 60% vs. 22%, p < 0.0001; 150 J: 77% vs. 44%, p < 0.0001; 200 J: 90% vs. 53%, p < 0.0001). Through four shocks, at a maximum of 200 J, biphasic performance was similar to monophasic performance at 360 J (91% vs. 85%, p = 0.29). Biphasic patients required fewer shocks (1.7 +/- 1.0 vs. 2.8 +/- 1.2, p < 0.0001) and lower total energy delivered (217 +/- 176 J vs. 548 +/- 331 J, p < 0.0001). The biphasic shock waveform was also associated with a lower frequency of dermal injury (17% vs. 41%, p < 0.0001). CONCLUSIONS: For the cardioversion of AF, a biphasic shock waveform has greater efficacy, requires fewer shocks and lower delivered energy, and results in less dermal injury than a monophasic shock waveform.