[Preparing for a pandemic]. / Vorbereitungen auf eine pandemische Welle.

On 16 March 2020 the government of Bavaria declared a state of emergency due to the coronavirus disease 2019 (COVID-19) pandemic. This confronted all clinics with completely new and difficult challenges. In accordance with the official requirements, pandemic officers were appointed at the Kempten Clinic and a clinical management team was established. It was important to keep a relevant proportion of employees off duty at all times, and thus to have a constant reserve available in the event of expected infection-related absences of physicians and nurses. These structural changes were complemented by staff briefings and the creation of a training program on the subject of COVID-19. Within a very short time, algorithms were designed and defined how to manage patients presenting in the hospital or in the emergency room. The surgical program was limited to operations that could not be postponed, such as extrauterine pregnancy or adnexal torsion, and oncological diagnoses without the possibility of primary systemic therapy. In the case of breast cancer, however, therapy was started in all cases in which primary systemic therapy (PST), whether cytotoxic or endocrinological, appeared possible and indicated. As of 1 April 2020, more than 50% of the usable beds in the Kempten Clinic were empty. The utilization of the intensive care unit had also been reduced so that higher numbers of patients requiring artificial respiration could have been cared for at any time.

Myocardial Minimal Damage After Rapid Ventricular Pacing - the prospective randomized multicentre MyDate-Trial.

Therapy of choice for the primary and secondary prevention of sudden cardiac death is the implantation of an implantable cardioverter defibrillator (ICD). Whereas appropriate and inappropriate ICD shocks lead to myocardial microdamage, this is not known for antitachycardia pacing (ATP). In total, 150 ICD recipients (66 ± 12 years, 81.3% male, 93.3% primary prevention, 30.0% resynchronization therapy) were randomly assigned to an ICD implantation with or without intraoperative ATP. In the group with ATP, the pacing maneuver was performed twice, each time applying 8 impulses à 6 Volt x 1.0 milliseconds to the myocardium. High sensitive Troponin T (hsTnT) levels were determined prior to the implantation and thereafter. There was no significant difference in the release of hsTnT between the two randomization groups (delta TnT without ATP in median 0.010 ng/ml [min. -0.016 ng/ml-max. 0.075 ng/ml] vs. with ATP in median 0.013 ng/ml [min. -0.005-0.287 ng/ml], p = 0.323). Setting a hsTnT cutoff of 0.059 ng/dl as a regularly augmented postoperative hsTnT level, no relevant difference between the two groups regarding the postoperative hsTnT levels above this cutoff could be identified (without ATP n = 10 [14.7%] vs. with ATP n = 16 [21.9%], p = 0.287). There was no significant difference in the release of high sensitive Troponin between patients without intraoperative ATP compared to those with intraoperative ATP. Hence, antitachycardia pacing does not seem to cause significant myocardial microdamage. This may further support its use as a painless and efficient method to terminate ventricular tachycardia in high-risk patients.

[Temporary Pacemakers - Step by Step]. / Passagerer Herzschrittmacher.

Symptomatic bradycardia is usually caused by abnormalities of atrioventricular conduction or sinus node dysfunction. Reversible and irreversible causes must be considered.Temporary pacemakers are used in the emergency treatment in case of severe bradyarrhythmia.They help to bridge the acute phase until spontaneous restoration of atrioventricular or sinus node function or -if spontaneous restoration fails- until a permanent pacemaker system was implanted.In the following article we discuss the commonly used temporary pacemaker systems. We demonstrate their use and correct programming by an illustrated step by step explanation. For troubleshooting a flow chart was added.

Pacemaker Implantation Associated Myocardial Micro-Damage: A Randomised Comparison between Active and Passive Fixation Leads.

Fixation of the pacemaker leads during pacemaker implantation leads to an increase of cardiac Troponin T (cTnT) that can be interpreted as a sign of minimal myocardial damage. This trial evaluates whether the mechanism type of lead fixation influences the magnitude of cTnT release. Patients having a de-novo cardiac pacemaker implantation or a lead revision were centrally randomized to receive either a ventricular lead with an active (screw) or passive (tine) fixation mechanism. High-sensitive Troponin T (hsTnT) was determined on the day of the procedure beforehand and on the following day. 326 Patients (median age (IQR) 75.0 (69.0-80.0) years, 64% male) from six international centers were randomized to receive ventricular leads with an active (n = 166) or passive (n = 160) fixation mechanism. Median (IQR) hsTnT levels increased by 0.009 (0.004-0.021) ng/ml in the group receiving screw-in ventricular leads and by 0.008 (0.003-0.030) ng/ml in the group receiving tined ventricular leads (n.s.). In conclusion pacemaker implantations are followed by a release of hsTnT. The choice between active or passive fixation ventricular leads does not have a significant influence on the extent of myocardial injury and the magnitude of hsTnT release.

Takotsubo Syndrome After Cardiopulmonary Resuscitation During Emergency Cesarean Delivery.

BACKGROUND: Takotsubo syndrome is a rare, stress-related, and reversible form of acute heart failure primarily affecting postmenopausal women. It is characterized by left ventricular dysfunction with a classic apical and midventricular wall motion abnormality (apical ballooning). CASE: A 28-year-old woman, gravida 2 para 1, at 30 4/7 weeks of gestation was admitted with fetal bradycardia, a fully dilated cervix, and breech presentation. During emergency cesarean delivery, the patient had intraoperative cardiac arrest. Resuscitation was successful. Twelve hours postoperatively, after demonstrating symptoms of acute heart failure, she was diagnosed with Takotsubo syndrome. CONCLUSION: Peripartum Takotsubo syndrome must be differentiated from peripartum cardiomyopathy. Cesarean delivery and sympathomimetic medications can increase the risk of occurrence. Early recognition and interdisciplinary management are essential in the prevention of serious and potentially fatal complications.

Cryoablation versus radiofrequency energy for the ablation of atrioventricular nodal reentrant tachycardia (the CYRANO Study): results from a large multicenter prospective randomized trial.

BACKGROUND: Cryoablation has emerged as an alternative to radiofrequency catheter ablation (RFCA) for the treatment of atrioventricular (AV) nodal reentrant tachycardia (AVNRT). The purpose of this prospective randomized study was to test whether cryoablation is as effective as RFCA during both short-term and long-term follow-up with a lower risk of permanent AV block. METHODS AND RESULTS: A total of 509 patients underwent slow pathway cryoablation (n=251) or RFCA (n=258). The primary end point was immediate ablation failure, permanent AV block, and AVNRT recurrence during a 6-month follow-up. Secondary end points included procedural parameters, device functionality, and pain perception. Significantly more patients in the cryoablation group than the RFCA group reached the primary end point (12.6% versus 6.3%; P=0.018). Whereas immediate ablation success (96.8% versus 98.4%) and occurrence of permanent AV block (0% versus 0.4%) did not differ, AVNRT recurrence was significantly more frequent in the cryoablation group (9.4% versus 4.4%; P=0.029). In the cryoablation group, procedure duration was longer (138±54 versus 123±48 minutes; P=0.0012) and more device problems occurred (13 versus 2 patients; P=0.033). Pain perception was lower in the cryoablation group (P<0.001). CONCLUSIONS: Cryoablation for AVNRT is as effective as RFCA over the short term but is associated with a higher recurrence rate at the 6-month follow-up. The risk of permanent AV block does not differ significantly between cryoablation and RFCA. The potential benefits of cryoenergy relative to ablation safety and pain perception are counterbalanced by longer procedure times, more device problems, and a high recurrence rate. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00196222.

Very late relapse of atrial fibrillation after pulmonary vein isolation: incidence and results of repeat ablation.

BACKGROUND: There are few data about the incidence of very late (>12 months) arrhythmia relapse after pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation (AF) and about the success rate of repeat ablation procedures in this population. METHODS: All patients treated with PVI for paroxysmal AF were screened in the institution's electrophysiology database. Follow-up data at 1, 3, 6, and 12 months and yearly thereafter including repetitive (7 days or 1 day) Holter electrocardiograms were assessed as well as the technique and success rate of repeat ablations. RESULTS: Overall, 24 of 356 (6.7%) patients experienced their first AF recurrence more than 12 months after PVI. Of these 24 patients, 14 underwent reablation for paroxysmal (11 patients) or persistent AF (three patients). Repeat ablation included re-PVI in all 14 patients (43 of 48 initially isolated PVs with recovered left atrial-PV conduction). Ablation of complex fractionated atrial electrograms or left/right atrial lines was performed in eight patients, including the three patients with persistent AF. During follow-up of 15.1 ± 9 months after the second ablation, 10 of 14 (71%) reablated patients remained in sinus rhythm. CONCLUSIONS: After PVI for paroxysmal AF, very late arrhythmia recurrence occurs in less than 10% of patients. The success rate of the repeat procedure is high.

The modified anterior line: an alternative linear lesion in perimitral flutter.

INTRODUCTION: Ablation of left atrial flutter (LAF) is often limited by the need for technically demanding linear lesions. We evaluated the safety and efficacy of a new modified anterior line (MAL), connecting the anterior/anterolateral mitral annulus with the left superior pulmonary vein for ablation of perimitral flutter. METHODS AND RESULTS: MAL was performed in 65 patients (15 females, age 63.6 +/- 9.8 years) with perimitral flutter using 3D mapping systems (70.8% Carto, 29.2% NavX). Perimitral flutter was either the presenting arrhythmia (73.8%) or an intermediate organized rhythm during atrial fibrillation ablation. Follow-up included repetitive 7-day Holter with 93.8% of patients off antiarrhythmics. MAL was acutely effective in 63/65 patients (96.9%). Termination to sinus rhythm occurred in 36 of 65 patients (55.4%), and in 27 of 65 patients (41.5%) there was a change to another LAF type. Bidirectional block across the MAL was achieved in 56 of 65 patients (86.1%). After 6 months of follow-up, 20 of 41 patients (48.8%) had a LAF recurrence, with 6 patients undergoing a reablation. In all redo patients the MAL was still complete and LAF mechanism was different to the initially targeted. No major complication occurred during the ablation procedures or in the postablation period. CONCLUSION: The MAL is a safe and effective linear lesion for the treatment of perimitral LAF. Its value compared to more established linear lesions as the mitral isthmus line has to be evaluated in larger studies.

Serial contrast-enhanced cardiac magnetic resonance imaging demonstrates regression of hyperenhancement within the coronary artery wall in patients after acute myocardial infarction.

OBJECTIVES: Our aim was to determine whether serial contrast-enhanced cardiac magnetic resonance (CE-CMR) is useful for the characterization of tissue signal changes within the coronary vessel wall in patients after acute myocardial infarction (AMI). BACKGROUND: Inflammation plays a key role in the development of AMI. CE-CMR of the vessel wall has been found useful for the characterization of inflammatory tissue signal changes in patients with carotid artery stenosis, giant cell arteritis, or Takayasu's arteritis; however, it has never been serially performed in the coronary artery wall in patients with acute and chronic myocardial infarction using a gadolinium-based contrast medium and compared with systemic markers of inflammation. METHODS: CE-CMR using a T1-weighted 3-dimensional gradient echo inversion recovery sequence of the coronary artery wall and 0.2 mmol/kg of gadolinium-diethylenetriaminepentaacetic acid was performed in 10 patients with AMI 6 days and 3 months after coronary intervention and in 9 subjects without coronary artery disease on invasive coronary angiography. Contrast-to-noise ratio (CNR) within the coronary artery wall was quantified in comparison with blood signal. RESULTS: Patients with AMI demonstrated a significantly increased coronary vessel wall enhancement 6 days after infarction compared with normal subjects (CNR 7.8 +/- 4.4 vs. 5.3 +/- 3.2, p < 0.001). Three months after infarction, CNR decreased to 6.5 +/- 4.7 (p < 0.03). This decrease paralleled declines in C-reactive protein. Angiographically normal segments showed no contrast changes, but CNR significantly decreased in stenotic segments, from 10.9 +/- 3.8 to 6.8 +/- 5.0 (p < 0.002), resulting in a reduction of enhanced segments from 70% to 25% (p < 0.01). CONCLUSIONS: Serial CE-CMR identified changes in spatial extent and intensity of coronary contrast enhancement in patients after AMI. This technique may be useful for the characterization of transient coronary tissue signal changes, which may represent edema or inflammation during the post-infarction phase. In addition, CE-CMR may offer the potential for visualization of inflammatory activity in atherosclerosis associated with acute coronary syndromes.

Electrogram-guided substrate ablation with or without pulmonary vein isolation in patients with persistent atrial fibrillation.

AIMS: Ablation of complex fractionated atrial electrograms (CFAEs) is a new approach for the treatment of atrial fibrillation (AF). The purpose of the study was to assess the efficacy of CFAE ablation as a stand-alone strategy in patients with persistent AF and to compare it with a combined approach of CFAE ablation and pulmonary vein isolation (PVI). METHODS AND RESULTS: The study included 77 consecutive patients with persistent AF who underwent radiofrequency (RF) ablation of CFAE as a sole ablation procedure (CFAE group, n = 23 patients) or a combined approach of CFAE ablation and PVI (CFAE plus PVI group, n = 54 patients). Procedures were guided by three-dimensional mapping systems. After the procedure, AF recurrences were evaluated with 7-day Holter recordings at 1, 3, and 6 months and every 6 months thereafter. Treatment failure was defined as >or=1 AF episode lasting >30 s on Holter recordings during follow-up. After a mean follow-up time of 13 +/- 10 months, 2 of 23 patients (9%) with CFAE ablation and 22 of 54 patients (41%) with CFAE plus PVI were in sinus rhythm after a single ablation procedure without anti-arrhythmic medication (P = 0.008). CONCLUSION: Ablation of CFAE as a stand-alone ablation strategy seems insufficient for the treatment of patients with persistent AF. Pulmonary vein isolation plus CFAE ablation significantly increases the mid-term success rate.

Radiofrequency ablation of complex fractionated atrial electrograms (CFAE): preferential sites of acute termination and regularization in paroxysmal and persistent atrial fibrillation.

INTRODUCTION: Complex fractionated atrial electrograms (CFAE) have been described as a new target for ablation of atrial fibrillation (AF). This prospective study evaluates the acute effects of CFAE ablation in patients with paroxysmal or persistent AF and analyzes the preferential anatomic sites where these effects occur. METHODS AND RESULTS: Ablation of CFAE was performed in 66 symptomatic patients (mean age of 58 +/- 12 years) with paroxysmal (n = 36) or persistent AF (n = 30). Termination or regularization of AF during ablation of CFAE was achieved in 56 of 66 patients (84%), with termination in 28 of 66 patients (42%) and regularization of AF in 28 of 66 patients (42%). Ablation of CFAE showed no effect in 10 of 66 patients (16%). Termination of AF occurred at 53 sites and AF regularization at 81 sites. The preferential sites of AF termination or regularization were found around the pulmonary veins (termination n = 15; regularization n = 22), at the anterior wall (termination n = 14; regularization n = 19) and at the interatrial septum (termination n = 8; regularization n = 17). CONCLUSION: Termination or regularization of AF was achieved acutely in 84% of patients by ablation of CFAE. The preferential sites of AF termination or regularization were found around the pulmonary veins, at the anterior wall of the LA and at the interatrial septum. These findings may have implications for future ablation concepts.

Effects of circumferential or segmental pulmonary vein ablation for paroxysmal atrial fibrillation on cardiac autonomic function.

BACKGROUND: Circumferential and segmental pulmonary vein ablations are two established treatment strategies for ablation of atrial fibrillation. Both techniques require the application of radiofrequency current at anatomical sites that are close to autonomic ganglia. However, the effects of current pulmonary vein ablation techniques on cardiac autonomic function are unknown. OBJECTIVE: The purpose of this study was to analyze the short- and long-term effects of circumferential and segmental pulmonary vein ablation on cardiac autonomic function. METHODS: One hundred patients with highly symptomatic atrial fibrillation were randomly assigned to undergo either circumferential or segmental pulmonary vein ablation. Holter recordings were recorded at baseline and at regular intervals for up to 1 year after ablation. Autonomic function was assessed by deceleration capacity and acceleration capacity of heart rate as well as by standard measures of heart rate variability. RESULTS: In the circumferential pulmonary vein ablation group, deceleration capacity and acceleration capacity decreased highly significantly from 5.7 +/- 2.1 ms and -8.0 +/- 1.9 ms at baseline to 3.3 +/- 1.8 ms and -5.5 +/- 2.3 ms directly after ablation, respectively (P<.00001). Impairment of deceleration capacity and acceleration capacity was present up to 1 year after ablation. In the segmental pulmonary vein ablation group, deceleration capacity and acceleration capacity decreased from 5.8 +/- 2.0 ms and -7.8 +/- 1.6 ms at baseline to 3.4 +/- 1.2 ms and -6.0 +/- 2.4 ms directly after ablation (P<.00001), respectively. However, deceleration capacity and acceleration capacity returned to baseline values within 1 month. CONCLUSIONS: Circumferential and segmental pulmonary vein ablations induce an immediate decrease of autonomic function. However, while this decrease is only transient with segmental pulmonary vein ablation, it persists with circumferential pulmonary vein ablation for at least 1 year.

Long-term follow-up of patients supplied with single-chamber or dual-chamber cardioverter defibrillators.

INTRODUCTION: In patients who have an indication for an implantable cardioverter defibrillator (ICD) a dual-chamber device is indicated in the case of concomitant significant sinus node disease or atrioventricular block. It is a matter of debate whether dual-chamber ICD may be beneficial for patients with preserved sinus and atrioventricular nodal function as data from prospective randomized trials are limited. Mid- or long-term follow-up data are unavailable. METHODS AND RESULTS: One hundred patients (age 60+/-12 years, 11 women) with the indication for the implantation of an ICD and without antibradycardia pacing indication were randomly assigned to either receive a dual-chamber ICD (n=52) or a single-chamber ICD (n=48). Patients were followed-up for a mean of 52+/-14 months. Mortality and arrhythmogenic morbidity were assessed. All-cause mortality was 21% for single-chamber and 31% for dual-chamber ICD recipients, respectively (P=0.26). Cardiovascular mortality was 13% for single-chamber ICD recipients versus 21% in the dual-chamber group (P=0.25). Subgroup analysis using 35% of ventricular paced beats as cutoff value in the dual-chamber ICD group revealed a 42% mortality rate for the patients with frequent ventricular pacing compared to 10% of patients with a low rate of ventricular pacing (P=0.05, relative risk 4.21, 95% confidence interval: 0.9-19.8). As for arrhythmogenic morbidity, the difference in the ventricular tachyarrhythmia load was not different in both groups (single chamber: 23+/-74 VT episodes, dual chamber: 54+/-134 VT episodes, P=0.17). CONCLUSION: In ICD recipients without conventional indication for dual-chamber pacing, dual chamber compared to single-chamber ICD has no advantage concerning mortality and arrhythmogenic morbidity in a long-term follow-up. In these patients the implantation of a single-chamber device is sufficient.

Left atrial tachycardia after circumferential pulmonary vein ablation for atrial fibrillation: incidence, electrophysiological characteristics, and results of radiofrequency ablation.

AIMS: To investigate the incidence, electrophysiological properties, and ablation results for left atrial (LA) tachycardia as a sequel to the circumferential pulmonary vein ablation (CPVA) for atrial fibrillation (AF). METHODS AND RESULTS: Sixty-seven patients with AF underwent CPVA. Sustained LA tachycardia developed in 21/67 (31%) patients and in 16/21 symptomatic patients 55 LA tachycardias (3.4+/-2.4 per patient) were mapped: 18 (33%) tachycardias were related to macro-re-entry around the mitral valve (7) or pulmonary vein(s) (11). In 20 tachycardias (36%), a 'small-loop' LA re-entrant tachycardia (LART) was identified; gaps in prior ablation lines (7 LART) or an area of extremely slow conduction adjacent to the CPVA lesions (13 LART) were crucial for these re-entries. Seventeen tachycardias (31%) were too unstable for complete mapping. Ablation was a primary success in 34 of 38 (89%) mapped LART, but in eight of 21 procedures, cardioversion was necessary to achieve sinus rhythm. CONCLUSION: LART develops in a high percentage of patients after CPVA. Small-loop re-entry, which is difficult to map, may arise and patients suffer from several and/or unstable variants of LART. Thus, mapping and ablation of these LART is challenging and the overall success is yet not satisfactory.

Phrenic nerve injury after catheter ablation: should we worry about this complication?

INTRODUCTION: Phrenic nerve injury (PNI) is a complication that can occur with catheter ablation. METHODS: Data from 17 patients with PNI following different catheter ablation techniques were reviewed. PNI was defined as decreased motility (transient) or paralysis (persistent) of the hemi-diaphragm on fluoroscopy or chest X-ray. Patient's recovery was monitored. Normalization of chest images and sniff test would be considered as complete clinical recovery. RESULTS: Out of the 17 PNI patients (16 right, 1 left), 13 (11 persistent, 2 transient) occurred after pulmonary veins isolation with or without superior vena cava ablation. Three patients had persistent PNI after sinus node modification and one other patient experienced PNI after epicardial ventricular tachycardia ablation. Ablation was performed with different energy source including radiofrequency (n = 13), cryothermal (n = 1), ultrasound (n = 2) and laser (n = 1). Patient's symptoms varied broadly from asymptomatic to dyspnea, and even to respiratory insufficiency that required temporary mechanical ventilation support. Two patients with transient PNI resolved immediately after the procedure and the other 15 persistent PNI patients resolved within a mean time of 8.3 +/- 6.6 months. CONCLUSIONS: PNI caused by catheter ablation appears to functionally recover over time regardless of the energy sources used for the procedure.

Catheter ablation of left atrial focal tachycardia guided by electroanatomic mapping and new insights into interatrial electrical conduction.

BACKGROUND: Experience in catheter ablation of left atrial (LA) focal tachycardia and information about interatrial electrical connections during LA focal tachycardia are limited. OBJECTIVES: The purpose of this study was to describe our experience in electroanatomic mapping-guided catheter ablation of LA focal tachycardia and to investigate interatrial electrical connections during LA focal tachycardias. METHODS: Thirty-three patients undergoing catheter ablation for LA focal tachycardia guided by electroanatomic mapping were reported. Interatrial electrical connections were analyzed in LA focal tachycardias with biatrial electroanatomic maps. RESULTS: Of the 35 LA focal tachycardias (cycle length 309 +/- 100 ms) mapped, 19 (54%) originated from the pulmonary veins (PVs), 6 (17%) from the mitral annulus, 3 (8.6%) from LA roof, 3 (8.6%) from LA posterior wall, 2 (5.7%) from LA appendage, and 2 (5.7%) from LA septum. Fourteen of the 19 PV tachycardias (74%) were located in proximity to PV ostia. In 14 (7 PV, 7 non-PV) LA focal tachycardias with biatrial electroanatomic maps, posterior right atrium breakthrough sites at the intercaval area were identified in 7 PV tachycardias and 1 non-PV tachycardia. Five of the 7 PV tachycardias used only the posterior breakthrough for interatrial propagation. Procedural success was achieved in 33 of 35 LA focal tachycardias (94%) in 31 patients. During 23 +/- 19 months of follow-up, 2 patients (6%) had recurrence of ablated tachycardia, and 3 (10%) developed new LA focal tachycardias. CONCLUSIONS: The PVs and the mitral annulus were the main sources of LA focal tachycardias. The majority of PV tachycardias originated from PV ostia. A posterior interatrial connection appeared to play a major role in interatrial electrical propagation during PV tachycardias. Electroanatomic mapping facilitated precise localization of LA focal tachycardias and achievement of a high rate of ablation success.

Freedom from atrial tachyarrhythmias after catheter ablation of atrial fibrillation: a randomized comparison between 2 current ablation strategies.

BACKGROUND: Data on the comparative value of the circumferential pulmonary vein and the segmental pulmonary vein ablation for interventional treatment of atrial fibrillation are limited. We hypothesized that the circumferential pulmonary vein ablation approach was superior to the segmental pulmonary vein ablation approach. METHODS AND RESULTS: One hundred patients with highly symptomatic atrial fibrillation were randomly assigned to undergo either circumferential (n=50) or segmental pulmonary vein ablation (n=50). Freedom from atrial tachyarrhythmias in a 7-day Holter monitoring at 6 months was the primary end point. Secondary end points were freedom of arrhythmia-related symptoms and a composite of pericardial tamponade, thromboembolic complications, and pulmonary vein stenosis (safety end point). On the basis of the results of the 7-day Holter monitoring at 6 months, 21 patients (42%) after circumferential pulmonary vein ablation and 33 patients (66%) after segmental pulmonary vein ablation (P=0.02) were free of atrial tachyarrhythmia episodes. During the 6-month follow-up period, 27 patients (54%) after circumferential pulmonary vein ablation and 41 patients (82%) after segmental pulmonary vein ablation remained free of arrhythmia-related symptoms (P<0.01). No significant difference was found in the safety end point (6 versus 7 events; P=0.77) in the circumferential versus segmental pulmonary vein ablation group, respectively. CONCLUSIONS: This study demonstrates no superiority of the circumferential pulmonary vein ablation over segmental pulmonary vein ablation for treatment of atrial fibrillation in terms of efficacy and safety.

Acute and long-term results of slow pathway ablation in patients with atrioventricular nodal reentrant tachycardia--an analysis of the predictive factors for arrhythmia recurrence.

BACKGROUND: Predictors of atrioventricular nodal reentrant tachycardia (AVNRT) recurrence after radiofrequency ablation including the importance of residual slow pathway conduction are not known. The aim of this study was to report the acute and long-term results of slow pathway ablation in a large series of consecutive patients with AVNRT and to analyze the potential predictors of arrhythmia recurrence with a particular emphasis on the residual slow pathway conduction after ablation. METHODS: The study included 506 consecutive patients with AVNRT (mean age 52.6 +/- 16 years, 315 women) who underwent slow pathway ablation using a combined electrophysiological and anatomical approach. The end point of ablation procedure was noninducibility of the arrhythmia. The primary end point of the study was the recurrence of AVNRT. RESULTS: Acute success was achieved in 500 patients (98.8%). After ablation, 471 patients (93%) were followed up for a mean of 903 +/- 692 days. Of the 465 patients with successful ablation, 24 patients (5.2%) developed AVNRT recurrences during the follow-up. No significant differences in the cumulative rates of AVNRT recurrence were observed in groups with or without electrophysiological evidence of residual slow pathway conduction (P = 0.25, log-rank test). Multivariate analysis identified only age as an independent predictor of AVNRT recurrence (hazard ratio 0.96, 95% confidence interval 0.94-0.99, P = 0.004) with younger patients being at an increased risk for arrhythmia recurrence. CONCLUSIONS: Our study demonstrated that only younger age, but not other clinical or electrophysiological parameters including residual slow pathway conduction predicted an increased risk for AVNRT recurrence after slow pathway radiofrequency ablation.

Transvenous cryoablation versus radiofrequency ablation of the slow pathway for the treatment of atrioventricular nodal re-entrant tachycardia: a prospective randomized pilot study.

AIMS: This is a prospective, randomized study comparing transvenous cryoablation with radiofrequency (RF) ablation of atrioventricular nodal re-entrant tachycardia (AVNRT). METHODS AND RESULTS: In this pilot trial, 200 patients with AVNRT were randomized to undergo cryoablation or RF ablation of the slow pathway. A 7 Fr 4-mm-tip cryocatheter (Cryocath) was used for cryomapping and cryoablation. Cryomapping was performed at the temperature of -30 degrees C to test the effect on the candidate ablation site. Following successful cryomapping, cryoablation was performed to produce an irreversible lesion by freezing to -75 degrees C. Procedural success, defined as elimination of the slow pathway or noninducibility of AVNRT, was achieved in 97/100 (97%) patients in the Cryo group vs. 98/100 (98%) patients in the RF group. No permanent complete AV-block occurred in either group. During a median of 246 days of follow-up, 8 patients in the Cryo group and 1 in the RF group had AVNRT recurrence. The cumulative incidence of primary endpoint (a combination of procedural failure, permanent complete AV-block and AVNRT recurrence) was significantly higher in the Cryo group than in the RF group (P=0.03, Log-rank test). CONCLUSIONS: The results of this pilot study indicate that transvenous cryoablation using a 4-mm-tip cryocatheter is associated with a comparable acute success rate but a higher recurrence rate as compared with RF ablation in patients with AVNRT. Potential benefits of cryoablation for ablation of AVNRT need to be determined in a larger multi-centre trial.