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Classic and concealed entrainment was demonstrated in a patient with spontaneous typical atrial flutter and pacing-induced atypical atrial flutter. The form of entrainment manifested depended on the site of pacing and the direction of tachycardia as determined by endocardial mapping.

We studied 16 patients with electrocardiographic evidence of advanced interatrial block and retrograde activation of the left atrium (P greater than or equal to 0.12 s, and diphasic (+/-) P waves in leads II, III, and VF). Eight patients had valvular heart disease, four had dilated cardiomyopathy and four had other forms of heart disease. Patients with valvular heart disease and cardiomyopathy were compared with a control group of 22 patients with similar clinical and echocardiographic characteristics, but without this type of interatrial block. Patients with advanced interatrial block and retrograde activation of the left atrium had a much higher incidence of paroxysmal supraventricular tachyarrhythmias (93.7%) during follow-up than did the control group, (27.7%) (P less than 0.001). Eleven of 16 patients (68.7%) with advanced interatrial block and retrograde activation of left atrium had atrial flutter (atypical in seven cases, typical in two cases, and with two or more morphologies in two cases). Six patients from the control group (27.7%) had sustained atrial tachyarrhythmias (five atrial fibrillation and one typical atrial flutter). The atrial tachyarrhythmias were due more to advanced interatrial block and retrograde activation of left atrium and frequent atrial extrasystoles than to left atrial enlargement, because the control group with a left atrium of the same size, but without advanced interatrial block and retrograde activation of left atrium and with less incidence of atrial extrasystoles, had a much lower incidence of paroxysmal tachycardia.

Six patients (5 men, 1 woman) with a history ranging from 3-16 years of resistant vagal atrial arrhythmias were treated by atrial pacing at a rate of 90/Min. These patients have been followed up for an average of 5.5 years (range 2-11 years) with favorable results. The arrhythmias were characterized by daily or weekly attacks of typical atrial flutter and atrial fibrillation occurring mainly or exclusively at night, at rest, or in the digestive periods in otherwise normal hearts of middle-aged patients (first attack between 25 and 54, mean 40). The arrhythmias were resistant to quinidine, and were usually aggravated by digitalis, beta-blockers and verapamil. Amiodarone is usually the only effective drug in this syndrome, but was not used before pacing in the 2 first cases, and was ineffective in the other 4 cases. Electrophysiologic studies confirmed the absence of sick sinus syndrome, and the close relationship between relative bradycardia and the onset of the arrhythmia. Atrial pacing alone totally controlled the arrhythmia in 1 patient; amiodarone was used in conjunction with pacing in 3 patients. In 1 patient the improvement was clear but incomplete, and in 1 patient permanent atrial fibrillation occurred shortly after pacemaker implantation.

Typical atrial flutter is characterized by its sawtooth flutter wave in leads II, III, aVF, and V1. Atrioventricular reciprocating tachycardia is characterized by its small retrograde P wave after completion of QRS complex, where sawtooth flutter-like P waves are rarely seen in the electrocardiogram during atrioventricular reciprocating tachycardia. We report on a 62-year-old patient who presented the characteristic sawtooth flutter-like P waves in the electrocardiogram during attack of supraventricular tachycardia. By electrophysiologic study, the mechanism of his supraventricular tachycardia was atrioventricular reciprocating tachycardia using the left posterior lateral concealed accessory pathway for retrograde conduction. The accessory pathway was successfully ablated by radiofrequency ablation therapy.

Objective: Conduction velocity around the tricuspid valve annulus (TA. during typical atrial flutter (AFL. has been shown to be slowest in the inferior vena cava-tricuspid valve (IVC-TV. isthmus when compared to the septal or free wall segments of the TA. We investigated the conduction velocity in IVC-TV isthmus, dividing into three areas. Methods: We evaluated conduction velocity around the TA during typical AFL in 10 patients, using an electro-anatomic mapping system (CARTO™). Conduction velocity was calculated at six areas around the TA including the septal wall, upper wall, lateral wall, and isthmus wall, which was further divided into three areas, lateral isthmus, mid isthmus, and septal isthmus. Results: Conduction velocity around the TA during typical AFL was slowest in the IVC-TV isthmus. Further, conduction velocities (m/sec. in the mid isthmus (0.44±0.17. and septal isthmus (0.45±0.22. were significantly slower (p < 0.05. than that in the upper wall (0.67±0.26). Conclusions: The relatively slower conduction in IVC-TV isthmus resulted from the relatively slower conduction in the area from mid to septal isthmus.

A 75-year-old man with a prior myocardial infarction, who underwent a coronary artery bypass graft, suffered from typical atrial flutter. He underwent a cavotricuspid linear catheter ablation. Eighteen days after the ablation, he suddenly died. A transmural ablation line was created between the inferior vena cava and tricuspid annulus. Transmural loss of the cardiomyocytes and small clusters of coagulative necrosis were observed. Evidence of edema and a patchy hemorrage remained in the extracellular space.

Purpose Catheter-based cryoablation (cryo) has proven to be as effective as radiofrequency energy (RF) ablation for the treatment of arrhythmias. Nevertheless, the duration of cryoapplications has been reported as being significantly longer than RF applications. Methods Thirty-seven consecutive patients (28 men; mean age 59 ± 14 years) with typical atrial flutter (AFL) underwent cryo of the cavotricuspid isthmus (CTI). Applications of 1 min were delivered with a 10-French, 10-mm tipped catheter (CryoCor™). If bidirectional CTI block was not obtained after 12 1-min applications, applications of 3 min were selectively delivered to areas of conduction breakthrough. The endpoint of the procedure was creation of bidirectional CTI block and non-inducibility of AFL. Results A median of 7 (range 3 to 12) 1-min applications were given along the CTI with a mean temperature of −88.6 ± 2.3°C. Mean fluoroscopy and procedure time were 27 ± 14 min and 110 ± 28 min respectively. Five patients required additional 3-min applications; in one patient an overextended ablation catheter prevented the completion of the index-procedure. The acute success rate of the index-procedure was 97%. In 12/24 patients, two with AFL recurrence, resumption of CTI conduction was found 4 months post-ablation. In all patients bidirectional CTI block was re-obtained after a median of one 1-min application. No additional AFL recurrences occurred, after a mean follow-up of 37 ± 3 (range 30 to 44) months. Conclusions Cryo of AFL can successfully be performed using the same application duration as used for RF ablation. Both acute and long-term results are comparable to RF ablation. AFL recurrences occurred in only a minority of patients with resumption of CTI conduction.

Background Noncontact mapping is useful for the diagnosis of various arrhythmias. Virtual unipolar electrogram morphologies (VUEM) of the conduction block and the turnaround points, however, are not well defined. We compared the VUEM characteristics of a transverse conduction block in the posterior right atrium (RA) with those of contact bipolar electrograms obtained during typical atrial flutter (AFL). Methods Contact bipolar electrograms were used to map the posterior RA during typical AFL in 16 patients. Twenty points of the VUEM recorded along the block line were analyzed and compared with contact bipolar electrograms. Results Seventeen AFLs were analyzed. Fifteen AFLs showed an incomplete transverse conduction block in the posterior RA by contact bipolar mapping. A double potential on the block line corresponded to the two components of the VUEM, in which the second component showed an Rs, RS, or rS pattern. At the turnaround point, a fused double potential of the contact bipolar electrograms corresponded to a change of the second component of the VUEM from an rS to a QS morphology. Two AFLs showed a complete block line in the posterior RA. The contact bipolar electrogram showed double potentials from the inferior vena cava to the superior vena cava, whereas the second component of the VUEM remained in an unchanged Rs, RS, or rS pattern. Conclusion VUEM analysis was a reliable method for identifying the posterior block line during AFL. This method may also be applicable for detecting block lines and turnaround points of circuits in other unmappable arrhythmias.

BACKGROUNDDespite the high success rate of radiofrequency (RF) ablation, pharmacologic therapy is still considered the standard initial therapeutic approach for atrial flutter.OBJECTIVEWe prospectively compared the outcome at follow-up of patients with atrial flutter randomly assigned to drug therapy or RF ablation.METHODSPatients with at least two episodes of symptomatic atrial flutter in the last four months were randomized to regimens of either antiarrhythmic drug therapy or first-line RF ablation. After institution of therapy, end points included recurrence of atrial flutter, rehospitalization and quality of life.RESULTSA total of 61 patients entered the study, 30 of whom were randomized to drug therapy and 31 to RF ablation. After a mean follow-up of 21 ± 11 months, 11 of 30 (36%) patients receiving drugs were in sinus rhythm, versus 25 of 31 (80%) patients who underwent RF ablation (p < 0.01). Of the patients receiving drugs, 63% required one or more rehospitalizations, whereas post-RF ablation, only 22% of patients were rehospitalized (p < 0.01). Following RF ablation, 29% of patients developed atrial fibrillation which was seen in 53% of patients receiving medications (p < 0.05). Sense of well being (pre-RF 2.0 ± 0.3 vs. post-RF 3.8 ± 0.5, p < 0.01) and function in daily life (pre-RF 2.3 ± 0.4 vs. post-RF 3.6 ± 0.6, p < 0.01) improved after ablation, but did not change significantly in patients treated with drugs.CONCLUSIONIn a selected group of patients with atrial flutter, RF ablation could be considered a first-line therapy due to the better success rate and impact on quality of life, the lower occurrence of atrial fibrillation and the lower need for rehospitalization at follow-up.

Ablation of cavotricuspid isthmus flutter and atrial tachycardia in a complex substrate has never been reported using remote navigation via superior approach. Venous access was obtained via right internal jugular for ablation and left subclavian for duodecapolar catheter placement into the coronary sinus. In a posttransplant patient presenting with both regular and irregular tachycardia, both cavotricuspid isthmus flutter in the donor and atrial tachycardia in the recipient was mapped using a two catheter approach. Successful ablation of typical atrial flutter and anastomotic block was achieved. This is the first report of successful ablation of cavotricuspid isthmus flutter and posttransplant atrial tachycardia using magnetic navigation via superior approach. Using only two catheters, this approach is logical and feasible in complex substrates with interrupted inferior venous access.

BACKGROUND Sarcoidosis is a multisystem granulomatous disease of not sufficiently understood origin. Some patients develop cardiac involvement in course of the disease which is mostly responsible for adverse outcome. In addition to complications like high degree atrioventricular (AV) block or ventricular tachyarrhythmias, there is a certain percentage of patients developing atrial tachyarrhythmias. Data is limited and the role of catheter ablation uncertain. Therefore, we studied sarcoid patients who presented with supraventricular tachyarrhythmias. HYPOTHESIS Treatment and ablation of supraventricular tachycardia could be hampered by inflammation in patients with cardiac sarcoidosis. METHODS We enrolled 37 consecutive patients with cardiac sarcoidosis who presented with atrial tachyarrhythmias and underwent an electrophysiologic study over a period of 6 years (03/2013-04/2019). In total, 16 catheter ablations for atrial tachyarrhythmias were performed. Mean follow-up duration was 2.5 years. RESULTS Most common ablation performed was cavo-tricuspid isthmus ablation for typical atrial flutter in seven patients (54%). Pulmonary vein isolation for treatment of atrial fibrillation (AF) was performed in five patients (38%). Two patients received slow-pathway modulation for treatment of recurrent atrioventricular nodal reentry tachycardia (AVNRT). All but two patients with AF had no clinical recurrence during follow-up. Two patients had recurrence of AF but still reported markedly improved european heart rhythm association (EHRA) class. Periprocedural safety was very high. There were no adverse events related to the ablation procedure. One patient died during follow-up in the presence of electrical storm. CONCLUSION Catheter ablations of supraventricular tachycardias seem to be safe and effective in patients with cardiac sarcoidosis. Outcome is comparable to patients without inflammatory heart disease, although data from larger patient collectives are mandatory to make recommendations in this special entity.

INTRODUCTION The PREVENT AF I study demonstrated that prophylactic pulmonary vein isolation (PVI) in patients with pure typical atrial flutter (AFL) resulted in substantial reduction of new-onset atrial fibrillation (AF) during 1-year follow-up as assessed by continuous implantable cardiac monitor (ICM). The objective of this study was to assess 3-year outcomes. METHODS AND RESULTS Fifty patients with documented AFL were randomized to either cavotricuspid isthmus (CTI) ablation alone (n = 25) or CTI with concomitant PVI (n = 25). The primary endpoint of the study was the occurrence of any atrial tachyarrhythmia with the monthly burden exceeding 0.5% on the ICM. At the end of 3 years, freedom from any atrial tachyarrhythmia was 48% (95% confidence interval [CI]: 32-72%) in the CTI plus PVI group as compared to 20% (95% CI: 9-44%) in the CTI-only group (P = 0.01). Freedom from redo procedures was also higher: 92% (95% CI: 82-100%) versus 68% (95% CI: 52-89%), respectively (P = 0.027). The 3-year AF burden favored the combined ablation group: 6.2% versus 16.8% (P = 0.03). In the CTI-only group, 12 (48%) patients were hospitalized compared to 4 (16%) in the PVI + CTI group (P = 0.03). Two patients in the CTI-only group developed stroke with no serious adverse events in the PVI + CTI group. CONCLUSION Prophylactic PVI in patients with only typical AFL resulted in a significant reduction of new-onset AF and burden during long-term follow-up as assessed by ICM, with consequent reduction in hospitalizations and need to perform repeat ablation for AF.

Background: Atrial tachycardia is very frequent after mitral valve surgery using the superior transseptal approach. Methods: Sixteen patients operated on for mitral valve disease (superior transseptal approach = Group A, n = 9, and left atrial approach = Group B, n = 7) underwent radiofrequency catheter ablation of atrial tachycardia guided by electroanatomic mapping. Twenty-six consecutive patients without previous cardiac surgery with typical atrial flutter served as controls (Group C). Results: Atrial tachycardia occurred earlier after the operation in Group A than in Group B (median 97 vs 2,159 days, P = 0.003). Typical atrial flutter was the most frequent circuit in all groups (Group A—7 patients, Group B—5 patients, Group C—26 patients). Three patients in Group A developed right atrial incisional tachycardia. Ten of 14 tachycardia circuits (typical atrial flutter, n = 7, incisional tachycardia, n = 3) in Group A depended on the corridor between the right atrial part of the atriotomy and the tricuspid annulus. Slow conduction during typical atrial flutter was detected in this corridor in Group A, but not in the corresponding region in Groups B and C (P < 0.001). The cycle length of typical atrial flutter was longer in Groups A and B than in Group C (mean 283 ms and 282 ms vs 233 ms, P = 0.003). Patients in Group B with typical atrial flutter had larger right atria than patients in Group A or Group C (mean 156 mL vs 96 mL and 113 mL, P = 0.033). Conclusions: The superior transseptal incision may predispose to atrial tachycardia by creating slow conduction between the atriotomy and the tricuspid annulus.

Background MicroFidelity catheter technology may facilitate voltage-guided ablation by high-resolution electroanatomic mapping (HR-EAM) and precisely targeted energy application. Objective To evaluate the performance of minielectrode (ME) technology for zero-fluoroscopy substrate-guided cavotricuspid isthmus (CTI) ablation. Methods Eighty-two patients underwent near zero-fluoroscopy substrate-guided CTI ablation using a nonirrigated large-tip catheter with 3 MEs. The CTI was subdivided into 15 electroanatomic segments. Bipolar voltage maps were compared with ME signals. The outcome was compared with a historic cohort of 92 patients who underwent linear ablation. Results Compared with linear ablation, the substrate-guided approach was associated with an almost halved ablation duration (336 ± 228 vs 649 ± 409 seconds, P Conclusion HR-EAM-based substrate-guided CTI ablation may improve procedural outcome compared with the linear approach. Enhanced identification of discrete conductive pathways correlates with ablation efficacy. The electroanatomic subdivision of the CTI into 15 segments was feasible and may improve the understanding and comparability of anatomic variants and ablation results. Independent of the ablation strategy, modern EAM technology enables safe zero-fluoroscopy procedures in the majority of cases.

We report the first case of acute right coronary artery occlusion in an adult patient during radiofrequency catheter ablation of typical atrial flutter. ST segment elevation rapidly resolved with antithrombotic therapy. This complication was thought to be due to the short distance between the endocardium and the right coronary artery at the ablation site, the high-wattage output from the radiofrequency generator, and the lack of sufficient cooling effect related to a severe upstream coronary stenosis. In patients with known right coronary artery stenosis who are suffering from typical atrial flutter, evaluation of the significance of the stenosis would be reasonable.

Background —RS morphology of the unipolar electrogram is associated with propagation of the wave front through the exploring electrode, whereas positive uniphasic (R) unipolar electrograms are characteristic of the end of activation. Methods and Results —Unipolar electrograms were recorded in 45 consecutive patients with atrial flutter who were undergoing radiofrequency ablation (RFA). Bidirectional cavotricuspid isthmus (CTI) block was achieved in 44 patients. The unipolar electrogram obtained before RFA at the low anterolateral right atrium during coronary sinus pacing changed from RS, rS, or QS to R or Rs in all patients after clockwise CTI block was obtained. The morphology of unipolar electrograms recorded close to the coronary sinus during pacing from the low anterolateral right atrium changed from RS or rS to R or Rs in all but 4 patients after counterclockwise CTI block. In the patient in whom CTI block was not achieved, the RS morphology of the unipolar electrogram remained unchanged. In 18 patients, the results of the RFA were assessed with only the unipolar electrogram. The unipolar electrogram correctly predicted 100% and 89% of the cases of clockwise and counterclockwise CTI block, respectively. Conclusions —The creation of CTI block is associated with an easily detectable loss of negative components and development of an R or Rs pattern of the unipolar electrogram recorded close to the ablation line while pacing at the opposite side of the CTI.

Here, we report a case of a 69-year-old patient with paroxysmal atrial fibrillation and inducible typical atrial flutter who required catheter ablation. After pulmonary vein isolation, cavotricuspid isthmus ablation was performed. During ablation at a lateral site of the cavotricuspid isthmus, a spiky potential appeared at the distal electrode of the ablation catheter, and subsequently, a 2:1 atrioventricular (AV) block occurred. Radiofrequency (RF) delivery at the same site caused a similar phenomenon, implying that the spiky potential may reflect a slow pathway potential as an anatomical variant of the rightward extension of the AV node.

Background Radiofrequency ablation (RFA) is the only curative treatment for typical atrial flutter (AFL) and allows stopping antiarrhythmic drugs. However, management of long-term anticoagulant therapy (LT ACT) remains unclear, especially in lone AFL successfully treated and CHA 2 DS 2 VASc score ≥1. Abstract 0163 – Table: Table Long-term anticoagulation therapy management A GROUP (N=74) B GROUP (N=63) C GROUP (N=17) AF YES (N [%]) NO (N [%]) YES (N[%]) NO (N [%]) YES (N [%]) NO (N [%]) TAC YES (N [%]) 14 (18.9) 11 (14.9) 29 (46) 20 (31.7) 4 (23.5) 0 (0) NO (N [%]) 2 (2.7) 43 (58.1) 3 (4.8) 7 (11.1) 6 (35.3) 5 (29.4) LTFUP (N [%]) 4 (5.4) 4 (6.4) 2 (11.8) AF: Atrial fibrillation ACT: anticoagulant therapy LTFUP: lost to follow up patient Aims Assessment of long-term ACT after AFL RFA according to associated atrial fibrillation (AF) and CHA 2 DS 2 VASc score. Methods From January 2012 to December 2013, patients who underwent RFA of cavotricuspid isthmus for typical atrial flutter in our centre were retrospectively included. Results Of 166 patients (137 men, mean age: 66.7±10years), 61 (36.7%) had a history of AF. The mean CHA 2 DS 2 VASc score was 2.49. The patients were classified according to theoretical indication of LT ACT (patients with a non rhythmic ACT indication excluded – N=12; 7.2%): group A (LT ACT unclear) included patients with CHA 2 DS 2 VASc score ≥1, successful RF ablation and without AF history (N=74); group B (LT ACT indicated) included patients with CHA 2 DS 2 VASc score ≥1, AF history and/or failed AFL RFA (N=63); group C (LT ACT not indicated)included patient with CHA 2 DS 2 VASc score=0 (N=17). During a mean follow up of 489±244 days, 45 (60.8), 10 (15.9%) and 11(64.7) patients stopped ACT respectively in group A, B and C differently according to AF onset (table). There were 8 (4.8%) hemorrhagic and 2 (1.2%) ischemic complications, all in patients with correct ACT management. The prevalence of AF during follow-up was 38%. Conclusion After successful AFL RF ablation, ACT was frequently stopped in the absence of associated AF. However, AF was frequent even inpatients with no AF history. Ischemic and hemorrhagic complications were rare. ACT should be regularly evaluated during follow-up especially according to CHA 2 DS 2 VASc score and new onset of AF.

Prior studies have shown that atrial fibrillation (AF) following successful cavotricuspid isthmus (CTI) ablation of atrial flutter (AFL) can occur in 12%-54% of the patients. However, studies to report the risk factor for ischemic stroke after successful typical AFL ablation are limited, and the

Radiofrequency (RF) ablation is a treatment of choice of typical atrial flutter (AFl). However the risk of atrial fibrillation (AF) is high. Heart disease (HD) presence may modify this risk. The purpose of the study was to look for the role of associated HD on previous history of AF and later occurrence of AF after AFl ablation.Methods965 patients, mean age 64±12, were consecutively referred for ablation of recurrent or poor-tolerated AFL. Clinical history, occurrence of AF, data of echocardiography was collected. Patients were followed from 3 months up to 10 years. Antiarrhythmic drugs were stopped after ablation except in patients with history of AF before ablation.ResultsHD was present in 744 patients (77%): hypertensive disease (HTD) (n=186), ischemic HD (IHD) (n=163), valvular HD (VHD) (n=113), dilated cardiomyopathy (DCM) (n= 87), respiratory failure (resp) (n=84), congenital HD (cong) (n=26), miscellaneous HD (n=59). Prior AF was more frequent in patients without HD (67%) than in patients with HD (26%)(p