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ObjectiveAtrial fibrillation or atrial flutter (AF) and heart failure (HF) often go hand in hand and, in combination, lead to an increased risk of death compared with patients with just one of both entities. Sex-specific differences in patients with AF and HF are under-reported. Therefore, the aim of this study was to investigate sex-specific catheter ablation (CA) use and acute in-hospital outcomes in patients with AF and concomitant HF in a retrospective cohort study.MethodsUsing International Statistical Classification of Diseases and Related Health Problems and Operations and Procedures codes, administrative data of 75 hospitals from 2010 to 2018 were analysed to identify cases with AF and HF. Sex differences were compared for baseline characteristics, right and left atrial CA use, procedure-related adverse outcomes and in-hospital mortality.ResultsOf 54 645 analysed cases with AF and HF, 46.2% were women. Women were significantly older (75.4±9.5 vs 68.7±11.1 years, pConclusionsThere are sex differences in patients with AF and HF with respect to demographics, resource utilisation and in-hospital outcomes. This needs to be considered when treating women with AF and HF, especially for a sufficient patient informed decision making in clinical practice.

After His bundle electrography was established in 1967, the step from invasive electrophysiologic diagnosis of arrhythmias to interventional treatment by catheter ablation was imminent. The time interval of 15 years between the diagnosis and treatment of arrhythmias was even shorter than the 19 years between the first selective coronary angiography in 1958 at the Cleveland Clinic in the USA and the first percutaneous coronary intervention in 1977 in Zurich. During each time period, a great amount of knowledge was gained in cardiac surgery, which proved to be very helpful for the development of the interventional treatment. The history of endovascular treatment is an impressive reminder that the preparation and support of cardiovascular surgeons and their handling of complications played a decisive role in the further development of cardiovascular internal medicine. The history of catheter ablation teaches us that the joint work of cardiologists and cardiovascular surgeons is of great importance for the choice and further development of the best possible treatment as for future development of the techniques of therapy.

Aims To evaluate the effectiveness and safety of cryoballoon ablation (CBA) compared with radiofrequency ablation (RFA) for symptomatic paroxysmal or drug-refractory persistent atrial fibrillation (AF). Methods and results Prospective cluster cohort study in experienced CBA and RFA centres. Primary endpoint was ‘atrial arrhythmia recurrence’, secondary endpoints were as follows: procedural results, safety, and clinical course. A total of 4189 patients were included: CBA 2329 (55.6%) and RFA 1860 (44.4%). Cryoballoon ablation population was younger, with fewer comorbidities. Procedure time was longer in the RFA group (P = 0.01). Radiation exposure was 2487 (CBA) and 1792 cGycm2 (RFA) (P Conclusions The primary endpoint did not differ between CBA and RFA. Cryoballoon ablation was completed rapidly; the radiation exposure was greater. Rehospitalization due to re-ablations and adverse events during follow-up were observed significantly less frequently after CBA than after RFA. Subgroup analysis suggested a lower risk of recurrence after CBA in paroxysmal AF. Trial Registration ClinicalTrials.gov (NCT01360008), https://clinicaltrials.gov/ct2/show/NCT01360008.

We aimed to compare patient characteristics and outcome of patients who had either undergone pulmonary vein isolation (PVI) or AV-node ablation (AVN) to control AF-related symptoms.From the German Ablation Registry, we analyzed data of 4444 patients (95%) who had undergone PVI and 234 patients (5%) with AVN.AVN patients were on average 10 years older than PVI patients (71 ± 10 vs. 61 ± 10 years, p 0.001) with 33% aged 75 years. AVN patients had significantly more cardiovascular comorbidities (diabetes 21% vs. 8%, renal insufficiency 24% vs. 3%, underlying heart disease 80% vs. 36%, severely reduced left ventricular function 28% vs. 1%, all p 0.001). Significantly more PVI patients had paroxysmal AF (63% vs. 18%, p 0.001), and more AVN patients had long-standing persistent AF (44% vs. 7%, p 0.001). At 1-year follow-up, mortality in the AVN group was much higher (Kaplan-Meier estimates 9.8% vs. 0.5%). 20% of PVI patients had undergone another ablation vs. 3% AVN patients (p 0.001). Symptomatic improvement was equally achieved in about 80%. Re-hospitalization for cardiovascular reasons occurred significantly more often in PVI vs. AVN patients (31% vs. 18%, p 0.001).In the large German Ablation Registry, AVN ablation was performed much less frequently than PVI for symptomatic treatment of AF and typically in older patients with more comorbidity. Symptomatic improvement was similar in both groups. Hospitalizations for cardiovascular reasons were lower in AVN patients despite older age and more cardiovascular comorbidities. 20% of PVI patients had undergone at least one re-ablation.

After His bundle electrography was established in 1967, the step from invasive electrophysiologic diagnosis of arrhythmias to interventional treatment by catheter ablation was imminent. The time interval of 15 years between the diagnosis and treatment of arrhythmias was even shorter than the 19 years between the first selective coronary angiography in 1958 at the Cleveland Clinic in the USA and the first percutaneous coronary intervention in 1977 in Zurich. During each time period, a great amount of knowledge was gained in cardiac surgery, which proved to be very helpful for the development of the interventional treatment. The history of endovascular treatment is an impressive reminder that the preparation and support of cardiovascular surgeons and their handling of complications played a decisive role in the further development of cardiovascular internal medicine. The history of catheter ablation teaches us that the joint work of cardiologists and cardiovascular surgeons is of great importance for the choice and further development of the best possible treatment as for future development of the techniques of therapy.

AimsCatheter ablation (CA) of ventricular arrhythmias is one of the most challenging electrophysiological interventions with an increasing use over the last years. Several benefits must be weighed against the risk of potentially life-threatening complications which necessitates a steady reevaluation of safety endpoints. Therefore, the aims of this study were (i) to investigate overall in-hospital mortality in patients undergoing such procedures and (ii) to identify variables associated with in-hospital mortality in a German-wide hospital network.Methods and resultsBetween January 2010 and September 2018, administrative data provided by 85 Helios hospitals were screened for patients with main or secondary discharge diagnosis of ventricular tachycardia (VT) or premature ventricular contractions (PVCs) in combination with an arrhythmia-related CA using ICD- and OPS codes. In 5052 cases (mean age 60.9 ± 14.3 years, 30.1% female) of 30 different hospitals, in-hospital mortality was 1.27% with a higher mortality in patients ablated for VT (1.99%, n = 2, 955) compared to PVC (0.24%, n = 2, 097, P 24 h after initial admission (n = 861, P 24 h [odds ratio (OR) 2.28, 95% confidence interval (CI) 1.59–3.28, P ConclusionsWe reported in-hospital mortality rates after CA of ventricular arrhythmias in the largest multicentre, administrative dataset in Germany which can be implemented in quality management programs. Aside from comorbidities, a delayed hospital transfer to a CA performing centre is associated with an increased in-hospital mortality. This deserves further studies to determine the optimal management strategy.

Stratification of patients with atrial fibrillation (AF) according to mechanistic and prognostic criteria may optimize the effectiveness and safety of catheter ablation. In women, AF is associated with more severe symptoms and worse prognosis.We sought to assess sex-related differences in catheter ablation procedures and outcome in a large cohort of patients with AF.A total of 3652 patients (1198 women [33%]; 2454 men [67%]) included in the German Ablation Registry were analyzed. Periprocedural parameters and outcome at 12-month follow-up were compared between male and female patients.Women were older at the time of ablation (women: 63.6 years; men: 59.1 years; P.0001) and exhibited a higher prevalence of paroxysmal AF (women: 72%; men: 61%; P.0001). They were less often affected by cardiovascular disease and reduced left ventricular function. Energy application duration and overall procedure duration were shorter in women. Conversely, the rate of major inhospital complications was increased in female patients (1.9% vs 0.8%; P = .023) and mainly driven by major bleeding events. At follow-up, women experienced higher AF recurrence rates (women: 50%; men: 45%; P = .017) and more often received oral medication for rhythm and rate control. In addition, the rate of pacemaker implantation was higher in the female cohort. Women more frequently reported femoral access site complications (women: 6%; men: 3%; P.001). Overall, male patients were more often free from AF-related symptoms and satisfied with the treatment.Catheter ablation of AF was associated with a distinct sex-related outcome and complication profile that requires consideration in clinical practice.

Background Although radiofrequency (RF) ablation has long been the standard of care for atrial fibrillation (AF) ablation, cryoballoon technology has emerged as a feasible approach with promising results. Prospective multicenter registry data referring to both ablation technologies in AF ablation are lacking so far. Objective The purpose of this study was to report data from the German ablation registry with respect to efficacy and safety in pulmonary vein ablation with different energy sources for paroxysmal AF after 1-year follow-up. Methods A total of 2306 patients with symptomatic paroxysmal AF from the German ablation registry were included in this analysis. The cohort was divided into two groups according to the ablation energy source used: cryoballoon and RF ablation. MACCE was defined as a combination of death, myocardial infarction, or stroke. Results AF recurrence rate after a single ablation procedure at 1 year follow-up was not significantly different between the two groups (45.8% after cryoablation and 45.4% after RF ablation, P = .87). Also, the rate of patients without AF recurrence and free of antiarrhythmic drug at 12-month follow-up was similar (cryoablation 44.2% and RF 41.4%, P = .25). MACCE occurred with an incidence of 0.7% within 500 days after cryoablation and 1.4% after RF ablation ( P = .30). Persistent phrenic nerve palsy was more common after cryoablation compared to RF ablation (1.1% vs 0.3%, P Conclusion AF recurrence rate at 1-year follow-up was similar in RF ablation compared to cryoablation, whereas the spectrum and relevance of complications were significantly different between the two ablation methods. This finding might influence the choice of ablation method offered to the individual paroxysmal AF patient.

Aims: Catheter ablation is an established therapy in patients with symptomatic atrial fibrillation (AF) with increasing popularity. Pericardial effusion requiring intervention (PE) is one of the most threatening adverse outcomes. The aim of this study was to examine rates of PE after catheter ablation in a large 'real-world' data set in a German-wide hospital network. Methods and results: Using ICD and OPS codes, administrative data of 85 Helios hospitals from 2010 to 2017 was used to identify AF catheter ablation cases [Helios atrial fibrillation ablation registry (SAFER)]. PE occurred in 0.9% of 21 141 catheter ablation procedures. Patients with PE were significantly older, to a higher percentage female, had more frequently hypertension, mild liver disease, diabetes with chronic complications, and renal disease. Low hospital volume (

Aims: Atrial fibrillation (AFib) and atrial flutter (AFlut) are common arrhythmias with increased use of invasive procedures. A steady re-evaluation of relevant safety endpoints is recommended and both quality management and pay-for-performance programs are evolving. Therefore, the aims of this study were (i) to investigate and report overall in-hospital mortality and mortality of invasive arrhythmia-related procedures and (ii) to identify mortality predictors in a German-wide hospital network. Methods and results: Administrative data provided by 78 Helios hospitals between 2010 and 2017 were examined using International Statistical Classification of Diseases and Related Health Problems- and Operations and Procedures-codes to identify patients with AFib or AFlut as main discharge diagnosis or secondary diagnosis combined with invasive arrhythmia-related interventions. In 161 502 patients, in-hospital mortality was 0.6% with a significant decrease from 0.75% to 0.5% (P

Aims: The FREEZE-cohort study (NCT 01360008) is a prospective observational, multicenter and multinational study to evaluate safety and effectiveness of cryoballoon ablation for pulmonary vein isolation as compared to radiofrequency ablation in patients with paroxysmal or persistent atrial fibrillation (lasting < one year) under the conditions of clinical routine. Methods and Results: The study started in 2011 and anticipates inclusion up to 2000 patients in each of the two treatment groups. A total of 37 centers from 8 countries worldwide, all experienced in at least one of the two ablation techniques, participate in the study. The primary outcome parameter of the study is defined as atrial fibrillation recurrence rate during twelve months of follow-up. Secondary outcome parameters include primary success rates, complication rates in general, specific complications with respect to phrenic nerve palsy and pulmonary vein stenosis, radiation exposure, clinical course including death and repeat ablation. Finally specific procedural aspects will be evaluated in a descriptive manner. Preliminary data of the first 1882 patients show that in clinical practice cryoablation is preferentially performed in patients with paroxysmal atrial fibrillation, whereas application of radiofrequency ablation is equally distributed between patients with persistent and paroxysmal atrial fibrillation. Conclusion: Based on multi-center and multi-national data the FREEZE-cohort study will provide important information on long-term efficacy, clinical effectiveness, complication rates and procedural differences between atrial fibrillation patients treated with either cryoablation or radiofrequency ablation.

Catheter ablation (CA) is considered the treatment of choice for patients with atrioventricular nodal reentrant tachycardia (AVNRT). However, there is a tendency to avoid CA in the elderly because of a presumed increased risk of periprocedural atrioventricular (AV) nodal block.The purpose of this prospective registry was to assess age-related differences in the efficacy and safety of CA within a large population with AVNRT.A total of 3,234 consecutive patients from 48 German trial centers who underwent CA of AVNRT between March 2007 and May 2010 were enrolled in this study. The cohort was divided into three age groups:50 years (group 1, n = 1,268 [39.2%]; median age = 40 [30.0-45.0] years, 74.1% women), 50-75 years old (group 2, n = 1,707 [52.8%]; 63.0 [58.0-69.0] years, 63.0% women), and75 years old (group 3, n = 259 [8.0%]; 79.0 [77.0-82.0] years, 50.6% women).CA was performed with radiofrequency current (RFC) in 97.7% and cryoablation technology in 2.3% of all cases. No differences were observed among the three groups with regard to primary CA success rate (98.7% vs. 98.8 % vs. 98.5%; P = .92) and overall procedure duration (75.0 minutes [50.0-105.0]; P = .93). Hemodynamically stable pericardial effusion occurred in five group 2 (0.3%) and two group 3 (0.8%) patients but in none of the group 1 (P.05) patients. Complete AV block requiring permanent pacemaker implantation occurred in two patients in group 1 (0.2%) and six patients in group 2 (0.4%) but none in group 3 (P = 0.41). During a median follow-up period of 511.5 days (396.0-771.0), AVNRT recurrence occurred in 5.7% of all patients. Patients75 years (group 3) had a significantly longer hospital stay (3.0 days [2.0-5.0]) compared with group 1 (2.0 days [1.0-2.0]) or group 2 (2.0 days [1.0-3.0]) patients (P.0001).CA of AVNRT is highly effective and safe and does not pose an increased risk for complete AV block in patients over 75 years of age, despite a higher prevalence of structural heart disease. Antiarrhythmic drug therapy is often ineffective in this age group; thus, CA for AVNRT should be considered the preferred treatment even in elderly patients.

Herausgegeben vom Vorstand der Deutschen Gesellschaftfur Kardiologie – Herz- und Kreislaufforschung e.V.Bearbeitet im Auftrag der Kommission fur Klinische KardiologieM. Borggrefe, M. Bohm, J. Brachmann, H.-R. Figulla, G. Hasenfus,A. Osterspey, K. Rybak, U. Sechtem, S. Silberauserdem H.M. HoffmeisterOnline publiziert: 26. Oktober 2007Prof. Dr. med. Karl-Heinz Kuck (

Aims Complications such as thermal oesophageal lesions, phrenic nerve injury, and pulmonary haemorrhage were found in cryoballoon (CB) ablation. Whether shortening of freezing times translates into equal efficacy rate and outcome is unknown. The aim of this study was to test the hypothesis that a single freeze cycle per pulmonary vein (PV) without dormant conduction during adenosine infusion is equally effective to standard CB procedure with a bonus freeze after documented PV isolation (PVI). Methods and results In 53 patients with drug-refractory atrial fibrillation (AF) demonstrating PVI after a single 240 s freeze cycle without PV activity during adenosine no additional bonus freeze was applied (study group). In 139 patients, PVI was performed using a bonus freeze (240 s) after documented PVI (control group). Primary endpoint was recurrence of AF. Secondary endpoint was the assessment of quality of life (QoL-score from 1 to 6, being 1 the best and 6 the worst). Follow-up (FU) was performed at 3, 6, and 12 months. Freedom from symptomatic AF during a mean FU of 458 ± 107 days was achieved in 43 (81%) patients in the study group and in 110 (79%) control patients ( P = ns). The QoL-score improved equally in both groups (4.8 ± 0.9 to 2.1 ± 0.7, P < 0.05 and 4.7 ± 0.6 to 2.2 ± 0.6, P < 0.05). Procedure duration (79 ± 14 vs. 98 ± 16 min, P < 0.01) was shorter in the study group. Complication rate was similar in both groups. Conclusion Shortening of freezing times to 4 min per PV without residual dormant PV conduction after adenosine provocation is equally effective to the standard CB ablation protocol using a bonus freeze.

Appropriate and inappropriate therapies of implantable cardioverter defibrillators have a major impact on morbidity and quality of life in ICD recipients, but have not been systematically studied in children and young adults during long-term follow-up. ICD implantation was performed in 20 patients at the mean age of 16 +/- 6 years, 11 of which had prior surgical repair of a congenital heart defect, 9 patients had other cardiac diseases. Implant indications were aborted sudden cardiac death in six patients, recurrent ventricular tachycardia in 9 patient, and syncope in 5 patients. Epicardial implantation was performed in 6 and transvenous implantation in 14 patients. Incidence, reasons and predictors (age, gender, repaired congenital heart disease, history of supraventricular tachycardia, and epicardial electrode system) of appropriate and inappropriate ICD therapies were analyzed during a mean follow-up period of 51 +/- 31 months range 18-132 months. There were a total 239 ICD therapies in 17 patients (85%) with a therapy rate of 2.8 per patient-years of follow-up. 127 (53%) ICD therapies in 15 (75%) patients were catagorized as appropriate and 112 (47%) therapies in 10 (50%) patients as inappropriate, with a rate of 1.5 appropriate and 1.3 inappropriate ICD therapies per patient-years of follow-up. Time to first appropriate therapy was 16 +/- 18 months. Appropriate therapies were caused by ventricular fibrillation in 29 and ventricular tachycardia in 98 episodes. Termination was successful by antitachycardia pacing in 4 (3%) and by shock therapy in 123 episodes (97%). Time to first inappropriate therapy was 16 +/- 17 months. Inappropriate therapies were caused by supraventricular tachycardia in 77 (69%), T wave oversensing in 19 (17%), and electrode defect in 16 episodes (14%). It caused shocks in 87 (78%) and only antitachycardia pacing in 25 episodes (22%). No clinical variable could be identified as predictor of either appropriate or inappropriate ICD therapies. There is a high rate of ICD therapies in young ICD recipients, the majority of which occur during early follow-up. The rate of inappropriate therapies is as high as 47% and is caused by supraventricular tachycardia and electrode complications in the majority of cases. Prospective trials are required to establish preventative strategies of ICD therapies in this young patient population.

Dual chamber ICDs are increasingly implanted nowadays, mainly to improve discrimination between supraventricular and ventricular arrhythmias but also to maintain AV synchrony in patients with bradycardia. The aim of this study was to investigate a new single pass right ventricular defibrillation lead capable of true bipolar sensing and pacing in the right atrium and integrated bipolar sensing and pacing in the right ventricle. The performance of the lead was evaluated in 57 patients (age 61 +/- 12 years; New York Heart Association 1.9 +/- 0.6, left ventricular ejection fraction 0.38 +/- 0.15) at implant, at prehospital discharge, and during a 1-year follow-up. Sensing and pacing behavior of the lead was evaluated in six different body positions. In four patients, no stable position of the atrial electrode could intraoperatively be found. The intraoperative atrial sensing was 2.3 +/- 1.6 mV and the atrial pacing threshold 0.8 +/- 0.5 V at 0.5 ms. At follow-up, the atrial sensing ranged from 1.5 mV to 2.2 mV and the atrial pacing threshold product from 0.8 to 1.7 V/ms. In 11 patients, an intermittent atrial sensing problem and in 24 patients an atrial pacing dysfunction were observed in at least one body position. In 565 episodes, a sensitivity of 100% and a specificity of 96.5% were found for ventricular arrhythmias. In conclusion, this single pass defibrillation lead performed well as a VDD lead and for dual chamber arrhythmia discrimination. However, loss of atrial capture in 45% of patients preclude its use in patients depending on atrial pacing.

KORTE, T., et al.: 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.

Background —The purpose of the present study was to determine the role of a novel, noncontact mapping system for assessing a variety of atrial reentrant tachycardias (ART) in patients after the surgical correction of congenital heart disease. Methods and Results —In 14 patients, an electrophysiological study using the Ensite 3000 system was performed to assess ARTs resistant to medical treatment. Sixteen different forms of ART were inducible in the 14 patients studied. The reentrant circuit of all ARTs could be characterized and localized with respect to anatomic landmarks such as atriotomy scars, intraatrial patches/baffles, and cardiac structures. In 15 of the 16 ARTs (in 13 of the 14 patients), a target area of the reentrant circuit for radiofrequency current application (ie, an area of conduction between 2 anatomical obstacles such as surgical barriers and cardiac structures of electrical isolation) could be localized within the systemic venous atrium. Nine patients exhibited macroreentry, and 4 showed microreentry. In 12 patients, ART could be terminated by creating linear radiofrequency current lesions (75°C, 180 to 390 s). Completeness of linear lesions after radiofrequency current delivery was proven by analyzing color-coded isopotential maps of atrial activation while applying atrial pacing techniques. The mean duration of the procedures was 286 minutes (range, 130 to 435 minutes); fluoroscopy time ranged from 7 to 33.8 minutes (mean, 17.4 minutes). Conclusions —In patients with ART after the surgical correction of congenital heart disease, the use of the noncontact mapping system allows for characterization of the tachycardia and guidance for effective radiofrequency current delivery.

A marker for the efficiency of heating would be helpful in radiofrequency ablation of tachyarrhythmias. We hypothesized that changes of the catheter tip temperature during nontraumatic, very low power radiofrequency exposure would correlate with the temperature achieved during radiofrequency ablation, and therefore, could be used as a marker for heating efficiency. In 71 ablation attempts for drug refractory supraventricular tachycardias, the catheter tip temperature response to a 1-W-5-second test pulse was measured. Subsequently at the same site, radiofrequency current was delivered with a target temperature of 70 degrees C and a power limit of 50 W. The test pulse, with a measured power level of 1.62 +/- 0.28 W, resulted in a heating efficiency of 0.78 +/- 0.60 degree C/W. During ablation, the achieved tip temperature was 52.9 +/- 7.5 degrees C, requiring a power output of 40.7 +/- 10.9 W. The heating efficiency was 0.57 +/- 0.74 degree C/W. The correlation between heating efficiency at low power and during radiofrequency ablation was linear with a correlation coefficient of 0.88. Regression analysis demonstrated that a heating efficiency above 1 degree C/W predicts a mean ablation temperature above 50 degrees C with more than 95% confidence interval. The temperature response to a very low power radiofrequency application correlates with the temperature rise achieved during radiofrequency ablation. It is suggested that delivery of low power radiofrequency current could be used to determine and monitor efficiency of heating during catheter mapping and ablation procedures.

Vorhofflimmern ist die haufigste anhaltende tachykarde Herzrhythmusstorung im Erwachsenenalter. Bei kritisch kranken Patienten auf der Intensivstation nimmt das Vorhofflimmern eine grose Bedeutung ein und geht mit einer erhohten Morbiditat und Mortalitat auf der Intensivstation einher. Patienten, die auf Intensivstation Vorhofflimmern entwickeln, weisen vermehrte Komplikationen auf. Wesentlich ist sicherlich die konsequente Antikoagulation bei Patienten mit Vorhofflimmern. Bei entsprechender Kreislaufkompromittierung ist in der Regel eine elektrische Kardioversion in Kurznarkose notwendig. Sofern keine eigentliche Notfallsituation besteht und das Vorhofflimmern langer als 48 Std. anhalt oder der Beginn des Vorhofflimmerns unklar ist, bedarf es einer vorherigen transosophagealen Echokardiographie- Untersuchung zum sicheren Ausschluss von linksatrialen Thromben. Schlieslich wird in der Regel biphasischer Energie ein Kardioversionsschock in Kurznarkose abgegeben. Die Erfolgsraten liegen uber 90%, anschliesend Sinusrhythmus zu erreichen. Sofern die Kardioversion nicht erfolgreich war oder – was sehr viel haufiger ist – primar nicht das Ziel, sondern die reine Frequenzkontrolle, bedarf es einer adaquaten medikamentosen Therapie. Bewahrt haben sich Calciumantagonisten (z. B. Verapamil 5–10 mg i.v.) oder Betablocker (z. B. Metoprolol 5–10 mg i.v.). Bei tachyarrhythmischem Vorhofflimmern und Herzinsuffizienz kann auch Digoxin oder Amiodaron verabreicht werden.

Adenosine provokes atrial fibrillation (AF) in some patients withparoxysmal supraventricular tachycardia (PSVT). Which patients are moresusceptible to develop atrial fibrillation after the administration ofadenosine to terminate PSVT is unknown. We prospectively measured atrialaction potential duration (APD) at incremental doses of 3, 6, and 12 mg ofadenosine at paced cycle lengths (CLs) of 600, 500, and 400 ms in 25patients. Bolus injection of adenosine decreased APD at 90%repolarization in a dose- and rate-dependent manner. During paced CLs of600, 500, and 400 ms, decreases of 8%, 13%, and 19% (p< 0.05), respectively, were found after bolus administration of 3 mg ofadenosine. After 6 mg of adenosine, the APD shortened by 12%, 19%, (p 0.05),and 27% (p < 0.01), respectively. After 12 mg of adenosine, the APDshortened by 15%, 27% (p < 0.05), and 38% (p < 0.01), respectively.Transient AF occurred in 4 of 25 (16%) patients, all during paced CLs of 400ms, and after adenosine 6 mg in one patient and 12 mg in three patients.Adenosine shortens atrial action potential duration in a dose- andrate-dependent manner. Whether patients with faster rates during PSVT andthose given higher doses of adenosine are more prone to develop atrialfibrillation remains to be determined.

Changes in the amplitude of endocardial electrograms after an unsuccessful shock attempt have been demonstrated to cause failure of redetection of ventricular fibrillation in patients using an integrated sense-pace defibrillating lead system. Thus, the objective of this study was to compare the effects of defibrillator shocks on the amplitude of endocardial electrograms in 26 patients using two different nonthoracotomy systems, a previous lead (model 0062) or a redesigned version (model 0072). At implant, bipolar endocardial electrograms were obtained before each shock application, during initial detection and redetection of ventricular fibrillation in case the applied shock was unsuccessful, and during intervals of 5, 10, 20, 30, 60, and 120 seconds after each shock delivery. No significant difference was noted in endocardial amplitudes between the lead models 0062 and 0072 during baseline sinus rhythm (12.2 +/- 4.6 mV vs 11.4 +/- 3.8 mV), and during initial ventricular fibrillation (7.0 +/- 2.4 mV vs 7.6 +/- 2.3 mV). During redetection of ventricular fibrillation, however, there was a significant difference (P = 0.0006) in endocardial amplitudes (3.4 +/- 1.9 mV vs 6.6 +/- 2.3 mV) between both leads tested. Comparing lead models 0062 and 0072, marked differences were found in endocardial amplitudes during sinus rhythm 5, 10, and 20 seconds after successful arrhythmia termination: 2.8 +/- 1.9 mV vs 8.6 +/- 2.9 mV (P < 0.0001), 4.6 +/- 2.9 mV vs 9.2 +/- 3.2 mV (P = 0.0007), and 6.4 +/- 4.0 mV vs 10.5 +/- 3.6 mV (P = 0.01). At predischarge testing, failure of redetection of ventricular fibrillation was documented in two patients with the lead model 0062 requiring external defibrillation to restore sinus rhythm. These findings demonstrate a significant less postshock attenuation of the endocardial electrogram amplitudes during persistent ventricular fibrillation after an unsuccessful shock attempt as well as during sinus rhythm immediately following an effective shock delivery using the redesigned lead system model 0072 compared to the electrogram amplitudes obtained in patients using the previous lead model 0062.

Influence of Slow Pathway Ablation on Atrial Fibrillation. Introduction: The mechanisms whereby radiofrequency catheter modification of AV nodal conduction slows the ventricular response are not well defined. Whether a successful modification procedure can be achieved by ablating posterior inputs to the AV node or by partial ablation of the compact AV node is unclear. We hypothesized that ablation of the well-defined slow pathway in patients with AV nodal reentrant tachycardia would slow the ventricular response during atrial fibrillation. Methods and Results: In 34 patients with dual AV physiology and inducible AV nodal reentrant tachycardia, atrial fibrillation was induced at baseline and immediately after successful slow pathway ablation and at 1-week follow-up. The minimal, maximal, and mean RR intervals during atrial fibrillation increased from 353 ± 76,500 ± 121, and 405 ± 91 msec to 429 ± 84 (P < 0.01), 673 ± 161 (P < 0.01), and 535 ± 98 msec (P < 0.01), respectively. These effects remained stable during follow-up at 1 week. The AV block cycle length increased from 343 ± 68 msec to 375 ± 60 msec (P < 0.05) immediately and to 400 ± 56 msec (P < 0.01) at 1-week follow-up. The effective refractory period of the AV node prolonged from 282 ± 83 msec to 312 ± 89 msec and to 318 ± 81 msec after 1 week (P < 0.05), respectively. Conclusion: This study shows a decrease in ventricular response to pacing-induced atrial fibrillation after ablation of the slow pathway in patients with AV nodal reentrant tachycardia. Since the AV nodal conduction properties could be defined, this study supports the hypothesis that the main mechanism of AV nodal modification in chronic atrial fibrillation is caused by ablation of posterior inputs to the AV node.

OMRAN, H., et al.: Echocardiographic Imaging of Coronary Sinus Diverticula and Middle Cardiac Veins in Patients with Preexcitation Syndrome: Impact on Radiofrequency Catheter Ablation of Posteroseptal Accessory Pathways. To determine the value of echocardiography for identifying coronary sinus (CS) diverticula and middle cardiac veins (MCVs) in patients with posteroseptal accessory pathways (PAPs), transthoracic (TTE) and transesophageal echocardiography (TEE) were performed in 18 consecutive patients with PAP and in 15 control subjects with left lateral accessory pathway before CS angiography. The size, shape, and location of CS diverticula and MCV were described and compared to angiography. TEE and angiography were concordant for the identification of diverticula (n = 5) and agreed for depicting MCV in 22 of the 27 cases. TTE revealed 4 of 5 diverticula and identified 4 of 27 MCV (P < 0.001). Fourteen MCV but no diverticula were found in the control subjects. There was no significant difference between transesophageal and angiographic measurements for the width (23.5 ± 4.9 vs 26.8 ± 6.6 mm) and height (13.5 ± 3.8 vs 15.7 ± 3.4 mm) of the diverticula, and the width (3.5 ± 0.7 vs 3.7 ± 0.6 mm) of MCV. TEE underestimated the length of the MCV (12.0 ± 1.8 vs 27.2 ± 6.0, P < 0.001). Delivery of radiofrequency energy within the neck of a diverticulum or within an MCV was successful in 5 of 5, and 6 of 13 cases in patients with PAPs, respectively. In conclusion, echocardiography was as reliable as angiography for detecting and describing CS diverticula and MCV in patients with preexcitation syndrome. Echocardiography is recommended prior to electrophysiological study because it may simplify radiofrequency catheter ablation.

Adenosine is considered to be a safe agent for termination of orthodromic atrioventricular reentrant tachycardia in patients with accessory pathways. A case with initially successful accessory pathway ablation and without preexcitation during sinus rhythm is presented, in which intravenous adenosine (6 mg) during orthodromic tachycardia was followed by atrial fibrillation and sudden onset of preexcitation with subsequent rapid ventricular response with moderate hemodynamic compromise.

Catheter ablation of septal accessory pathways in preexcitation syndrome is associated with special problems because of the risk of impairment of atrioventricular nodal conduction during ablation of anteroseptal and midseptal pathways. The complex morphology of the posteroseptal space has special problems for ablation with unclear location of the ablation catheter in the left or right atrial or ventricular cavum, in the coronary sinus, ventricular veins, or the neck of a coronary sinus diverticulum. Therefore, the visualization of the pyramidal space using echocardiographic investigations before the ablation procedure and retrograde coronary sinus phlebography during the ablation session has proven to be very helpful in placement of the electrode to the successful position. Reported herein are the techniques, results, and problems of radiofrequency ablation of 30 patients with septal accessory pathways compared to published data.

Background and objective: Atrial fibrillation (AF) is the most common cardiac arrhythmia. Recent studies suggest there is an angiotensin II-dependent increase in adhesion molecules and oxidative stress parameters during AF. These alterations appear to contribute to inflammatory and prothrombotic changes in the atrial endocardium (‘endocardial remodelling’), suggesting that patients with increased levels of these factors might be at risk of thromboembolic events. The purpose of the CREATIVE-AF (Impact of Irbesartan on Oxidative Stress and C-Reactive Protein Levels in Patients with Persistent Atrial Fibrillation) trial is to prove the principle concept that blockade of angiotensin II type 1 receptors by irbesartan reduces levels of circulating adhesion molecules and oxidative stress parameters in patients with persistent AF by 25% compared with placebo. Methods: This is a prospective, randomized, double-blind, placebo-controlled, crossover study in patients with persistent/permanent AF. A total of 60 patients are planned to be included in the study. Patients will receive placebo and irbesartan therapy for 9 weeks each. Levels of adhesion molecules (intercellular adhesion molecule-1, vascular cell adhesion molecule-1), inflammatory markers (high sensitivity C-reactive protein, monocyte chemoattractant protein-1, von Willebrand factor, tumour growth factor-β1, tumour necrosis factor-α, interleukin-6) and oxidative stress parameters (8-iso-prostaglandin F2α) will be determined after each treatment phase and compared with baseline levels. Conclusion: Angiotensin II type 1 receptor antagonists may help reduce levels of circulating adhesion molecules and oxidative stress parameters in patients with persistent AF. This article summarizes the rationale and design of the CREATIVE-AF trial, which has been designed to test this hypothesis. ClinicalTrials.gov identifier: NCT00613496.

The case of a patient with recurrent VT and an ICD is reported. After appropriate device discharges, the patient experienced 40 episodes of inappropriate shock therapy due to atrial arrhythmias confirmed as type I atrial flutter. Since programmed stimulation could reliably initiate atrial flutter, catheter ablation was performed. During delivery of RF current, atrial flutter terminated and was no longer inducible. The patient had no further inappropriate device discharges during 12 months of follow-up. In patients with ICDs suffering from recurrences of atrial flutter leading to inappropriate shock therapy, RF catheter ablation is an effective and curative approach.

Clinical data using the noncontact mapping system (Ensite 3000) suggest that characteristics of the reconstructed unipolar electrograms may predict the origin of electrical activation within the atrial and ventricular walls (endocardial vs myocardial vs epicardial origin). Experimental data are lacking. In ten open-chest pigs (mean body weight 62 kg) cardiac pacing was performed at a cycle length of 600 ms with a pulse width of 2 ms and twice diastolic threshold from the endo-, the myo-, and the epicardium, respectively. Pacing was undertaken at three right atrial and three left ventricular sites, and cardiac activation was recorded with the Ensite system. Reconstructed unipolar electrograms at the location of earliest endocardial activation assessed by color coded isopotential maps were analyzed systematically for differences in morphology. The positive predictive value of atrial electrograms exhibiting an initial R wave during pacing for a subendocardial origin (i.e., myocardial or epicardial) was 0.96. The negative predictive value was 0.48. Electrograms generated during myocardial pacing exhibited increased maximal negative voltage and maximal dV/dt (−3 ± 1.8 mV, −798 ± 860 mV/ms, respectively) than the electrograms obtained during endocardial (−2 ± 1 mV, −377 ± 251 mV/ms, respectively) and epicardial pacing (−2.1 ± 0.7 mV, −440 ± 401 mV/ms, respectively, P < 0.01 for both parameters). During pacing at the left ventricular wall, occurrence of an initial R wave did not differ significantly between electrograms reconstructed during endocardial and subendocardial pacing. All other characteristics of the unipolar ventricular electrograms analyzed, except latency, did not differ significantly when compared to stimulation depth. Morphological characteristics of unipolar electrograms generated by the noncontact mapping system during pacing of the atrium allowed for discrimination of an endocardial versus a subendocardial origin of activation. At the ventricular level, characteristics of unipolar electrograms did not predict the origin of cardiac activation in this experimental setting. (PACE 2003; 26:1970–1978)

An increasing number of genetically altered mice with specific molecular cardiac defects are being assessed by electrophysiological studies and ECG monitoring. This approach should allow for the identification of critical genes involved in the arrhythmogenesis in myocardial infarction. Therefore it was the aim of this study to establish a standard for the in-vivo electrophysiological characteristics in the mouse model of chronic anterior myocardial infarction.Using a minimized, invasive, in-vivo electrophysiological study, surface ECG parameters, sinus node function, atrial, atrio-ventricular and ventricular conduction and ventricular repolarization, and enhanced vulnerability to atrial and ventricular arrhythmia were studied in 20 wild-type C57BL/6 mice either under control or 11 weeks after large anterior myocardial infarction induced by ligation of the left anterior descending coronary artery. Telemetric ECG recording was performed in the same animals at baseline unrestrained, conscious condition to study surface ECG parameters, heart rate variability and the prevalence of supraventricular and ventricular arrhythmia. During electrophysiological study, infarcted mice showed an 81% increase of the angle of the QRS axis (p0.001) and a prolongation of the P wave by 23% (p = 0.01), the QRS complex by 39% (p = 0.001), the QT interval by 23% (p0.05), the QT(c) interval by 30% (p0.005) and the JT(c) interval by 31% (p0.05) in comparison to control animals. Furthermore, there was a prolongation of the atrio-ventricular interval by 28% (p0.0005) and the atrio-ventricular functional refractory period by 26% in infarcted animals (p0.05), and inducibility of ventricular tachycardia in 4 of 6 infarcted versus in none of control animals (00.01). During telemetric ECG recording, there was a marked increase in ventricular ectopic activity in infarcted mice in comparison to controls (p0.05). Heart rate and time- and frequency-domain of heart rate variability were not significantly different in both groups (p0.05, respectively).The mouse model of chronic anterior myocardial infarction is associated with significant atrial and ventricular conduction disturbances and vulnerability to ventricular arrhythmia and thus may provide a highly valuable tool to study molecular determinants of arrhythmogenesis in myocardial infarction.

Since short action potentials and short refractory periods facilitate the induction of atrial reentry, this maladaptation has been proposed as the pathophysiological basis of the frequent immediate recurrences of atrial fibrillation (IRAF) after internal cardioversion. However, short-term reverse electrophysiological changes of the atria after cardioversion have not been studied in humans.Thirty-seven patients with chronic atrial fibrillation of 16+/-19 months and ten patients with an atrial fibrillation durationor =48 h underwent internal cardioversion. Antiarrhythmic medication was only continued in 10 patients (21%), who were on amiodarone before cardioversion. Atrial monophasic action potential duration at 90% repolarization (APD(90)), sinus rate, P wave duration and interatrial conduction times between high right atrium and coronary sinus were recorded at min 0, 1, 3, 5, 10, 15 and 20 after cardioversion.Internal cardioversion was successful in all patients, but twelve of the patients with chronic AF (32%) and three of the patients with intermittent AF (30%) had one to four episodes of IRAF after 16+/-28 s. There was a significant 52+/-30 ms APD(90) prolongation, 83% of which occurred in min 0-3 (P0.0001) and 17% in min 3-20 (P0.05) after internal cardioversion. There was no significant temporal change in sinus rate, P-wave and interatrial conduction time during the time studied. APD(90) prolongation and its time dependence did not show a detectable difference in subgroups with chronic AF, IRAF, left atrial size40 mm and treatment with amiodarone.There is a significant prolongation of action potential duration in min 0-3 after internal cardioversion of atrial fibrillation, whereas sinus rate and intra- and interatrial conduction time remain unchanged. APD(90) prolongation in min 0-3 shows a temporal relationship to the high rate of immediate recurrences of atrial fibrillation during this time interval. The data imply that there is a transient recovery of atrial refractoriness after cardioversion and suggest a mechanism of the high rate of early recurrences of atrial fibrillation.

NIEHAUS, M., et al.: Adjustment of Maximum Automatic Sensitivity (Automatic Gain Control) Reduces Inappropriate Therapies in Patients with Implantable Cardioverter Defibrillators. Patients with ICDs might experience oversensing associated with inappropriate shock therapy when paced at low bradycardia rates or if they have a low intrinsic rhythm. The amplifier gain of automatic gain control is maximal at long RR intervals and might lead to oversensing of myopotentials. The hypothesis was that an individual adjustment of the sensitivity floor could reduce inappropriate ICD therapies. Fourteen patients implanted with the VENTAK MINI I/II and III in whom oversensing and/or inappropriate shocks had been documented were included in this evaluation based on stored episodes. Sensitivity was modified in all ICDs by means of noninvasive software downloading that allowed reprogramming of the maximum sensitivity from 0.14 mV in two steps to 0.27 mV (“Normal,”“Less,”“Least”). Provocation testing (deep inspiration, sit-ups, and abdominal pressing) was conducted at “Nominal” settings (0.14 mV) while the intracardiac electrogram with annotated event marker was running continuously and was repeated at 0.22 mV (Less) and 0.27 mV (Least). All patients evaluated had documented spontaneous episodes due to oversensing before the sensitivity floor was reprogrammed. During provocation testing at Nominal settings, oversensing could be documented in 9 of (64.3%) 14 patients. Provocation testing was repeated after the sensitivity selection was reprogrammed and oversensing could not be provoked in any of the 14 implanted devices. Sensitivity was reprogrammed in all 14 patients to a higher value (5 patients Less, 9 patients Least). After sensitivity adjustment, VF was induced in all patients to verify appropriate arrhythmia detection and termination. Sensitivity reprogramming in patients with documented oversensing eliminates the incidence of inappropriate shock therapy without compromising the ability to detect VF appropriately.

Background — Patients with idiopathic dilated cardiomyopathy (DCM) and impaired left ventricular ejection fraction have an increased risk of dying suddenly. Methods and Results — Patients with recent onset of DCM (≤9 months) and an ejection fraction ≤30% were randomly assigned to the implantation of an implantable cardioverter-defibrillator (ICD) or control. The primary end point of the trial was all-cause mortality at 1 year of follow-up. The trial was terminated after the inclusion of 104 patients because the all-cause mortality rate at 1 year did not reach the expected 30% in the control group. In August 2000, the vital status of all patients was updated by contacting patients, relatives, or local registration offices. One hundred four patients were enrolled in the trial: Fifty were assigned to ICD therapy and 54 to the control group. Mean follow-up was 22.8±4.3 months, on the basis of investigators’ follow-up. After 1 year, 6 patients were dead (4 in the ICD group and 2 in the control group). No sudden death occurred during the first and second years of follow-up. In August 2000, after a mean follow-up of 5.5±2.2 years, 30 deaths had occurred (13 in the ICD group and 17 in the control group). Cumulative survival was not significantly different between the two groups (93% and 80% in the control group versus 92% and 86% in the ICD group after 2 and 4 years, respectively). Conclusions — This trial did not provide evidence in favor of prophylactic ICD implantation in patients with DCM of recent onset and impaired left ventricular ejection fraction.

Background The coronary venous system is increasingly used for left ventricular or biventricular pacing in patients with severe heart failure. The present study investigated the structure of the coronary veins in patients presenting with structural heart disease and malignant ventricular tachyarrhythmias. The availability of veins for possible lead placement was assessed. Methods and Results The number, relative size, and location of coronary veins were evaluated by retrograde venography in 129 patients undergoing cardioverter-defibrillator implantation. Detailed x-ray image analysis was performed in 86 patients, for whom optimal coronary sinus occlusion and vein visualization was achieved. The anterior interventricular vein and the middle cardiac vein were visible in 85 (99%) of 86 patients and in 86 (100%) of 86 patients, respectively. Between these 2 veins, at least 1 additional prominent vein was visible in 85 (99%) of 86 patients. Just 1 vein was present in 44 (51%) of 86 patients. Two veins were observed in 40 (46%) of 86 patients, and >2 veins were visualized in 2 (2%) of 86 patients. Venous anatomy allowed positioning of a 0.014-in guidewire in a coronary vein in 115 (93%) of 124 patients. Conclusions The presence, diameter, angulation, and tortuosity of veins as visualized by retrograde venography determine their acceptability for the placement of a lead in a predetermined location. Despite the considerable variability of the coronary venous system among patients, a lateral vessel for lead introduction was available in 82%, and a posterior or lateral vessel was available in 99% of individuals within a patient population that could potentially benefit from a lead on the left ventricle.

Bimodal RR Interval Distribution, Introduction: Radiofrequency (RF) catheter modification of the AV node hi patients with atrial fibrillation (AF) is limited by an unpredictable decrease of the ventricular rate and a wish incidence of permanent AV block, A bimodal RR histogram has been suggested to serve as a predictor for successful outcome but the corresponding AV node properties have never been characterized, We hypothesized that a bimodal histogram indicates dual AV nodal physiology and predicts a better outcome after AV node modification in chronic AF. Methods and Results: Thirty-seven patients were prospectively subdivided into two groups according to the RR histogram of 24-hour ECC monitoring, Before to RF ablation, internal cardioversion and programmed stimulation were performed, Among the 22 patients (group I) with a bimodal RR histogram, dual AV nodal physiology was found in 17 (779f) patients, Ablation significantly decreased ventricular rate with loss of the peak of short RR cycles after ablation (mean and maximal ventricular rates: 32% and 35% rate reduction, respectively; P < 0,01), In 15 patients with a unimodal RR histogram (group II), dual AV nodal physiology was found in 2 (13%), and rate reductions were 16% and 17%, respectively, At 6 months, 3 (14%) patients in group 1 and 6 (40%) in group II underwent elective AV nodal ablation with pacemaker implantation due to intolerable rapid ventricular response to AF. Conclusion: Bimodal RR interval distribution during chronic AF suggests the presence of dual AV nodal physiology and predicts a better outcome of RF ablation of the posterior atrionocdal input.

Noninvasive Diagnosis in Patients with Undocumented Tachycardias. Introduction: Patients with symptoms suggestive of paroxysmal supraventricular tachycardia (PSVT) but no tachycardia documentation often undergo diagnostic electrophysiologic study. In dual AV node physiology with AV node reentrant tachycardia (AVNRT), the anterograde fast pathway is more sensitive than the slow pathway to the effects of adenosine. The purpose of the study was to test the hypothesis that adenosine can be used as a bedside test for the diagnosis of dual AV node physiology and hence for AVNRT. Methods and Results: During electrophysiologic study, 37 patients without prior documentation hut symptoms indicative for PSVT received incremental dosages of adenosine during sinus rhythm until second-degree or greater AV block was observed. Suggestive signs of dual AV node physiology on the surface ECG (sudden jump of PQ interval ≥ 50 msec) were found in 13 (76%) of 17 patients with inducible AVNRT but in only 1 (5%) of the remaining patients (P < 0.01). In the AVNRT group, the maximal increase of the PQ interval between two beats was greater (88 ± 45 msec) than in the remaining 20 patients (17 ± 11 msec) (P < 0.01). Conclusion: Careful evaluation of surface ECG during administration of adenosine helps to identify patients prone to AVNRT. The adenosine test is a valuable noninvasive adjunct in patients with undocumented palpitations suggestive of PSVT

Effects of Atrial Flutter Ablation. Introduction: Bidirectional conduction block at the subeustachian isthmus predicts long-term efficacy of atrial flutter ablation. Limited data are available on the incidence and outcome of minor conduction changes such as unidirectional or incomplete block. This prospective study sought to systematically assess discrete acute and long-term alterations of bidirectional conduction prior to a complete conduction block. Methods and Results: In 41 patients with type I atrial flutter, pulse propagation through the subeustachian isthmus during low lateral and proximal coronary sinus pacing was documented and analyzed following each consecutive radiofrequency (RF) application. In cases of altered conduction properties and noninducibility of atrial flutter, patients were followed-up for 12 months. Three sets of results were found. First, following RF application. 23 patients presented a progressive conduction delay prior to a complete conduction block. Second, RF application did not always affect counterclockwise and clockwise conduction simultaneously or to the same extent. In 13 patients, an initial alteration of counterclockwise conduction was present before an alteration of clockwise conduction; in 5 patients, clockwise conduction was primarily affected. Third, the recurrence rate of typical atrial flutter was 9% (2/22) in patients with a complete bidirectional conduction block, 54% (7/13) in patients with unidirectional conduction block, and 100% (6/6) in patients with sole bidirectional conduction delay. Conclusion: In 50% of the patients, consecutive RF applications resulted primarily in a progressive conduction delay rather than a sudden conduction block. Since counterclockwise and clockwise conduction were not always affected simultaneously or to the same extent, lateral as well as septal pacing is recommended for improvement of bidirectional conduction block. Normalization of primarily altered conduction and, therefore, recurrence of atrial flutter are high in all patients without bidirectional block.

Introduction: Ablation is a standard option in the treatment of atrial fibrillation (AF). Patients with AF and hypertrophic cardiomyopathy (HCM) may represent a more difficult substrate for AF ablation. Hypothesis: Is ablation AF in patients with HCM as successful as in patients with lone AF? Methods: Patient and procedural data as well as acute and long-term outcome data from pts. with ablation of AF were prospectively collected in 55 centres. One-year follow-up (1yFU) data were gathered by telephone call. Data collection and the statistical analysis were performed for the German Ablation Registry organized. Results: In total, 63 pts. with HCM (71% men, mean age 57y, 70% complete follow-up) and 4437 pts. without structural heart disease (65% men, mean age 61y, 59% complete follow-up) underwent ablation for AF. Pts. with HCM had additional coronary artery disease in 11%, valvular heart disease in 9.5% and a reduced ejection fraction (

Nonpharmacologic tools to treat atrial fibrillation (AF) are direct current cardioversion, radiofrequency (RF) current catheter ablation, antiarrhythmic surgery, pacing, and atrial defibrillation. In patients with sustained AF, when no cause can be found forAF or when the associated disease is mild, an attempt should be made to restore sinus rhythm. Electrical cardioversion by synchronized direct current shock can be attempted when drugs have failed and is the first choice in acutely ill patients. Virtually all patients should be anticoagulated. Temporary pacing should be available in patients with evidence of previous bradycardia. Although efficacy may be improved in patients pretreated with antiarrhythmic drugs, there is a considerable risk of adverse events. In AF and sinus node dysfunction, both pacing and antiarrhythmic drugs may be necessary. Pacing should be atrial or dual chamber, since ventricular pacing provokes AF. Failure to control the ventricular rate in AF can be treated by RF : atrioventricular (AV) node ablation, ablation of accessory pathways in preexcitation syndrome with AF, modulation of AV node, or ablation of AF. Antiarrhythmic surgery is a major procedure and may be the therapy of last resort in AF : the so-called corridor procedure isolates the fibrillating atria from a strip of tissue connecting the sinus and AV nodes. The maze procedure attempts to abolish AF by channeling the atrial activation between a series of incisions. In patients with chronic AF, internal cardioversion should be attempted if conventional transthoracic electrical cardioversion is ineffective. Several studies demonstrated the feasibility and efficacy of internal atrial defibrillation in selected patients with recent onset, as well as with chronic, AF. An implantable atrial defibrillator-as a stand-alone device or as part of a whole heart cardioverter-might be an option in the future. Nonpharmacologic tools play only a minor role in the management of paroxysmal and chronic AF. If symptoms persist despite pharmacologic therapy and other causes of persisting symptoms are excluded, consideration should be given to cardiac pacing, RF catheter treatment, or surgery. In some cases nonpharmacologic therapy of the AV node must be followed by implantation of a permanent pacemaker (due to complete AV block) and anticoagulation (due to persistence of underlying AF). (Am J Cardiol 1996 ; 77 :45A-52A)